25
CAUTION:
To avoid electric shock, personal
injury, or death, turn off the power at
the disconnect or the main service
panel before making any electrical
connections.
ELECTRICAL WIRING
Electrical connections must be made in ac-
cordance with all applicable local codes and
ordinances, and with the current revision of the
National Electric Code (ANSI/NFPA 70).
For Canadian installations electrical connections
and grounding must be done in accordance
with the current Canadian Electrical Code (CSA
C22.1 Part 1) and/or local codes. If any of the
original wire as supplied with the furnace must be
replaced, it must be replaced with wire having a
minimum temperature rating of 105°C. Refer to
the furnace nameplate and Table 10 for electrical
requirements.
Line Voltage Wiring
The line voltage (115 volt) to the furnace must
be supplied from a dedicated branch circuit
containing the correct fuse or circuit breaker for
the furnace. See Table 10. An electrical switch
should be readily accessible from and within
sight of the furnace. (See the Wiring Diagram
label in the furnace and Figure 21.)
The furnace cabinet must have an uninterrupted,
unbroken ground to minimize injury should an
electrical fault condition occur. The controls used
in this furnace require an earth ground to operate
properly. Acceptable methods for grounding are
electrical wire or conduit approved for electrical
ground service. Do not use gas piping as an
electrical ground.
NOTE: Proper line voltage polarity must be
maintained in order for the control system
to operate correctly. Verify that the incoming
neutral line is connected to the white wire and
the incoming “hot” line is connected to the
black wire in the junction box. These furnaces
will not operate unless polarity and ground
are properly connected. See Figure 21.
CAUTION:
Label all wires prior to disconnection
when servicing controls. Wiring errors
can cause improper and dangerous
operation. Verify proper operation
after servicing.
NOTE:
The following procedure describes
how to connect the furnace for a two-stage
application.
Low Voltage Wiring
Furnace is factory confi gured to operate on low
and high fi re – two stage mode confi gurations.
The second stage will function based on the
program settings in the thermostat controller.
The furnace integrated control board consists of
two boards – main and add-on boards. The two
boards are pre-wired with the furnace interface
board. The IQ thermostat controller requires
wiring to the interface board in the fi eld (see
Figures 22 and 25).
IMPORTANT NOTE: The use of shielded cable
is required for the connection to the thermo-
stat controller. This wire is fi eld supplied.
Ground the shielded cable at the furnace end
only on the grounding lug on the interface
board bracket.
Table 8. Natural and LP Gas Orifi ce Sizes
for Elevations between
zero and 4999 ft. Above Sea Level
Table 9. Natural and LP gas Orifi ce Sizes
for Elevations between 5000 and 10,000 ft.
Above Sea Level
Furnace High Fire Rating
Orifi ce Drill Size
Plate Input (Btu/h)
Nat.
LP
60,000
49
56
80,000
45
55
100,000
45
55
120,000
45
55
Furnace High Fire Rating
Orifi ce Drill Size
Plate Input (Btu/h)
Nat.
LP
60,000
49
57
80,000
45
56
100,000
45
56
120,000
46
56
