If manual disconnect switch is to be mounted on furnace,
select a location where a drill or fastener will not contact
electrical or gas components. Failure to follow this caution
will result in intermittent unit operation or performance
satisfaction.
24-V WIRING
Make field 24-v thermostat connections at 24-v terminal block on
furnace control. Y wire from thermostat MUST be connected to
Y/Y2 terminal on control, as shown in Fig. 28, for proper cooling
operation. The 24-v terminal block is marked for easy connection
of field wiring. (See Fig. 32.) The 24-v circuit contains a 3-amp,
automotive-type fuse located on furnace control. (See Fig. 32.)
Any electrical shorts of 24-v wiring during installation, service, or
maintenance may cause fuse to blow. If fuse replacement is
required, use only a fuse of identical size (3 amp) and type. The
furnace control will flash status code 24 when fuse needs replace-
ment.
NOTE: Use AWG No. 18 color-coded copper thermostat wire for
lengths up to 100 ft. For wire lengths over 100 ft, use AWG No.
16 wire.
NOTE: For additional thermostat connection diagrams, reference
Fig. 54-61.
Fig. 28—Heating and Cooling Application Wiring Diagram
A98325
115-V
FIELD-SUPPLIED
DISCONNECT
SWITCH
115-V
SINGLE
PHASE
AUXILIARY
J-BOX
FURNACE
CONTROL
CENTER
TWO WIRE
24-V
TERMINAL
BLOCK
THREE-WIRE
HEATING
ONLY
FIVE
WIRE
NOTE 5
NOTE 1
NOTE
3
THERMOSTAT
TERMINALS
FIELD-SUPPLIED
DISCONNECT
CONDENSING
UNIT
R
W2
WCR GY
GND
GND
GND
GND
FIELD 24-V WIRING
FIELD 115-, 208/230-, 460-V WIRING
FACTORY 24-V WIRING
FACTORY 115-, 208/230-, 460-V WIRING
208/230- OR
460-V
THREE PHASE
208/230-V
SINGLE
PHASE
W/W1
Y/Y2
G
C
NOTES:
1.
2.
3.
4.
5.
Connect Y or Y/Y2 terminal as shown for proper cooling operation.
Proper polarity must be maintained for 115-v wiring.
Use W2 with 2-stage thermostat when zoning.
If any of the original wire, as supplied, must be replaced, use
same type or equivalent wire.
Some thermostats require a "C" terminal connection as shown.
Do not connect aluminum wire between disconnect switch
and furnace. Use only copper wire. (See Fig. 29.) Failure to
follow this caution will result in intermittent unit operation or
performance satisfaction.
A93033
Fig. 29—Disconnect Switch and Furnace
COPPER
WIRE ONLY
ELECTRIC
DISCONNECT
SWITCH
ALUMINUM
WIRE
Fig. 30—Relocating J-Box
A00212
FACTORY
INSTALLED
LOCATION
ALTERNATE
FIELD
LOCATION
21
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