This furnace is equipped with a manual reset limit switch in
the gas control area. The switch will open and shut off power
to the gas valve if a flame rollout or overheating condition
occurs in the gas control area. DO NOT bypass the switch.
Correct inadequate combustion-air supply, component fail-
ure, or restricted flue gas passageway before resetting the
switch.
Before operating furnace, check each manual reset switch for
continuity. If necessary, press and release button to reset switch.
Step 2—Sequence of Operation
Using schematic diagram in Fig. 19, follow the sequence of
operation through the different modes. Read and follow diagram
very carefully.
NOTE:
If power interruption occurs during
″
call for heat
″
(W/W1
or W/W1 and W2) and if the thermostat is still calling for gas
heating, the control will start a 90-sec blower only on period 2 sec
after power is restored. The red LED will flash code 12 during
90-sec period, after which the LED will be on continuously as long
as no faults are detected. After 90-sec period, furnace will respond
to the thermostat normally.
Fig. 15—Heating and Cooling Application Wiring Diagram 1–Stage Thermostat and Condensing Unit
A99071
115-V FUSED
DISCONNECT
SWITCH
(WHEN REQUIRED)
JUNCTION
BOX
CONTROL
BOX
24-V
TERMINAL
BLOCK
TWO-WIRE
HEATING-
ONLY
FIVE
WIRE
1-STAGE THERMOSTAT TERMINALS
FIELD-SUPPLIED
FUSED DISCONNECT
CONDENSING
UNIT
FURNACE
COM
R
W
Y
R
G
C
GND
GND
GND
GND
GND
GND
FIELD 24-V WIRING
FIELD 115-, 208/230-, 460-V WIRING
FACTORY 24-V WIRING
FACTORY 115-V WIRING
208/230- OR
460-V
THREE
PHASE
208/230-V
SINGLE
PHASE
WHT
BLK
WHT
BLK
W/W1
W2
Y/Y2
G
NOTES:
1. Connect Y-terminal as shown for proper operation.
2. Some thermostats require a "C" terminal connection as shown.
3. If any of the original wire, as supplied, must be replaced,
use same type or equivalent wire.
Fig. 16—Heating and Cooling Application Wiring Diagram 2-Stage Thermostat and Condensing Unit
A99072
115-V FUSED
DISCONNECT
SWITCH
(WHEN REQUIRED)
JUNCTION
BOX
CONTROL
BOX
24-V
TERMINAL
BLOCK
THREE-WIRE
HEATING-
ONLY
SEVEN
WIRE
2-STAGE THERMOSTAT TERMINALS
FIELD-SUPPLIED
FUSED DISCONNECT
2-SPEED
CONDENSING
UNIT
FURNACE
G
R
W2
Y2
G
Y1
C
GND
GND
GND
GND
GND
GND
FIELD 24-V WIRING
FIELD 115-, 208/230-, 460-V WIRING
FACTORY 24-V WIRING
FACTORY 115-V WIRING
208/230- OR
460-V
THREE
PHASE
208/230-V
SINGLE
PHASE
Y2
Y1
C
WHT
BLK
WHT
BLK
W1
R
W2
COM
W/W1
Y/Y2
NOTES:
1. Connect Y-terminal as shown for proper operation.
2. Some thermostats require a "C" terminal connection as shown.
3. If any of the original wire, as supplied, must be replaced,
use same type or equivalent wire.
12