Install the harness as follows:
a. Remove lock nuts from the end of each conduit connector.
b. Route the end of the harness that mates to the TKR relay harness of the LH furnace through the unused condensate trap hole in the casing
of the blower compartment.
c. Route the end of the harness that mates to the 4-wire harness of the RH furnace through the unused condensate trap hole in the casing
of the blower compartment.
d. Install the lock nuts on the 90° conduit connectors.
e. Install the two kit-supplied straps approximately 18 inches from each end of extension harness.
3.
Fixed Capacity Furnace/Single-Stage Heat with Single-Stage Gas-Heat Thermostat (Field Supplied) OR Two-Stage Furnace with
Single or Two-Stage Gas-Heat Thermostat (Field-Supplied)
NOTE:
This application of TKR allows both furnaces to operate as 1 furnace gas heat mode as determined by an individual thermostat.
Install twinning kit relay (TKR):
a. Mount TKR assembly to underside of LH furnace control enclosure using 1 No. 6 sheet metal screw (factory supplied). Screw hole is
located to left of door switch near front edge of control. (See Fig. 28.)
NOTE:
See Fig. 13 or 15 for twinning kit wiring.
b. Route 3 loose wires (black, yellow, and white) from TKR assembly wire harness through T-STAT/HUM hole adjacent to door switch.
(See Fig. 28.)
c. Connect TKR white wire labeled W from TKR to LH furnace control thermostat connection W or W/W1.
d. Connect TKR black wire labeled C from TKR to LH furnace control thermostat connection C
OM
24V.
e. Connect yellow wire labeled TEST to LH furnace control TEST/TWIN terminal.
f. Route female four-pin connector end of TKR wires:
(1.) For
Side-by-Side
applications, see Fig. 20 and 29. Route female, four-pin connector through previously installed bushings in unused
condensate drain holes, located on casing in blower compartment area. Connect to male four-pin connector of RH furnace.
(2.) For
Back-to-Back
applications, see Fig. 21 and 30. Connect the female, four pin connector to the male four pin connector of the
previously installed External Extension Kit. Connect the female four pin connector of the External Extension Kit to the male four
pin connector of the RH furnace.
g. Route four wires through thermostat cable hole of RH furnace control box.
h. Connect TKR red wire labeled R-SECONDARY from TKR to RH furnace control thermostat connection R.
i. Connect TKR white wire labeled W-SECONDARY from TKR to RH furnace control thermostat connection W or W/W1.
j. Connect TKR black wire labeled C-SECONDARY from TKR to RH furnace control thermostat connection C
OM
24V.
k. Connect yellow wire labeled TEST SECONDARY from LH furnace control TEST/TWIN terminal to RH furnace control TEST/TWIN
terminal.
l.
For Two-Stage Furnace Control Boards
–In addition to the wiring of the twinning kit, the LHT switch and a single OR two-stage
gas-heat thermostat must be configured to one of the two methods describe below:
Two-Stage Heat with Single-Stage Gas-Heat Thermostat (allows the LH or Main Furnace’s algorithm control low and high-heat
operation)
(1.) Position LHT switch on Main or LH furnace control to OFF.
(2.) Position LHT switch on Secondary or RH furnace control to ON.
Two-Stage Heat with Two-Stage Gas-Heat Thermostat (allows a two-stage thermostat to control low and high-heat operation)
Position LHT switch furnace controls in BOTH furnaces to ON
m. Proceed to #5
″
Install LH furnace auxiliary limit switch harness ALS-M
″
to complete electrical connections.
Fig. 28—Twinning Kit Relay Mounted on Control Mounting Bracket for LH Furnace
A02226
—31—