507769-05G / 31-5000656
Page 36 of 55
Issue 2223
Electrical
ELECTROSTATIC DISCHARGE (ESD)
Precautions and Procedures
Electrostatic discharge can affect
electronic components. Take
precautions to neutralize electrostatic
charge by touching your hand and tools
to metal prior to handling the control.
CAUTION
Figure 48.
Interior Make-Up Box
(Factory - Installed Left Side)
MAKE−UP
BOX INSIDE
CABINET
Left side
Figure 49.
Exterior Make-Up Box
(Field Provided Right Side)
MAKE−UP
BOX
OUTSIDE
CABINET
Right Side
The unit is equipped with a field makeup box on the left
hand side of the cabinet. A field-provided make-up box can
be installed on the exterior of the right side of the furnace
to facilitate installation. Seal unused openings on left side
with plugs removed from right side. Secure the excess wire
to the existing harness to protect it from damage.
Refer to Figure 51 for field wiring and Figure 52 for
schematic wiring diagram and troubleshooting.
The power supply wiring must meet Class I restrictions.
Protected by either a fuse or circuit breaker, select circuit
protection and wire size according to unit nameplate.
NOTE:
Unit nameplate states maximum current draw.
Maximum Over-Current Protection allowed is 15 AMP.
Holes are on both sides of the furnace cabinet to facilitate
wiring.
Install a separate (properly sized) disconnect switch 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. Make sure that thermostat wire
is long enough to facilitate future removal of blower for
service.
Complete the wiring connections to the equipment. Use the
provided unit wiring diagram and the field wiring diagram
shown in Figure 51. 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/HFPA 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 makeup box.
NOTE:
The gas furnace contains electronic components
that are polarity sensitive. Make sure that the furnace is
wired correctly and is properly grounded.
Accessory Terminals
One line voltage “ACC” 1/4” spade terminal is provided
on the furnace control board. Any accessory rated up to
one amp can be connected to this terminal with the neutral
leg of the circuit being connected to one of the provided
neutral terminals. If an accessory rated at greater than one
amp is connected to this terminal, it is necessary to use an
external relay. See Figure 53 or Figure 54 for control board
configuration. This terminal is energized when the indoor
blower is operating.
One line voltage “120 HUM” 1/4” spade terminal is provided
on the furnace integrated control board. See Figure 53 or
Figure 54 for integrated control configuration. This terminal
is energized in the heating mode when the combustion air
inducer is operating. Any humidifier rated up to one amp
can be connected to this terminal with the neutral leg of
the circuit being connected to one of the provided neutral
terminals. If a humidifier rated at greater than one amp
is connected to this terminal, it is necessary to use an
external relay.
One 24V “H” 1/4” spade terminal is provided on the furnace
integrated control board. See Figure 53 or Figure 54 for
control board configuration. The terminal is energized