Junction Box Relocation
Edges of sheet metal holes may be sharp. Use gloves as
a precaution when removing hole plugs.
Line voltage connections can be made through either the right-
hand or left-hand side panel. The furnace is shipped configured
for a right-hand side electrical connection. To make electrical
connections through the opposite side of the furnace, the
junction box must be relocated to the left-hand side prior to
making electrical connections. To relocate the junction box,
perform the following steps.
Disconnect ALL power before servicing.
Multiple power sources may be present.
Failure to do so may cause property damage,
personal injury or death.
1. Remove both doors from the furnace.
2. Remove and save the screws holding the junction box to the
left-hand side of the furnace.
3. Models that have the junction box located in the burner
compartment will need to move the junction box directly over.
4. Attach the junction box to the right-hand side of the furnace,
using the screws removed in Step 2.
5. Check the location of the wiring. Confirm that it will not be
damaged by heat from the burners or by the rotation of the
fan. Also confirm that the wiring location will not interfere with
filter removal or other maintenance.
After the junction box is in the desired location, use washers to
connect field-supplied conduit to the junction box in accordance
with NEC and local codes. Connect hot, neutral and ground wires
as shown in the furnace wiring diagram. The wires and ground
screw are located in the furnace junction box.
Low voltage wires may be connected to the terminal strip.
IMPORTANT: To avoid possible equipment malfunction, route the
low voltage wires to avoid interference with filter removal or other
To avoid the risk of injury, electrical shock or death, the
furnace must be electrically grounded in accordance with
local codes or, in their absence, with the latest edition of the
National Electric Code (NEC).
To ensure proper unit grounding, the ground wire should run from
the furnace ground screw located inside the furnace junction box
all the way back to the electrical panel.
NOTE: Do not use gas piping as an electrical ground. To confirm
proper unit grounding, turn off the electrical power and perform
the following check.
1. Measure resistance between the neutral (white) connection
and one of the burners.
2. Resistance should measure 10 ohms or less.
This furnace is equipped with a blower door interlock switch
which interrupts unit voltage when the blower door is opened for
NOTE: Do not defeat this switch.
24-Volt Thermostat Wiring
NOTE: Wire routing must not interfere with circulator blower
operation, filter removal or routine maintenance.
Low voltage connections can be made through either the right-
hand or left-hand side panel. Thermostat wiring entrance holes
are located in the blower compartment. See "Typical Field
Wiring—24 VAC Control Circuit" for heat only and heat/cool
Typical Field Wiring—24 VAC Control Circuit
A. Heating room thermostat
B. Heating/cooling room thermostat
This furnace is equipped with a 40 VA transformer to facilitate use
with most cooling equipment. Consult the wiring diagram,
located on the blower compartment door, for further details of
115-volt and 24-volt wiring.
A single-stage thermostat with only 1 heating stage can be used
to control this furnace.
Setting the Heat Anticipator
The following method should be used in measuring the amp draw
of the control circuit to assure proper adjustment of the
thermostat heat anticipator.
1. Wrap the "R" leg around a clip-on ammeter 10 times.
2. Energize the furnace in the heat mode.
3. Record the reading.
4. Divide this reading by 10.
5. Set the heat anticipator on the thermostat to match this
Example: If the reading on the ammeter is 4, divide by 10. The
anticipator setting will be 0.4 amps.
C. Furnace control
D. Remote condensing unit