INSTALLATION INSTRUCTIONS - Lennox

Electrical
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
CAUTION
Electrostatic discharge can affect electronic components.
Take precautions during furnace installation
and service to protect the furnace’s electronic
controls. Precautions will help to avoid control exposure
to electrostatic discharge by putting the furnace,
the control and the technician at the same
electrostatic potential. Neutralize electrostatic
charge by touching hand and all tools on an unpainted
unit surface, such as the gas valve or blower
deck, before performing any service procedure.
INTERIOR MAKE−UP BOX INSTALLATION
MAKE−UP
BOX
FIGURE 37
Right Side
INTERIOR MAKE−UP BOX INSTALLATION
Left side
FIGURE 38
MAKE−UP
BOX
The unit is equipped with a field make−up box. The make−
up box may be moved to the right side of the furnace to facilitate
installation. If the make−up box is moved to the right
side, the excess wire must be pulled into the blower
compartment. Secure the excess wire to the existing harness
to protect it from damage.
Refer to figure 40 for field wiring and figure 41 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 facilitate
wiring.
Install a separate disconnect switch (protected by either
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 wiring
diagram shown in figure 40. 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 G43UF furnace contains electronic components
that are polarity sensitive. Make sure that the
furnace is wired correctly and is properly grounded.
One line voltage EAC" accessory terminal is provided
on the furnace 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 the
any of the NEUTRAL" terminals. See figure 42 for control
board configuration. This terminal is energized
whenever the blower is operating.
One line voltage HUM" accessory terminal is provided
on the furnace 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 42 for control board
configuration. This terminal is energized in the heating
mode whenever the combustion air inducer is operating.
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