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24-Volt Thermostat Wiring - Whirlpool WGFD28 Installation Instructions Manual

80% 2-stage variable speed gas furnace gold models
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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 or
left side panel. The furnace is shipped configured for a left side
electrical connection. To make electrical connections through the
opposite side of the furnace, the junction box must be relocated
to the left side prior to making electrical connections. To relocate
the junction box, perform the following steps.
To prevent personal injury or death due to electric shock,
disconnect electrical power before installing or servicing
this unit.
1. Remove both doors from the furnace.
2. Remove and save the screws securing the junction box to the
left 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 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 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.
In downflow applications, the power leads should be routed
through the supplied wire tabs when rotating the junction box
to the left side.
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 the 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 the unit voltage when the blower door is opened
for servicing.
NOTE: Do not defeat this switch.

24-Volt Thermostat Wiring

Wire routing must not interfere with circulator blower
operation, filter removal or routine maintenance. A removable
plug connector is provided with the control to make
thermostat wire connections. This plug may be removed to
allow wire connections to be made to the plug and then
replaced. It is STRONGLY recommended that multiple wires
into a single terminal be twisted together prior to inserting
into the plug connector. Failure to do so may result in
intermittent operation.
As a 2-stage furnace, the furnace integrated control module
provides terminals for both W1 and W2, and Y1 and Y2
thermostat connections. This allows the furnace to support the
following system applications: 2-stage heating only, 2-stage
heating with single-stage cooling and 2-stage heating with
2-stage cooling. Refer to the following thermostat wiring
diagrams for proper connections to the integrated control
Low voltage connections can be made through either the right or
left side panel. Thermostat wiring entrance holes are located in
the blower compartment. The following illustration shows the
connections for a heat/cool system.
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.
Thermostat Wiring Diagram—Single-Stage Thermostat
A. Thermostat—single-stage heating
and single-stage cooling
B. Furnace integrated control module
C. Dehumidistat (optional)
NOTE: To apply a single-stage heating thermostat, the
thermostat selector switch on the integrated control module must
be set on single-stage.
D. Remote condensing unit
(single-stage cooling)
E. Thermostat R required if
outdoor unit is equipped
with a Comfort Alert™



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