NOTE:
See Fig. 14.
a. Disconnect TKR white wire labeled W from LH furnace control thermostat connection W.
b. Cut terminal off TKR white wire labeled W and strip 1/4 in.
c. Connect 2-stage thermostat W2 connection to TKR white wire labeled W.
NOTE:
ALL other 2-stage thermostat connections are to be made to LH furnace control center ONLY.
d. Proceed to #5 “Install LH furnace Auxiliary Limit Switch - Main ALS-M” harness to complete electrical connections.
5. Install LH furnace (main) auxiliary limit switch harness ALS-M.
NOTE:
LH furnace ALS-M assembly DOES NOT include door switch.
a. Drill 1/8-in. hole in blower housing 8 in. below blower shelf as shown in Fig. 29.
b. Position ALS-M so reset button faces front of furnace.
c. Secure bracket to blower housing using factory-supplied No. 6 X 3/4-in. LG screw.
d. Disconnect red transformer wire from SEC-1 connection.
e. Connect removed red transformer wire to ALS-M wire connector labeled TRAN. Route through thermostat holes of control box.
f. Connect ALS-M connector labeled SEC 1 to LH furnace control SEC-1 terminal.
g. Route 2-wire ALS-M connector from LH furnace to RH furnace through unused condensate drain line hole with snap bushing.
6. Install RH furnace (SECONDARY) auxiliary door switch and harness (ALS-S/ILK-1).
NOTE:
RH furnace ALS-S assembly HAS door switch included.
a. Install auxiliary limit switch (ALS-S).
(1.) Drill 1/8-in. hole in blower housing 8 in. below blower shelf as shown in Fig. 23.
(2.) Position ALS-S so terminals face front of furnace.
(3.) Secure bracket to blower housing using factory-supplied No. 6 X 3/4-in. LG screw.
b. Install auxiliary door switch (ILK-1).
(1.) Drill 7/32-in. hole in left side of RH furnace blower shelf for mounting door switch as shown in Fig. 29.
(2.) Secure ALS-S door switch (ILK-1) using factory-supplied flat screw No. 6 X 3/4-in. LG screw.
c. Connect RH furnace 2-wire ALS-S connector PL6 to LH furnace 2-wire ALS-M connector PL6 that was routed through furnace casings.
7. Select identical blower speed taps at blower motor connections on control center in both furnaces.
CAUTION: UNIT DAMAGE HAZARD
Failure to select identical blower speed taps in both furnaces can result in overheating of furnace components and possible loss of
furnace operation and damage to the furnace.
8. Dress wires to ensure they do not contact sharp edges or moving parts, nor interfere with blower operation, removal of filters, or operation
of switches.
9. Make all thermostat connections to the LH furnace only.
PROCEDURE 3—CONNECT ELECTRICAL COMPONENTS—COOLING
WARNING: UNIT DAMAGE AND FIRE HAZARD
Failure to follow this warning culd result in unit damage, fire, personal injury or death.
Make no connections between the R 24-vac connector in 1 furnace and the R 24-vac connector in other furnace.
When installing twinned outdoor units with twinned gas furnaces, it is necessary to use a field-supplied 24-vac pilot-duty relay and a field-supplied
24/115-vac transformer as shown in Fig. 13, 14, or 15 to prevent overloading furnace 24/115-vac transformer.
Fig. 31—LHT Switches
A02237
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