Kool Kit

• Easy to use power kit for common WiFi

thermostats

• Universal Fit – Works with Carlin, Beckett

and Honeywell primary controls

• Replaces Beckett 51950U Ready Kit or

51970U Terminal base

• Replaces Honeywell R8184M when

installed with Carlin primary control

• Heavy Duty 16 Amp Relay for added

durability

• Designed for quick installation

Warning

1. The 98435S kit must be installed only by a quali-

ed service technician.

2. Always disconnect power source before wiring to

avoid electrical shock or damage to the control.

All wiring must comply with applicable codes and

ordinances.

3. Thermostat terminals (T-T) provide a current

source. Never apply external power to these

terminals under any circumstances.

Mounting

• Mount the interface board on the burner 4x4 junc-

tion box as shown in Figure 1. Insert the trans-

former hub through a junction box knockout and

secure with lock nut.

• The control location must not exceed the ambi-

ent temperature limit, listed in the primary control

data sheet.

Operation

1. Fan and cooling check – Set thermostat to call

for cooling or fan. Verify correct operation.

2. Heating control check – Set thermostat to call

for heat. Follow the primary control data sheet

checkout procedure to verify.

3. If control does not operate correctly, check all

wiring and wiring connections.

Transformer input (primary)

120 VAC, 60 HZ

Transformer output (secondary)

24 VAC, 60 HZ, 40 VA

Control speciﬁcations

Refer to primary control

data sheet

Max ambient temp

140°F

Kool Kit

24 VAC power adapter kit for adding

WiFi thermostats with AC interface to

Oil Boilers and Furnaces

Model 98435S

Includes circuit board, quick connect

wire harness, 24 VAC transformer

Model 98435S1

Includes replacement circuit board only,

24 VAC transformer not included

Installing & Wiring

Carlin Combustion Technology, Inc.

126 Bailey Road • North Haven, CT 06473 • 203-680-9401 • Fax 203-680-9403

Tech Support 800-989-2275 • carlincombustion.com

Figure 1

The following are common

thermostat terminal designations.

Refer to your thermostat

installation/wiring instructions for

the proper terminal designations.

C = 24 VAC common

R = 24 VAC hot

W = Heat

Y = Cool

G = Fan

The following are common thermostat terminal

designations. Refer to your thermostat installation/wiring

instructions for the proper terminal designations.

C = 24 VAC common

R = 24 VAC hot

W = Heat

Y = Cool

G = Fan

Thermostat wired into the

burner primary control

WARNING: Wiring must comply with local and national

electrical codes.

1. Remove the factory installed jumper from the T-T terminals of the burner

primary control.

2. Connect the red and white wires from the Kool Kit board to the T-T

terminals on the burner primary control. The wires are not polarity

sensitive.

3. Connect the thermostat terminals to the Kool Kit interface board as

shown.

Note: Thermostat designations may vary depending on the thermostat

brand. Refer to the thermostat wiring instructions for the proper terminal

designations.

4. (Optional) Connect the cooling contactor and the fan relay to the Kool Kit

interface board as shown.

Thermostat wired into the

HydroStat 3250-Plus

WARNING: Wiring must comply with local

and national electrical codes.

1. Verify the factory installed jumper is

installed on the T-T terminals of the burner

primary control.

2. Connect the red and white wires from the

Kool Kit board to the T-T terminals on the

HydroStat 3250-Plus. The wires are not

polarity sensitive.

3. Connect the thermostat terminals to the

Kool Kit interface board as shown.

Note: Thermostat designations may vary

depending on the thermostat brand. Refer

to the thermostat wiring instructions for the

proper terminal designations.

4. (optional) Connect the cooling contactor

and the fan relay to the Kool Kit interface

board as shown.

AcuTemp Indirect Tank Control wired into the HydroStat 3250-Plus

WARNING: Wiring must comply with local and national electrical codes.

1. Verify the factory installed jumper is installed on the T-T terminals of the burner primary control.

2. Connect the output contacts from the AcuTemp to the R and W terminals on the Kool Kit interface board. The terminals are not

polarity sensitive.

3. Connect the 24 VAC input AC1 on the AcuTemp to the C terminal on the Kool Kit interface board. Connect the 24 VAC input AC2 on

the AcuTemp to the R terminal on the Kool Kit interface board.

4. Connect the red wire from the Kool Kit board to the L1 Terminal on the Hydrostat 3250-Plus. Be sure to comply with local and

national electric codes as this is a 120 VAC connection

5. Connect the white wire from the Kool Kit board to the ZR terminal on the Hydrostat 3250-Plus. Be sure to comply with local and

national electric codes as this is a 120 VAC connection.

6. Connect the domestic hot water circulator to the L2 (neutral) and ZR (hot) terminals on the Hydrostat 3250-Plus.

7. Set the Z/I switch on the Hydrostat 3250 to the I position. If the switch is left in the Z position the boiler may not provide adequate

hot water.

MN98435 082119

126 Bailey Road • North Haven, CT 06473

203-680-9401 • Fax 203-680-9403

Tech Support 800-989-2275 • carlincombustion.com

ZONE/

INDIRECT

SWITCH

POSITION