5894307-UIM-B-0920
Johnson Controls Ducted Systems
9
SUPPLY VOLTAGE CONNECTIONS
1. Provide a power supply separate from all other circuits. Install over-
current protection and disconnect switch per local/national electrical
codes. The switch must be close to the unit for convenience in ser-
vicing. With the disconnect or fused switch in the OFF position,
check all wiring against the unit wiring label. See the wiring diagram
in this instruction.
2. Remove the wiring box cover screws. Route all power wiring
through a conduit connector or other proper bushing that is field
installed into the unit opening and the junction box. In the junction
box there is a black wire, a white wire, and a green ground screw.
Connect the power supply as shown on the unit’s wiring label
located on the inside of the blower compartment door, or the wiring
schematic in this section. Connect the black wire to L1 (hot) from
the power supply. Connect the white wire to neutral. Connect the
ground wire (installer-supplied) to the green (equipment ground)
screw. An alternate wiring method is to use a field-provided 2 in.
(5.1 cm) x 4 in. (10.2 cm) box and cover on the outside of the fur-
nace. Route the furnace leads into the box using a protective bush-
ing where the wires pass through the furnace panel. After making
the wiring connections, replace the wiring box cover and screws.
Figure 11.
3. The furnace's control system requires correct polarity of the power
supply and a proper ground connection. See Figure 11.
LOW VOLTAGE CONTROL WIRING CONNECTIONS
Install the field-supplied thermostat by following the instructions that
come with the thermostat. With the thermostat set in the OFF position
and the main electrical source disconnected, connect the thermostat
wiring from the wiring connections on the thermostat to the low-voltage
terminal block on the integrated furnace control board, as shown in Fig-
ures 12, 13, and 14. Electronic thermostats require the common wire to
be connected. Apply strain relief to thermostat wires passing through
the cabinet. If air conditioning equipment is installed, use thermostat
wiring to connect the Y and C terminals on the furnace control board to
the correct wires on the outdoor unit.
The 24-V, 40-VA transformer is sized for the furnace components only,
and must not be connected to power auxiliary devices such as humidifi-
ers and air cleaners. The transformer can provide power for a split sys-
tem air conditioner or heat pump.
Figure 11:
Electrical Wiring
JUNCTION
BOX
CONNECT
GROUND LEAD
TO SCREW
ELECTRICAL
ENTRY
L1-HOT
NEUTRAL
A1126-001
IMPORTANT:
The power connection leads and wiring box can be
relocated to the opposite side of the furnace. Remove the screws and
cut wire tie holding excess wiring. Reposition on the opposite side of
the furnace and fasten using holes provided.
IMPORTANT:
Set the heat anticipator in the room thermostat to
0.4 A. Setting it lower causes short cycles. Setting it higher causes
the room temperature to exceed the setpoints.
IMPORTANT:
Some electronic thermostats do not have adjustable
heat anticipators. They should be set to six cycles per hour. Follow
the thermostat manufacturer's instructions.
