Page 20
INTERIOR MAKE−UP BOX INSTALLATION
FIGURE 17
MAKE−UP
BOX
Refer to figure 19 for field wiring and figure 21 for schematic
wiring diagram and troubleshooting.
Select circuit protection and wire size according to the
unit nameplate. The power supply wiring must meet
Class I restrictions.
Holes are on both sides of the furnace cabinet to facili-
tate wiring.
Install a separate disconnect switch (protected by ei-
ther fuse or circuit breaker) near the furnace so that
power can be turned off for servicing.
Before connecting the thermostat or the power wiring,
check to make sure the wires will be long enough for
servicing at a later date. Remove the blower access
panel to check the length of the wire.
Complete the wiring connections to the equipment.
Use the provided unit wiring diagram and the field wir-
ing diagram shown in figure 19. Use 18−gauge wire or
larger that is suitable for Class II rating for thermostat
connections.
Electrically ground the unit according to local codes or,
in the absence of local codes, according to the current
National Electric Code (ANSI/NFPA No. 70) for the
USA and current Canadian Electric Code part 1 (CSA
standard C22.1) for Canada. A green ground wire is
provided in the field make−up box.
NOTE − The G40DF(X) furnace contains electronic
components that are polarity sensitive. Make sure
that the furnace is wired correctly and is properly
grounded.
One line voltage EAC" terminal is provided on the fur-
nace control board. Any electronic air cleaner rated up
to one amp can be connected to this terminal with the
neutral leg of the circuit being connected to any of the
NEUTRAL" terminals. See figure 20 for control board
configuration. This terminal is energized when the
blower is operating.
One line voltage HUM" terminal is provided on the fur-
nace control board. Any humidifier rated up to one amp
can be connected to this terminal with the neutral leg
of the circuit being connected to any of the NEUTRAL"
terminals. See figure 20 for control board configura-
tion. This terminal is energized in the heating mode
whenever the combustion air inducer is operating.
Install the room thermostat according to the instruc-
tions provided with the thermostat. See figure 18 for
thermostat designations. If the furnace is being
matched with a heat pump, refer to the FM21 installa-
tion instruction.
Thermostat
A/C UNIT
COMMON
A/C UNIT
G40DF(X)
Furnace
Condensing
Unit
G40DF(X) and CONDENSING UNIT
THERMOSTAT DESIGNATIONS
(Refer to specific thermostat and outdoor unit.)
COMMON
POWER
HEAT
INDOOR BLOWER
Y
C
R
G
W1
Y
C
R
G
W
COOLING
FIGURE 18
Indoor Blower Speeds
When the thermostat is set to FAN ON," the indoor
blower will run continuously on the heat speed when
there is no cooling or heating demand.
When the G40DF(X) is running in the heating mode,
the indoor blower will run on the heating speed.
When
there is a cooling demand, the indoor blower will
run on the cooling speed.
