FV4C Service Manual.pdf

TABLE OF CONTENTS

Page

SAFETY CONSIDERATIONS.....................................................................................................................................................................................2

INTRODUCTION..........................................................................................................................................................................................................2

UNIT IDENTIFICATION.............................................................................................................................................................................................2

FAN COIL DESCRIPTION & TROUBLESHOOTING.....................................................................................................................................2 - 25

FK4B.................................................................................................................................................................................................................2 - 11

FV4A/FV4B/FK4C/FK4D/40FK ...................................................................................................................................................................11 - 20

FE4A...............................................................................................................................................................................................................20 - 25

CARE & MAINTENANCE................................................................................................................................................................................25 - 28

FF1A/FF1V/FF1C SERVICE & TROUBLESHOOTING.................................................................................................................................28 - 32

FD3A SERVICE & TROUBLESHOOTING.....................................................................................................................................................32 - 35

FG3A SERVICE & TROUBLESHOOTING.....................................................................................................................................................35 - 36

CIRCUIT BOARD FUNCTION & TROUBLESHOOTING ............................................................................................................................36 - 56

FA4, FB4, FC4, FX4 Smart Heat Circuit Board (PCB)...............................................................................................................................36 - 42

FA4, FB4, FC4, FF1, FH4, FX4, CES013003-00 and 01 (HK61EA002) PCB..........................................................................................42 - 45

HK61GA001 and 003 PCB............................................................................................................................................................................45 - 56

ELECTRIC HEATER FUNCTION AND TROUBLESHOOTING..................................................................................................................56 - 58

THERMOSTATIC EXPANSION VALVES (TXV)..........................................................................................................................................58 - 59

COIL AND CONDENSATE PAN REMOVAL & REPLACEMENT.............................................................................................................59 - 63

FOR FV/FA/FB/FC/FK FAN COILS ..........................................................................................................................................................59 - 61

FOR FX4 AND FV4 FAN COILS................................................................................................................................................................61 - 63

PURON® QUICK REFERENCE GUIDE.................................................................................................................................................................64

Fig. 1—Typical Fan Coil

A98023

SERVICE MANUAL

FA4, FB4, FC4,

FD3, FE4, FF1,

FG3, FH4, FK4,

FV4, FX4, 40FK

RESIDENTIAL FAN COIL UNITS

Form: F-6SM Cancels: F-5SM / SM03-5 Printed in U.S.A. 02-05 Catalog No. 03FA-4A6

This symbol → indicates a change since the last issue.

SAFETY CONSIDERATIONS

Improper installation, adjustment, alteration, service, maintenance, or use can cause explosion, fire, electrical shock, or other conditions which may

cause personal injury or property damage. Consult a qualified installer, service agency, or your distributor or branch for information or assistance.

The qualified installer or agency must use factory-authorized kits or accessories when modifying this product. Refer to the individual installation

instructions packaged with the kits or accessories for detailed information.

Follow all safety codes. Wear safety glasses and work gloves. Use quenching cloth for brazing operations. Have fire extinguisher available. Read

these instructions thoroughly and follow all warnings or cautions attached to the unit. Consult local building codes and National Electrical Code

(NEC) for special installation requirements.

It is important to recognize safety information. This is the safety-alert symbol

. When you see this symbol on the unit or in instructions and

manuals, be alert to the potential for personal injury.

Understand the signal words DANGER, WARNING, and CAUTION. These words are used with the safety-alert symbol. DANGER identifies the

most serious hazards which will result in severe personal injury or death. WARNING signifies hazards which could result in personal injury or

death. CAUTION is used to identify unsafe practices which would result in minor personal injury or product and property damage.

WARNING: UNIT OPERATION AND SAFETY HAZARD

Failure to follow this caution could result in personal injury or possible equipment damage.

Puron (R-410A) systems operate at higher pressures than R-22 systems. Do not use R-22 service equipment or components on

R-410A equipment. Ensure service equipment is rated for R-410A.

INTRODUCTION

The "F" series fan coil units are designed for flexibility in a variety of applications, meeting upflow, horizontal, or downflow requirements. Units

are available in 1-1/2 through 5 ton nominal cooling capacities. Factory-authorized, field-installed electric heater packages are available in 3

through 30 kilowatts.

WARNING: ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury or possible equipment damage.

Before installing or servicing fan coil, always turn off all power to unit. There may be more than 1 disconnect switch. Turn off accessory

heater power if applicable.

UNIT IDENTIFICATION

The 16 position numbering chart allows identification of all available fan coil units. (See Fig. 2.)

FAN COIL DESCRIPTION

AND TROUBLESHOOTING

FK4B

The FK4B has an integrated control and motor (ECM/ECM/ICM) and special circuit board.

Setting up desired airflow on the FK4B is obtained by the selections made on Easy Select™ circuit board. The motor delivers requested airflow

as defined by signals received from Easy Select Board and its internal programming. The major difference is that the FK4B motor reacts to changes

in system static pressures to maintain constant airflow.

Unlike conventional fan coils where static pressure affects airflow, the FK4B is a constant airflow unit. The blower delivers requested airflow up

to about 0.7 in. of static pressure. The motor is pre-programmed and contains airflows for all modes of operation. Blower characteristics (airflow,

torque, and speed-vs-static pressure) are known from laboratory testing. If any 3 characteristics are known, the fourth is defined.

Requested airflow is known because of Easy Select board configuration and thermostat signals. Torque is known because it is directly related to

armature current which is measured by motor control. Speed is measured from its generated back EMF. This information is entered into an

expression which calculates torque from speed and airflow numbers. If calculation does not match stored blower characteristics, torque is adjusted

every 0.8 seconds until agreement is reached. The unit does not directly measure static pressure, but does react to a change in static to maintain

constant airflow.

PROCEDURE 1—INTEGRATED CONTROLS AND MOTOR - FK4B

The motor is similar to the ECM/ICM1 used in FK4A series units, but cannot be used as a replacement without some modification to FK4A unit.

The electronics of motor are built into rear of motor, deriving the name ECM/ICM. (See Fig. 3.)

An ECM/ECM/ICM is first fed high voltage AC power through the 5-pin connector. The AC power is then rectified to DC by a diode module.

After rectification, DC signal is electronically communicated and fed in sequential order to 3 stator windings. The frequency of communication

pulses determines motor speed. The rotor is permanently magnetized.

An ECM/ICM is powered with high voltage at all times. The motor will not run with high voltage alone. Low voltage must be applied to control

plug to run motor.

PROCEDURE 2—PCB LAYOUT AND DESCRIPTION - FK4B

NOTE: Layout of actual PCB is depicted in Fig. 4 and 5.

The control is a single PCB which interfaces a variable-speed motor with other system components.

Power for system is supplied from a 230-vac, 60-Hz line. Class 2 voltage (24 vac nom), used for thermostat connections, is derived from a

transformer located in close proximity to control. The primary and secondary of transformer are connected to control board. The 24-vac secondary

circuit includes a socket, soldered into circuit at SEC2, to receive a 5-amp automotive-type fuse.

—2—

Fig. 2—Fan Coil 16-Position Numbering System

A98114

2nd Position—Fan Coil

A - RNC

B - Standard

C - Deluxe

D - Furred in, Cased

E - Furred in, Uncased

F - Through the Wall

G - Commercial

H - Standard Electric Furnace

J - Standard Hot Water

K - ICM Motor, High Efficiency

V - ICM Motor, Puron R-410A

X - Standard, Puron R-410A

Unit Specifics

1 - Upflow

2 - Downflow

3 - Horizontal

4 - Multipoise

5 - Upflow/Downflow

Airflow

018 (1

⁄2 Ton)

024 (2 Ton)

001 (Multi Tons)

002 (Multi Tons)

Etc.

Cooling Size

10th, 11th, 12th Positions—Fan Coil

005

010

Etc.

Heating Size (KW)

6th Position—Fan Coil

A - Standard

B - Modular

F - Single Piece

Coil Type

5th Position—Fan Coil

A - 115-1-60

N - 208/230-1-60

S - 230-1-50

Electrical

F - Fan Coil

Type of Unit

A - Original

B - Second Series

Major Series

A - Original

Minor Series

A - Standard Unit

Variations

A - Common Unit

Variations

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

—3—

Connection to heater panel is made through 12-circuit connector P1. Connections to thermostat are made at screw terminals. Line voltage for motor

is made through 12-circuit connector P1. Eighteen quick-connect terminals comprise field select taps for motor.

Fig. 3—FK4B, FK4C and FV4A motor Motor

A94079

12345

12345678

10 11 12 13 14 15 16

POWER CONNECTOR

CONTROL CONNECTOR

OPTIONAL SAFETY GROUND

OPTIONAL

SAFETY

GROUND

DO NOT REMOVE

DRAIN

HOLE

Fig. 4—Easy Select Board (FK4B)

A94076

EASY SELECT

GROUND

SCREW

REQUIRED

Y/ Y 2

CES0130007–00

D8 D7 D5 D6

D2 D9 D4

HEATER

240

VAC

XFORM

MOTOR

240

VAC

SEC2 SEC1

24VAC

JW3

JW4

AUX2

AUX1

HUM1

HUM2

24VDC

JW1

JW2

D11

CESS430023–01

CEBD430023–01

D10

FS1

5 AMP

MAX

ST1

RED

MOTOR

AMP 12-PIN MATE-N-LOCK

CONNECTOR (1)

⁄16-IN. MALE

FASTON

AMP–TYP

(21) PLCS

MOLEX 7-PIN

CONNECTOR (1)

LOW VOLTAGE

TERMINAL BLOCK

W2-E JUMPER

3RD STAGE

W2-W3 JUMPER

2ND STAGE

PRINTED

CIRCUIT

BOARD

⁄4-IN. MALE

FASTON

AMP–TYP

(9) PLCS

AUX HEAT RANGE

AC/HP SIZE

TYPE

AC/HP CFM ADJUST

DELAY

AC/HP

TIME

ENH

VIO

ORN

BLK

GRY

BLU

OFF

HIMEDLO

HP-EFFHP-COMFORTAC

CFM

0-30

1200

0-20

1000

0-10

800

0-5

600

042 036 030 024

—4—

Fuse Data: 5-amp automotive-type ATC/ATO (tan)

32v

200 percent current opening time of 5 sec maximum

A. Electrical Connections

Eighteen 0.187-in quick-connect terminals are used to provide programming selections for operating modes of motor. The 5 selection modes are

listed below. For additional information, refer to Easy Select Configuration Taps section.

AUX Heat Range—(Violet Wire)

AC/HP Size—(Blue Wire)

Type—(Orange Wire)

AC/HP CFM Adjust—(Black Wire)

AC/HP Time Delay—(Grey Wire)

PROCEDURE 3—SEQUENCE OF OPERATION - FK4B

A. Continuous Fan Mode

The thermostat closes circuit R to G. The G signal is sent directly to motor.

B. Cooling Mode—Single Speed or 2-Speed High

Thermostat closes circuits R to Y/Y2 and R to O (heat pump only) for single speed. A circuit from R to Y1 is also required for 2-speed high. The

Y/Y2 signal is sent directly to motor.

C. Cooling Mode—Two-Speed Low

Thermostat closes circuits R to Y1 and R to O (heat pump only). The Y1 signal is sent directly to motor.

D. Electric Heat Heating Mode

Thermostat closes circuit R to W2, W3, or E.

The terminal block positions W2, W3, and E are tied together by jumpers JW1 and JW2. These jumpers are provided for field staging of electric

heater banks through use of thermostats. When staging is a requirement, installer cuts jumpers and wires in thermostats as is the common practice

with other fan coils. To ensure motor operation if any 1 of the inputs is energized, the 3 electric heater inputs are also interlocked through diodes

D1, D2, and D3 to motor W input.

E. Heat Pump Heating Mode—Single Speed or 2-Speed High

Thermostat closes circuit R to Y/Y2 for single speed. A circuit from R to Y1 is also required for 2-speed high. The Y/Y2 signal is sent directly

to motor.

F. Heat Pump Heating Mode—Two-Speed Low

Thermostat closes R to Y1. The Y1 signal is sent directly to motor.

Fig. 5—Easy Select Board Circuitry (FK4B)

A94077

ST1

Y/Y2

ST1

JW2

JW1

JW3

JW4

1K 2W

SEC1

SEC2 PS1

1K 2W

123

789

10 11 12

HIGH VOLTAGE

AUX1

HUM1

AUX2

HUM2

W/W1

Y/Y2

D11

D10

5 – 30

1200

5 – 20

1000

5 – 10

800

0 – 5

600

RED

QC19

QC4

QC8

QC3

QC7

QC2

QC6

QC1

QC5

024030036042

QC9

QC12

QC15

OFF

LOW

QC13

MED

QC10

HP–COM.

QC11

HP–EFF.

QC14

QC16

QC17

QC18

AUX. HEAT

RANGE

AC/HP

SIZE

AC/HP

TYPE

AC/HP

CFM TRIM

AC/HP

DELAY

—5—

G. Heat Pump Heating With Auxiliary Electric Heat

Thermostat closes circuits R to Y/Y2 and/or R to Y1 with R to W2, W3, or E (and R to O in the case of defrost).

See previously described modes for circuit paths.

In the event that electric heating is called for by thermostat while heat pump is also operating in either heating or defrost mode, electric heating

signal will appear at motor connector pin 1 as described previously. If necessary, the motor will modify its airflow output to provide an airflow

which is defined as safe for operation of electric heater.

H. CFM Select Configuration Taps

The CFM Select taps are used by installer to configure system. The motor is capable of discerning wave shapes on some of its inputs and uses

this capability to modify its operation to a pre-programmed table of airflows and can be modified in response to other inputs such as the need for

de-humidification.

I. Motor Control Power

The motor control power is supplied from R circuit through printed circuit runs to motor control connector pin 6, through motor control harness

to motor. The C side of low-voltage control power circuit is connected by printed circuit runs to motor connector pins 4 and 5, then through motor

control harness to motor.

J. Low-Voltage Circuit Fusing and Reference

The low-voltage circuit is fused by a board-mounted 5-amp automotive-type fuse placed in series with transformer SEC2 and R circuit. The C

circuit of transformer is referenced to chassis ground through a printed circuit run at SEC1 connected to metal standoff marked GROUND SCREW

REQUIRED.

NOTE: A ground screw must be in place or erratic motor operation can result.

K. Transformer, Motor, and Electric Heater

Power Connections

The high-voltage (230-vac) power input to board is provided through electric heater connector pins 7 and 9. The high voltage is then connected

through printed circuit runs to motor power connections M1 and M2 and transformer power connections T1 and T3. Transformer connection T2

is a dummy terminal used for unused primary power lead. The transformer secondary connections are made at SEC1 and SEC2 connectors.

Table 1—Male/Female Quick-Connect Terminals (FK4B)

Size Female Size Male Description

0.250 X 0.032 M2 Motor line voltage connection (230 vac 60 Hz)

T3 Transformer line voltage connection (230 vac 60 Hz)

T2 Transformer tap storage terminal for 208-vac lead

SEC1 Secondary connection from transformer (24 vac)

This connection is common to chassis ground through eyelet marked GROUND SCREW REQUIRED.

SEC2 Secondary connection from transformer (24 vac)

HUM1 Low voltage ground for humidifier option (24 vdc)

HUM2 Low voltage output for humidifier option (24 vdc)

AUX1 Low voltage ground for auxiliary option (24 vdc)

AUX2 Low voltage output for auxiliary option (24 vdc)

0.187 X 0.032 M1 Common connection to blower motor

T1 Common connection for transformer

RED Common to R screw terminal and SEC2

Table 2—Connections on FK4B Screw Terminal Block

Screw

Terminal

Description

W2 Connection for W2 signal from thermostat

W3 Connection for W3 signal from outdoor thermostat

E Connection for E signal from thermostat

Y/Y2 Connection for Y signal from thermostat

G Connection for G signal from thermostat

O Connection for O signal from thermostat

L This connection is a field termination for use in connecting L lines of thermostat and outdoor unit to-

gether. There is no connection of this terminal with control circuity.

Y1 Connection for low-speed compressor operation

R Connection for R signal to thermostat (24 vac)

C Connection for C terminal to thermostat (24 vac common)

—6—

PROCEDURE 4—EASY SELECT CONFIGURATION TAPS - FK4B

The Easy Select taps are used by installer to configure system. The motor uses selected taps to modify its operation to a pre-programmed table

of airflows. Airflows are based on system size or mode of operation and those airflows are modified in response to other inputs such as the need

for de-humidification.

(See Fig. 4.)

The FK4B Fan Coil must be configured to operate properly with system components with which it is installed. To successfully configure a basic

system (see information printed on circuit board located next to select pins), move the 5 select wires to pins which match components used.

A. Auxiliary Heat Range

The installer must select the auxiliary heat airflow approved for application with kw size heater installed. If no heater is installed, skip this step.

Each select pin is marked with a range of heaters for which airflow (also marked) is approved. For increased comfort select the narrowest kw range

matching the heater size, for example, 0-10 for a 10-kw heater. This airflow must be greater than the minimum CFM for electric heater application

with the size system installed for safe and continuous operation. Note that airflow marked is the airflow which will be supplied in emergency heat

mode and heating mode on air conditioners when electric heat is primary heating source. To ensure safe heater operation in heat pump heating

mode when electric heaters are energized, the motor will run the higher of heat pump efficiency airflow and electric heater airflow. The factory

selection is largest heater range approved. (See Fig. 4.)

B. AC/HP Size

The factory setting for air conditioner or heat pump size is largest unit meant for application with model of fan coil purchased. The installer needs

to select air conditioner or heat pump size to ensure that airflow delivered falls within proper range for size of unit installed in all operational

modes. (See Fig. 4.)

C. System Type

The type of system must be selected.

1. AC—air conditioner

2. HP-COMFORT—provides same airflow as air conditioner selection (approximately 375 CFM/ton)

3. HP-EFF—provides most efficient airflow for heating and cooling modes (approximately 410 CFM/ton heating and 375 CFM/ton cooling)

The factory setting is AC. (See Fig. 4.)

D. AC/HP CFM Adjust

Select low, medium, or high airflow. The factory selection is LO. The adjust selections HI/LO will regulate airflow supplied for all operational

modes, except non heat pump heating modes, +10 percent and -10 percent respectively. The adjust selection options are provided to adjust airflow

supplied to meet individual installation needs for such things as noise, comfort, and humidity removal. (See Fig. 4.)

E. AC/HP Time Delay

Select desired time delay profile. Four motor operation delay profiles are provided to customize and enhance system operation. (See Fig. 4.) The

selection options are:

NOTE: Selectable ON and OFF delay active in heat pump heating and cooling modes only. Auxiliary heat modes have a fixed delay profile: 0

seconds ON or 2 minutes OFF. This cannot be overridden.

Table 3—Connections and Connector (FK4B)

Type

Connection

Type

Connector

Pin No. Description

Heater

Connection

12-Pin Pin 1 Common to E screw terminal

Pin 2 Common to W2 screw terminal

Pin 3 Common to C screw terminal, SEC1 terminal, and chassis ground

Pin 4 Common to C screw terminal, SEC1 terminal, and chassis ground

Pin 5 No connection

Pin 6 Common to W3 screw terminal

Pin 7 Common to M2 and T3 quick-connects, 230 vac input

Pin 8 No connection

Pin 9 Common to M1 and T1 quick-connects, 230 vac input

Pin 10 No connection

Pin 11 No connection

Pin 12 No connection

Motor 7-Pin Header Pin 1 Diode OR output of E or W3 or W2 thermostat signals

Pin 2 Thermostat G signal

Pin 3 Common to C, SEC1, and chassis ground

Pin 4 Common to C, SEC1, and chassis ground

Pin 5 Common to R and SEC2 (via 5-amp fuse)

Pin 6 Thermostat Y/Y2 signal

Pin 7 Thermostat Y1 signal

—7—

1. The standard 90 sec off delay (factory setting).

2. No delay option used for servicing unit or when a thermostat is utilized to perform delay functions.

3. A 30 sec on/90 sec off delay profile used when it is desirable to allow system coils time to heat up/cool down prior to airflow. This profile

will minimize cold blow in heat pump operation and could enhance system efficiency.

4. ENH, enhanced selection provides a 30 sec on/180 sec off delay at half airflow, adding comfort and efficiency.

PROCEDURE 5—TROUBLESHOOTING CIRCUIT BOARD - FK4B

Use Fig. 5 and 6 and Tables 3, 4, 5, and 6 as guides in troubleshooting PCB unless otherwise noted.

A. If Fan Will Not Turn On From Thermostat:

IF THERE IS NO HIGH VOLTAGE TO PCB:

1. Check connection of 12-pin plug from heaters to receptacle on Easy Select board. This supplies power to PCB. Be sure plug is connected

properly.

2. Check sequencer number 1 and plug wiring. Yellow wire should be connected to pin number 9 of plug and to limit switch. Black wire should

be connected to pin number 7 of plug and to sequencer number 1.

3. Check power leads L1 and L2. If these are not receiving power, system cannot function.

IF PCB HAS HIGH VOLTAGE APPLIED TO IT:

1. Check low-voltage transformer leads (red and brown). Be sure they are wired to correct locations. (See Fig. 14)

and 18.)

2. Check output voltage of transformer secondary side SEC2 and SEC1. Be sure transformer output is around 24 vac. If transformer output

is zero vac and transformer is receiving correct input voltage (208v or 240v), then transformer needs to be replaced with recommended

transformer. If transformer output is 24 vac, proceed to items 3 and 4.

3. Check low-voltage fuse shown in Fig. 4. If fuse is blown, replace it. The transformer cannot supply power to board with fuse blown or loose.

If fuse blows when unit has power applied to it, the system most likely has 1 of the following problems:

a. Check control circuit for a short or miswiring problem.

b. The maximum load on transformer is 40 VA. If load on transformer is excessive, the low-voltage 5-amp fuse will blow to protect

transformer. If load exceeds VA rating of transformer, a larger VA rated transformer needs to be installed. Check sequencers for

excessive current draw.

c. Check wiring of heaters. If a heater is miswired, fuse may blow. If a heater is miswired, correct miswiring.

4. Check T1, T2, and T3 connections on primary side of transformer. If they are not connected properly, low-voltage terminal board cannot

supply 24-v signal to energize fan motor. If transformer is receiving correct primary voltage but is not putting out correct secondary voltage,

transformer needs to be replaced.

B. If Electric Heat Stages Will Not Turn On But Fan Will Turn On:

1. Check wiring of sequencers. Pay particular attention to high- and low-voltage wiring of sequencers.

2. Check plug wiring to make sure that it is wired correctly.

3. Check voltage to sequencer. Sequencer number 1 receives a 24-vac signal. If it is receiving correct voltage, check to see if sequencer is

closing. If sequencer is not closing but is receiving correct voltage, replace sequencer. If sequencer is closing, check high-voltage wiring

as discussed in items 1 and 2.

IF THERE ARE BLOWN DIODES:

If diodes are blown, it is probable that electric heater plug is miswired. Correct miswiring.

NOTE: Board will need to be replaced if diode is bad.

IF TRACES ARE OVERHEATED ON BACK OF PCB:

Usually whenever there is a trace blown on PCB, it means either there has been a high-voltage short or high voltage has been applied to low-voltage

circuit. This can be prevented by making sure PCB is wired correctly before PCB has power applied to it.

C. If PCB Fuse Keeps Blowing:

When low-voltage fuse blows, it means transformer would have blown if fuse had not been in circuit to protect it. The fuse usually blows when

there is a high current drawn on transformer, high voltage applied to low-voltage circuit, or a direct secondary short. When there is a high current

drawn on transformer, it is most likely because transformer has been shorted or system is trying to draw more VA than transformer rating allows.

When fuse blows because of high voltage, the system has mixed high- and low-voltage signals.

1. Check transformer and thermostat wiring. (See Fig. 4 and 6.) Be sure transformer is not shorting out because thermostat wires are miswired.

2. Check wiring of sequencers. (See Fig. 4 and 6.) Be sure low-voltage and high-voltage wiring are connected to proper sequencers.

3. Check VA draw on transformer. If VA draw is more than VA rating of transformer, fuse will blow. If this is the case, replace transformer

with one that has a higher VA rating and meets system specifications.

PROCEDURE 6—TROUBLESHOOTING FAN MOTOR - FK4B

A. If Motor Does Not Run:

1. With power turned off, check all plugs and receptacles on circuit board and at motor for any deformation that may cause a bad connection.

Be sure all plugs are placed fully seated.

—8—

Fig. 6—Typical FK4B Wiring Diagram with 6-Element Heater

A94078

ICM

TRAN

GND

RECP

SEE RATING PLATE

FOR VOLTS & HERTZ

(SEE NOTE 1)

FIELD POWER WIRING

YEL

GND

30KW 1PH SCHEMATIC DIAGRAM

DISCONNECT PER NEC

THIS COMPARTMENT MUST BE CLOSED EXCEPT FOR SERVICING

NOT SUITABLE FOR USE ON SYSTEMS

EXCEEDING 150V TO GROUND

CAUTION:

ATTENTION:

NE CONVIENT PAS AUX INSTALLATIONS

DE PLUS DE 150 V A LA TERRE

BLOWER MOTOR

ROTATION

HVTB

SEQ 3

CB/FU4

FU6

YEL

12 11

BLK

FU5

CB/FU2

CB/FU1

YEL

BLK

10 9

BLKBLK

SEQ 2

YEL

BLK

CB/FU3

HTR6

HTR5

HTR4

HTR3

HTR2

HTR1

LS6

LS5

LS4

LS3

LS2

LS1

BLK

SEQ 1

YEL

BLK

BLU

BLK

YEL

BLU

PLUG 1

RED

GRY

BRN

SEQ1

SEQ2

SEQ3

ORN

VIO

123456789101112

24567

FIELD POWER WIRING

DISCONNECT PER NEC

SCHEMATIC DIAGRAM

SEE RATING PLATE

FOR VOLTS & HERTZ

(SEE NOTE 1)

YEL BLK

GND

COOLING CONTROL WIRING

COOLING CONTROL ONLY

AUX HEAT RANGE

AC/HP SIZE

TYPE

A–C HP–COMFORT HP–EFF

AC/HP CFM TRIM

AC/HP DELAY ON/OFF

0/30 30/30 30/30 0/0

RECP 2

TRAN

COMMON

BRN

RED

BLK

RED

GRY

BLK

ORN

BLU

VIO

RECP 1

RED

BLU

RED

SEC2

SEC1

PCB

PLUG

24VAC

LVTB

JW2

JW1

GRN/YEL

YEL

BLK

54321

PLUG 3

PLUG 4

YEL

RECP 3

RECP 4

ICM

BRN

YEL

RED

VIO

RED

ORN

BRN

VIO

ORN

GRY

BLU

BLK

PLUG 2

BLK

YEL ORN GRN

RED BRN VIO

(SEE NOTE 3)

(SEE NOTE 2)

HPTB

NOTES:

1. Use copper wire only between disconnect switch and unit.

2. Connect (Y) to (Y), (C) to (C), etc. in pattern shown.

3. Transformer primary leads: BLUE 208V, RED 230V.

4. To be wired in accordandce with NEC and local codes.

5. If any of the original wire, as supplied, must be replaced, use the same or

equivalent type wire.

6. Replace low voltage fuse with no greater than 5 amp fuse.

7. Fuse is wired in series between transformer SEC2 and low voltage "R" circuit.

8. 20KW heater uses one double pole LS on middle top element.

9. 18, 24 and 30KW heaters use double pole limit switches.

10. Largest heaters are shown, smaller heaters will have fewer elements and

components.

11. 1 phase heaters are shown wired for single supply circuit. Multiple

supply circuits may be wired directly to fuse/C.B.'S.

- LEGEND -

MARKED TERMINAL

UNMARKED TERMINAL

FIELD POWER WIRING

PLUG AND RECEPTACLE

PCB BREAKOFF JUMPER

AUXILIARY

PRINTED CIRCUIT BOARD

HEAT PUMP TERM BRD

LOW VOLT TERM BRD

SEQUENCER

HEATER

HIGH VOLTAGE TERMINAL BOX

HUMIDIFIER

AUX

PCB

HPTB

LVTB

SEQ

HTR

HVTB

HUM

320486 - 301 REV. C

LIMIT SWITCH

FAN MOTOR

TRANSFORMER

EQUIPMENT GROUND

FUSE

RECEPTACLE

CIRCUIT BREAKER

LOW VOLTAGE FUSE

BLU

OLRY

INDOOR THERMOSTAT

MED HI

AUX1 HUM1

AUX2 HUM2

—9—

2. Verify that there are approximately 230v at terminals M1 and M2. If not, determine if high voltage is entering board. It enters through black

and yellow wires at pins 7 and 9 in 12-pin plug.

3. Verify that there is a low-voltage control signal to motor. The motor receives its control signals through the 7-pin motor plug P2. The voltage

output of each pin in plug will be different for each mode of operation. Table 4 lists circuit board screw terminals that have 24 vac present

(powered by thermostat) and lists voltage that is present at each pin of 7-pin plug for each operating mode. Tests should be taken between

points listed and common (C screw terminal). If all values of any 1 of operating modes checks OK and motor fails to run, then motor is

defective and should be replaced.

B. If Motor Does Not Run Smoothly:

First verify that the cause is not an out of balance or damaged blower wheel. If it is not blower wheel, motor is defective and should be replaced.

C. If Motor Shaft Does Not Rotate Smoothly:

When manually turning shaft of ECM/ICM, the shaft does not rotate smoothly. The shaft has steps during rotation referred to as motor cogging.

The cogging is caused by permanent magnets passing each pole of motor. However, shaft should not require excessive force to turn. If shaft is

VERY difficult to turn, motor control or bearings have failed and motor must be replaced.

D. If Motor Does Not Stop Running

1. Check for good ground between motor ground lead and transformer common lead.

2. If motor continues to run, remove all thermostat wires. If motor stops, check thermostat wiring for short.

3. If motor continues to run, remove the 7-pin plug. If motor continues to run after 2 minutes, replace motor.

PROCEDURE 7—CONDENSED VERSION OF TROUBLESHOOTING FK4B MOTOR AND CONTROLS

This section provides a quick summary of how to troubleshoot the FK4B. If more information is needed, refer to appropriate sections of this service

manual.

+ MOTOR

- If motor is hard to turn manually, but turns freely, replace module.

- If motor does not run, check the components listed below according to their instructions.

- If motor runs in some operation modes and not in others, check for a good ground connection between motor ground lead and circuit board

screw marked "ground screw" and check the room thermostat and wiring harness according to instructions listed in Table 4.

- If motor does not stop running, remove the 7-pin plug from circuit board. If motor continues to run, replace motor. If motor stops running

after 2 minutes, it is either the circuit board or thermostat causing the problem. Test whether thermostat is at fault by disconnecting it from the

board.

+ CIRCUIT BOARD

- Check 5-amp fuse.

- Check for 230v between terminals M1 and M2. If no voltage is present, check power to board. 230-v power enters the board through the black

and yellow lead in the 12-pin plug.

- Check for 24v between SEC1 and SEC2. If no voltage is present, check the transformer.

- Check for burn traces or burnt components. If burn spots are present, replace board.

+ ROOM THERMOSTAT

- Remove thermostat wires from the circuit board.

- Jumper screw terminals (1 at a time) R-G, R-Y/Y2, R-Y1, and R-W2. If motor runs in all cases, thermostat or thermostat wiring is bad. If

motor does not run, or runs in some cases but not in others, continue by checking the wiring harness.

+ WIRING HARNESS

- Shut off power to unit.

- Remove 5-pin plug from motor.

WARNING: ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury or possible equipment damage.

Never remove 5-pin high voltage plug from the motor with the power on.

- Remove 16-pin plug from motor.

- Replace 5-pin plug and turn on power.

Table 4—FK4B Motor Control Test Values

(With 16-pin connector at motor unplugged)

Terminals Jumpered Volt Meter on 16 PIN

Harness Plug

Volt Meter on 7-pin

Easy Select Board Plug

Voltage

+-+ -

R to W1 or W2 Pin 2 Pin 1 or 3 Pin 1 Pin 3 or 4 12vdc

R to Y1 Pin 6 Pin 1 or 3 Pin 7 Pin 3 or 4 24vac

R to Y/Y2 Pin 14 Pin 1 or 3 Pin 6 Pin 3 or 4 24vac

R to G Pin 15 Pin 1 or 3 Pin 2 Pin 3 or 4 24vac

—10—

- Check for 24v between pin-1 and pin-12 on the 16-pin plug. (See Fig. 7.) If no voltage is present, replace wiring harness. If voltage is present,

jumper screw terminal R-Y/Y2 on circuit board and check for 24v between pin 1 and pin 12 and pin 1 and pin 14 on 16-pin plug. (See Fig. 7.)

If voltage is present, replace harness.

- If 24v is present on both pins, the motor or module is bad. Replace motor.

PROCEDURE 8—ACCESSORIES (FK4B)

A. Electronic Air Cleaner (EAC)

Familiar 230-vac EAC control/power signal EAC1 and EAC2 is not available, because the motor blower motor used in the FK4B Fan Coil is

controlled by low-voltage signals. This signal is replaced by a 24-vdc signal which is provided at circuit board terminals AUX1 and AUX2. (See

Fig 16.)

This signal is present when either G or W is present and is active in all heating and cooling modes. Because 24-vdc relays may not be readily

available to installer, a kit exists, KFAIR0101ACR, containing a 24-vdc relay which mounts directly inside EAC cabinet. User-supplied 110 vac

is switched by relay to power air cleaner when G or W are present. (See Fig. 8)

In heat pump applications, the G signal is present in both cooling and heating modes, permitting EAC to be controlled from G signal only. For

this application, a user-supplied 24-vac relay can be driven by G terminal eliminating need for relay kit.

B. FK4B De-Humidify Mode

NOTE: Humidistat must open on humidity rise.

Latent capacities for systems using the FK4B Fan Coil are better than average systems. If increased latent capacity is an application requirement,

the FK4B can be wired to provide this requirement by adjusting its airflow in response to standard humidistat input. Fig. 9 illustrates the wiring

connections to activate de-humidify mode. Carefully consult product airflow data for cooling and dehumidifying mode.

FV4B, FK4D, FK4C, FV4A, AND 40FKA

The FK4C fan coil was introduced several years before the FV4A and 40FKA models. All three units contain the motor and use the same control

board. The 40FKA was introduced as part of the Comfort Heat Pump system and is identical to the FK4C except it is factory supplied with a

Thermidistat Control. Both the 40FKA and FK4 R-22 units with a factory supplied R-22 TXV. Other than the pressure differences in the Puron

system, all three units are constant airflow machines and operate the same way. The FV4B and FK4D include the added benefits of low sweat/low

leak cabinet.

Fig. 7—Wiring Harness 16-Pin Plug

A94375

16 15 14 13 12 11 10 9

8 7 6 5 4 3 2 1

16-PIN PLUG

Fig. 8—Mounting KFAIR0101ACR Relay Kit

A93216

MOUNT FLUSH WITH

THESE TWO EDGES

Fig. 9—Humidistat Wiring for De-Humidify Mode

A93215

HUMIDISTAT

TO PCB TERMINAL

MARKED 'RED'

RED WIRE

FROM ICM2

MOTOR

HUMIDISTAT WIRING FOR

DE-HUMIDIFY MODE

—11—

Constant Air Flow

Unlike fan coils using induction motors where static pressure affects airflow, these fan coils are constant airflow units. The blower delivers

requested airflow regardless of static pressure. Consult fan coil Product Data for static pressure limits. The motor/ECM2 is pre-programmed and

contains airflow tables for all modes of operation. Blower characteristics (requested airflow, torque, and speed) are known from laboratory testing.

If any 2 characteristics are known, the third is defined.

Requested airflow is known from Easy Select board configuration and thermostat signals. Torque is known because it is directly related to stator

current which is measured by motor control. Speed is measured by counting back EMF pulses from stator windings. This information is entered

into an expression which calculates torque from speed and airflow numbers. If calculation does not match stored blower characteristics, torque is

adjusted until agreement is reached. This calculation and adjustment is performed every 0.8 sec while motor is in operation. There is no direct

measure of static pressure, but unit does react to a change in static to maintain constant airflow. A change in pressure will result in a change in

stator speed and torque. The motor will begin to adjust on the next sampling, calculate new desired speed and torque, and adjust as necessary.

PROCEDURE 1—INTEGRATED CONTROLS AND MOTOR ECM / /ECM2)

An motor/ECM2 is fed high voltage AC power through the 5-pin connector. (See Fig. 10.) The AC power is then internally rectified to DC by

a diode module. After rectification, DC signal is electronically communicated and fed in sequential order to 3 stator windings. The frequency of

these commutation pulses determines motor speed. The rotor is permanently magnetized.

An motor/ECM2 is powered with high voltage at all times. The motor will not run with high voltage alone. Low voltage must be applied to control

plug to run motor.

ECM/ICM 2 CONTROL POWER

The motor/ECM2 control power is supplied from R circuit through printed circuit runs to motor control connector pin 8, through motor control

harness to motor. The C side of low-voltage control power circuit is connected by printed circuit runs to motor connector pins 9, 10, and 11 then

through motor control harness to motor.

LOW-VOLTAGE CIRCUIT FUSING AND REFERENCE

The low-voltage circuit is fused by a board-mounted 5-amp automotive-type fuse placed in series with transformer SEC2 and R circuit. The C

circuit of transformer is referenced to chassis ground through a printed circuit run at SEC1 connected to metal standoff marked.

NOTE: The PCB must be mounted with 2 screws and motor ground lead secured to blower housing or erratic motor operation can result.

TRANSFORMER, MOTOR, AND ELECTRIC HEATER POWER CONNECTION

Transformer high voltage supplied from electric heater package or high voltage leads through 12-pin heater connector plug/recp2. The

motor/ECM2 power connections are made at the transformer primary terminals. The transformer secondary connections are made at SEC1 and

SEC2 connectors.

COMFORT HEAT PUMP SYSTEM

In 1998, the Comfort Heat Pump System was introduced in which a 40FK, FK4 or FV4 fan coil can be installed. This introduced many new features

for enhanced comfort. To activate these modes, they must be configured into the indoor control. The Thermidistat Control and current zoning have

the capability of both of these modes.

To initiate these operating modes, the control drops out the G signal to reduce airflow for extra comfort in heating and maximum dehumidification

in cooling. This must be kept in mind while troubleshooting these fan coils. Be aware that a cooling or heating input without the G input energized

will result in significantly lower airflow than may be expected. When verifying airflow in normal heating and cooling modes (including emergency

heat in newer motors), remember that G must be energized to achieve full airflow.

Fig. 10—FK4C, FV4A, and 40FKA motor/ECM2.3 Motor

A98201

12345

12345678

10 11 12 13 14 15 16

POWER CONNECTOR

CONTROL CONNECTOR

OPTIONAL SAFETY GROUND

DRAIN HOLE

OPTIONAL SAFETY GROUND

ENDSHIELD

DRAIN HOLE

CONTROL

POWER

—12—

The FK4 has some earlier series that were produced before the Comfort Heat Pump System was introduced. Some of the motors will not have the

programming that slows the fan down on a loss of the G signal. The following units are factory programmed for Super Comfort Heat and

SuperDehumidify Modes:

40FKA/B.........ALL

FV4A/B..........ALL

FK4C..........Series A through E (1995-1997)NONE

FK4C..........Series F reduces airflow in heat pump heating and cooling modes only (not in electric heating modes).

FK4C/D..........Series G reduces airflow in all modes

FK4A..........NONE with original motor. If upgraded to motor/ECM2 motor, it may have programming

FK4B..........NONE with original motor. Replacement motor or module may have programming.

IF an original motor or module has been replaced, it may have Super Comfort Heat and SuperDehumidify capability.

PROCEDURE 2—PCB LAYOUT AND DESCRIPTION (FK4, FV4, 40FK)

NOTE: Layout of actual PCB is depicted in Fig. 11 and 25.

The Easy Select Board is the interface between the ECM motor and other system components. The board offers choices of electric heater size,

outdoor unit size and type, comfort or efficiency settings, on and off delay profiles, and continuous fan speed. The installer should select the correct

size of components that are being installed in each installation. If no selections are made, the factory default settings are for the largest heater,

largest outdoor unit, AC system type, nominal airflow adjust, and 0/90 time delay.

NOTE: Outdoor unit model should have an ARI rating with the variable speed fan coil. Some outdoor unit models will not work properly with

this fan coil.

Power for system is supplied from a 230-vac, 60-Hz line. Class 2 voltage (24 vac nom.), used for thermostat connections, is derived from

transformer located in close proximity to PCB. The 24-vac secondary circuit includes 5-amp automotive-type fuse in SEC2 circuit.

Connection to heater panel is made through 12-pin connector PL-1. Connections to thermostat are made at screw terminals. Twenty-one pin

terminals comprise field select taps for motor.

Fuse Data: 5-amp automotive-type ATC/ATO (tan)

32v

200 percent current opening time of 5 sec maximum

A. Electrical Connections

Twenty-one 0.110-in pin terminals are used to provide programming selections for operating modes of motor/ECM2. The 6 selection modes are

listed below. For additional information, refer to Easy Select Configuration Taps section.

AUX Heat Range—(Violet Wire)

AC/HP Size—(Blue Wire) Type—(Orange Wire)

AC/HP CFM Adjust—(Black Wire)

AC/HP Time Delay—(Grey Wire)

Continuous Fan—(Yellow Wire)

PROCEDURE 3—SEQUENCE OF OPERATION (FK4, FV4, 40FK)

A. Continuous Fan Mode

The thermostat closes circuit R to G. The unit delivers the airflow selected for fan only operation.

B. Cooling Mode—Single Speed or 2-Speed High

Thermostat closes circuits R to G, R to Y/Y2 and R to O (heat pump only). A circuit R to Y1 is required for 2-speed high operation. Airflow

delivered the airflow selected by AC/HP SIZE selection and CFM ADJUST selection.

C. Cooling Mode—Two-Speed Low

Thermostat closes R to G and R to Y1 and R to O (heat pump only). Unit delivers 2-speed low airflow for AC/HP SIZE and CFM ADJUST

selected.

D. Cooling + Dehumidify Mode (Thermidistat or Comfort Zone II-B and Single-Speed Outdoor Unit Installed)

J1 jumper must be pulled from Easy Select Board. Control closes R to G, R to Y/Y2, and R to O (heat pump only) and open R to DH.

Dehumidification is active when 24vac is removed from DH terminal. Unit delivers 20% less airflow.

E. SuperDehumidify Mode

(Thermidisat or Comfort Zone II-B indoor control, Single-Speed Outdoor Unit)

This mode is only activated by the indoor control when COOL to DEHUMIDIFY and SUPERDEHUMIDIFY are configured at the control and

there is a call for dehumidfication without a call for cooling. The control closes R to Y/Y2, R to O (heat pump only) and opens R to DH and R

to G. This signals the fan coil to run at minimum airflow for maximum humidity removal. The control will cycle the equipment 10 minutes on

and 10 minutes off until satisfied.

Table 5 — Motor & Modules Capable of Comfort Heat / SuperDehumidfy Modes

Model Motor Part Number Replacement Module

Part No.

FK4C, FV4A, 40FKA001, 002 HD44AE128, 131, 125* RMOD44AE128, 131

FK4C, FV4A, 40FKA003 HD44AE129, 132, 127* RMOD44AE129, 131

FK4C, FV4A, 40FKA005 HDD44AE130, 133, 126* RMOD44AE130, 133

FK4C, FV4A, 40FKA006 HD46AE243, 244, 242* RMOD46AE243, 244

*These motors will not adjust airflow with G in electric heat modes.

—13—

F. Heat Pump Heating Mode — Single Speed or 2-Speed High

Thermostat closes R to Y/Y2 and R to G. A circuit R to Y1 is required for 2-speed high operation. The unit delivers airflow selected by AC/HP

SIZE selection and CFM ADJUST selection. Selected delay profile is active in this mode.

G. Heat Pump Heating Mode — 2-Speed Low

Thermostat closes R to G and R to Y1. Unit delivers 2-speed low airflow for AC/HP SIZE and CFM ADJUST selected. Selected delay profile

is active in this mode.

Fig. 11—Easy Select Board

A96430

YYWWX

AUX/HEAT KW/CFM

AC/HP SIZE

AC/HP CFM ADJUST

ON/OFF DELAY

CONTINUOUS FAN

HEATER/MOTOR

AUX1 HUM1

AUX2

24VAC

HUM2

LO MED HI YEL

SYSTEM TYPE

SEC1

EASY SELECT

SEC2

5 AMP.

MAX.

D5D2

CES0130035-00

STI

YEL

PL1

GRY

WHT

BLK

ORN

BLU

VIO

0-30

1075

0-20

875

0-10

725

0-5

625

036 030 024 018

AC HP-COMFORT HP-EFF

NOM LO HI

ENH

Y/Y

Fig. 12—Easy Select Board Schematic

A96431

AUX1

SYSTEM DIAGRAM

HEATER/MOTOR

SEC1 SEC2

5 AMP

Y/Y

HUM1

AUX2

HUM2

DIODE

LOGIC

AUX HEAT

KW/CFM

AC/HP

SIZE

SYSTEM

TYPE

AC/HP CFM

ADJUST

ON/OFF

DELAY

CONTINUOUS

FAN

GRY

/4"

—14—

H. Non-Staged Auxiliary Heat with Heat Pump Heating Mode

Thermostat should already have closed R to G, R to Y2 for heat pump heating operation. With J2 jumper in place, energizing either W1 or W2

will produce the W2 airflow. This is the greater of heat pump heating and auxiliary heat airflow plus an additional 15%. The elected delay profile

is not active in this mode.

I. Staged Auxiliary Heat with Heat Pump Heating Mode

The auxiliary heat can be staged by removing the J2 jumper that ties W1 and W2 terminals together. Staging can be done by using outdoor

thermostats or by using the Intelligent Heat Staging option where the indoor control can be configured for 3-stage electric heat. The unit will

automatically adjust airflow when the different stages of heat are energized. The airflow delivered will depend on the heat pump size selected and

electric heat size selected. The greater of the two airflows will be delivered. The selected delay profile is not active in this mode.

J. Electric Heat without Heat Pump

Thermostat closes R to W and thermostat should be set up to energize G with W. This is due to the Super Comfort Heat programming in the motor.

Energizing W without G will result in 25% lower airflow delivery. The selected delay profile is not active in this mode.

K. Super Comfort Heat Mode

This is a special heating mode only available on FK4, FV4, and 40FK fan coils combined with a Thermidistat Control or Comfort Zone II-B. When

this option is selected, the indoor control will monitor the outdoor temperature. The control will drop the G signal to the fan coil when the outdoor

temperature is between 10° and 40° F. This triggers the motor to slow to approximately 213 CFM per ton. The heaters will stage as needed during

this mode and the motor will adjust airflow as required. Below 10° F., theW1 control output will automatically energize on a call for heat. The

motor/ECM2 power connections are made at the transformer primary terminals. The transformer secondary connections are made at SEC1 and

SEC2 connectors.

PROCEDURE 4—EASY SELECT CONFIGURATION TAPS

The Easy Select taps are used by installer to configure system. The motor/ECM2 uses selected taps to modify its operation to a pre-programmed

table of airflows. Airflows are based on system size and mode of operation and those airflows are modified in response to other inputs such as

the need for de-humidification. (See Fig. 11.)

The FK4, FV4, and 40FK Fan Coils must be configured to operate properly with system components with which it is installed. To successfully

configure a basic system (see information printed on circuit board located next to select pins), move the 6 select wires to pins which match

components used, along with homeowner preferences.

A. Auxiliary Heat Range

The installer must select the auxiliary heat airflow approved for application with kw size heater installed. Each select pin is marked with a range

of heaters for which airflow (also marked) is approved. For increased comfort select the narrowest kw range matching the heater size, for example,

0-10 for a 10-kw heater. This airflow must be greater than the minimum CFM for electric heater application with the size system installed for safe

and continuous operation. Note that airflow marked is the airflow which will be supplied in emergency heat mode and heating mode on air

conditioners when electric heat is primary heating source. To ensure safe heater operation in heat pump heating mode when electric heaters are

energized, the motor/ECM2 will run the higher of heat pump airflow and electric heater airflow. The factory default selection is largest heater range

approved. (See Fig. 11.)

B. AC/HP Size

The factory default setting for air conditioner or heat pump size is largest unit meant for application with model of fan coil purchased. The installer

needs to select air conditioner or heat pump size to ensure that airflow delivered falls within proper range for size of unit installed in all operational

modes. (See Fig. 11.)

C. System Type

The type of system must be selected.

1. AC—air conditioner (approx. 350 CFM/ton)

2. HP-COMFORT—provides lower airflow than air conditioner selection (approximately 315 CFM/ton) in heating mode. In cooling mode

supplies 350 CFM/ton.

Table 6—Connections and Connector (FK4C)

Type

Connection

Type

Connector

Pin No. Description

Heater

Connection

12-Pin Pin 1 Common to screw terminal G

Pin 2 Common to screw terminal Y/Y2 through diode D3

Pin 3 Common to Y1 through diode D2

Pin 4 Common to W2 screw terminal

Pin 5 Common to W2 screw terminal

Pin 6 Common to screw terminal W1 screw terminal

Pin 7 Common to W1 screw terminal

Pin 8 R 24VAC

Pin 9 Common to transformer C

Pin 10 Common to transformer C

Pin 11 Common to transformer C

Pin 12 Common to DH screw terminal

—15—

3. HP-EFF—provides same airflow for heat pump heating and cooling modes (approximately 350 CFM/ton).

The factory setting is AC. (See Fig. 11.)

D. AC/HP CFM Adjust

Select low, nominal, or high airflow. The factory selection is NOM. The adjust selections HI/LO will regulate airflow supplied for cooling and

heat pump heating modes only, +15 percent and -10 percent respectively. The adjust selection options are provided to adjust airflow supplied to

meet individual installation needs for such things as noise, comfort, and humidity removal. (See Fig. 11.)

E. ON/OFF Delay

NOTE: ON/OFF Delay is active only in cooling and heat pump only heating modes. In auxiliary heat mode or emergency heat mode, the ON

delay is 0 seconds and the OFF delay is fixed and cannot be overridden.

Select desired time delay profile. Four motor operation delay profiles are provided to customize and enhance system operation. (See Fig. 11.) The

selection options are:

1. The standard 90 sec off delay (factory setting 0/90).

2. No delay option used for servicing unit or when a thermostat is utilized to perform delay functions (0/0).

3. A 30 sec on/90 sec off delay profile used when it is desirable to allow system coils time to heat up/cool down prior to airflow. This profile

will minimize cold blow in heat pump operation and could enhance system efficiency (30/90).

4. ENH, enhanced selection provides a 30 sec on/150 sec at 70 percent airflow and no off delay.

F. Continuous Fan

Select desired Continuous fan profile LO, MED, or HI. Airflow are provided to customize and enhance the continuous fan functions. (See Fig.

11.) The possible selections are:

1. LO—provides 50% of Y/Y2 Cool airflow.

2. MED—provides 65% of Y/Y2 Cool airflow (71% on 006 model).

3. HI—provides 100% of Y/Y2 Cool airflow.

The factory setting is LO.

NOTE: If applied to two-speed unit, do not select continuous fan as HI since low speed cooling will also run at HIGH airflow and insufficient

dehumidification may result.

G. Easy Select Board Jumpers

J1 - This jumper must be pulled to activate dehumidification mode. The jumper connects R to DH. With the jumper in, the DH terminal is always

energized. With the jumper pulled, the DH terminal is de-energized. A control such as the Thermidistat must be used to supply the 24-volt signal

when there is no call for dehumidification, and turn off the 24 volts when there is a call for dehumidfication.

J2 - This jumper activates heat staging. The jumper connects the W1 and W2 terminals together. If either is energized, W2 airflow is delivered.

With the jumper pulled, there are separate airflows for W1 and W2.

H. Airflow Delivery

These units deliver airflow depending on the system size selections and operating mode. The thermostat energizes a combination of terminals on

the Easy Select Board which tells the motor what CFM to deliver. The following are typical operating modes and the terminals that should be

energized on the Easy Select Board.

NOTE: The DH terminal on the Easy Select Board is for dehumidification. It is de-energized on a call for dehumidification.

I. Variable Speed Motor Logic Sequence:

The ECM motors in these fan coils are programmed to deliver a variety of airflows. The motor goes through:

COOLING

The nominal cooling airflow for these fan coils is 350 CFM per ton. Selecting the HI adjust tap increases the airflow to 400 CFM per ton. The

LO tap decreases airflow to 315 CFM per ton. The low adjustment is only active during normal cooling mode. Removing the signal from the DH

terminal reduces the airflow to 80% of cooling airflow. Removing the G signal for Superdehumidify reduces the airflow to 50% of cooling.

HEATING

The base heat pump only heating airflow is determined by the SYSTEM TYPE selection on the Easy Select Board. If HP-EFFICIENCY is selected,

the airflow is the same as Cooling. IF HP-COMFORT is selected, the airflow is 315 CFM per ton. The airflow will adjust up if necessary when

auxiliary heating is required. When both the Y/Y2 and W1 or W2 terminals are energized, the motor will run the higher of the heat pump or electric

heat airflows. During Super Comfort Heat mode, the indoor control removes the G signal from the board. This slows the motor to 75% of heat

pump airflow. If the CFM adjust is set to LO, it will deliver 67.5% of heat pump airflow during Super Comfort Heat mode.

Table 7—Typical Operating Modes

Operating

Mode

Terminals Energized

Heat Pump Only Heating R, Y/Y2, G, DH

Heat Pump Only Heating + Super Comfort Heat Mode R, Y/Y2, DH

Heat Pump Heating + Auxiliary Heat (non-staged) R, Y/Y2, G, DH, W2

Cooling R, Y/Y2, G, DH, O

Cooling + Dehumidification R, Y/Y2, G, 0

Cooling + Superdehumidify R, Y/Y2, O

—16—

PROCEDURE 5—TROUBLESHOOTING

A. Troubleshooting Easy Select Board (FK4, FV4, 40FK)

IF TRACES ARE OVERHEATED ON BACK OF PCB:

Usually whenever there is a trace broken on PCB, it means either there has been a high-voltage short or high voltage has been applied to

low-voltage circuit. This can be prevented by making sure PCB is wired correctly before fan coil has power applied to it.

If PCB Fuse Keeps Blowing:

When low-voltage fuse blows, it means transformer would have blown if fuse had not been in circuit to protect it. The fuse usually blows when

there is a high current drawn on transformer, high voltage applied to low-voltage circuit, or a direct secondary short. When there is a high current

drawn on transformer, it is most likely because transformer has been shorted or system is trying to draw more vac than transformer rating allows.

When fuse blows because of high voltage, the system has mixed high- and low-voltage signals.

1. Check transformer and thermostat wiring. (See Fig. 11 and 13.) Be sure transformer is not shorting out because thermostat wires are

miswired.

2. Check wiring of relays. (See Fig. 11 and 13.) Be sure low-voltage and high-voltage wiring are connected to proper sequencers.

3. Check VA draw on transformer. If VA draw is more than VA rating of transformer, fuse will blow. If this is the case, replace transformer

with one that has a higher VA rating.

B. Troubleshooting Common Problems

Airflow Too Low:

Y1 instead of Y/Y2 on single-speed air conditioner or heat pump application. Y1 input is only for 2-speed applications. Using this terminal will

deliver about 60% of full cooling airflow.

Wrong Easy Select Board selection. Selecting an outdoor unit or electric heater smaller than actually installed will result in low airflow for the

application.

G not energized with call for cooling or heating. This triggers Super Comfort Heat or SuperDehumidify mode which delivers 50% of cooling

airflow.

J1 jumper pulled with no Thermidistat or dehumidistat installed. The J1 jumper ties the DH terminal to R and is installed at the factory. When

pulled, a Thermidistat or dehumidistat supplies a 24-volt signal to DH when there is no call for dehumidification (reverse logic). When there is

no signal on DH, the motor reduces airflow to 80% for better dehumidification.

Airflow Too High:

Wrong Easy Select Board selection. Fan coil is factory set for the largest outdoor unit and largest electric heater. Select sizes that are actually

installed.

Continuous fan set too high for 2-speed applications. Set to MED or LO.

Motor Will Not Stop:

Allow time for off delay to time out. In units built before serial number 0101A, any W call will have a 2 minute off delay independent of delay

selection. This is programmed into the motor and cannot be overridden.

In units built after 0101A, the off delay on any W call is 1 minute and cannot be overridden.

Some power stealing thermostats could bleed enough voltage to cause motor to run slowly when there is no heating or cooling call. Disconnect

thermostat wires and wait 2 minutes to see if motor stops. If it stops, replace thermostat, or install resistor per thermostat installation instructions.

Motor Will Not Start:

See following section, ″Troubleshooting motor/ECM2 Motor and Controls″

C. Troubleshooting motor/ECM2 Motor and Controls

CAUTION: ELECTRICAL OPERATION HAZARD

Failure to follow this caution may result in equipment damage or improper operation.

High voltage is always present at motor. Disconnect power to unit before removing or replacing connectors or servicing

motor. Wait at least 5 minutes after disconnecting power before opening motor.

The ECM/ICM motor used with this product contains two parts: the control module and the motor winding section. Do not assume the motor or

module is defective if it will not start. Go through the steps described below before replacing control module, Easy Select Board or entire motor.

The control module is available as a replacement part.

D. If Motor Turns Slowly:

1. It is normal operation to run noticeably slower if G terminal is not energized in cooling or heat pump heating modes.

2. Attach blower access panel. Motor may appear to run slowly if access panel is removed.

E. If Motor Does Not Run:

Turn power off, wait 5 minutes and check the following:

1. With power turned off, check 5 amp fuse on Easy Select Board

2. Check all plugs and receptacles for any deformation or corrosion that could cause bad connections. Be sure plugs are fully seated.

CAUTION: ELECTRICAL OPERATION HAZARD

Failure to follow this caution may result in equipment damage or improper operation.

DO NOT remove or apply 5-pin plug on motor with power on. Arcing could occur which can damage control module.

—17—

Fig. 13—FK4C, FV4A, and 40FKA Wiring Diagram

with 20kw heater after heater serial # 1900A56372

A00178

THIS COMPARTMENT MUST BE CLOSED EXCEPT FOR SERVICING

CAUTION:

ATTENTION:

NOT SUITABL E FOR USE ON SYSTEMS EXCEEDING

150V TO GROUND

NE CONVIENT PAS AUX INSTALLA TIONS DE PLUS DE 150

V A LA TERRE

BLOWER MOTOR

ROTATI ON

COM

ICM

GND

HVTB

HTR

REC

COMMON

LOW VOLTAGE FUSE

FAN MOTOR

FIELD POWER WIRING

LINE FUSE

EQUIPMENT GROUND

HIGH VOLT AGE TERM BLOCK

HEATER

RECTIFIER

PCB

TRAN

RECP

TDR

LEGEND

20KW 1PH SCHEMATI C DIAGRAM

YEL

LIMIT SWITCH

MARKED TERMINAL

PLUG AND RECEPTACLE

PRINTED CIRCUIT BOARD

TRANSFORMER

RECEPTACLE

CIRCUIT BREAKER

RELAY

TIME DELAY RECTIFIER

YEL

VIO

ORN

BLU

BLK

208/240VAC 24VAC

24VAC

PLUG 2

11 7

L1 L2

FIELD POWER WIRING

FIELD

POWER

WIRING

BLK

YEL

RECP 2

COOLING CONTROL ONLY

TRAN

SEC2SEC1

RED

BRN

AUX HEAT KW/CFM

VIO

CFM

AC/HP SIZE

BLU

SYSTEM TYPE

ORN

AC HP-COMFORT HP-EFF

AC/HP CFM ADJUST

BLK

NOM

ON/OFF DELAY

WHT

YEL

LO MED HI YEL

PL1

HEATER / MOTOR

CONTINUOUS FAN

24 VAC

AUX 2

HUM2

AUX1 HUM1

GRY

VIO

BLU

ORN

BLK

WHT

PLUG 3

230V

208V

Com

YEL

BLK

YEL

ICM

RECP 4

RECP 3

GRY

BRN

5 4 3 2 1

GRN

BLK

RED

VIO

RED

ORN

BRN

PLUG 1

11 1 0

PLUG 4

BLK

BLU

WHT

ORN

VIO

BRN

GRN

YEL

WHT

RED

VIO

GRY

ORN

1. USE COPPER WIRE (75*C MIN) ONLY BETWEEN DISCONNECT

SWITCH AND UNIT.

2. TO BE WIRED IN ACCORDANCE WITH NEC AND LOCAL CODES.

3. TRANSFORMER PRIMARY LEADS, BLUE 208V, RED 230V.

4. IF ANY OF THE ORIGINAL WIRE, AS SUPPLIED, MUST BE REPLACED,

USE THE SAME OR EQUIVALENT TYPE WIRE.

5. REPLACE LOW VOLTAGE FUSE WITH NO GREATER THAN 5 AMP FUSE.

6. DUAL CIRCUIT WIRING SHOWN.

7. USE 60 AMP CLASS K FUSES ONLY, FOR REPLACEMENT.

8. CONNECT R TO R, G TO G, ETC., SEE OUTDOOR INSTRUCTION FOR

DETAI LS.

NOTES:

325653-101 REV. B

PCB

GRN/YEL

GND

OUTDOOR UNITINDOOR THERMOSTAT

COMPONENT ARRANGEMENT

COM

208 V

230 V

TRAN

RED

24 V

BRN

SYSTEM TRANSFORMER: 40.0VA

FAN COIL/HEATER: 8.2VA

REMAINING VA AVAILABLE: 31.8VA

Y/Y

GND

ICM

Y/Y

PCB

SEC2SEC1

PL1

HEATER / MOTOR

RELAY 1

R E C

T D R

RED

BRN

GRY

LABEL (2)

SEE INSTRUCTION FOR INSTALLATION

REC

RELAY 3

22 VDC COIL

RELAY 2

22 VDC COIL

HTR1

HTR3

HTR2

HTR4

LS1

LS2

PLUG 2

RECP 2

FIELD POWER WIRING DISCONNECT PER NEC

SEE RATING PLATE

FOR VOLTS & HERTZ

GND

HTR4

BLK

YEL

LS4

YEL

BLK

HTR3

BLK

LS3

RELAY 2

BLK

HTR2

BLK

YEL

LS2

YEL

BLK

HTR1

BLK

LS1

RELAY 1

BLK

FU4

FU2

CB1

CB2

FU1

FU3

CB1

CB2

INTERNAL PROTECTION MAY

BE EITHER FUSES OR CIRCUIT

BREAKERS

SEE NOTE #1

BLK

BLU

RELAY 3

RELAY 2

RELAY 3

RELAY 1

REC

RELAY 2

TDR

REC

L4 L3

CB1

60A 60A

CB2

60A 60A

FU3

FU1

FU2

FU4

—18—

Turn power back on and check the following:

3. Check for 24vac on SEC1 and SEC2. If no voltage is present, check transformer.

4. Verify that approximately 230vac is present at motor.

5. Verify low voltage control signals to motor according to procedure below.

Use following procedure to check low voltage signals:

The ECM motor in these fan coils receive low voltage signals from the Easy Select Board through the wiring harness assembly. The combination

of pins energized at the motor determines the speed the motor will run. The procedure below isolates the fan coil from all external devices such

as a thermostat, condensing unit, humidifier or electronic air cleaner. There is also a specific troubleshooting example to demonstrate the process.

Table 7 provides information needed to verify that the correct voltages are present at the motor and the Easy Select Board.

THERMOSTAT:

1. Remove all thermostat and accessory wires from Easy Select Board.

2. On Easy Select Board, jumper screw terminals (1 at a time): R-G, R-Y/Y2, R-Y1, R-W1, R-W2. If motor runs in all cases, check thermostat

outputs. Thermostat wires may be broken, or thermostat may be miswired, configured incorrectly, or defective. If the motor does not run,

or runs in some cases, but not others, continue this procedure to check wiring harness and circuit board.

WIRING HARNESS:

1. Remove 16-pin plug from motor.

2. Check for appropriate voltages on 16-pin connector with screw terminals jumpered. (See Table 6.)

3. If signals check correctly, and motor does not run, inspect wiring harness for loose pins or damaged plastic that could cause poor

connections.

4. If connections are good, either control module or motor is defective.

5. If proper signals are not present, check circuit board using procedure below:

12-PIN PLUG (PL-1) ON EASY SELECT BOARD:

1. Completely disconnect wire harness from Easy Select Board.

2. Jumper the screw terminals one at a time; R-G, R-Y/Y2, R-Y1, R-W1, R-W2 and check for appropriate voltages on the Easy Select Board

pins. If proper signals are not present, replace Easy Select Board. If proper signals are present at the pins and not at 16-pin connector to

the motor, the wiring harness is defective.

TROUBLESHOOTING EXAMPLE:

Motor is not running on a call for heat pump heating after jumpering the Easy Select Board screw terminals as described in Thermostat section

above:

With all thermostat wires removed from Easy Select Board, place a jumper wire between R and Y/Y2 low-voltage screw terminals on the Easy

Select Board

1. Check Table 8 for pin number on 16-pin connector associated with the Y/Y2 signal. The correct pin is #14. The far right column of Table

8 shows that (-) 12vdc should be present between pin #14 and pin #1 (common) on the 16-pin connector.

2. Set meter to read DC voltage. Place meter leads between pins #1 (common) and #14 and check for (-) 12vdc. If signal is present, the problem

is in the module or motor. If signal is not present, the problem is either in wiring harness or Easy Select Board.

These steps can be repeated for other modes of operation.

To check Easy Select Board:

1. Leave jumper wire in place between R and Y/Y2.

2. Check Table 8 under ″Volt Meter on Easy Select Board Plug″ column and row for pin #14 on motor plug to see pin # on Easy Select Board

that should have voltage. The correct pin is #2. The column on far right will show voltage that should be present between pin #2 and pin

#9 (common).

3. Place meter leads between pins #2 and #9 on Easy Select Board and check for (-) 12vdc.

4. If voltage is present, the wiring harness is bad. If not, the Easy Select Board is bad.

Verify Motor Winding Section:

Before proceeding with module replacement, check the following to ensure motor winding section is functional. With control module removed

and unplugged from winding section:

1. The resistance between any 2 motor leads should be similar.

2. The resistance between any motor lead and the unpainted motor end plate should be greater than 100K ohms.

If motor winding fails one of these tests, it is defective and must be replaced.

F. Accessories

AUXILIARY TERMINALS

The AUX and HUM terminals on the Easy Select Board are tied directly to the G terminal, and provide a 24-vac signal whenever the G terminal

is energized (See Fig. 5 and Fig. 6). During Superdehumidify mode, the G signal is not present and the auxiliary terminals are not energized. If

the installation includes the use of this operating mode, do not use these terminals to control accessories. See Electronic Air Cleaner and Humidifier

sections for further information.

—19—

ELECTRONIC AIR CLEANER CONNECTIONS

The AUX1 and AUX2 terminals are not always energized during blower operation, as described above. When using an electronic air cleaner with

the FV4 fan coil, use Airflow Sensor . The airflow sensor turns on electronic air cleaner when the fan coil blower is operating.

HUMIDIFIER / HUMIDISTAT CONNECTIONS

Easy Select Board terminals HUM1 and HUM2 are provided for direct connection to the low-voltage control of a humidifier through a standard

humidistat. These terminals are energized with 24vac when G thermostat signal is present. Alternately, the 24-vac signal may be sourced from the

W and C terminal block connections when electric heaters are used as primary heating source. When using a Thermidistat™ Control, Zone Perfect

Plus, or Comfort Zone II, the 24-vac signal may be source directly from the Thermidistat HUM terminal.

G. FK4, FV4, and 40FK Dehumidify Mode

NOTE: Humidistat must open on humidity rise.

Latent capacities for systems using the FK4, FV4, and 40FK fan coils are better than average systems. If increased latent capacity is an application

requirement, the field wiring terminal block provides connection terminals for use of a standard humidistat. The FK4, FV4, and 40FK fan coils

will detect the humidistat contacts opening on increasing humidity and reduce its airflow to approximately 80 percent of nominal cooling mode

airflow. This reduction will increase the system latent capacity until the humidity falls to a level which causes the humidistat to close its contacts.

When the contacts close, airflow will return to 100 percent of the selected cooling airflow. To activate this mode, remove jumper J1 and wire in

a standard humidistat. (See Fig. 15.) Carefully consult product airflow data for cooling and dehumidification modes.

FE4

Model FE4A fan coil is designed to be installed with a communicating user interface. The FE4A fan coil will provide airflow at a rate commanded

by the User Interface. The nominal airflow/ton rate is 350 CFM/ton. The User Interface will modify the commanded airflow under certain operating

modes. Refer to the User Interface literature for further system control details. This fan coil will not respond to commands from a common

thermostat except under certain emergency situations explained in this document.

PROCEDURE 1—ELECTRONICALLY COMPUTED MOTOR (ECM2.5)

An ECM2.5 is fed high voltage AC power through the 5-pin connector. The AC power is then internally rectified to DC by a diode module. After

rectification, DC signal is electronically communicated and fed in sequential order to 3 stator windings. The frequency of these communication

pulses determines motor speed. The rotor is permanently magnetized.

Table 8—FK4C Motor Control Test Values

(With 16-pin connector at motor unplugged)

Terminals Jumpered Volt Meter on 16 PIN

Harness Plug

Volt Meter on 12-pin

Easy Select Board Plug

Voltage

+-+ -

R to W1 Pin 2 Pin 1 Pin 7 Pin 9 24vac

R to W2 Pin 13 Pin 1 Pin 4 Pin 9 24vac

R to Y1 Pin 6 Pin 1 Pin 3 Pin 9 (-)12vdc

R to Y/Y2 Pin 14 Pin 1 Pin 2 Pin 9 (-)12vdc

R to G (LO) Pin 15 Pin 1 Pin 3 Pin 9 Ovac

R to G (MED) Pin 6 Pin 1 Pin 3 Pin 9 (-)12vdc

R to G (HI) Pin 14 Pin 1 Pin 2 Pin 9 (-)12vdc

Fig. 14—KFAIR0201ACR Relay Kit

Wiring Schematic

A98625

24 VAC RELAY

FAN COIL

230 VAC OR

115 VAC BRANCH CKT

AUX1

(C)

AUX2

(G)

GND HOT NEUT

GRN

BLK

WHT

COM

BLK

RED

WHT

TO EAC

—20—

ECM2.5 CONTROL POWER

The ECM2.5 control power is supplied from R circuit through printed circuit runs to motor control connector Plug 1, pin 1, through motor control

harness to motor. The C side of low-voltage control power circuit is connected by printed circuit runs to motor connector Plug1, pin 2 then through

motor control harness to motor. A digital signal is sent from Plug 1, pins3 and 4 to communicate with the motor including all airflow requirements.

LOW-VOLTAGE CIRCUIT FUSING AND REFERENCE

The low-voltage circuit is fused by a board-mounted 5-amp automotive type fuse placed in series with transformer SEC2 and R circuit. The C

circuit of transformer is referenced to chassis ground through a printed circuit run at SEC1 connected to metal standoff.

NOTE: The PCB must be mounted with 2 screws and motor ground lead secured to blower housing or erratic motor operation can result.

TRANSFORMER, MOTOR, AND ELECTRIC HEATER POWER CONNECTION

Transformer high voltage supplied from electric heater package or high voltage leads through 12-pin heater connector plug/recp2. The ECM2.5

power connections are made at the transformer primary terminals. The transformer secondary connections are made at SEC1 and SEC2 connectors.

PROCEDURE 2—TROUBLESHOOTING (FE4)

NOTE: Always check high and low voltage supply to the fan coil components. Check the integrity of the plug receptacle connections and fan

coil wiring harness prior to assuming a component failure.

A. LED Description:

LEDs built into fan coil control provide installer or service person information concerning operation and/or fault condition of the fan coil control

and ECM motor. This information is also available at system User Interface in text with basic troubleshooting instructions. Careful use of

information displayed will reduce the need for extensive manual troubleshooting.

The amber LED located at bottom center of control adjacent to motor harness plug is Motor Status LED and it is labeled MOTOR. A second amber

LED located in upper right center of control adjacent to System Communications connector (A,B,C,D) is the System Status LED and it is labeled

STATUS. The green LED labeled COMM is also located adjacent to System Communications connector, below STATUS LED, and is used as

an indicator of system communications status. Status Codes will be displayed on the STATUS LED using the following protocol:

1. The number of short flashes indicates first digit of code.

2. The number of long flashes indicates second digit of code.

3. A short flash is 0.25 seconds on. A long flash is 1 second on.

4. The time between flashes is 0.25 seconds.

5. The time between last short flash and first long flash is 1 second.

6. The LED will be off for 2.5 seconds before repeating code.

B. Fan Coil Control Start-Up and System Communications Troubleshooting:

On power up, green COMM LED will be turned off until successful system communications are established (this should happen within 10

seconds). Once communications with User Interface are successful, COMM LED will be lit and held on. At the same time, amber STATUS LED

will be lit and held continuously on until a request for operating mode is received. The STATUS LED will be on any time fan coil is in idle mode.

If, at any time, communications are not successful for a period exceeding 2 minutes, fan coil control will only allow emergency heating or cooling

operation using a common thermostat, a non-communicating outdoor unit and the R, C, Y, O, W outdoor unit terminal strip connections and will

display Status Code 16, System Communication Fault, on amber STATUS LED. No further fan coil troubleshooting information will be

available at User Interface until communications are re-established.

If COMM LED does not light within proper time period and status code is not displayed,

1. Check system transformer high and low voltage to be sure the system is powered.

2. Check fuse on fan coil control to be sure it is not blown. If fuse is open, check system wiring before replacing it to be sure a short does

not cause a failure of replacement fuse.

If COMM LED does not light within proper time period and status code is displayed,

1. Check system wiring to be sure User Interface is powered and connections are made A to A, B to B, etc. and wiring is not shorted.

Mis-wiring or shorting of the ABCD communications wiring will not allow successful communications.

NOTE: Shorting or mis-wiring low voltage system wiring will not cause damage to fan coil control or User Interface but may cause low voltage

fuse to open.

Fig. 15—Humidistat Wiring for De-Humidify Mode

A95316

EASY SELECT

BOARD TERMINAL

BLOCK

HUMIDISTAT

REMOVE

JUMPER

—21—

C. ECM Motor Troubleshooting

The ECM motor used in this product consists of two parts: the control module and the motor winding section. Do not assume motor or module

is defective if it will not start. Use the designed-in LED information aids and follow troubleshooting steps described below before replacing motor

control module or entire motor. Motor control module is available as a replacement part.

VERIFY MOTOR WINDING SECTION:

WARNING:

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury or possible equipment damage.

After disconnecting power from the ECM motor, wait at least 5 minutes before removing the control section. Internal capacitors require

time to discharge. Minor injury from electrical shock may result from early contact with live metal parts.

Before proceeding to replace a motor control module:

1. Check motor winding section to be sure it is functional.

2. Remove motor control module section and unplug winding plug. Motor shaft should turn freely, resistance between any two motor leads

should be similar and resistance between any motor lead and unpainted motor end should exceed 100,000 ohms.

3. Failing any of these tests, entire ECM motor must be replaced.

4. Passing all of the tests, motor control module alone can be replaced.

MOTOR TURNS SLOWLY:

1. Low static pressure loading of blower while access panel is removed will cause blower to run slowly. Particularly at low airflow requests.

This is normal, do not assume a fault exists.

2. Recheck airflow and system static pressure using User Interface service screens with access panel in place.

NOTE: Blower motor faults will not cause a lockout of blower operation. Fan coil control will attempt to run the blower motor as long as User

Interface maintains a demand for airflow. Fan coil control will not operate electric heaters while a fault condition exists. The fan coil control

communicates with the motor at least once every 5 seconds, even when the motor is idle. If, during operation, the fan coil control does not

communicate with the motor for more than 25 seconds, the motor will shut itself down and wait for communications to be reestablished.

D. Using Motor LED in Troubleshooting

The MOTOR LED is connected to the blower motor communication line and works with the fan coil control microprocessor and the STATUS

LED to provide fan coil operation and troubleshooting information. When the motor is commanded to operate, the MOTOR LED will be turned

on and will flash each time instructions are sent to the motor. When the motor is commanded to stop, the MOTOR LED will be turned off.

If the MOTOR LED is lit, flashing and the motor is running or if the MOTOR LED is off and the motor is stopped, operation is normal and no

motor fault exists.

If the MOTOR LED is lit, flashing and the motor does not run, or if the MOTOR LED is off and the motor is running, check the STATUS LED

for the Status Code. Refer to the troubleshooting instructions for the indicated Status Code in Section E, Fan Coil Troubleshooting.

E. Fan Coil Troubleshooting

Fan coil faults indicated by flashing codes on the amber system STATUS LED can be resolved using troubleshooting information provided below.

Codes are listed in order of their priority, highest to lowest. Though multiple faults can exist at any time, only the highest priority code will be

displayed on STATUS LED. Clearing the indicated fault when multiple faults exist will cause the next highest priority Status Code to be flashed.

All existing faults, as well as a fault history, can be viewed at User Interface.

Fig. 16—FE4A ECM2.5 Motor

A98201

12345

12345678

10 11 12 13 14 15 16

POWER CONNECTOR

CONTROL CONNECTOR

OPTIONAL SAFETY GROUND

DRAIN HOLE

OPTIONAL SAFETY GROUND

ENDSHIELD

DRAIN HOLE

CONTROL

POWER

—22—

STATUS CODE 45, CONTROL BOARD TEST FAULT:

Fan coil control has failed internal start-up tests and must be replaced. No other service procedure will correct.

STATUS CODE 37, HEATER OUTPUT SENSED ″ON″ WHEN NOT ENERGIZED:

Fan coil control is provided with circuitry to detect presence of a 24 vac signal on Electric Heater stage 1 and stage 2 outputs.

If fan coil control detects a 24 vac signal on either heater stage output and it is not supplying signal, Status Code 37 will be displayed on STATUS

LED. Fan coil control will turn off output and command blower motor to supply an airflow determined to be safe for current operation mode with

electric heaters energized.

To find the fault:

1. Stop all system operations at User Interface and check heater stage 24 vac outputs.

2. Disconnect electric heater at plug/receptacle 2 and check heater wiring for faults. See Status Code 36 for more information.

STATUS CODE 44, MOTOR COMMUNICATION FAULT:

The MOTOR LED is connected to the blower motor communication line and works with the fan coil control microprocessor and STATUS LED

to provide fan coil operation and troubleshooting information.

When motor is commanded to operate, the MOTOR LED will be turned on and will flash each time instructions are sent to the motor.

When the motor is commanded to stop, the MOTOR LED will be turned off. The MOTOR LED will not flash to indicate communications when

it is turned off.

Fan coil control is constantly communicating with the motor, even when the motor and MOTOR LED are off. If motor does not acknowledge

receipt of communications, the control will display Status Code 44 on STATUS LED and continue to try to communicate with the motor. If motor

acknowledges communication, status code will be cleared.

If MOTOR LED is lit and flashing and motor does not run:

1. Check the STATUS LED. If STATUS LED is indicating a Status 44 code, check the motor wiring harness for proper connection to control

and motor receptacles.

2. Check motor wiring harness to be sure all wiring complies with wiring diagram description, makes a complete circuit from connector to

connector and is not shorted.

3. Check 12 Vdc low voltage supply to motor at pins 1 (+) and 2 (-) of motor header connection to fan coil control. See wiring diagram Fig.

17.

If all checks are normal, fan coil control is good and control module on motor may need replacement. Check motor and Motor Control Module

following the instructions in Section C. ECM Motor Troubleshooting.

Shorted or mis-wiring of the low voltage motor harness wiring will not cause damage to fan coil control or to motor control module.

If the MOTOR LED is off, STATUS LED is indicating a Status Code 44 and motor is running:

1. Disconnect the motor harness at the fan coil control. If motor continues to run, fan coil control is good and control module on motor may

need replacement

STATUS CODE 25, INVALID MOTOR / MODEL SELECTION:

On initial start-up, fan coil control shall poll motor for its size data and check fan coil size data stored in fan coil control memory.

1. If motor size is incorrect for fan coil size or fan coil size data is invalid, Status Code 25 will be displayed on STATUS LED.

2. If model size data is missing (as is the case when a replacement fan coil control is installed), system User Interface will prompt installer

to enter correct model size from a list of valid sizes.

3. If motor size is incorrect for model size, motor must be replaced with proper size motor. Fan coil control will not respond to operation

requests until this fault condition is resolved.

STATUS CODE 27, INVALID OUTDOOR UNIT SIZE:

On initial power-up, fan coil control will write into memory outdoor unit size as provided by User Interface in a fully communicating system.

1. If outdoor unit size is invalid, Status Code 27 will be displayed on STATUS LED.

2. User Interface will prompt the installer to choose size from a list of valid sizes for application with fan coil.

3. Check communications wiring to be sure User Interface has established communications with outdoor unit or select proper size from valid

size list provided at User Interface.

4. Check motor and motor control module following the instructions in Section C. ECM Motor Troubleshooting.

STATUS CODE 26, INVALID HEATER SIZE:

On initial power-up, fan coil control will write into memory electric heater size as read from heater if heater is provided with Identifier Resistor

(IDR). Heater size must be valid for combination of indoor and outdoor components installed. Fan coil control will read IDR value connected to

pins 5 and 8 of heater harness connector. If no resistor is found, system User Interface will prompt installer to verify that no heater is installed.

Verifying that this is correct will establish that fan coil is operating without an electric heater accessory. Upon choosing negative option, installer

will be prompted to select heater size installed from a list of valid heater sizes for fan coil and outdoor unit size installed.

If heater ID resistor value read is invalid, Status Code 26 will be displayed on STATUS LED.

If heater installed is equipped with a resistor connected to pins 5 and 8 of heater harness connector and status code 26 is displayed on STATUS

LED,

1. Check wiring harness connections to be sure connections are secure.

—23—

2. If symptoms persist, disconnect wiring harness at fan coil control heater header and check for a resistance value greater than 5000 ohms.

3. Check for proper wiring of resistor assembly.

4. Make sure heater size installed is an approved size for outdoor unit and fan coil sizes installed.

NOTE: Fan coil control will not operate electric heater until this Status Code is resolved. If the heater size is set through the User Interface, the

heater will be operated as a single stage heater. If staging is desired, the IDR value must be read in by the fan coil control.

STATUS CODE 36, HEATER OUTPUT NOT SENSED WHEN ENERGIZED:

Fan coil control is provided with circuitry to detect presence of a 24 vac signal on Electric Heater stage 1 and stage 2 outputs.

If fan coil control energizes either heater stage and does not detect the 24 vac signal on output, Status Code 36 will be displayed on the STATUS

LED Fan coil control will continue to energize heater output(s) and adjust blower operation to a safe airflow level for energized electric heat

stage(s).

To find the fault,

1. Check for 24 vac on heater stage outputs. Fan coil control or sensing circuit may be bad.

NOTE: It may be useful as an electric heater troubleshooting procedure to disconnect the system communications to force Status Code 16

enabling of emergency heat mode. It is difficult to know which heater output is energized or not energized in normal operation. When fan coil

is operated in emergency heat mode using electric heaters, both outputs are energized and de-engergized together. Terminal strip inputs to control

can then be connected R to W to turn on both electric heat outputs. Heater output sensing circuits can then be checked to resolve Status Code 36

or 37 problems.

STATUS CODE 41, BLOWER MOTOR FAULT:

If MOTOR LED is lit and flashing and motor does not run:

1. Check STATUS LED. If STATUS LED is indicating Status Code 41, motor control has detected that the motor will not come up to speed

within 30 seconds of being commanded to run or that the motor has been slowed to below 250 rpm for more than 10 seconds after coming

up to speed. Motor wiring harness and fan coil control are operating properly, do not replace.

2. Check to be sure that the blower wheel is not rubbing the housing.

Fig. 17 - Typical FE4 Wiring Diagram

A04159

—24—

3. Check motor to be sure that the motor shaft is not seized (motor control module must be removed and electronics disconnected from

windings to perform this check properly).

4. Check motor windings section following instructions in Section C. ECM Motor Troubleshooting.

If all these checks are normal, the motor control module may need replacement.

STATUS CODE 16, SYSTEM COMMUNICATION FAULT:

If, at any time, system communications are not successful for a period exceeding 2 minutes, the fan coil control will only allow emergency heating

or cooling operation using a common thermostat, a non-communicating outdoor unit, and the R, C, Y, O, W outdoor unit terminal strip connections

and will display Status code 16 on the amber STATUS LED (see section E, Emergency Heating and Cooling Modes). No further fan coil

troubleshooting information will be available at the User Interface until communications are reestablished.

Check system wiring to be sure the User Interface is powered and connections are made A to A, B to B, etc. and wiring is not shorted. Mis-wiring

or shorting of the ABCD communications wiring will not allow successful communications. Correcting wiring faults will clear the code and

reestablish communications.

Shorting or mis-wiring the low voltage system wiring will not cause damage to fan coil control or to User Interface but may cause the low voltage

fuse to open.

STATUS CODE 46, BROWNOUT CONDITION:

If the secondary voltage of the transformer falls below 15 vac for a period exceeding 4 seconds, Status Code 46 will be displayed on STATUS

LED. If system includes a non-communicating outdoor air conditioner or heat pump, the User Interface will command the fan coil to turn off Y

output controlling compressor.

When secondary voltage rises above 17 vac for more than 4 seconds, the brownout condition is cleared and normal system operation will resume

subject to any minimum compressor off delay function which may be in effect. Brownout does not affect blower or electric heater operation.

STATUS CODE 53, OUTDOOR AIR TEMPERATURE SENSOR FAULT:

If an OAT sensor is found at power-up, input is constantly checked to be within a valid temperature range. If sensor is found to be open or shorted

at any time after initial validation, Status Code 53 will be displayed at amber STATUS LED.

Check for faults in wiring connecting sensor to OAT terminals. Using an Ohmmeter, check resistance of thermistor for a short or open condition.

If thermistor is shorted or open, replace it to return the system to normal operation. If fault is in the wiring connections, correcting the fault will

clear the code and return the system to normal operation.

NOTE: If fault condition is an open thermistor or a wiring problem that appears to be an open thermistor and the power to the fan coil control

is cycled off, the fault code will be cleared on the next power-up but the fault will remain and system operation will not be as expected. This is

because on power-up, the fan coil control cannot discern the difference between an open sensor or if a sensor is not installed.

F. Emergency Heating and Cooling Modes

Fan coil control can provide emergency heating or cooling using a common heat/cool thermostat in the event that there are no system

communications, fault is in User Interface and no replacement is immediately available.

To activate these modes, the thermostat and outdoor unit must be wired as a common heating/cooling system to fan coil control RYWC terminals

. Fan coil control must be powered and displaying Status Code 16, System Communication Fault.

NOTE: These emergency modes do not provide the level of comfort and efficiency expected by the consumer and should only be activated when

User Interface cannot be replaced immediately.

PROCEDURE 3—FE4A FAN COIL SEQUENCE OF OPERATION

The FE4A fan coil is designed for installation with a communicating User Interface. This fan coil will not respond to commands provided by a

common thermostat except under certain emergency situations described in Procedure 9 — Start Up and Troubleshooting.

The User Interface uses temperature; humidity and other data supplied from indoor and outdoor system components to control heating or cooling

system for optimum comfort. The fan coil will be commanded by User Interface to supply airflow and, in the case of a non-communicating outdoor

unit, Air Conditioner or Heat Pump control. The fan coil will operate blower at requested airflow for most modes.

The nominal requested airflow will be 350 cfm per ton of nominal cooling capacity as defined by outdoor unit size. Actual airflow request will

be adjusted from nominal using indoor and outdoor temperature and indoor humidity data to optimize the system operation for occupant comfort

and system efficiency. Refer to User Interface literature for further system control details.

FE4 ADVANCED TROUBLESHOOTING:

Further diagnostics can be done by following the flow chart shown in Fig. 18. Voltages can be measured at the communication bus with the

voltages show in Table 9.

CARE AND MAINTENANCE

To continue high performance, and minimize possible equipment failure, it is essential periodic maintenance be performed on this equipment.

The ability to properly perform maintenance on this equipment requires certain mechanical skills and tools. The only consumer service

recommended or required is filter maintenance. (See Filter Assembly.)

WARNING: ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury or death.

Disconnect all power to the unit before servicing the field wires or removing the control package. The disconnect (when used) on the

access panel does not disconnect power to the line side of the disconnect, but does allow safe service to all other parts of the unit.

The minimum maintenance requirements for this equipment are as follows:

1. Inspect and clean or replace air filter each month or as required.

—25—

2. Inspect cooling coil, drain pan, and condensate drain each cooling season for cleanliness. Clean as necessary. An inspection port is provided

on all A-coil delta plates. Remove plastic plug to inspect. Replace plug after inspection.

3. Inspect blower motor and wheel for cleanliness each heating and cooling season. Clean as necessary.

4. Inspect electrical connections for tightness and controls for proper operation each heating and cooling season. Service as necessary.

CAUTION: CUT HAZARD

Failure to follow this caution could result in personal injury.

As with any mechanical equipment, personal injury can result from sharp metal edges. Be careful when removing parts.

PROCEDURE 1—FILTER ASSEMBLY

To clean or replace air filter, push plastic connectors toward center of unit and remove filter access panel outward. Push filter up and back into

unit. Then slide filter out. Clean filter by using cold water and mild detergent. Rinse and allow filter to dry. No oiling or coating of filter is required.

New filters are available from your local distributor. Place filter in slot with cross-mesh binding up or facing cooling coil and replace filter access

panel.

PROCEDURE 2—COOLING COIL, DRAIN PAN, AND CONDENSATE DRAIN

The cooling coil is easily cleaned when it is dry. Inspect the coil and clean (if necessary) before each cooling season. To check or clean cooling

coil, remove coil access panel. If coil is coated with dirt or lint, vacuum it with a soft brush attachment.

Be careful not to bend coil fins. If coil is coated with oil or grease, clean it with a mild detergent and water solution. Rinse coil thoroughly with

clear water. Be careful not to splash water on insulation.

Inspect drain pan and condensate drain at the same time cooling coil is checked. Clean drain pan and condensate drain by removing any foreign

matter from pan. Flush pan and drain tube with clear water.

If drain tube is restricted, it can generally be cleared by high-pressure water. Cut plastic line and work outside condensate pan and away from coil

to clean drain tube.

CAUTION: UNIT DAMAGE HAZARD

Failure to follow this caution could result in equipment damage.

Do not use caustic household drain cleaners in the condensate pan or near the coil. Drain cleaners can quickly destroy a coil.

PROCEDURE 3—BLOWER MOTOR AND WHEEL

Clean blower motor and wheel when cooling coil is cleaned.

WARNING: ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury or death.

Disconnect electrical power before removing any access panels.

To clean blower motor or blower wheel:

1. Remove blower access panel.

2. Remove motor leads from PCB. Note lead location for ease of reassembly.

3. Remove 2 outside screws holding blower/motor assembly against blower deck flange and slide assembly out of cabinet.

4. Remove screw in strap holding motor capacitor to blower housing and slide capacitor out from under strap. Remove screw with green wire

from blower housing. Mark blower wheel, motor, and motor support in relation to blower housing before disassembly to ensure proper

reassembly. Note position of blades on wheel.

5. Loosen setscrew holding blower wheel onto motor shaft.

6. Remove 3 bolts holding motor mount to blower housing and slide motor and mount out of housing. Further disassembly should not be

necessary as adequate clearance is available.

7. Remove blower wheel from housing by removing cutoff plate from blower housing outlet. Note wheel orientation and cutoff location for

reassembly. The blower motor and wheel may be cleaned by using a vacuum with a soft brush attachment.

8. Remove grease with a mild solvent such as hot water and detergent. Be careful not to disturb balance weights (clips) on blower-wheel vanes.

Also, do not drop or bend wheel, as balance will be affected.

Table 9—Advanced Troubleshooting

Fan Coil / Furnace / 2-Spd. Communication Bus

Voltage Readings

With board power applied and no U.I. connected

A to B ~3 vdc

A to C ~3 vdc

B to C ~.01 to 0.3 vdc

C to D 24 vac

FE Control Board HK38EA002

Furnace Control Board HK42FZ022

Two-Speed Control Board HK38EA001

—26—

To reassemble blower:

1. Place blower wheel back into housing. Be sure to position correctly for proper location.

2. Reassemble cutoff plate to housing using identified holes from disassembly procedure.

3. Position motor and mount in same position as when blower housing was in unit. Secure motor mount on housing, using removed bolts. Make

sure mount or motor is grounded to blower housing.

4. Locate blower wheel setscrew over flat on motor shaft. Rotate wheel in housing. It should not rub housing and should be centered in inlet

opening. If not, loosen setscrew and align as necessary.

5. Attach green wire to blower housing with screw.

6. Secure motor capacitor under strap and tighten strap screw.

CAN NOT FIND INDOOR UNIT

Disconnect O.D. unit

and all other deviices

on ABCD bus except

indor unit and UI

Cycle system power.

Indoor

unit

found?

Connect UI to indoor unit

at the indoor unit.

Indoor

unit

found?

Tr y

another

UI?

Measure voltage on ABC

terminals at indoor unit

(see Table-1) Possible indoor

unit problem.

Check wiring to UI

mounting location.

YES

Reconnect one

device at a time to

ABCD bus.

Device

found?

YES

Check device

wiring.

Wiring

OK?

YES

Measure

voltage on

ABC terminals

at device (see

Table-1)

Possible

device

problem.

Correct

wiring and

reinstall

system.

Fig. 18 - FE4 Advanced Troubleshooting Flow Chart

A04160

—27—

7. Slide blower assembly to blower deck. Be sure (once blower is within the unit casing) to force blower assembly toward control box while

sliding assembly into unit to ensure that blower assembly engages deck properly.

8. Fasten blower assembly to deck with screws previously removed.

9. Reconnect electrical leads to PCB.

10. Reconnect electrical power to unit and test fan for proper rotation.

FF1A/FF1B/FF1C SERVICE AND TROUBLESHOOTING

NOTE: For FF1D Service and Troubleshooting refer to FA4A, FB4A, FF1D, FH4A, AND FX4A Circuit Board Function and Troubleshooting

on page 2. (For FF1D typical wiring diagram, see Fig. 19.)

WARNING:

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury or death.

Before installation or servicing system, always turn off main power to system. There may be more than 1 disconnect switch. Turn off

accessory heater power if applicable.

PROCEDURE 1—FAN MOTOR

The motor is 2-speed direct drive. High-speed lead is black, low-speed lead is red, and common lead is violet. Be sure proper blower speed has

been selected. For units with electrical heat, low-speed tap can be used. For cooling, use high-speed tap.

The motor is turned on through 2 different routes. The first occurs when thermostat calls for the fan in cooling, heat pump, or fan-only mode. A

24-vac signal is sent to relay, causing relay to close its normally open contacts, turning fan on. The second occurs when there is a call for electric

heat. A 24-vac signal is sent to heater sequencer/relay, causing it to close, directing 230v through the normally closed contact of fan relay, turning

fan on. The fan remains on until sequencer/relay opens. Refer to FF1A/FF1B/FF1C typical wiring diagram. (See Fig. 21.)

If motor does run, test motor for an open winding or a winding shorted to motor case. If any 1 of the 2 is present, replace motor.

PROCEDURE 2—ELECTRIC HEATER SERVICE

Service can be completed with heater in place. Shut off power before servicing.

A. Limit Switch

Refer to Electric Heater Function and Troubleshooting section of this manual.

Fig. 19—FF1D Typical Wiring Diagram

A98229

SEE NOTE #7

SPT

OUTDOOR

UNIT

PCB

BLK

INDOOR

THERMOSTAT

BARRIER

NOTES:

SEE RATING PLATE FOR VOLTS & HERTZ

DISCONNECT PER NEC

FIELD POWER WIRING

COOLING CONTROLS

ELECTRIC HEAT

230V

208V

BRN

RED

TRAN

COM

GRN/YEL

GND

YEL

COM

RED

YEL

BLK

BRN

CAP

RELAY 1

22 VDC COIL

R E C

SCHEMATIC DIAGRAM

COMPONENT ARRANGEMENT

CAUTION:

ATTENTION:

NOT SUITABLE FOR USE ON SYSTEMS EXCEEDING 150V TO GROUND

NE CONVIENT PAS AUX INSTALLATIONS DE PLUS DE 150 V A LA TERRE

COM

208 V

230 V

TRAN

RED

24 V

BRN

GND

SPT

PCB

L2 L1

DISC

60A 60A

RED-LOW

BLK-HI

GRN/YEL-GND

BRN

YEL-COM

FAN MOTOR THERMALLY PROTECTED

CAP

GND

SEE NOTE #5

LEGEND

RED

ORN

VIO

GND

HTR2

BLK

LS2

HTR1

BLK

LS1

RELAY 1

YEL

BLK

SEE NOTE #1

BLK

SYSTEM TRANSFORMER: 40.0VA

FAN COIL/HEATER: 8.4VA

REMAINING VA AVAILABLE: 31.6VA

REC

RELAY 1

CAP

CAPACITOR

COM

COMMON

FUSE

FAN MOTOR

FIELD POWER WIRING

PCB FAN RELAY

EQUIPMENT GROUND

GND

SPT

FAN SPEED TAP LOCATION

HTR

HEATER

LIMIT SWITCH

MARKED TERMINAL

PLUG AND RECEPTACLE

PCB

PRINTED CIRCUIT BOARD

REC

RECTIFIER

TRAN

TRANSFORMER

UNMARKED TERMINAL

RWG

324494-101 REV. A

1. Use copper wire (75¡c min) only between disconnect switch and unit.

2. To be wired in accordance with nec and local codes.

3. If any of the original wire, as supplied, must be replaced, use the same or

equivalent type wire.

4. Replace low voltage fuse with no greater than 5 AMP fuse.

5. (2) Speed Motor uses HI (BLK) and LOW (RED).

6. Smaller heaters will have fewer components.

7. Connect R to R, G to G, etc., see outdoor instructions for details.

8. Cooling controls wiring not used with electric heaters.

HTR

DISC

DISCONNECT

YEL

BLU

BLK

BRN

RED

GRY

ORN

YEL

BLK

DISC

BLU

BLK

DISC

YEL

DISC

VIO

BLK

SEE NOTE #8

YEL

SEE NOTE #6

MINIMUM MOTOR SPEED SELECTION

FAN COIL SIZE

MOTOR SPEED ONE HTR

MOTOR SPEED TWO HTR

LO LO

018 024 030

ROTATION

This compartment must be closed except

when servicing.

—28—

B. Sequencer

Refer to Electric Heater Function and Troubleshooting section of this manual.

C. Transformer

A 40-VA transformer supplies 24-v power for control circuit. Check for 208/230v on primary side of transformer. If present, check for 24v on

secondary side.

NOTE: Transformer is fused. Do not short circuit.

D. Fan Relay

Relay coil is 24 volts. Check for proper control voltage. Replace relay if faulty.

PROCEDURE 3—CLEANING OR REPLACING REFRIGERANT FLOW-CONTROL DEVICE

Refer to Fig. 27 and instructions given in Piston Body Cleaning or Replacement section above.

PROCEDURE 4—LIQUID TUBE STRAINER

The refrigerant flow-control device is protected by a wire mesh strainer. It is located inside the 3/8-in. liquid tube at field braze joint next to

flow-control device. Access to strainer is through field braze joint.

PROCEDURE 5—SEQUENCE OF OPERATION

Refer to Fig. 21.

A. Condensing Unit

COOLING

When thermostat calls for cooling, the circuit between R and G is complete and single-pole single-throw relay FR is energized. The normally open

contacts close causing blower to operate. The circuit between R and Y is also complete. This completed circuit causes contactor in outdoor unit

to close which starts compressor and outdoor fan.

HEATING

When thermostat calls for heating and FAN switch is set on AUTO, the circuit between R and W is complete. The heater sequence SEQ is

energized which closes contacts of relay. There will be a time delay. This completed circuit energizes all heating elements HTR and blower motor.

B. Heat Pump

COOLING

On a call for cooling, the thermostat makes circuits R-O, R-Y, and R-G. Circuit R-O energizes reversing valve, switching it to cooling position.

Circuit R-Y energizes contactor starting outdoor fan motor and compressor. Circuit R-G energizes indoor unit blower relay starting indoor blower

motor. When thermostat is satisfied, its contacts open de-energizing contactor reversing valve and blower relay. This stops compressor and fan

motors.

HEATING

On a call for heating, the thermostat makes circuits R-Y and R-G. Circuit R-Y energizes contactor starting outdoor fan motor and compressor.

Circuit R-G energizes indoor blower relay starting blower motor. Should temperature continue to fall, R-W circuit is made through second-stage

room thermostat bulb. Circuit R-W energizes a sequencer bringing on supplemental electric heat. When thermostat is satisfied, its contacts open

de-energizing contactor and sequencer. All heaters and motors should stop.

PROCEDURE 6—CARE AND MAINTENANCE

The minimum maintenance requirements for this equipment are as follows:

1. Inspect and clean or replace air filter each month or as required.

2. Inspect cooling coil, drain pan, and condensate drain each cooling season for cleanliness. Clean as necessary.

Fig. 20—Electric Heater Control Boxes

A98184

312753

T-O-D 60TX11

HH19ZA945

C9725

L145-55F

312753

T-O-D 60TX11

HH19ZA945

C9725

L145-55F

SPT

FAN

RELAY

PULL TO OPEN

WARNING

ELECTRIC SHOCK

HAZARD

DISCONNECT

REMOTE POWER

SUPPLY BEFORE

OPENING PANEL.

322861-101 REV. A

PULL TO OPEN

WARNING

ELECTRIC SHOCK

HAZARD

DISCONNECT

REMOTE POWER

SUPPLY BEFORE

OPENING PANEL.

322861-101 REV. A

312753

T-O-D 60TX11

HH19ZA945

C9701

L145-55F

312753

T-O-D 60TX11

HH19ZA945

C9701

L145-55F

FF1D CONTROL BOX

FF1A/FF1B/FF1C CONTROL BOX

—29—

Fig. 21—FF1A/FF1B/FF1C Typical Unit Wiring Label

A91140

LS1

COMPONENT ARRANGEMENT

2 4 5

1 3 6

3 2

1 4

SEQ

LS1 LS2

HTR1 HTR2

WHEN EQUIPPED

CHASSIS

GROUND

DISCONNECT

BLK

COM

208

BLU

230

RED

24VTRANS

UNIT WIRED FOR 230V OPERATION USING

BLACK AND RED TRANSFORMER PRIMARY

LEADS. FOR 208V OPERATION, USE BLACK

AND BLUE TRANSFORMER PRIMARY LEADS.

UNUSED TRANSFORMER LEADS MUST BE TAPED

AND LOOPED.

IF ANY OF THE ORIGINAL WIRE, AS

SUPPLIED, MUST BE REPLACED, USE THE

SAME OR EQUIVALENT WIRE.

FIELD WIRING, USE COPPER CONDUCTORS,

ONLY.

FAN RELAY #4 IS A DEAD TERMINAL FOR

UNUSED MOTOR LEAD STORAGE. TO CHANGE

MOTOR SPEEDS, EXCHANGE THE BLACK AND

RED MOTOR LEADS ON THE FAN RELAY.

MOTOR SPEED SELECTION

HI = BLACK LOW = RED COMMON = VIO

FIELD WIRE

HEAT PKG.

2 KW

3 KW

5 KW

7.5 KW

11 KW

0 (COOLING)

SIZE

TEMP.

RATING

90°C

NOTES

316596 - 401 REV. B

BLK

SEQ

IFR/TD

SCHEMATIC DIAGRAM FOR 2, 3, & 5 KW HEATERS

BLK

IFR (TDR OPTIONAL) MOTOR

BLK BRN

CAP

BRN

RED

BLK

HTR

YEL

VIO

BLK

RED BLU

TRANS

DISCONNECT

SEE RATING PLATE

FOR VOLTS & HZ

FIELD

POWER

SUPPLY

CHASSIS

GROUND

RED

VIO

ORN

BRN

CHASSIS

GROUND

RED

ORN

AP2

BRN

SEQ

CHASSIS

GROUND

VIO

OPTIONAL IFR/TDR

BRN

TRANS

BRN

VIO

BLK

IFR/TD

SCHEMATIC DIAGRAM FOR COOLING CONTROL

BLK

IFR (TDR OPTIONAL) MOTOR

BLK BRN

CAP

BRN

RED

VIO

BLK

RED BLU

TRANS

DISCONNECT

SEE RATING PLATE

FOR VOLTS & HZ

FIELD

POWER

SUPPLY

CHASSIS

GROUND

RED

ORN

BRN BRN

CHASSIS

GROUND

RED

ORN

AP2

BRN

CHASSIS

GROUND

OPTIONAL IFR/TDR

BRN

TRANS

RED

BLK

SEQ

IFR/TD

SCHEMATIC DIAGRAM FOR 7.5 & 11 KW HEATERS

BLK

IFR (TDR OPTIONAL) MOTOR

BLK BRN

CAP

BRN

RED

BLK

HTR2

LS2

YEL

VIO

BLK

RED BLU

TRANS

DISCONNECT

SEE RATING PLATE

FOR VOLTS & HZ

FIELD

POWER

SUPPLY

CHASSIS

GROUND

RED

VIO

ORN

BRN

CHASSIS

GROUND

RED

ORN

AP2

BRN

SEQ

CHASSIS

GROUND

VIO

OPTIONAL IFR/TDR

BRN

TRANS

BRN

VIO

SEQ

BLK

HTR1

YEL

MARKED TERMINAL

UNMARKED TERMINAL

LIMIT SWITCH

FAN RELAY

INDOOR FAN RELAY

INDOOR FAN RELAY/TIME DELAY

SEQUENCER

CAPACITOR

HEATER

TRANSFORMER

FIELD POWER WIRING

OPTIONAL WIRING

FUSE

CHASSIS GROUND

LEGEND

IFR

IFR/TD

SEQ

CAP

HTR

TRANS

SEQ

BLK

—30—

3. Inspect blower motor and wheel for cleanliness each heating and cooling season. Clean as necessary.

4. Inspect electrical connections for tightness and controls for proper operation each heating and cooling season. Service as necessary.

WARNING: CUT HAZARD

Failure to follow this warning could result in personal injury.

As with any mechanical equipment, personal injury can result from sharp metal edges. Be careful when removing parts.

A. Air Filter

To clean or replace air filter, grasp it at bottom and lift it out of unit. Clean filter using cold water. Rinse clean and let dry. Oiling or coating of

filter is not required. To replace, stand filter in rack with binding facing coil. Press top edge under access panel.

NOTE: Steel rods in filter prevent it from being pulled into coil. Retain these rods and reinstall after cleaning or before replacement if new filter

is used.

CAUTION:

UNIT DAMAGE HAZARD

Failure to follow this caution could result in equipment damage.

Never operate unit without a filter.

B. Cooling Coil, Drain Pan, and Condensate Drain

The cooling coil is easily cleaned when it is dry. Inspect coil and clean (if necessary) before each cooling season. To check or clean cooling coil,

remove blower/heater access panel to gain full access to cooling coil. If coil is coated with dirt or lint, vacuum with a soft brush attachment.

Be careful not to bend coil fins. If coil is coated with oil or grease, clean it with a mild detergent and water solution. Rinse coil with clear water.

Be careful not to splash water onto insulation.

Inspect drain pan and condensate drain at same time cooling coil is checked. Clean drain pan and condensate drain by removing any foreign matter

from pan. Flush pan and drain tube with clear water.

If drain tube is restricted, it can generally be cleared by high-pressure water. Cut plastic line and work outside condensate pan and away from coil

to clear drain tube.

NOTE: There MUST be a trap in condensate line. Trap must be at least 3-in. deep, not higher than the bottom of unit condensate drain opening,

and pitched downward to an open drain or sump.

CAUTION:

UNIT DAMAGE HAZARD

Failure to follow this caution could result in equipment damage.

Do not use caustic household drain cleaners in condensate pan or near coil. Drain cleaners can quickly destroy coils.

C. Blower Motor and Wheel

Clean blower motor and wheel when cooling coil is cleaned.

To clean or service wheel or motor, proceed as follows:

1. Pull unit disconnect (when used) and remove blower access panel.

2. Disconnect motor electrical leads from control box and capacitor. Mark location of wires for reassembly.

3. Remove 3 bolts holding motor mount to blower housing while supporting motor shell with hand.

4. Pull motor inlet ring and blower wheel assembly out of blower housing.

5. With blower wheel, inlet ring, and motor mount still attached to motor, place motor on flat, horizontal surface, shaft up. Mark position of

wheel on motor shaft for reassembly.

6. Loosen blower wheel setscrew and remove blower wheel from motor shaft.

NOTE: Further disassembly of motor and mount is not necessary as adequate clearance is available to clean motor.

Table 10—PSC Fan Motor Speed Taps

Model Unit

Size

Number of

Speeds

High

Speed

Medium

Speed

Low

Speed

Common

FA4A 018-036 2 Black — Blue Yellow

FA4A 042-060 3 Black Blue Red Yellow

FB4A 018-070 3 Black Blue Red Yellow

FC4B 024-070 3 Black Blue Red Yellow

FD3A 018-030 2 Black — Red Yellow

FF1A/FF1B/FF1C/FF1D 018-030 2 Black — Red Violet**

FG3A 024, 036, 048, 060 1* — — — —

FH4A 001-004 3 Black Blue Red Yellow

FX4A 030-060 3 Black Blue Red Yellow

*Belt drive.

→**Yellow on FF1D

—31—

7. Clean blower motor and wheel using a vacuum with a soft brush attachment. Remove grease with a mild solvent such as hot water and

detergent. Be careful not to disturb balance weights (clips) on blower wheel vanes. Do not drop or bend wheel as balance will be affected.

To reassemble unit, proceed as follows:

1. Place motor with mount attached on flat, horizontal surface with shaft up.

2. Set inlet ring on top of motor mount grommets. Center inlet ring flush on all 3 grommets.

3. Slide blower wheel onto motor shaft with setscrew upward and aligned with shaft flat portion. Vertically position wheel along shaft to

position marked during disassembly.

NOTE: If previous shaft was not marked or if replacing previous motor, set blower wheel position by sliding blower wheel along motor shaft

to 1-1/8 in. above rubber grommets. (See Fig. 22.)

4. Hold blower wheel in place and carefully tighten setscrew.

5. Position motor and blower wheel assembly to blower housing as originally oriented.

6. Secure motor mount to blower housing using bolts previously removed.

7. Attach green wire to blower housing with screw.

8. Connect electrical and capacitor leads to original terminals.

9. Replace blower access door and tighten all 4 screws.

10. Reinsert disconnect pullout only after blower access door is secured. Test blower for proper operation.

FD3A SERVICE AND TROUBLESHOOTING

WARNING: ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury or death.

Before installation or servicing system, always turn off main power to system. There may be more than 1 disconnect switch. Turn off

accessory heater power if applicable.

PROCEDURE 1—FAN MOTOR

The motor is 2-speed direct drive. High-speed lead is black, low-speed lead is red, and common lead is yellow.

NOTE: Unused fan speed leads must be tapped off to prevent direct short to cabinet surface.

The motor is turned on through 2 different routes. The first occurs when thermostat calls for the fan in cooling, heat pump, or fan-only mode. A

24-vac signal is sent to relay, causing relay to close its normally open contacts, turning fan on. The second occurs when there is a call for electric

heat. A 24-vac signal is sent to heater sequencer, causing it to close, directing 230v through the normally closed contact of fan relay, turning fan

on. The fan remains on until sequencer opens. Refer to FD3A typical wiring diagram. (See Fig. 23.)

PROCEDURE 2—ELECTRIC HEATER SERVICE

Service can be completed with heater in place. Shut off power before servicing.

A. Limit Switch

Refer to Electric Heater Function and Troubleshooting section of this manual.

B. Sequencer

Refer to Electric Heater Function and Troubleshooting section of this manual.

C. Transformer

A 60-VA transformer supplies 24-v power for control circuit. Check for 208/230-v on primary side of transformer. If present, check for 24-v on

secondary side. Replace transformer if faulty.

NOTE: Transformer is fused. Do not short circuit.

Fig. 22—FF1A/FF1B/FF1C Motor, Inlet Ring, and Blower Wheel Assembly

A86006

GROMMET

BLOWER

WHEEL

INLET

RING

MOTOR

⁄8″

—32—

Fig. 23—FD3A Typical Wiring Diagram

A94376

FIELD POWER WIRING

FIELD GROUND WIRING

FIELD CONTROL WIRING

FIELD SPLICE

JUNCTION

MARKED CONNECTION

UNMARKED CONNECTION

FAN CAPACITOR

FAN RELAY

HEATER

INDOOR FAN MOTOR

LIMIT SWITCH

QUAD TERMINAL

SEQUENCER

TERMINAL BLOCK

TRANSFORMER

WIRE SLEEVE

FUSIBLE LINK

(OPTIONAL)

- LEGEND -

YEL

BLK

BLK BLK

BLK

BLU

BLK

RED

RED RED

BLU

BRN

YEL

GRNBLK

BLK

YEL

VIO

VIOVIO

BRN

ORN

BRN

BRN BRN

BRN

VIO

ORN

BRN

YEL

GRN

BRN

SCHEMATIC DIAGRAM

COMPONENT ARRANGEMENT

HTR

IFM

SEQ

TRANS

NOTES:

1. TRANSFORMER PIGTAILS:

BLUE 208V; RED 230V; INSULATE

UNUSED LEAD.

2. FAN MOTOR PIGTAILS: RED LOW;

BLACK HIGH, INSULATE UNUSED

LEAD.

3. FAN MOTOR THERMALLY

PROTECTED.

4. SUITABLE FOR USE WITH COPPER

OR COPPER CLAD ALUMINUM

CONDUCTORS RATED FOR 75°C

MINIMUM. FOR COPPER USE 6

AWG. FOR COPPER CLAD

ALUMINUM USE 4 AWG.

40DQ500784 REV. C

SEE NOTE #4

FIELD POWER SUPPLY

SEQ

234

HTR-2

LS-2

LS-1

LS-2

SEQ

TRANS

SEQ

IFM

TRANS

HTR-1

FL-2

212

24V

SEQ

SEE NOTE #4

EQUIP. GND.

FIELD POWER WIRING

DISCONNECT

PER

N.E.C.

IFM

SEQ

TRANS

(OPTIONAL)

FL-1

(OPTIONAL)

FL-1

HTR-1

HTR-2

TRANS

(OPTIONAL)

FL-2

(OPTIONAL)

NOTE #2

NOTE #1

FIELD

CONTROL

WIRING

—33—

D. Fan Relay

Relay coil is 24 volts. Check for proper control voltage. Replace relay if faulty.

E. Heater Removal

Disconnect wiring, remove 2 sheet metal screws, and pull heater out through open hinged access panel. When replacing heater, ensure orientation

of heater element is same as when removed.

PROCEDURE 3—CLEANING OR REPLACING REFRIGERANT

FLOW-CONTROL DEVICE

1. Pump down outdoor unit. Close service valves at outdoor unit.

CAUTION: UNIT DAMAGE HAZARD

Failure to follow this caution could result in equipment damage.

Damage may occur to the scroll compressor if operated at a negative suction pressure during a system pumpdown.

2. Bleed and (if possible) recover remaining refrigerant from tubing and coil through gage port on vapor-tube service valve.

3. Disconnect liquid refrigerant tube from refrigerant flow-control device. Refer to Fig. 24.

4. Remove refrigerant flow-control device piston retainer. Avoid damaging O-ring or machined surfaces on piston, bore, and retainer.

5. Using small wire with a hook on end of it, remove piston from refrigerant flow-control device body.

CAUTION: UNIT DAMAGE HAZARD

Failure to follow this caution could result in equipment damage.

When cleaning piston orifice, be careful not to scratch or enlarge opening as this will affect operation.

CAUTION: UNIT COMPONENT HAZARD

Failure to follow this caution could result in equipment damage.

Use a backup wrench and do not overtighten as deformation of refrigerant flow-control device body will occur, causing piston to lodge

in a partially open or closed position.

6. Install new or cleaned piston in refrigerant flow-control device body.

7. Install new retainer (because of probable damage which occurred in initial removal).

8. Reconnect refrigerant tube to refrigerant flow-control device.

9. Pressurize tubing and coil, then leak-check.

10. Evacuate tubing and coil as necessary.

PROCEDURE 4—LIQUID TUBE STRAINER

The refrigerant flow-control device is protected on indoor coil by a wire mesh strainer. If strainer becomes plugged:

1. Complete items 1 and 2 under Cleaning or Replacing Refrigerant Flow-Control Device section.

2. Loosen flare fitting joint connecting refrigerant flow-control device to coil liquid refrigerant tube.

3. Remove sheet metal screw holding bracket clip in place. Screw is located between coil and refrigerant flow-control device.

4. Pull bracket clip out.

5. Remove refrigerant flow-control device assembly.

6. Pull strainer out of coil liquid refrigerant tube and replace with new strainer.

Fig. 24—Refrigerant Flow-Control Device

(For FD3A and FG3A)

A92219

PISTON

BODY

RUBBER

O-RING

THREAD

PROTECTOR

PISTON

RETAINER

—34—

PROCEDURE 5—CARE AND MAINTENANCE

WARNING: PERSONAL INJURY HAZARD

Failure to follow this caution could result in personal injury.

Hinged access panel contains electrical components and is heavy. Support panel when lowering to clean unit to avoid personal injury.

WARNING:

ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury or death.

Disconnect electrical power to all circuits before servicing unit. Failure to do so may result in personal injury from electrical shock or

moving parts.

WARNING: CUT HAZARD

Failure to follow this warning could result in personal injury.

As with any mechanical equipment, personal injury can result from sharp metal edges. Be careful when removing parts.

The minimum maintenance requirements for this equipment are as follows:

1. Inspect and clean or replace field-supplied air filter each month or as required.

2. Inspect cooling coil, drain pan, and condensate drain each cooling season for cleanliness. Clean as necessary. (To be performed by trained

personnel.)

3. Inspect blower motor and wheel for cleanliness each heating and cooling season. Clean as necessary.

4. Inspect electrical connections for tightness and controls for proper operation each heating and cooling season. Service as necessary.

NOTE: Never operate without a filter or with hinged access door open. Damage to blower motor may result.

A. Cooling Coil, Drain Pan, and Condensate Drain

Remember to disconnect electrical power before opening hinged access panel.

The cooling coil is easily cleaned when dry. Inspect coil and clean (if necessary) before each cooling season. If coil inlet face is coated with dirt

or lint, vacuum with a soft brush attachment.

Be careful not to bend coil fins. If coil is coated with oil or grease, clean it with a mild detergent and hot water solution. Rinse coil with clear

water. Be careful not to splash water onto insulation.

Inspect drain pan and condensate drain at same time cooling coil is checked. Clean drain pan and condensate drain by removing any foreign matter

from pan. Flush pan and drain tube with clear water. Clear drain line if restricted.

NOTE: There MUST be a trap in condensate line. Trap must be at least 3-in. deep, not higher than the bottom of unit condensate drain opening,

and pitched downward to an open drain or sump.

B. Blower Motor and Wheel

Clean blower motor and wheel when cooling coil is cleaned. Lubricate motor every 5 years if motor is used on intermittent operation (thermostat

FAN switch at AUTO position), or every 2 years if motor is in continuous operation (thermostat FAN switch at ON position). Remove motor to

lubricate. Put approximately 8 drops of SAE 10 nondetergent oil in each oil hole. Do not over oil motor. Plug hole securely so that oil does not

drip when hinged access panel is lowered to open position.

Blower motor and wheel may be cleaned using a vacuum with a soft brush attachment. Remove grease with a mild solvent such as hot water and

detergent. Be careful not to disturb balance weights (clips) on blower wheel vanes. Do not drop or bend wheel as balance will be affected.

FG3A SERVICE AND TROUBLESHOOTING

PROCEDURE 1—SERVICE

A. Motor

Ball bearing oilers are provided on blower motor. Use electric motor oil or SAE 10 or 20 nondetergent oil. Check motor mount bracket and base

bolts. Tighten as required.

B. Blower

Check ball bearings for wear. Ball bearings are self-aligning and grease packed. Replace as required. Check thrust collars for end play and

alignment of wheel. Check blades for accumulation of dirt. Clean as required. Check mounting brackets, base bolts, and isolation material.

See Fig. 25 for diagram of internal wiring for blower coil assembly. Control box (standard 4-in. junction box) is mounted on refrigerant connection

side of unit. All leads pass through strain relief where they enter control box. Wiring inside cabinet is located so it does not come in contact with

moving parts or sharp edges.

C. Pulley and Belts

Check belt tension and pulley alignment. (See Fig. 26.) Belt tension is adjusted by motor tailpiece bolt. A deflection of about 3/4 in. to 1 in. per

foot of span should be obtained by pressing belt firmly. Lock adjusting bolt in position after adjustment is made. Align pulley grooves by locating

motor pulley on motor shaft or by moving entire motor along motor mounting bracket. Adjust blower speed by loosening setscrew in outer

(moveable) pulley face and turning this face (half or full turns) so that adjusting setscrew is positioned precisely over the flat on pulley hub. Speed

is reduced by adjusting pulley faces so they are further apart; speed is increased with faces closer together. Check pulley setscrews and bolts.

D. Cleaning or Replacing Refrigerant

Flow-Control Device

Refer to Fig. 24 and instructions given in FD3A Service and Troubleshooting section above.

—35—

PROCEDURE 2—MAINTENANCE

WARNING: ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury or death.

Disconnect electrical power to all circuits before servicing unit. Failure to do so may result in personal injury from electrical shock or

moving parts.

WARNING: CUT HAZARD

Failure to follow this warning could result in personal injury.

As with any mechanical equipment, personal injury can result from sharp metal edges. Be careful when removing parts.

A. Return-Air Filter

To clean or replace air filter, remove screws and filter access door. Slide out filter. For washable type filters, clean with hot soapy water. Rinse

clean and let dry.

New filters are available from a local distributor. Place filter in slot with filter arrow facing direction of airflow. Replace filter access doors with

screws previously removed.

CAUTION: UNIT DAMAGE HAZARD

Failure to follow this caution could result in equipment damage.

Never operate unit without a filter or with filter access door removed. Damage to blower motor may result.

B. Coil, Drain Pan, and Condensate Drain

WARNING: ELECTRICAL SHOCK HAZARD

Failure to follow this warning could result in personal injury or death.

Disconnect electrical power before removing any access panels or electrical shock may result.

The coil is easily cleaned when dry. To check or clean coil, remove coil access panel. If coil is coated with dirt or lint, vacuum with a soft brush

attachment.

Be careful not to bend fins. If coil is coated with oil or grease, it may be cleaned with mild detergent and water solution. Rinse coil with clean

water. Be careful not to splash water on insulation or filter.

Check drain pan and condensate drain at same time cooling coil is checked. Clean drain pan and condensate drain by removing any foreign matter

from pan. Check for rust and holes. Flush pan and drain tube with clear water. If drain is restricted, clean with high-pressure water. If this does

not work, use a plumber’s snake or similar probe device. Repitch drain pan to promote proper drainage.

FA4, FB4, FC4, FX4

SMART HEAT CIRCUIT BOARD

FUNCTION AND TROUBLESHOOTING

PROCEDURE 1—PCB COMPONENT LAYOUT, DESCRIPTION,

AND FUNCTION

NOTE: All voltages are AC unless otherwise specified.

1. The low-voltage terminal board is used to connect indoor thermostat to low, 24-v side of transformer and to serve as a junction between

indoor thermostat and outdoor section.

Fig. 25—Wiring Schematic

A91151

BLOWER

MOTOR

GROUND

UTILITY

BOX

GROUND

LEAD

LINE

Fig. 26—Checking Pulley Alignment and Tightness

A91150

′

⁄4″

BELT ADJUSTMENTPULLEY ALIGNMENT

MUST BE

PARALLEL

FOR PROPER

ALIGNMENT

—36—

a. R terminal is used to connect secondary side of transformer to thermostat and outdoor unit. R is fused.

b. C terminal is used to connect transformer secondary common for thermostat and outdoor unit.

c. Y terminal provides input signal from thermostat signaling heat pump operation.

d. G terminal provides input signal from thermostat signaling continuous fan operation.

e. O terminal provides input and junction terminal for reversing valve signal.

f. W2D terminal provides input from outdoor unit (heat pump) signaling control board that heat pump is in defrost.

g. W2T terminal provides input from thermostat signaling for supplemental or emergency heat.

h. W3 terminal provides input from outdoor thermostat. W3 and W2T are factory connected by JW1. This input is used only if an outdoor

thermostat is required by local codes.

i. Y

terminal provides output from control board to energize outdoor unit (heat pump) contactor.

2. Jumper wires (JW1 and JW2). (See Fig. 27.)

a. JW1 connects W2T to W3 to limit staging of electric heat with use of an outdoor thermostat. See Table 11 for staging. Smart Heat PCB

controls staging to the extent that this feature is unnecessary unless required by local codes or regulations.

b. Cutting JW2 sets Smart Heat PCB in efficiency mode. With JW2 cut, there is no loss of performance due to reduced indoor blower speed

when heat pump is operating near balance point. This jumper may need to be cut if selected cooling fan speed is the same as required

minimum motor LO speed tap selection. With JW2 cut, fan terminal LO becomes a dummy terminal.

3. A fuse is used to protect low-voltage transformer and PCB.

4. AUX+ and AUX- are connections for air conditioning accessories (EAC, humidifier, etc.).

5. F1, F2, HI, and LO are connections for indoor fan.

6. The 9-pin receptacle connects heater package wiring harness.

7. SEC1 and SEC2 are used to connect secondary side of transformer to PCB. SEC1 is internally connected to equipment ground.

PROCEDURE 2—UNIT FUNCTIONS

A. Transformer

NOTE: Terminals T1, T2 (if used), and T3 are wired to primary or high side of transformer. The 208-v terminal (or blue wire if transformer has

primary leads) is used on T3 for 208-v applications. The 230-v terminal (or red wire) is used on T3 for 230-v applications. T2 is a dummy terminal.

B. Electric Heat

NOTE: When troubleshooting elements, position thermostat to emergency heat. Wait approximately 12 minutes after all thermostat delays for all

elements to come on.

1. When thermostat calls for supplementary heat, a 24-v signal is sent to PCB through W2T. The PCB energizes first stage of electric heat.

Fig. 27—Smart Heat Printed Circuit Board (PCB)

A94127

ST1

HSCI

COMMON

DUMMY

240 VAC

240

VAC

JW4

JW2

JW3

JW5

JW6

JW8

JW1

R15

R27

R41

R40

R19

R10

R18

R11

XFORM

AUX+

AUX–

FAN

R13

C10

C12

C13

FS1

R20

MOV1

R23

R30

W2D

W 3

Y o

W 2T

R21

JW7

R16

R12

C11

R17

R29

R26

R14

LED1

LR40061

CLIP JUMPER FOR

HIGH SPEED FAN ONLY

123

456

789

R38

R22

R28

R25

R24

CESS430121-01A

R36

R37

C15

C14

R39

CES0130025 –

SEC1

SEC2

CEPL130121-01

JW1

JW2

RECEPTACLE

LOW VOLTAGE

TERMINAL

BOARD

(CUT WHEN

OUTDOOR

THERMOSTAT

IS USED)

(HIGH FAN

ONLY WHEN

CUT)

—37—

2. The first 2 stages come on if W2T and Y are energized at the same time. After each 10 minutes W2T is energized, another stage of electric

heat is energized.

3. As W2T is de-energized, electric heat stages down in 8 minute steps with the exception of first step. The first step will be on only half as

long as it was prior to W2T de-energizing.

4. When W2T is energized by itself, JW1 is cut, and an outdoor thermostat is used and is open, staging is limited as in Table 11.

5. When both W3 and W2T are energized without JW1 being cut or with outdoor thermostat closed, system operation stages heat up to

maximum level if signal is energized for proper amount of time.

6. If only W3 is energized (JW1 is cut), there is no effect on PCB. No heat is energized.

C. Accessories

Terminals AUX+ and AUX- are energized with 24 vdc when fan is energized. The accessory kit KFAIR0101ACR is used to connect an EAC or

humidifier.

NOTE: Loads cannot be connected directly to AUX+ and AUX-. Use the specified kit only.

Fig. 28—Smart Heat Typical Wiring Diagram

(Motor Speed at 20kw Shown)

A94132

COM

MED

LO LO

070060

MED

LOLO

033 038 048042036030

LO LO

CAP

COMM

GND

HPLV

HTR

CAPACITOR

COMMON

LOW VOLT FUSE

FAN MOTOR

EQUIPMENT GROUND

HEAT PUMP LOW VOLT

HEATER

LIMIT SWITCH

LED

LVTB

SEQ

TRAN

XFORM

DIAGNOSTIC LIGHT

LOW VOLT TERM BRD

SEQUENCER

TRANSFORMER

PCB TRAN TERMINALS

FIELD LOW VOLTAGE

HPLV LEADS

MARKED TERMINAL

PCB JUMPER (JW)

UNMARKED TERMINAL

YEL

322251-101

REV. B

SEE NOTE #3

230V

208V

FU1

BLK

910

SEQ3

FU3

BLK

ORG

SEQ1

YEL

FU4

BLK

SEQ 2

YEL

BLK

LS1

BLK

HTR1

HTR4

FU3 60A

FU1 60A

FU2 60A

FU4 60A

LED

PCB

HEAT PUMP HEAT

ONLY OPERATING

JW1

JW2

LEADS

JW1

NO POWER OR

BOARD FAILURE

STAND BY CONDITION

OR FAN ONLY

HEAT PUMP PLUS

1 SEQUENCER

HEAT PUMP PLUS

2 SEQUENCERS

HEAT PUMP PLUS

3 SEQUENCERS

COOL MODE

DEFROST MODE

EMERGENCY HEAT

MODE

7 FLASHES

6 FLASHES

5 FLASHES

4 FLASHES

3 FLASHES

2 FLASHES

1 FLASH

STEADY FLASH

STEADY LIGHT

NO LIGHT OR FLASH

LED FLASH CODES

987

654

321

W2T

W2D

AUX +

AUX -

SEC 2

SEC 1

PCB

SEC 2

SEC 1

BLK

RED-LO

DUMMY

240 VAC

XFORM

DUMMY

VAC

240

COMM

FAN

HPLV

LS3/4

INDOOR THERMOSTAT

YCR

LVTB

W2T

W2D

YEL

BLK

VIO

BRN

789

654

YEL

SEQ 3

HTR3

SEQ1

SEQ2

SEE NOTE #1

SEE NOTES #2, #7,AND #8

YEL-COM

CAP

BRN

GRN/YEL-GND

BLK-HI

BLU-MED

BRN

RED

TRAN

MOTOR SPEED AT 20 KW

FAN COIL SIZE

MINIMUM MOTOR LO SPEED TAP SELECTION

NOTES:

LS2

LS1

RED

SEQ3

SEQ2

SEQ 2

BLK

LS2

YEL

BLK

HTR2

SEQ 1

LS3

BLK

LS4

BLK

HTR4

FOR VOLTS & HERTZ

SEE RATING PLATE

DISCONNECT PER NEC

FIELD POWER WIRING

SCHEMATIC DIAGRAM

GND

CAP

FAN MOTOR THERMALLY PROTECTED

YEL-COM

BRN

GRN/YEL-GND

BLK-HI

BLU-MED

RED-LOW

GND

1. USE COPPER WIRE (75°C MIN) ONLY BETWEEN

DISCONNECT SWITCH AND UNIT.

2. CONNECT LOW VOLTAGE WIRING AS SHOWN (24VAC).

3. CONNECT TRANSFORMER PRIMARY TO THE PROPER

VOLTAGE TERMINAL

4. TO BE WIRED IN ACCORDANCE WITH NEC AND LOCAL CODES.

5. IF ANY OF THE ORIGINAL WIRE, AS SUPPLIED, MUST BE

REPLACED, USE THE SAME OR EQUIVALENT TYPE WIRE.

6. REPLACE LOW VOLTAGE FUSE WITH NO GREATER THAN

5 AMP FUSE.

7. REFER TO THERMOSTAT INSTRUCTIONS FOR "E" JUMPER

INSTALLATION.

8. DO NOT

CONNECT THERMOSTAT "E" TO PCB "W3".

LEGEND

REMAINING VA AVAILABLE: 13.7VA

FAN COIL/HEATER: 26.3VA

SYSTEM TRANSFORMER: 40.0VA

BRN

24 V

RED

TRAN

230 V

208 V

COM

HTR2HTR3

HTR1

COMPONENT ARRANGEMENT

ROTATION

BLOWER MOTOR

NE CONVIENT PAS AUX INSTALLATIONS DE PLUS DE 150

V A LA TERRE

NOT SUITABLE FOR USE ON SYSTEMS EXCEEDING

150V TO GROUND

ATTENTION:

CAUTION:

THIS COMPARTMENT MUST BE CLOSED EXCEPT FOR SERVICING

Table 11—Electric Heater Stage Limiting

Heater Part No. Stages (KW Operating)

W2T Only (JW1 cut) W2T and W3

Heater Stage 1 2 3 4

KFAEH2201H10 or

KFCEH0101H10

10 kw Non-Fused 3 6 9 9

KFAEH2301H15 or

KFCEH0201H15

15 kw Fused 3 8 11 15

KFAEH2401H20 or

KFCEH0301H20

20 kw Fused 5 10 15 20

—38—

D. Blower

1. Blower On Delay—To optimize comfort, there is a 30-sec blower on delay in heat pump heating mode only.

2. Blower Off Delay—Smart Heat control uses a 60-sec off blower delay, as opposed to the standard 90-sec delay.

PROCEDURE 3—SMART HEAT OPERATION

A. Cooling

The Smart Heat option controls cooling mode in same manner as conventional heat pumps are controlled. The fan has a 90-sec delay off/on cycle

down.

B. Heat Pump Heating

The Smart Heat option does not control heating in the conventional method. The PCB energizes compressor 30 sec before indoor fan is energized.

This allows indoor coil to heat up eliminating cold-blow on start-up.

The electric heat is staged-on to allow continuous operation of heat pump and electric resistance heat below balance point (below point where heat

pump cannot maintain dwelling temperature without supplemental heat) independent of outdoor thermostats.

Although PCB has provisions for an outdoor thermostat, it is not needed for staging. On cycle down, indoor fan remains on 60 sec to recover heat

stored in indoor coil.

C. Defrost

The Smart Heat PCB stages the correct amount of supplemental heat during defrost. If too much heat is added, system stays in defrost for

completion of defrost cycle even though thermostat is satisfied. On next cycle, 1 less element is energized during next defrost period.

NOTE: If the signal from thermostat is interrupted (ie., thermostat is satisfied) while unit is in defrost mode, the defrost cycle will be completed

before unit shuts down.

D. Troubleshooting Printed Circuit Board

(Diagnostic LED)

The PCB of Smart Heat option heater package contains a microprocessor which controls fan operation, fan speed, outdoor unit, and heater

elements. For troubleshooting, a service LED indicates condition of PCB. See Table 12 for LED flash codes.

PROCEDURE 4—ELECTRICAL OPERATING SEQUENCES AND

TROUBLESHOOTING

NOTE: Refer to Table 13 for proper input and output voltages. See Fig. 28 for Smart Heat Proper Wiring Diagram.

A. Ready-To-Start

In ready-to-start (standby) mode, LED on board indicates a steady flash.

In this mode, 24-v power should be available at control’s low voltage terminal strip terminals R and C. If 24v is not present across R and C, check

the following:

• Is low-voltage fuse on control board good?

• Are line voltage fuses FU1 and FU2 good?

• Is LED on control on steadily or not on at all? Both of these indications signal a possible board failure.

• Is 208/230-v power available to control across pins 7 and 9 of 9-pin connector? Is connection to board tight?

B. Continuous Fan

On a call for continuous fan, thermostat provides a 24-v input signal to G terminal on low-voltage terminal strip. Sensing this signal, the

microprocessor energizes a relay on control to provide power to high-speed winding of fan motor, at 1. The fan continues to run until fan switch

on thermostat is turned off.

Table 12—LED Codes for Smart Heat PCB

Flash Condition Input Signals System Operation

No Light/Flash — No Power or

Board Failure

Steady Light — Board Failure

Steady Flash — Stand By Condition

or Fan Only

1 Flash Y only Heat Pump Only

Operating

2 Flashes Y and/or W2T Heat Pump Plus

1 Sequencer

3 Flashes Y and/or W2T Heat Pump Plus

2 Sequencers

4 Flashes Y and/or W2T Heat Pump Plus

3 Sequencers

5 Flashes Y, O Cool Mode

6 Flashes Y, W2D, and/or W2T Defrost Mode

7 Flashes W2T Emergency Heat Mode

—39—

During continuous fan operation with no call for heating or cooling, LED indicates a steady flash, the same indication seen when system is in

standby.

The call for continuous fan operation signal can be checked by placing voltmeter leads across terminals G and C of control’s low-voltage terminal

strip. If 24v is not seen across these terminals, check for the following:

• Is 24v available across R and C? If not, refer to Ready-To-Start section for items to check if 24v is not available.

• Is thermostat fan switch set for continuous operation?

Confirm fan operation. Voltage to operate fan can be confirmed by placing voltmeter leads across terminals F1 and HI on control. The reading

should be 208/230v. If 208/230v is not observed, check the following:

• Is 208/230v available at pins 7 and 9 of 9-pin connector? Is connection to board tight?

• Are line voltage fuses FU1 and FU2 good?

If 208/230v is available across terminals F1 and HI and fan does not operate, check the following:

• Is fan motor capacitor good?

• Is blower wheel jammed or loose? Are there any other mechanical problems preventing fan operation?

C. Cooling

On a call for cooling, room thermostat provides input signals to control board at terminals Y and O. The O signal is also available to heat pump

to energize reversing valve.

When it receives both these signals, the microprocessor responds by providing a 24-v output signal at the Y

terminal. This output signal energizes

contactor in heat pump and starts compressor. There isa3to5secdelay in output of Y

signal.

At the same time, control energizes fan coil’s fan motor on high speed through terminals F1 and HI. The LED indicator on control signals 5 flashes,

indicating cooling operation.

The call for cooling signals can be confirmed by placing voltmeter leads across low-voltage terminals Y, O, Y

, and C. The reading should be

24v. If 24v is not available, check the following:

• Is 24v available across R and C? See Ready-To-Start section for items to check if 24v is not available.

• Is thermostat function switch set in COOL position with thermostat calling for cooling?

Assuming heat pump has power and is adequately charged, it should be running at this time in cooling mode. Indoor fan should also be running

at this time. If indoor fan is not running, refer to Continuous Fan section for items to check.

Table 13—Troubleshooting Voltage Readings and Test Points

Input Voltages

Location Normal Reading Purpose

L1 and L2 208/230 vac Main power supply input to fan coil

L3 and L4 208/230 vac Power to electric heaters

9-pin connector

7 and 9

208/230 vac Power to smart control

T1 and T3 208/230 vac Power to transformer

SEC1 and SEC2 24 vac Power from transformer secondary

R and C 24 vac Power from transformer secondary

G and C 24 vac Call for continuous fan signal from room thermostat

Y and C 24 vac Call for heat/cool signal from room thermostat

O and C 24 vac Signal to energize reversing valve from room thermostat (cooling).

Also present during defrost.

W2T and C 24 vac Call for electric heat from room thermostat

W2D and C 24 vac Defrost initiation signal from heat pump

Output Voltages

Location Normal Reading Purpose

HI and F1 208/230 vac Power to blower motor (high speed)

LO and F1 208/230 vac Power to blower motor (low speed)

and C 24 vac Power to energize contactor in heat pump (heat and cool modes)

9-pin connector

1 and 4

24 vdc Power to energize SEQ 1

NOTE: Sequencers use DC voltage

9-pin connector

2 and 4

24 vdc Power to energize SEQ 2

9-pin connector

3 and 4

24 vdc Power to energize SEQ 3

vac—volts AC

vdc—volts DC

—40—

D. Heating (Compressor Only)

On a call for heat, room thermostat provides an input signal to control board at terminal Y. This signal causes the microprocessor to provide a

24-v output signal at terminal Y

to energize contactor in heat pump. There isa3to5secdelay in output of Y

signal.

Thirty sec after Y is energized, control energizes fan motor. It may run on high or low speed, depending on its operation in previous cycle.

Compressor operation in current cycle is monitored by the smart control to determine whether a fan speed change is required for enhanced indoor

comfort. The LED indicator on control signals 1 flash, indicating compressor operation only with no electric heat.

The call for heat signals can be confirmed by placing voltmeter leads across low-voltage terminals Y, Y

, and C. The readings should be 24v. If

24v is not available, check the following:

• Is 24v available across R and C? See Ready-To-Start section for items to check if 24v is not available.

• Is thermostat function switch set in HEAT position with thermostat calling for heat?

Assuming heat pump has power and is adequately charged, it should be running at this time in heating mode. Indoor fan should also be running

at this time. If indoor fan is not running, refer to Continuous Fan section for items to check. When room thermostat is satisfied, indoor fan continues

to run an additional 60 sec to recover heat remaining in indoor coil.

E. Heating (Compressor and Electric Heat)

If heat pump alone cannot satisfy heat requirements of structure, room thermostat calls for additional heat by way of an input to W2 terminal of

control. When this occurs, control begins sequencing on electric heaters by energizing the first sequencer/heat relay. Indoor fan should be running

at this time.

If room temperature requirements cannot be met, additional stages of electric heat are energized through the other 2 sequencers/relays, at 2.

The logic of control determines how much and how soon these additional stages are brought on. By observing LED status light, the number of

operating stages of electric heat can be determined. The control also varies indoor fan speed depending on number of energized stages of heat.

In general, the more stages of electric heat, the higher the fan speed.

There is no hard and fast rule for determining exactly when stages will be energized since microprocessor in the smart control constantly monitors

duration of previous heating cycle, setting of room thermostat, and number of stages of heat needed in previous cycle to satisfy room thermostat.

Rather than try to determine what should be operating when, service technicians should check LED status light to see how many stages of electric

heat are energized at a given time and confirm operation of sequencer/relay using a voltmeter. If a quick check of all stages is desired, set room

thermostat as high as it will go. With a constant signal on W2T terminal, sequencers/relays energize every 10 minutes until all heaters are on.

The previous paragraphs described how to check for low-voltage inputs to control by placing voltmeter leads across low-voltage terminal strip and

checking for 24v. The call for electric heat can be confirmed by placing voltmeter leads across W2T and C.

To check for operation of sequencers/relays, check directly across appropriate coil for 24 volts DC.

NOTE: All sequencer/relay coils are powered by 24 volts DC. This voltage is generated internally by the smart control.

In this example, sequencer/relay 1 is being checked. The procedure is the same for all other sequencers/relays. If 24 volts DC is not observed, check

the following:

• Is room thermostat calling for electric heat? This can be confirmed by checking for 24 volts AC between low-voltage terminal strip terminals

W2T and C.

• Is LED flashing appropriate code for number of sequencers/relays energized? In this example, 2 flashes should be visible, indicating 1

sequencer/relay is energized. Indicator tells how many sequencers/relays are energized, but does not tell which ones are.

• Is 9-pin connector for heater package tightly secured to control board?

F. Checking Sequencer Operation

To check for operation of power circuit of sequencer/relay, place voltmeter leads across sequencer/relay terminal 4 of sequencer/relay 1 and

terminal 4 of limit switch 3. The reading should be 208/230v, and heater should be energized.

If 208/230v is not observed at terminals specified, check the following:

• Are fuses FU3 and FU4 good?

• Is limit switch LS3 open? If so, check fan coil air filter or air distribution system for blocking or restriction that might reduce airflow and

cause limit switch to open.

Operation of heaters can be confirmed further by using a clamp-on ammeter in circuit shown to verify current is flowing through heaters. Amperage

readings will depend on size of heater. The procedure for checking other sequencers/relays in system is identical to that just described.

G. Emergency Heat

Emergency heat mode requires that room thermostat be placed in EMERGENCY HEAT position. This locks out and prevents operation of heat

pump outdoor unit. In this mode, heat is provided exclusively by electrical heaters in fan coil.

In this mode, room thermostat, at 1, provides an emergency heat input signal to smart control at terminal W2T. If jumper JW1, at 2, has not been

cut and an outdoor thermostat installed to control electric heat stages, that same input signal is applied to terminal W3. For this example, assume

that jumper JW1 has not been cut.

Eventually, the total number of heaters is cycled on. In emergency heat mode, LED indicator signals 7 flashes.

The amount of emergency heat available depends on whether jumper JW1 is cut and the number of heating elements. Table 14 illustrates results

under various conditions. The heaters cycle on two elements initially and an additional element every 5 minutes until maximum level is reached.

With JW1 cut, an outdoor thermostat (if closed) could cycle on additional heaters and system would perform as if JW1 was not cut. In effect, closed

outdoor thermostat replaces cut jumper.

H. Defrost

In defrost mode, LED indicator signals 6 flashes. Defrost is initiated by heat pump and is signalled to smart control by an input to W2D terminal.

During defrost, outdoor unit switches to cooling mode, making it necessary to cycle on electric heaters to temper indoor air.

—41—

If electric heaters were not energized prior to defrost, smart control energizes sufficient elements to temper air. If heaters were energized prior to

defrost, additional heaters will be cycled on to provide additional heat.

A defrost initiation signal can be confirmed by attaching voltmeter leads across low-voltage terminals W2D and C. If 24v is not observed, check

the following:

• Is 24v available across R and C? See Ready-To-Start section for items to check if 24v is not available.

• Is there continuity in thermostat leads between heat pump and smart control?

• Is defrost control in heat pump operating properly?

CES013003-00 AND 01 (HK61EA002)

CIRCUIT BOARD FUNCTION & TROUBLESHOOTING

(FA4A, FB4A, FC4B, FF1D, FH4A, AND FX4A)

This section of the service manual describes the CESO130003-00 and -01 PCB by examining the functional operation of the PCB components.

PROCEDURE 1—PRINTED CIRCUIT BOARD (PCB) COMPONENT

LAYOUT AND DESCRIPTION

Layout of the actual PCB is depicted in Fig. 29.

1. The low-voltage stripped leads are used to connect the 24-v side of transformer to indoor thermostat and outdoor section.

2. A 5-amp fuse is used to protect the low-voltage transformer secondary.

3. The fan relay is controlled by thermostat and turns fan on and off.

4. A plug is used as the connection for PCB power and electric heaters. Note the pin numbers on plug.

5. A time-delay relay circuit keeps fan motor running for approximately 90 sec after G is de-energized. The time-delay can be defeated by

cutting jumper JW1 on the CES0130003-01 and HK61EA002.

PROCEDURE 2—UNIT FUNCTIONS

A. Transformer

1. Proper Wiring of Transformer Primary or High Side

Yellow wire from Molex plug is wired to C terminal on transformer and black wire from PCB relay (normally-open) terminal is wired to

208v or 230v terminal on transformer. Units are factory wired at 230v terminal.

2. Proper Wiring of Transformer Secondary or 24-v Side

Red wire of transformer is wired to T terminal on PCB and brown wire of transformer is wired to C terminal on PCB.

NOTE: T terminal on PCB is used to protect transformer. T terminal is connected through the fuse to R terminal on PCB.

B. Indoor Fan

1. Wiring

Indoor fan motor yellow lead is wired to C terminal on transformer. The red, blue, or black speed lead is wired to SPT terminal on fan relay

part of PCB. Units are factory wired on medium speed (blue lead connected).

NOTE: Unused fan speed leads must be capped or taped off to prevent direct short to cabinet surface.

2. Functional Control

a. Thermostat and Relay Control

When thermostat calls for the fan in cooling, heat pump, heating, or fan-only mode, a 24-vac signal is sent to relay. This causes the relay

to close its normally-open contacts, turning on fan. When thermostat no longer calls for the fan, the signal sent to relay is turned off and

relay opens causing fan to turn off after a 90-sec fan-off delay.

b. Sequencer/Electric Heat Relay Interlock

The fan will also operate whenever there is a call for electric heat, even if fan relay is not energized. This happens because fan is

interlocked with first stage of electric heat through the normally-closed contact of fan relay.

NOTE: The fan interlock is only connected to first stage electric heat (W2). W3 and E do not contain an interlock with fan. See outdoor thermostat

Installation Instructions when electric heat staging is desired.

C. Electric Heat

When thermostat calls for electric heat, a 24-vac signal is sent to sequencer/heat relay through W2, causing first stage to turn on. W3 and E also

receive signal if wired in with W2. If W3 and E are not wired to W2, the sequencers/heat relays can be controlled individually to stage additional

electric heat. The sequence control is described in the following section:

Table 14—Effect of JW1 on Emergency Heat

JW1 cut*

4 elements 3 elements

50% 66.7%

JW1 not cut

4 elements 3 elements

100% 100%

* Outdoor thermostat opens

—42—

1. W2

When thermostat sends a signal to W2, a 24-vac signal is applied across sequencer/relay number 1, causing it to close. When sequencer/relay

number 1 closes, first stage of electric heat is energized. In straight electric heat, fan is also energized through the normally closed contacts

of fan relay. In cooling, heat pump, or manual fan mode, fan will already be running since fan relay would have been energized. When

thermostat stops calling for electric heat, the 24-vac signal to sequencer/relay number 1 turns off and sequencer opens after a delay of 60

to 90 sec. Heaters equipped with relays will be de-energized immediately. When sequencer/relay opens, first stage of heat turns off along

with fan, providing thermostat is not calling for the fan.

2. W3

When a signal is sent to W3, a 24-vac signal to sequencer/relay number 2 causes it to close, with second stage of electric heat turning on.

The 24-vac signal applied to sequencer/relay number 1 causes fan to operate. Timing is such that sequencer/relay number 1 will turn on

before sequencer/relay number 2. When signal to W3 is turned off, sequencer/relay number 2 opens. If W2 is also satisfied, first stage of

electric heat and fan will also turn off, providing thermostat is not calling for the fan.

3. E

When thermostat sends a signal to E, a 24-vac signal is sent to sequencer/relay number 3. The 24-vac signal applied to sequencer/relay

number 3 turns on third stage of electric heat. The 24-vac signal applied to sequencer/relay number 1 turns on first stage of electric heat

and fan. When thermostat stops calling for electric heat, the signal to sequencers/relays 1, 2, and 3 are turned off, and sequencers/relays

open. This causes electric heat to turn off with fan providing thermostat is not calling for the fan.

NOTE: Electric heaters are factory wired with all stages tied together. If independent staging is desired, consult outdoor thermostat installation

instructions, or corporate thermostat instructions.

PROCEDURE 3—TROUBLESHOOTING THE PRINTED CIRCUIT BOARD (CES013000-00, 01 / HK61EA002)

Use wiring schematics shown in Fig. 30 and 29 as a guide in troubleshooting PCB unless otherwise noted.

A. If Fan Will Not Turn On from Thermostat:

IF THERE IS NO HIGH VOLTAGE TO TRANSFORMER:

1. Check plug/receptacle connection. This supplies power from heaters to PCB Fan Relay. Be sure plug is connected properly.

2. Check sequencer/relay number 1 and plug wiring. Yellow wire should be connected to pin number 9 of plug and to limit switch. Black wire

should be connected to pin number 7 of plug and to sequencer/relay number 1.

3. Check field power leads L1 and L2. If these are not receiving power, system cannot function.

If Transformer Has High Voltage Applied To It:

1. Check low-voltage transformer leads R (red) and C (brown). Be sure they are wired to correct locations.

2. Check output voltage of transformer secondary side R (red) and C (brown). Be sure transformer output is between 18 and 30 vac. If

transformer output is incorrect and transformer is receiving correct input voltage (208v or 230v), then transformer needs to be replaced with

recommended transformer. If no problem exists with transformer secondary, proceed to items 3 and 4.

3. Check low-voltage fuse shown in Fig. 29. If fuse is blown, replace it with an identical 5-amp fuse. The transformer cannot supply power

to board with fuse blown or loose. If fuse blows when unit has power applied to it, the system most likely has 1 of the following problems:

a. Check all 24-v wiring for an electrical short.

Fig. 29—Fan Coil Printed Circuit Board (CES013C00-00,01 / HK61EA002)

A97020

LOW

VOLTAGE

FUSE

FAN RELAY

FUSE

PCB BLOCK WIRING

TIME

DELAY

GRTC

SPT

1005-83-161ACPC-E

94V-0

1005-161

LR40061

CESO130003-01

HSCI

5 AMP

TRG C

SPT

R10

R11

C1C2

JW1

FAN

RELAY

—43—

b. The maximum load on transformer is 40 VA. If load on transformer is excessive, the low-voltage 5-amp fuse will blow to protect

transformer. If load exceeds VA rating of transformer, a larger VA rated transformer needs to be installed. Check sequencers/relays for

excessive current draw.

c. Check wiring of heaters. If a heater is miswired, fuse may blow. If a heater is miswired, correct miswiring by comparing it to heater

wiring label.

4. Check connections on primary side of transformer. If they are not connected properly, the transformer secondary cannot supply the 24-v

signal to energize fan relay. If transformer is receiving correct primary voltage but is not putting out correct secondary voltage, transformer

needs to be replaced.

B. If Electric Heat Stages Will Not Turn On But Fan Will Turn On:

IF THERE IS NO HIGH VOLTAGE TO TRANSFORMER:

1. Check plug connection between heaters and board. This supplies power to transformer and fan. Be sure plug is connected properly.

2. Check sequencer/relay number 1 and plug wiring. Yellow wire should be connected to pin number 9 of plug and to limit switch. Black wire

should be connected to pin number 7 of plug and to sequencer/relay number 1.

3. Check incoming high-voltage power leads. If these are not receiving power, system cannot function.

IF TRANSFORMER HAS HIGH VOLTAGE APPLIED TO IT:

1. Check low-voltage transformer leads R (red) and C (brown). Make sure they are wired to correct location. The unit will not function without

proper connections.

2. Check output voltage of transformer secondary side R (red) and C (brown). If transformer output is low (less than 18 vac), refer to items

3 and 4 of previous "If Transformer Has High Voltage Applied To It" section.

IF TRACES ARE OVERHEATED ON BACK OF PCB:

Usually whenever a trace is blown on PCB, it means either there has been a high-voltage short or high voltage has been applied to low-voltage

circuit. This can be prevented by making sure PCB is wired correctly before PCB has power applied to it.

Fig. 30—Wiring Diagram of 6-Element Sequencer Heater

A94346

1. USE COPPER WIRE (75°C MIN) ONLY BETWEEN DISCONNECT SWITCH AND UNIT.

2. TO BE WIRED IN ACCORDANCE WITH NEC AND LOCAL CODES.

3. TRANSFORMER PRIMARY LEADS, BLUE 208V, RED 230V.

4. IF ANY OF THE ORIGINAL WIRE, AS SUPPLIED, MUST BE REPLACED,

USE THE SAME OR EQUIVALENT TYPE WIRE.

5. REPLACE LOW VOLTAGE FUSE WITH NO GREATER THAN 5 AMP FUSE.

6. 20KW HEATER USES ONE DOUBLE POLE LS ON MIDDLE TOP ELEMENT.

7. 18, 24 AND 30KW HEATERS USE DOUBLE POLE LIMIT SWITCHES.

8. LARGEST HEATERS ARE SHOWN, SMALLER HEATERS WILL HAVE FEWER ELEMENTS AND

COMPONENTS.

9. 1 PHASE HEATERS ARE SHOWN WIRED FOR SINGLE SUPPLY CIRCUIT.

10. USE 60 AMP CLASS K FUSES ONLY, FOR REPLACEMENT.

11. (3) SPEED MOTOR SHOWN. OPTIONAL (2) SPEED MOTOR USES HI

(BLK) AND LOW

(BLU OR RED).

12. CONNECT R TO R, G TO G, ETC., SEE OUTDOOR INSTRUCTION FOR DETAILS.

13. IF WIRE CRIMP IS REMOVED AN EMERGENCY HEAT RELAY

IS REQUIRED.

(SEE OUTDOOR-THERMOSTAT INSTRUCTIONS)

THIS COMPARTMENT MUST BE CLOSED EXCEPT FOR SERVICING

CAUTION:

ATTENTION:

NOT SUITABLE FOR USE ON SYSTEMS EXCEEDING

150V TO GROUND

BLOWER MOTOR

ROTATION

CAP

COM

GND

HVTB

HTR

CAPACITOR

COMMON

LOW VOLTAGE FUSE

FAN MOTOR

FIELD POWER WIRING

PCB FAN RELAY

LINE FUSE

EQUIPMENT GROUND

HIGH VOLTAGE TERM BLOCK

HEATER

PCB

SEQ

TRAN

RECP

LEGEND

321214-101 REV. C

30KW 1PH SCHEMATIC DIAGRAM

FIELD POWER WIRING

DISCONNECT PER NEC

SEE RATING PLATE

FOR VOLTS & HERTZ

GND

HTR6

BLK

LS6

YEL

FU6

BLK

FU5

YEL BLK

HTR5

BLK

LS5

SEQ 3

BLK

HTR4

BLK

YEL

LS4

YEL

BLK

YEL

BLK

HTR3

BLK

LS3

SEQ 2

BLK

HTR2

BLK

YEL

LS2YEL

BLK

YEL

BLK

HTR1

BLK

LS1

SEQ 1

BLK

LIMIT SWITCH

MARKED TERMINAL

PLUG AND RECEPTACLE

PRINTED CIRCUIT BOARD

SEQUENCER

TRANSFORMER

UNMARKED TERMINAL

RECEPTACLE

CIRCUIT BREAKER

BLK

BLU

YEL

SEE NOTE #1

NOTES:

GRY

OUTDOOR

UNIT

WHT

GRY

RED

BRN

INDOOR

THERMOSTAT

RED

WHT

VIO

BRN

RECP

PLUG

SPT

PCB

BLK

BLU BLK

230V

208V

YEL

BRN

YEL

YEL-COM

CAP

BRN

GRN/YEL-GND

BLK-HI

BLU-MED

RED-LO

BRN

RED

TRAN

COM

RED

GRAY

VIO

ORN

BRN

BLU

BLK

SEQ1

SEQ3

SEQ2

CB/FU3

CB/FU1

CB/FU4

CB/FU2

HVTB

208/240VAC 24VAC 24VAC

PLUG

L1 L2

FIELD POWER WIRING

FIELD

POWER

WIRING

BLK

YEL

HTR6

BLK

LS6

YEL

FU6

FU5

YEL

BLK

HTR5

BLK

LS5

SEQ 3

BLK

HTR4

BLK

YEL

LS4

YEL

BLK

HTR3

BLK

LS3

SEQ 2

BLK

HTR2

BLK

YEL

LS2YEL

BLK

HTR1

BLK

LS1

SEQ 1

BLK

YEL

CB/FU3

CB/FU1

CB/FU4

CB/FU2

FIELD POWER WIRING

DISCONNECT PER NEC

SEE RATING PLATE FOR VOLTS & HERTZ

GND

BLK

SEE NOTE #1

HVTB

VIO

ORN

SEQ1

11 7 23

RED

PLUG

BRN

GRAY

BRN

SEQ3

SEQ2

164

208/240VAC 24VAC 24VAC

30KW 3PH SCHEMATIC DIAGRAM

RESP

BLK

COOLING CONTROL ONLY

SEE NOTE #13

BARRIER

SEE NOTE #12

BLU

—44—

C. If Transformer Fuse Keeps Blowing:

When low-voltage fuse blows, it means transformer would have blown if fuse had not been in circuit to protect it. The fuse usually blows when

there is a high current draw on transformer, high voltage applied to low-voltage circuit, or a direct secondary short. When there is a high current

draw on transformer, it is most likely because transformer has been shorted or system is trying to draw more VA than transformer rating allows.

When fuse blows because of high voltage, the system has mixed high- and low-voltage signals.

1. Check wiring of sequencers/relays as shown in Fig. 30 and 29. Be sure transformer is not shorting out because thermostat wires are

miswired.

2. Check wiring of sequencers/relays as shown in Fig. 30 and 29. Be sure low-voltage and high-voltage wiring is correct.

3. Check VA draw on transformer. If VA draw is more than VA rating of transformer, fuse will blow. If this is the case, replace transformer

with one that has a higher VA rating and meets system specifications.

D. If Fan Runs Continuously:

1. If PCB has no low-voltage power, check blue and black fan leads. These may be switched at sequencer/relay.

2. If PCB has low-voltage power, check fan relay to see if it is opening and closing. It may be stuck in the normally closed position due to

debris in relay.

E. Transformer Failure:

1. Check 208-v and 230-v transformer connections. They may be miswired.

HK61GA001 AND HK61GA003 CIRCUIT BOARD

FUNCTION & TROUBLESHOOTING

This section of the service manual describes the HK61GA001 and

HK61GA003 printed circuit boards (PCB) by examining the functional operation of the printed circuit board’s components.

PROCEDURE 1—PCB COMPONENT LAYOUT AND DESCRIPTION

Layout of the actual printed circuit boards are depicted in

Fig. 32 and Fig. 33.

Fig. 31—Wiring Diagram of 6-Element Relay Heater

A00173

THIS COMPARTMENT MUST BE CLOSED EXCEPT FOR SERVICING

CAUTION:

ATTENT ION :

NOT SUITABLE FOR USE ON SYSTEMS EXCEEDING

150V TO GROUND

NE CONVIENT PAS AUX INSTALLATIONS DE PLUS DE

150 V A LA TERRE

BLOWER MOTOR

ROTATION

COMPONENT ARRANGEMENT

HTR1 HTR4

HTR3

HTR2

HTR6 HTR5

COM

208 V

230 V

TRAN

RED

24 V

BRN

SYSTEM TRANSFORMER: 40.0VA

FAN COIL/HEATER: 15.2VA

REMAINING VA AVAILABLE: 24.8VA

1. Use copper wire (75°C min) only between disconnect switch and unit.

2. To be wired in accordance with N.E.C. and local codes.

3. If any of the original wire, as supplied, must be replaced, use the same or equivalent type wire.

4. Replace low voltage fuse with no greater than 5 amp fuse.

5. Use 60 amp class K fuses only, for replacement.

6. (3) speed motor shown. optional (2) speed motor uses HI

(BLK) and LOW (BLU or RED).

7. Connect R to R, G to G, etc., see outdoor instruction for details.

8. If wire crimp is removed an emergency heat relay

is required.

(see outdoor-thermostat instructions)

MINIMUM CFM / MOTOR SPEED SELECTION

FAN COIL SIZE

018 024 030 036 042 048 060

LO LO

MOTOR SPEED AT 24 KW

MOTOR SPEED AT 30 KW -- -- -- --

----

SEE NOTE #6

RED-LOW

BLU-MED

BLK-HI

GRN/YEL-GND

BRN

YEL-COM

FAN MOTOR THERMALLY PROTECTED

CAPGND

324994-101 REV. A

SCHEMATIC DIAGRAM

FIELD POWER WIRING

DISCONNECT PER NEC

SEE RATING PLATE

FOR VOLTS & HERTZ

GND

HTR6

BLK

LS6

YEL

FU6

BLK

FU5

YEL

BLK

L3 L5

HTR5

BLK

LS5

RELAY 3

BLK

HTR4

BLK

YEL LS4

YEL

FU4

BLK

YEL

BLK

HTR3

BLK

LS3

RELAY 2

BLK

HTR2

BLK

YEL

LS2

YEL

FU2

BLK

FU1

YEL

BLK

HTR

BLK

LS1

RELAY 1

BLK

BLKBLU

YEL

FU3

YEL

BLKBLU

BLK

BLU

BLK

YEL

SEE NOTE #1

070

NOTES:

BLK

PCB

SPT

PLUG

RECP

BRN

VIO

BLU

WHT

RED

BARRIER

INDOOR

THERMOSTAT

BRN

RED

GRY

WHT

OUTDOOR

UNIT

GRY

SEE NOTE #7

1623

711

FU5

FU3

FU1

FU6

FU4

FU2

GND

SPT

PCB

SEE NOTE #8

230V208V

BRN

RED

TRAN

GRN/YEL

GND

YEL

MED

COM

RED

BLU

YEL

BLK

BRN BRN

CAP

VIO

ORN

RELAY 1

22 VDC COIL

REC

RELAY 3

22 VDC COIL

T D R

RELAY 2

22 VDC COIL

T D R

BRN

GRY

RED

RELAY 3

LEGEND

CAPACITOR

COMMON

LOW VOLTAGE FUSE

FAN MOTOR

FIELD POWER WIRING

PCB FAN RELAY

EQUIPMENT GROUND

FAN SPEED TAP

LOCATION

LINE FUSE

CAP

COM

GND

SPT

HEATER

LIMIT SWITCH

MARKED TERMINAL

PLUG & RECEPTACLE

PRINTED CIRCUIT BOARD

RECTIFIER

TIME DELAY RECTIFIER

TRANSFORMER

UNMARKED TERMINAL

HTR

PCB

REC

TDR

TRAN

RELAY 1

REC

RELAY 2

TDR

GND

—45—

1. The low-voltage terminal board is used to connect the indoor thermostat to the low, 24-v side of the transformer, and to serve as a junction

between the indoor thermostat and the outdoor section.

2. Break off the tabs.

a. W2-3 — Used to control (stage) the second stage of electric heat. The first stage controlling electric heat and the indoor fan are

interlocked through diodes.

b. W2-E — Used to control (stage) the third stage of electric heat.

3. A fuse is used to protect the low-voltage transformer.

4. AUX 1 and AUX 2 are connections for the latent capacity control, delay off kit, 2-speed kit and air conditioning accessories.

5. F1, F2, F3, and F4 are connections for the indoor fan.

6. EAC1 and EAC2 are 240-v connections, which parallel fan lead connections, for the electronic air cleaner.

7. L1 and L2 are 240-v connections which parallel power input.

8. T1, T2 and T3 are connections for the primary, high-voltage side of the transformer.

9. The fan relay is controlled by the thermostat and turns the fan on and off.

10. A plug is used as the connection for the PCB power and electric heaters. Note the pin numbers on the plug.

11. Diodes provide DC power for the fan relay and the first stage of electric heat: W2, W3 or E.

PROCEDURE 2—PCB COMPONENT FUNCTIONS

A. Low-Voltage Terminal Board (HK61GA001, 003)

The low-voltage terminal board connects the indoor thermostat to

the outdoor unit as shown in Fig. 34. The terminals are listed as

follows along with their functional control.

Fig. 32—HK61GA001 Printed Circuit Board

A97025

2FC-1

AUX1

AUX2

DUMMY

COMMON

240 VAC 240 VAC

TRANSFORMER

AC LINE

FAN

RELAY

24VDC

FAN

EAC2L2T3T2T1

EAC1L1

123

456

789

101112

HK61GA001A

W2-3W2-E

5 AMP

FUSE

MAX

FAN

TDB

LOW VOLTAGE

TERMINAL BOARD

2ND STAGE

3RD STAGE

NOT USED

FUSE

(LOW VOLTAGE)

CONNECTIONS

FOR VARIOUS

ACCESSORIES

FAN CONNECTIONS

ELECTRONIC AIR

CLEANER CONNECTIONS

ELECTRIC HEAT

BREAKOFF TABS

FOR STAGING

HK61GA001

PLUG

INTERLOCK

DIODES

TRANSFORMER

CONNECTIONS

—46—

1. R is used to connect the secondary side of the transformer. The red wire provides low voltage (24v) to the PCB and the thermostat. R is

fused on the HK61GA003 board.

2. C is used to connect the brown wire of the thermostat to provide a return path to ground through the fuse which protects the transformer.

C is fused on the HK61GA001 board.

3. G is used to control the switching of the relay to turn the fan on through the normally open contact of the relay. Y on the HK61GA001

is used as the junction for the outdoor section’s Y connection which controls the compressor contactor for heat pump and cooling modes.

The HK61GA003 board contains a 90-sec fan-off delay which begins timing when the Y is de-energized.

4. O is used as a junction for a heat pump reversing valve circuit.

5. W2 is used to turn on the first stage of electric heat which is interlocked with the fan through the normally closed fan relay. Unless the tabs

are broken off, all stages of electric heat will turn on when W2 receives a signal from the thermostat.

6. W3 is used to turn on the second stage of electric heat. Note the W2 and W3 tab must be broken off for individual staging to take place.

Energizing W3 will always turn on the first stage through the diodes even if the tabs are broken off.

7. E is used to turn on the third stage of electric heat. Note that the W3 and E tab must be broken for this individual staging. Energizing E

will always turn on the first stage through the diodes even if the tab is broken off.

8. L is used as a junction to wire a diagnostic light (LED) on selected thermostats.

B. Transformer

The proper wiring of the transformer on the HK61GA001 board is illustrated in Fig. 34. Note that T1, T2, and T3 are wired to the primary or high

side of the transformer. The blue wire is connected to T3 for 208-v applications. The red wire is connected to T3 for 230-v applications. Units

are factory wired at 230v. The T2 terminal is a dummy.

C. Indoor Fan

1. Wiring--The fan connects to F1, F2, F3, and F4 as shown in Fig. 34. Note that F2 and F3 are dummy terminals. The desired fan speed is

connected to F4 and the common is connected to F1. Units are factory wired at medium speed.

2. Functional Control

Fig. 33—HK61GA003 Printed Circuit Board

A97026

36912

25811

14710

LOW VOLTAGE

TERMINAL BOARD

2ND STAGE

3RD STAGE

FUSE

(LOW VOLTAGE)

CONNECTIONS

FOR VARIOUS

ACCESSORIES

FAN CONNECTIONS

ELECTRIC HEAT

BREAKOFF TABS

FOR STAGING

HK61GA003

PLUG

TRANSFORMER

CONNECTIONS

ELECTRONIC AIR

CLEANER CONNECTIONS

FAN INTERLOCK

DIODES AND FAN

TIME DELAY OFF

CIRCUIT

AUX1

AUX2

DUMMY

COMMON

240 VAC 240 VAC

TRANSFORMER

AC LINE

FAN

RELAY

24VDC

FAN

EAC2L2T3T2T1

EAC1L1

HK61GA003

W2-3

5 AMP

FUSE

MAX

2FD-1

W2-E

—47—

Fig. 34— Typical HK61GA001 View

10kw to 20kw Circuits

A97027

2FC-1

AUX1

AUX2

DUMMY

COMMON

240 VAC 240 VAC

TRANSFORMER

AC LINE

RELAY

24VDC

FAN

EAC2L2T3T2T1

EAC1L1

123

456

789

101112

HK61GA001A

INDOOR

THERMOSTAT

W2-3W2-E

5 AMP

FUSE

MAX

FAN

TDB

YEL

LS 5 HTR5 BLK

BLK

10 9

YEL

FU5 FU6

SEQ 3

LS 6 HTR6 BLK

BLK

12 11

YEL

LS 5 HTR5 BLK

BLK

YEL

FU3 FU4

SEQ 2

LS 4 HTR4 BLK

BLK

YEL

LS 1 HTR1 BLK

BLK

BLU-MED

RED-LO

BRN

CAP

YEL

FU1 FU2

SEQ 1

LS 2 HTR2 BLK

BLK

SEQ1

GRAY

YEL

BLU

BLK

GRAY

BRN

BLK

COMM

TRAN BRN (24V)

RED (24V)

BLU

YEL

VIO

ORG

RED

SEQ2SEQ3

BLK-HI

GRN/YEL-GND

YEL-COM

BLU

(208V)

RED

(230V)

LOW VOLTAGE

TERMINAL BOARD

CONNECT E TO E

C TO C ETC.

—48—

a. Thermostat and Relay Control--When the thermostat calls for the fan in cooling, heat pump, electric heat, or fan-only mode, a 24-v dc

signal is sent to the relay. This causes the relay to close its normally open contacts, thus turning on the fan. When the thermostat no longer

calls for the fan, the signal sent to the relay is turned off and the relay opens causing the fan to turn off. The HK61GA003 board contains

a 90-sec fan-off delay when Y is de-energized.

a. Sequencer Interlock--The fan will also turn on whenever there is any call for electric heat, even if the fan relay is not energized. This

happens because the fan is interlocked with the first stage of electric heat through the normally closed contact of the fan relay.

D. Electric Heat

When the thermostat calls for electric heat, a 24-v signal is sent to the PCB through W2, causing the first stage to turn on. W3 and E also receive

the signal if the tabs are not broken off the PCB. The signal sent to W2 causes the first stage to turn on. If the tabs are broken off the PCB, the

sequencers can be controlled individually to stage the electric heat. The sequence control is described in the following section:

1. W2--When the thermostat sends a signal to W2, a 24-v dc signal is applied across sequencer number 1, causing it to close. When sequencer

number 1 closes, the first stage of electric heat energizes after a short delay. In straight electric heat, the fan is also energized through the

normally closed contacts of the fan relay. In cooling, heat pump, or manual fan mode, the fan will already be running since the fan relay

would have been energized. When the thermostat stops calling for electric heat, the 24-v dc signal to sequencer number 1 turns off and the

sequencer opens after a delay of 60 to 90 sec. When the sequencer opens, the first stage of heat turns off along with the fan, providing that

the thermostat is not calling for the fan. Note that the electric heat cannot be turned on without the fan being turned on at the same time.

This is a fan interlock system.

2. W3--When a signal is sent to W3, 2 control signals are sent out to the sequencers; a 24-v dc signal to sequencer number 1 through the diode

interlock, and a 24-vac signal to sequencer number 2. The 24-vac signal applied to sequence number 2 causes the sequencer to close, with

the second stage of electric heat turning on after a short delay.

The 24-v dc signal applied to sequencer number 1 causes the first stage of electric heat to turn on in the same manner as described in W2 above.

Note that W3 is interlocked with the fan, since sequencer number 1 is turned on whenever W3 has a signal sent to it. Timing is such that sequencer

number 1 will turn on before sequencer number 2. When the signal to W3 is turned off, sequencer number 2 opens after a short delay. If W2 is

also satisfied, the first stage of electric heat and the fan will also turn off, providing the thermostat is not calling for the fan to be on.

E--When the thermostat sends a signal to E 2 signals are sent out to the sequencers. A 24-vac signal is sent to sequencer number 3 and a 24-v

dc signal is sent to sequencer number 1. The 24-vac signal applied to sequencer number 3 turns on the third stage of electric heat. The 24-v dc

signal applied to sequencer 1 turns on the first stage of electric heat and the fan in the same manner as W3. Note that E is also interlocked with

the fan.

When the thermostat stops calling for electric heat, the signals to sequencers 1 and 3 are turned off and the sequencers open. This causes the electric

heat to turn off with the fan if the thermostat is not calling for the fan.

E. Accessories (HK61GA001, 003)

1. EAC1 and EAC2 for Electronic Air Cleaners

a. There are 240-v electronic air cleaner contacts provided at EAC1 and EAC2. The electronic air cleaner is connected in parallel with the

fan so that it is on whenever the fan is on. A 120-v installation is similar in function but connected between EAC2 and neutral of 230-v:

120-v transformer connected to EAC1 and EAC2. Refer to electronic air cleaner literature for further information.

2. AUX1 and AUX2 for 2-Speed Fan Relay Kit

a. Use to control fan speed operation, high speed for cooling, heat pump, and fan-only modes. Low speed is used for electric heat. Fig. 35

shows proper connection for 24-v dc 2-speed fan relay kit. Note that kit’s relay coil is in parallel with fan relay coil on PCB connected

to AUX1 and AUX2. Make sure the normally closed contact is connected to the lower speed.

b. The latent capacity control kit is used to control fan speed operation when the relative humidity is above a set point on humidistat.

Humidistat opens and 2-speed fan relay remains in normally closed position with fan motor running at a lower speed for maximum

humidity control. Fig. 36 shows proper connection for latent capacity control kit. Note that it is connected in the same manner as 2-speed

fan relay kit but with relay connected to humidistat (orange wires).

c. Time delay-off relay kit is used to increase the efficiency of the system by delaying the fan from turning off after the thermostat is

satisfied on the HK61GA001 board. The HK61GA003 board has this feature as standard. The proper wiring and mounting of the time

delay-off relay kit is shown in Fig. 37.

d. Latent capacity control and time delay-off connections are shown in Fig. 38, for the HK61GA001 board only.

PROCEDURE 3—TROUBLESHOOTING THE PRINTED CIRCUIT BOARD (HK61GA001, 003)

Use Fig. 39 wiring schematic as a guide in troubleshooting the

PCB unless otherwise noted.

A. If the fan will not turn on from the thermostat:

IF THERE IS NO HIGH VOLTAGE TO THE PCB:

1. Check the plug/receptacle connection; this brings power to the PCB. Make sure the plug is connected properly.

2. Check sequencer number 1 and the plug’s wiring; the yellow wire should be connected to pin number 9 of the plug and the limit switch.

A black wire should be connected to pin number 7 of the plug and to sequencer number 1.

3. Check power leads L1 and L2. If these are not receiving power, the system cannot function.

IF THE PCB HAS HIGH VOLTAGE APPLIED TO IT:

1. Check the low-voltage transformer leads, R and C. Make sure they are wired to the correct locations. Note that Fig. 39 shows wiring of

the HK61GA001 board.

—49—

Fig. 35—Two-Speed Fan Relay Kit

A97028

W3 W2 E G C

2-05868-2A

TWO SPEED FAN

RELAY WIRING

LOW VOLTAGE BOARD

FAN RELAY

CIRCUIT BOARD

MARKED TERMINAL

UNMARKED TERMINAL

FIELD CTRL WIRING

FACTORY POWER WIRING

FIELD POWER WIRING

AUX

24 VDC

ORG

RED

LOW MTR SPD

HI MTR SPD

FAN COMMON

UNUSED LEAD

BLK

208/240 VAC

COM

F3 F2

O Y R

TRANSFORMER

LINE

COMMON

DUMMY

2SD-1

AUX1

AUX2

VAC

EAC2

FAN

EAC1

AUX 1

AUX 2

ORG

RED

BLK

YEL

NO TO

HIGHER

FAN SPEED

LOW-VOLTAGE

COIL TERMINALS

NC TO

LOWER

FAN SPEED

DUMMY TERMINALS FOR

UNUSED FAN MOTOR

SPEED-TAP

LEADS

FAN MOTOR

COMMON LEAD

—50—

Fig. 36—Latent Capacity Control Kit

A97029

VAC

W3 W2 E G C

2-05868-1A

LATENT CAPACITY

CONTROL WIRING

LOW VOLTAGE BOARD

FAN RELAY

CIRCUIT BOARD

HST HUMIDISTAT

MARKED TERMINAL

UNMARKED TERMINAL

FIELD CTRL WIRING

FACTORY POWER WIRING

FIELD POWER WIRING

AUX

24 VDC

RED

LOW MTR SPD

HI MTR SPD

FAN COMMON

UNUSED LEAD

BLK

208/240 VAC

HST

ORG

COM

F3 F2

O Y R

TRANSFORMER

LINE

COMMON

DUMMY

2SD-1

AUX1

AUX2

EAC2

FAN

EAC1

AUX 1

AUX 2

RED

BLK

YEL

NO TO

HIGHER

FAN SPEED

ORANGE WIRES

TO HUMIDISTAT

NC TO

LOWER

FAN SPEED

FAN MOTOR

COMMON LEAD

—51—

Fig. 37—Time Delay-Off Relay Kit

A97030

W3 W2 E G C

2-05868-3A

TIME DELAY

RELAY WIRING

LOW VOLTAGE BOARD

FAN RELAY

CIRCUIT BOARD

TDR TIME DELAY RELAY

MARKED TERMINAL

UNMARKED TERMINAL

FIELD CTRL WIRING

FACTORY POWER WIRING

FIELD POWER WIRING

AUX

24 VDC

TDR

YEL

FAN COMMON

UNUSED LEAD

BLK

208/240 VAC

COM

F3 F2

O Y R

TRANSFORMER

LINE

COMMON

DUMMY

2FC-1

HK61GA001

AUX1

AUX2

EAC2

FAN

EAC1

TO FAN MTR

SPEED TAP

VIO

BRN

YEL

BLK

BRN

VIO

FAN

MOTOR

COMMON

LEAD

FAN

MOTOR

SPEED-TAP

LEAD

—52—

Fig. 38—Latent Capacity Control and Time Delay-Off Relay Kits

A97031

W3 W2 E G C

2-05868-4A

TIME DELAY RELAY

TWO SPEED FAN RELAY

(LATENT CAPACITY)

LOW VOLTAGE BOARD

FAN RELAY

CIRCUIT BOARD

HST HUMIDSTAT

TDR TIME DELAY RELAY

MARKED TERMINAL

UNMARKED TERMINAL

FIELD CTRL WIRING

FACTORY POWER WIRING

FIELD POWER WIRING

AUX

24 VDC

TDR

ORG

RED

YEL

FAN COMMON

UNUSED LEAD

LOW MTR SPD

HI MTR SPD

BLK

208/240 VAC

COM

F3 F2

O Y R

COM

TRANSFORMER

LINE

COMMON

DUMMY

2SD-1

VAC

EAC2

FAN

EAC1

VIO

BRN

YEL

VIO

FAN

MOTOR

COMMON

LEAD

RED

ORG

BLK

BRN

YEL

AUX 2

AUX 1

ORG

BLU

LOW-VOLTAGE

COIL TERMINALS

TO HUMIDISTAT

(OPTIONAL, SHOWN

WITH DASHED LINES)

NO TO

HIGHER

FAN SPEED

NC TO

LOWER

FAN SPEED

HST

—53—

Fig. 39—Wiring Schematic (HK61GA001)

A97032

DUMMY

240 VAC 240 VAC COMMON

240 VDC

COMMON

AC LINE

123

456

789

1011

PLUG

RELAY

L2 EAC2

AUX1

C 5 AMP

FUSE

MAX

AUX2

L1 EAC1

FAN

R L G E COYW2

INDOOR THERMOSTAT

YEL

YEL BLK

LS 3 HTR3 BLK

BLK

YEL

FU1 FU2FU3 FU4

SEQ 2

LS 4 HTR4 BLK

BLK

YEL

LS 1 HTR1 BLK

BLK

YEL

SEQ 1

LS 2 HTR2 BLK

BLK

SEQ1

SEQ2

BLU

BLK

YEL

BLU

BLK

BRN

RED

VIO

ORG

TERM BOARD

BLU-MED

RED-LO

BRN

CAP

BLK-HI

GRN/YEL-GND

YEL-COMMON

RED

(230V)

BLU

(208V)

RED

(24V)

BLK

COMM

BRN

COMM

TRAN

ON TERMINAL BOARD ABOVE

—54—

2. Check the output voltage of the secondary side, R and C, of the transformer. If the circuit board is a HK61GA003, make sure the ground

strap is in place from C to the bracket. This strap must be in place to complete the 24-v circuit. Make sure the transformer output is around

24-vac. If the transformer output is zero-vac and the transformer is receiving the correct input voltage (208-v or 240-v), then the transformer

needs to be replaced with the recommended transformer. If the transformer output is 24-vac, then proceed to 3 and 4.

3. Check the low-voltage fuse shown in Fig. 32 and Fig. 33. If the fuse is blown, replace it. The transformer cannot supply power to the board

with the fuse blown or loose. If the fuse blows when the unit has power applied to it, the system most likely has 1 of the following problems:

a. If the transformer is shorting out, check the wiring of the transformer.

a. The maximum load on the transformer is 40 VA. If the load on the transformer is excessive, the low-voltage, 5-amp fuse will blow to

protect the transformer. If the load exceeds the VA rating of the transformer, a larger VA rated transformer needs to be installed. Check

the sequencers for excessive current draw.

b. Check the wiring of the heaters. If the heater is miswired, the fuse may blow. Check the diodes shown in Fig. 40 for signs of overheating.

If the heater is miswired, correct the miswiring.

4. Check the T1, T2, and T3 connections on the primary side of the transformer. If they are not connected properly, the low-voltage terminal

board cannot supply the 24-v signal to energize the fan relay. If the transformer is receiving the correct primary voltage but is not outputting

the correct secondary voltage, the transformer needs to be replaced.

B. If the electric heat stages will not turn on but the fan will turn on:

1. Check the wiring of the sequencer. Pay particular attention to the high and low-voltage wiring of the sequencers.

2. Check the plug wiring to make sure that it is wired correctly.

3. Check the voltage to the sequencer; sequencer number 1 receives a 24-vac signal. If it is receiving the correct voltage, check to see if the

sequencer is closing. If the sequencer is not closing but is receiving the correct voltage, replace the sequencer. If the sequencer is closing,

check the high-voltage wiring as discussed in 1 and 2.

C. If the electric heat and the fan will not turn on:

IF THERE IS NO HIGH VOLTAGE TO THE PCB:

1. Check the plug connection. This brings power to the PCB transformer and the fan. Make sure the plug is connected properly.

2. Check sequencer number 1 and the plug wiring. The yellow wire should be connected to pin number 9 of the plug and the limit switch.

The black wire should be connected to pin number 7 of the plug and to sequencer number 1.

3. Check incoming high-voltage power leads. If these are not receiving power, the system cannot function.

IF THE PCB HAS HIGH-VOLTAGE APPLIED TO IT:

1. Check the low-voltage transformer leads, R and C. Make sure they are wired to the correct location. The unit will not function without

proper connections.

2. Check the output voltage of the secondary side, R and C, of the transformer. If the circuit board is an HK61GA003, make sure the ground

strap is in place from C to the bracket. This strap must be in place to complete the 24-v circuit. If the transformer output is zero-vac, refer

to "If the PCB has high voltage applied to it" in column 1, numbers 3 and 4.

D. If the traces are burnt off the back of the PCB:

Usually whenever there is a trace blown on the PCB it means either there has been a high-voltage short or high voltage has been applied to the

low-voltage circuit. This can be prevented by making sure the PCB is wired correctly before the PCB has power applied to it.

E. If there are blown diodes:

1. If diodes a and b are blown, it is probable the electric heater plug was miswired. Correct the miswiring. It should be noted the board will

need to be replaced if the diode indicated is bad.

2. If any of the c diodes are blown, the fan is miswired to 1 of the low-voltage terminals, AUX1 or AUX2. Check to make sure that the fan

leads are connected to the proper terminals as shown in Fig. 39. If the fan is connected properly, make sure that no other high voltage is

applied to the AUX terminals.

F. The PCB fuse keeps blowing:

When the low-voltage fuse blows, it means the transformer would have just blown if the fuse had not been in the circuit to protect it. The fuse

usually blows when there is a high current draw on the transformer, high voltage applied to the low-voltage circuit, or a direct secondary short.

When there is a high current draw on the transformer, it is most likely because the transformer has been shorted or the system is trying to draw

more VA than the transformer is rated for. When the fuse blows because of high voltage, the system has mixed high- and low-voltage signals.

1. Check the transformer and thermostat wiring as shown in Fig. 37. Make sure the transformer is not shorting out by the thermostat wires

being miswired.

2. Check the wiring of the sequencers as shown in Fig. 39. Make sure the low-voltage and the high-voltage wiring are connected to the proper

sequencers.

3. Check the VA draw on the transformer. If the VA draw is more than the VA rating of the transformer, the fuse will blow. If this is the case,

replace the transformer with 1 that has a higher VA rating and meets system specifications.

G. The fan runs continuously:

1. If the PCB has no low-voltage power, check the blue and black fan leads. These may be switched at the sequencer.

2. If the PCB has low-voltage power, check the fan relay to see if it is opening and closing. It may be stuck in the normally closed position

due to debris in the relay.

—55—

H. Transformer failure:

1. Check the 208-v and 240-v taps connected to T1, and T3. They may be miswired.

I. Replacement Motor Position:

The position of the blower motor should be properly located in the blower housing to reduce any frequency pulsations. The position is generated

based upon the bellyband placement around the center of the motor as shown in Fig. 41. Do not cover motor vent holes or the motor will overheat.

Table 15 shows the position of the motor from center.

ELECTRIC HEATER FUNCTION AND

TROUBLESHOOTING

This section describes KFA, KFB, KFC, and KFD series electric heaters in exclusion of Smart Heat by examining the functional operation of these

heaters.

PROCEDURE 1—DESCRIPTION OF ELECTRIC HEATER COMPONENTS

A. Limit Switch

The limit switch is a temperature sensitive control whose function is to prevent system from overheating in abnormal conditions. The temperature

settings often vary from heater to heater due to variations in airflow patterns and element radiant heat conditions. The devices are sized to remain

on-line under heat pump conditions (115°F air off coil) and minimum CFM, but trip to prevent outlet air conditions above 200°F or excessive

component or duct temperatures.

The device itself consists of a bimetallic disc, which when overheated "snaps through" to open a normally closed high-voltage, high-current switch.

When system temperatures cool sufficiently, the switch will automatically reset to its closed position. Normal failure mode for this switch is open.

If a limit switch has been determined to be defective, NEVER BYPASS THE LIMIT SWITCH. When replacing limit switch, ensure that it is

replaced with a limit switch of identical opening temperature and closing differential. Limits switches are typically color coded to identify their

range.

Fig. 40—Control Board Noting Diodes (HK1GA001)

A97033

123

456

789

101112

2FC-1

AUX1

AUX2

DUMMY

COMMON

240 VAC 240 VAC

TRANSFORMER

AC LINE

RELAY

24VDC

FAN

EAC2L2T3T2T1

EAC1L1

HK61GA001A

W2-3W2-E

5 AMP

FUSE

MAX

FAN

TDB

BLOWN

DIODE

(c)

BLOWN

DIODE

(a)

BLOWN

DIODE

(b)

Table 15—Replacement Motor Position

FA4, FB4, FC4, FX4 -030 Out ’3/8″

FA4, FB4, FC4, FX4, -036 Out ’3/4″

FA4, FB4, FC4, FX4 -060 In ’1/2″

FA4, FB4, FC4, FX4 -018, 024, 042, 048 Center

—56—

B. KFA and KFB Sequencer

The sequencer is essentially a thermally activated time-delay relay normally activated by low-voltage control signals from thermostat. The typical

sequencer is a 1- or 2-pole normally open device which energizes within 30 to 70 sec after application of control signal and de-energizes 60 to

90 sec after control signal is removed.

In simplistic terms, the sequencers which we use are nothing more than normally open limit switches which sit on top of a small resistive heater.

When voltage is applied to this heater, a positive temperature coefficient resistor (PTC), heat is supplied to a bimetallic disc which "snaps through"

and closes switch.

The time required for PTC to heat to a sufficient point controls ON timing of device. The time required for disc to cool down when power is

removed controls OFF time of device. The PTC can be varied to provide varied timing. Typically a short ON equates to a long OFF.

Because this is a thermally-activated device, ambient conditions affect the ON/OFF cycle. Higher ambient temperature means shorter ON times

and longer OFF times.

These sequencers may be "ganged up" to 3 on a common mounting plate to control up to 6 heater elements. In this situation, PTCs are different

in each sequencer to provide a staged ON of a minimum of 10 sec between each sequencer — 3 stages of 2 elements since the KFA and KFB

series heaters use sequencers in which both switches of the 2-pole sequencer close simultaneously. Older models used sequencers which had a

minimum delay of 10 sec between each switch.

Application of these devices is such that the first switch ON not only turns on first heater element, but also ensures that indoor fan is energized,

because first ON is last OFF. This ensures fan remains ON until the last heater de-energizes.

C. KFC and KFD Electric Heat Relay

KFC and KFD electric heater packages have relays controlling the heater elements instead of sequencers. A small rectifier PCB is mounted to each

relay which converts the incoming 24-vac control signal to dc. In addition to the rectifier circuit, the second and third stage relays contain a time-on

delay circuit of 5 seconds for second stage, and 8 seconds for third stage. When the control signal is removed from the relays, all relays will open

with no time-off delay.

PROCEDURE 2—TROUBLESHOOTING KFA, KFB, KFC, AND KFD

SERIES ELECTRIC HEATERS

A. Discolored Wire Insulation at Terminal

Check quick-connect terminal at discoloration. Connection may be loose, creating a high resistance through connection point.

B. Fuse Failure

1. Check for shorted wire. Replace wire. Never try to fix wire using electrical tape.

2. Check shorted element. If element is shorted, replace heater.

C. No Heat

1. Check fuse for failure. If fuse has failed, refer to Fuse Failure section.

2. Check for faulty transformer. Check output voltage of transformer secondary side R (red) and C (brown). Make sure output is between 18

and 30 vac. If output voltage is low and input voltage tests normal, replace transformer.

3. Check for miswired heater plug harness.

4. Check limit switch or sequencer failure. These switches should have failed in open position. If output voltage is zero volts, replace switch.

5. Check heater relay and PCB (KFC and KFD heaters only). Control voltage input to PCB should be 24-vac. Output to relay should be 18-vdc

minimum. If input is present but no output, replace PCB. If output is present, replace relay.

Fig. 41 - Motor Position from Center

A04161

—57—

D. Heater Will Not Turn Off

1. Check low-voltage wiring for miswire.

2. Check for shorted elements to ground.

3. Replace sequencer/relays. They may be stuck closed.

E. Nuisance Trips

1. Check for low airflow due to dirty filters, blocked registers, or undersized duct.

2. Check blower motor and wheel for proper operation. Excessive current draw of motor will cause internal overload to trip.

3. The fan speed may be low.

THERMOSTATIC EXPANSION VALVES (TXV)

The FC4, FK4, FX4, FV4, and 40FK Fan Coils are factory equipped with a hard shutoff (HSO) TXV.

The hard shutoff TXV has no bleed port and allows no bleed-through after system is shutdown. A start capacitor and relay must be installed on

single-phase reciprocating compressors to boost torque to compressor motor so it may overcome the unequalized system pressures.

The standard TXV is a bi-flow metering device that is used in condensing and heat pump systems to adjust to changing load conditions by

maintaining a preset superheat temperature at outlet of evaporator coil. The volume of refrigerant metered through valve seat is dependent upon

the following:

1. Superheat temperature sensed by sensing bulb on suction tube at outlet of evaporator coil. As long as this bulb contains some liquid

refrigerant, this temperature is converted into pressure pushing downward on the diaphragm, which opens the valve via push rods.

2. The suction pressure at outlet of evaporator coil is transferred via the external equalizer tube to underside of diaphragm.

3. The needle valve on pin carrier is spring-loaded, which also exerts pressure on underside of diaphragm via push rods, which closes valve.

Therefore, bulb pressure equals evaporator pressure at outlet of coil plus spring pressure. If load increases, temperature increases at bulb,

which increases pressure on topside of diaphragm, which pushes pin carrier away from seal, opening valve and increasing flow of

refrigerant. The increased refrigerant flow causes increased leaving evaporator pressure which is transferred via the equalizer tube to

underside of diaphragm, with which the pin carrier spring pressure closes valve. The refrigerant flow is effectively stabilized to load demand

with negligible change in superheat.

The bi-flow TXV is used on split system heat pumps. In cooling mode, TXV operates the same as a standard TXV previously explained. However,

when system is switched to heating mode of operation, refrigerant flow is reversed. The bi-flow TXV has an additional internal check valve and

tubing. These additions allow refrigerant to bypass TXV when refrigerant flow is reversed with only a 1- to 2-psig pressure drop through device.

When heat pump switches to defrost mode, refrigerant flows through a completely open (not throttled) TXV. The bulb senses the residual heat

of outlet tube of coil that had been operating in heating mode (about 85°F and 155 psig). This temporary, not throttled valve, decreases indoor

pressure drop, which in turn increases refrigerant flow rate, decreases overall defrost time, and enhances defrost efficiency.

PROCEDURE 1—PROBLEMS AFFECTING TXV

A. Low Suction Pressure

1. Restriction in TXV

2. Low refrigerant charge

3. Low indoor load

4. Low evaporator airflow

B. High Suction Pressure

1. Overcharging

2. Sensing bulb not secure to vapor tube

3. High indoor load

4. Large evaporator face area

When installing or removing TXV, wrap TXV with a wet cloth. When reattaching TXV, make sure sensing bulb is in good thermal contact with

suction tube.

PISTON BODY CLEANING OR REPLACEMENT

CAUTION: Do not vent refrigerant to atmosphere. Recover during system repair or final unit disposal.

CAUTION:

UNIT DAMAGE HAZARD

Failure to follow this caution could result in equipment damage.

Damage may occur to the scroll compressor if operated at a negative suction pressure during a system pumpdown.

1. Pump down outdoor unit. Close service valves at outdoor unit.

2. Recover remaining refrigerant from tubing and coil through gage port on vapor-tube service valve. Disconnect refrigerant (liquid) tube from

piston body. (See Fig. 42.)

—58—

3. Avoid damaging seal ring or machined surfaces on piston, bore, and retainer.

4. Using small wire with a hook on end of it, remove piston from body.

CAUTION: UNIT DAMAGE HAZARD

Failure to follow this caution could result in equipment damage.

When cleaning the piston orifice, be careful not to scratch or enlarge the opening, as this will affect operation.

5. Install new or cleaned piston into body.

6. Replace seal ring on retainer.

7. Reconnect refrigerant tube to piston body.

8. Pressurize tubing and coil, then leak check.

9. Evacuate tubing and coil as necessary.

CAUTION: UNIT DAMAGE HAZARD

Failure to follow this caution could result in equipment damage.

Use a backup wrench and do not over tighten, as deformation of the piston body will occur, causing the piston to lodge in a partially

open or closed position.

LIQUID TUBE STRAINER

In R-22 units, the TXV and refrigerant flow-control device is protected on the indoor coil by a wire mesh strainer. It is located inside the 3/8-in.

liquid tube at field braze joint just outside unit casing. Access to strainer is through field braze joint.

FV, FA, FB, FC, FK COIL/CONDENSATE PAN REMOVAL

AND REPLACEMENT

PROCEDURE 1—A-COIL UNITS

If it is determined that system does not have leaks and refrigerant is not contaminated, proceed as follows:

1. Recover system refrigerant.

a. Attach manifold/gage set to service valves.

b. Front seat (close) liquid tube service valve.

c. Start unit in cooling mode.

d. Run unit until low pressure switch opens at 27 psig or vapor pressure reaches 5 psig (35kPa). Do not allow compressor to pump into

a vacuum.

e. Turn off electrical supply to outdoor unit.

f. Front seat vapor service valve.

g. Recover any remaining refrigerant.

NOTE: All outdoor unit coils will hold only factory-supplied amount of refrigerant. Excess refrigerant, such as in long-line applications, may

cause compressor internal pressure relief valve to open (indicated by sudden rise in vapor pressure) before vapor pressure reaches 5 psig (35kPa).

If this occurs, turn off electrical supply to outdoor unit immediately, front seat vapor service valve, and recover any remaining refrigerant.

2. Turn off electrical supply to indoor unit.

3. Disconnect condensate drain tube.

4. Disconnect liquid and vapor tubes from indoor coil. Use a tubing cutter to cut tubes.

NOTE: If a torch is used to unbraze tube set, protect fitting panel with a wet cloth or braze shield, as necessary.

Fig. 42—Refrigerant Flow-Control Device

(For FA, FB, and FF)

A93530

PISTON

RETAINER

BRASS

HEX NUT

BRASS

HEX BODY

TEFLON SEAL

—59—

5. Remove coil access panel.

6. Remove clip securing fitting panel to condensate drain pan. Remove fitting panel.

7. Remove any shipping clips, including horizontal pan clip, and slide coil/condensate pan assembly out of unit.

8. Upflow or Horizontal Applications Only—Remove horizontal condensate drain pan from coil/condensate pan assembly. (See Fig. 43.)

9. Remove 4 coil brackets. (See Fig. 43.)

10. Remove screws at delta plates and remove coil from vertical condensate drain pan. (See Fig. 43.)

11. Horizontal Applications Only—Remove coil top seal (attached with 4 screws) and J-shaped tube from original coil and install it in same

position on new coil. (See Fig. 43.)

12. Place coil assembly in plastic condensate pan and secure using 4 screws through delta plate. (See Fig. 43.)

13. Horizontal and Upflow Applications Only—Attach 4 coil brackets to coil/pan assembly. (See Fig. 43.)

14. Horizontal Applications only—Place horizontal condensate pan into position on coil/pan assembly.

NOTE: Installation of horizontal condensate pan is not necessary for upflow or downflow applications.

15. Slide complete assembly into unit.

16. Reinstall fitting panel and reconnect clip securing fitting panel to condensate drain pan.

17. Horizontal Applications Only—Reinstall horizontal pan clip. Secure with 1 screw. (See Fig. 43.)

18. Reinstall coil access panel.

19. Reconnect liquid and vapor refrigerant tubes, and condensate drain tube. Install new liquid line filter-drier.

20. Evacuate tube set and indoor coil to 500 microns, back seat (open) liquid and vapor service valves.

21. Turn on electrical supplies to indoor and outdoor units.

22. Check system refrigerant charge and operation. See "Split-System Residential Air Conditioners and Heat Pumps Service Manual" for further

information.

PROCEDURE 2—SLOPE COIL UNITS

If it is determined that system does not have leaks and refrigerant is not contaminated, proceed as follows:

1. Recover system refrigerant.

a. Attach manifold/gage set to service valves.

b. Front seat (close) liquid tube service valve.

c. Start unit in cooling mode.

Fig. 43—A-Coil Component Location

A90268

COIL TOP SEA

EXPANSION DEVICE

(TXV SHOWN)

HORIZONTAL

CONDENSATE

PAN

HORIZONTAL

PAN CLIP

DELTA PLATE

VERTICAL

CONDENSAT

PAN

OIL BRACKET

(4 PER UNIT)

SCREWS–

DELTA PLATE TO

PAN (4 PER UNIT)

—60—

d. Run unit until low pressure switch opens or vapor pressure reaches 5 psig (35kPa). Do not allow compressor to pump into a vacuum.

e. Turn off electrical supply to outdoor unit.

f. Front seat vapor service valve.

g. Recover any remaining refrigerant.

NOTE: All outdoor unit coils will hold only factory-supplied amount of refrigerant. Excess refrigerant, such as in long-line applications, may

cause compressor internal pressure relief valve to open (indicated by sudden rise in vapor pressure) before vapor pressure reaches 5 psig (35kPa).

If this occurs, turn off electrical supply to outdoor unit immediately, front seat vapor service valve, and recover any remaining refrigerant.

2. Turn off electrical supply to indoor unit.

3. Disconnect condensate drain tube.

4. Disconnect liquid and vapor tubes from indoor coil. Use either a tubing cutter to cut tubes or a torch to unbraze tubes as required.

NOTE: If a torch is used to unbraze line set, protect fitting panel with a wet cloth or braze shield, as necessary. System contains oil vapors which

may ignite when exposed to a flame.

5. Remove coil access and fitting panels.

6. Remove 1 screw securing coil to unit casing.

7. Remove coil/pan assembly from unit.

8. Place assembly on a flat surface. Remove 2 screws securing coil support columns to pan. (See Fig. 44.)

9. Rotate columns 90°, pull away from coil, and remove columns from assembly.

10. Remove remaining 2 screws securing coil to condensate pan.

11. Remove coil from condensate pan.

12. Remove coil top seal. (See Fig. 44.)

13. Install new coil into condensate pan using 2 original screws and 2 support columns.

NOTE: Correct coil position in condensate pan is essential to reliable operation.

14. Install new coil/pan assembly into unit. Secure with 2 screws previously removed from unit casing.

15. Reinstall coil access and fitting panels.

16. Reconnect liquid and vapor refrigerant tubes, and condensate drain tube. Install new liquid line filter-drier.

17. Evacuate tube set and indoor coil to 500 microns, back seat (open) liquid and vapor service valves.

18. Turn on electrical supplies to indoor and outdoor units.

19. Check system refrigerant charge and operation. See "Split-System Residential Air Conditioners and Heat Pumps Service Manual" for further

information.

FX4 AND FV4 COIL/CONDENSATE PAN REMOVAL

AND REPLACEMENT (PURON REFRIGERANT)

PROCEDURE 1—A-COIL UNITS

If it is determined that system does not have leaks and refrigerant is not contaminated, proceed as follows:

1. Recover system refrigerant.

a. Attach manifold/gage set to service valves.

Fig. 44—Slope Coil Component Location

A98113

COIL MOUNTING

SCREW

COIL

SUPPORT

RAIL

SLOPE

COIL

SKI

REFRIGERANT

CONNECTIONS

COIL TO

PAN SCREW

(BOTH SIDES)

DRAINPAN

—61—

b. Front seat (close) liquid tube service valve.

c. Start unit in cooling mode.

d. Run unit until low pressure switch opens (350kPa) or vapor pressure reaches 5 psig (35kPa). Do not allow compressor to pump into a

vacuum.

e. Turn off electrical supply to outdoor unit.

f. Front seat vapor service valve.

g. Recover any remaining refrigerant.

NOTE: All outdoor unit coils will hold only factory-supplied amount of refrigerant. Excess refrigerant, such as in long-line applications, may

cause compressor internal pressure relief valve to open (indicated by sudden rise in vapor pressure) before vapor pressure reaches 5 psig (35kPa).

If this occurs, turn off electrical supply to outdoor unit immediately, front seat vapor service valve, and recover any remaining refrigerant.

2. Turn off electrical supply to indoor unit.

3. Disconnect condensate drain tube.

4. Disconnect liquid and vapor tubes from indoor coil. Use a tubing cutter to cut tubes.

NOTE: If a torch is used to unbraze tube set, protect fitting panel with a wet cloth or braze shield, as necessary.

5. Remove coil access panel.

6. Remove clip securing fitting panel to condensate drain pan. Remove fitting panel.

7. Remove any shipping clips, including horizontal pan clip, and slide coil/condensate pan assembly out of unit.

8. Upflow or Horizontal Applications Only—Remove horizontal condensate drain pan from coil/condensate pan assembly. (See Fig. 43.)

9. Remove 4 coil brackets. (See Fig. 43.)

10. Remove screws at delta plates and remove coil from vertical condensate drain pan. (See Fig. 43.)

11. Horizontal Applications Only—Remove coil top seal (attached with 4 screws) and J-shaped tube from original coil and install it in same

position on new coil. (See Fig. 43.)

12. Place coil assembly in plastic condensate pan and secure using 4 screws through delta plate. (See Fig. 43.)

13. Horizontal and Upflow Applications Only—Attach 4 coil brackets to coil/pan assembly. (See Fig. 43.)

14. Horizontal Applications only—Place horizontal condensate pan into position on coil/pan assembly.

NOTE: Installation of horizontal condensate pan is not necessary for upflow or downflow applications.

15. Slide complete assembly into unit.

16. Reinstall fitting panel and reconnect clip securing fitting panel to condensate drain pan.

17. Horizontal Applications Only—Reinstall horizontal pan clip. Secure with 1 screw. (See Fig. 43.) Reinstall coil access panel.

18. Reconnect liquid and vapor refrigerant tubes, and condensate drain tube. Install new Puron (R-410A) liquid line filter-drier.

19. Evacuate tube set and indoor coil to 500 microns, back seat (open) liquid and vapor service valves.

20. Turn on electrical supplies to indoor and outdoor units.

21. Check system refrigerant charge and operation. See "Application Guideline and Service Manual for R-410A" for further information.

PROCEDURE 2—SLOPE COIL UNITS

If it is determined that system does not have leaks and refrigerant is not contaminated, proceed as follows:

1. Recover system refrigerant.

a. Attach manifold/gage set to service valves.

b. Front seat (close) liquid tube service valve.

c. Start unit in cooling mode.

d. Run unit until low pressure switch opens at 50 psig (350kPa) or vapor pressure reaches 5 psig (35kPa). Do not allow compressor to pump

into a vacuum.

e. Turn off electrical supply to outdoor unit.

f. Front seat vapor service valve.

g. Recover any remaining refrigerant.

NOTE: All outdoor unit coils will hold only factory-supplied amount of refrigerant. Excess refrigerant, such as in long-line applications, may

cause compressor internal pressure relief valve to open (indicated by sudden rise in vapor pressure) before vapor pressure reaches 5 psig (35kPa).

If this occurs, turn off electrical supply to outdoor unit immediately, front seat vapor service valve, and recover any remaining refrigerant.

2. Turn off electrical supply to indoor unit.

3. Disconnect condensate drain tube.

4. Disconnect liquid and vapor tubes from indoor coil. Use either a tubing cutter to cut tubes or a torch to unbraze tubes as required.

NOTE: If a torch is used to unbraze line set, protect fitting panel with a wet cloth or braze shield, as necessary. System contains oil vapors which

may ignite when exposed to a flame.

—62—

5. Remove coil access and fitting panels.

6. Remove 1 screw securing coil to unit casing.

7. Remove coil/pan assembly from unit.

8. Place assembly on a flat surface. Remove 2 screws securing coil support columns to pan. (See Fig. 44.)

9. Rotate columns 90°, pull away from coil, and remove columns from assembly.

10. Remove remaining 2 screws securing coil to condensate pan.

11. Remove coil from condensate pan.

12. Remove coil top seal. (See Fig. 44.)

13. Install new coil into condensate pan using 2 original screws and 2 support columns.

NOTE: Correct coil position in condensate pan is essential to reliable operation.

14. Install new coil/pan assembly into unit. Secure with 2 screws previously removed from unit casing.

15. Reinstall coil access and fitting panels.

16. Reconnect liquid and vapor refrigerant tubes, and condensate drain tube. Install new Puron (R-410A) liquid line filter-drier.

17. Evacuate tube set and indoor coil to 500 microns, back seat (open) liquid and vapor service valves.

18. Turn on electrical supplies to indoor and outdoor units.

19. Check system refrigerant charge and operation. See "Application Guideline and Service Manual for R-410A" for further information.

—63—

PURON® (R-410A) QUICK REFERENCE GUIDE

FOR INSTALLERS AND TECHNICIANS

• Puron (R-410A) refrigerant operates at 50-70 percent higher pressures than R-22. Be sure that servicing equipment and replacement

components are designed to operate with Puron (R-410A).

• Puron (R-410A) refrigerant cylinders are rose colored.

• Recovery cylinder service pressure rating must be 400 psig, DOT 4BA400 or DOT BW400.

• Puron (R-410A) systems should be charged with liquid refrigerant.

• Use a commercial type metering device in the manifold hose.

• Manifold sets should be at least 750 psig high-side and 200 psig low-side with 520 psig low-side retard.

• Use hoses with 750 psig service pressure rating.

• Leak detectors should be designed to detect HFC refrigerant.

• Puron (R-410A), as other HFC’s, is only compatible with POE oils.

• Vacuum pumps will not remove moisture from oil.

• Do not use liquid-line filter driers with rated working pressures less than 600 psig.

• Do not install a suction-line filter drier in liquid line.

• POE oils absorb moisture rapidly. Do not expose oil to atmosphere.

• Wrap all filter driers and service valves with wet cloth when brazing.

• A liquid-line filter drier is required on every unit.

• Indoor unit is equipped with a TXV. Replacement TXV must be designed for Puron (R-410A).

• Do not use an R-22 TXV.

• Never open system to atmosphere while it is under a vacuum.

• When system must be opened for service, break vacuum with dry nitrogen and replace filter driers.

• Do not vent Puron (R-410A) into the atmosphere.

• Do not use capillary tube indoor coils.

• Observe all warnings, cautions and bold text.

—64—

Catalog No. 03FA-4A6