18
for heating only (two-wire) and heating/cooling (four-wire)
applications. Recommended minimum wire gauge for
thermostat wiring is shown in Table 2.
The thermostat must not be installed on an outside wall or
any other location where its operation may be adversely
affected by radiant heat from fi replaces, sunlight, or lighting
fi xtures, and convective heat from warm air registers or
electrical appliances.
The six pin terminal marked “Expansion Port” is not used
in the single stage furnace as shipped from the factory. It
is used for the furnace control board to communicate to
a fi xed speed or variable speed high effi ciency motor that
may be optionally installed. Please contact your distributor
for the proper upgrade motor kit.
Proper line voltage polarity must be maintained in
order for the control system to operate correctly.
Verify the incoming neutral line is connected to the
white wire and the incoming “hot” line is connected
to the black wire. The furnace will not operate unless
the polarity and ground are properly connected as
shown in Figure 13.
Low Voltage Wiring
The thermostat must be installed according to the
instructions supplied by the thermostat manufacturer. Low
voltage connections (24 VAC) from the thermostat are
wired to the terminal strip on the integrated control in the
furnace. See Figure 14 (page 19) for proper connections
Furnace
Model
Number
*SA/*SK
Furnace
Input
(Btuh)
Cabinet
Width
(in.)
Nominal
Electrical
Supply
Maximum
Operating
Voltage
Minimum
Operating
Voltage
Maximum
Furnace
Amperes
Minimum
Wire
Gauge
Maximum
Fuse or Circuit
Breaker Amps
σ
045(†)-23A
45,000
14 1/4
115-60-1
127
103
6.3
14
15
054(†)-23A
54,000
14 1/4
115-60-1
127
103
6.3
14
15
072(†)-24B
72,000
17 1/2
115-60-1
127
103
9.7
14
20
072(†)-35C
72,000
21
115-60-1
127
103
9.0
14
15
090(†)-24B
90,000
17 1/2
115-60-1
127
103
9.7
14
20
090(†)-35C
90,000
21
115-60-1
127
103
9.0
14
15
108(†)-35C
108,000
21
115-60-1
127
103
9.0
14
15
126(†)-45D
126,000
24 1/2
115-60-1
127
103
15.2
12
30
NOTES:
(
†
) “C” = Standard Models, “N” = 80% Low NOx Models
σ
Time-delay fuses or HACR-type circuit breakers are required.
Thermostat Wire Gauge
Recommended Thermostat Wire Length
2 - wire
(Heating)
4 or 5 wire
(Cooling)
24
55 ft.
25 ft.
22
90 ft.
45 ft.
20
140 ft.
70 ft.
18
225 ft.
110 ft.
Table 2. Wire Length and Voltage Specifi cations
Figure 13. Line Voltage Field Wiring
Field Supplied
Disconnect w/in
Sight of Furnace
Field Supplied
Panel Connector
Field Supplied
Fused Service
Panel
Black (Hot)
White (Neutral)
Green or Bare
(Ground)
Black
White
Black
White
Black
White
Field Line Voltage Wiring
Factory Line Voltage Wiring
Ground
Ground
Junction Box (may be int. or ext.
to the furnace). These connections
can be made in the field supplied
disconnect at the furnace.
Ground