BX CABLE INSTALLATION IN FURNACE J-BOX
1. Remove cover from J-Box.
2. Route BX cable into 7/8-inch diameter hole in J-Box.
3. Secure BX cable to J-Box bracket with connectors approved
for the type of cable used.
4. Secure field ground wire to green ground screw on J-Box
bracket.
5. Connect line voltage leads as shown in Fig. 25.
6. Reinstall cover to J-Box. Do not pinch wires between cover
and bracket.
24-V WIRING
Make field 24-v connections at the 24-v terminal strip. (See Fig.
24.) Connect terminal Y as shown in Fig. 25 for proper cooling
operation. Use only AWG No. 18, color-coded, copper thermostat
wire.
The 24-v circuit contains an automotive-type, 3-amp fuse located
on the control. Any direct shorts during installation, service, or
maintenance could cause this fuse to blow. If fuse replacement is
required, use ONLY a 3-amp fuse of identical size.
ACCESSORIES
1. Electronic Air Cleaner (EAC)
Connect an accessory Electronic Air Cleaner (if used) using
1/4-in female quick connect terminals to the two male 1/4-in
quick-connect terminals on the control board marked EAC-1
and EAC-2. The terminals are rated for 115 VAC, 1.0 amps
maximum and are energized during blower motor operation.
(See Fig. 24.)
2. Humidifier (HUM)
Connect an accessory 24 VAC, 0.5 amp maximum humidifier
(if used) to the 1/4-in male quick-connect HUM terminal and
C
OM
-24V screw terminal on the control board thermostat strip.
The HUM terminal is energized when pressure switch (PRS)
closes. (See Fig. 24.)
NOTE:
A field-supplied, 115-v controlled relay connected to
EAC terminals may be added if humidifier operation is desired
during blower operation.
NOTE:
DO NOT connect furnace control HUM terminal to HUM
(humidifier) terminal on Thermidistat™, Zone Controller or simi-
lar device. See Thermidistat™, Zone Controller, thermostat, or
controller manufacturer’s instructions for proper connection.
VENTING
The furnace shall be connected to a listed factory built chimney or
vent or a clay-tile lined masonry or concrete chimney. Venting into
an unlined masonry chimney or concrete chimney is prohibited.
When an existing Category I furnace is removed or replaced, the
original venting system may no longer be sized to properly vent
the attached appliances. An improperly sized Category I venting
system could cause the formation of condensate in the furnace and
vent, leakage of condensate and combustion products, and spillage
of combustion products into the living space.
Fig. 25—Heating and Cooling Application Wiring Diagram with 1–Stage Thermostat
A99440
115-V FIELD-
SUPPLIED
DISCONNECT
AUXILIARY
J-BOX
24-V
TERMINAL
BLOCK
THREE-WIRE
HEATING-ONLY
FIVE WIRE
NOTE 1
NOTE 2
FIELD-SUPPLIED
DISCONNECT
CONDENSING
UNIT
TWO
WIRE
FURNACE
C
O
N
T
R
O
L
R
G
COM
W
C
R
G
Y
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
BLOWER DOOR SWITCH
WHT
BLK
WHT
BLK
NOTES:
Connect Y-terminal in furnace as shown for proper blower operation.
Some thermostats require a "C" terminal connection as shown.
If any of the original wire, as supplied, must be replaced, use
same type or equivalent wire.
W
Y/Y2
GND
THERMOSTAT
TERMINALS
1.
2.
3.
22
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