24
ELECTRICAL WIRING
WARNING:
ELECTRICAL SHOCK, FIRE OR
EXPLOSION HAZARD
Failure to follow safety warnings exactly could
result in serious injury, death or property
damage.
Improper servicing could result in dangerous
operation, serious injury, death or property
damage.
• Before servicing, disconnect all electrical
power to furnace.
• When servicing controls, label all wires prior
to disconnecting. Reconnect wires correctly.
• Verify proper operation after servicing.
• Electrical connections must be in compliance with all
applicable local codes with the current revision of the
National Electric Code (ANSI/NFPA 70).
• For Canadian installations the electrical connections
and grounding shall comply with the current Canadian
Electrical Code (CSA C22.1 and/or local codes).
IMPORTANT NOTE:
If replacing any of the original wires supplied with the
furnace, the replacement wire must be copper wiring and
have a temperature rating of at least 105° F (40° C). For
electrical specifications, refer to the furnace nameplate
Line Voltage Wiring
It is recommended that the line voltage (115 VAC) to the
furnace be supplied from a dedicated branch circuit containing
the correct fuse or circuit breaker for the furnace as listed
The installer should become familiar with the units wiring
diagram before making any electrical connections to the
or
the unit wiring label.
IMPORTANT NOTES:
An electrical disconnect must be installed readily
accessible from and located within sight of the furnace.
or the wiring diagram label inside
of the control door. Any other wiring methods must be
acceptable to authority having jurisdiction.
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
.
Grounding
WARNING:
To minimize personal injury, the furnace cabinet
must have an uninterrupted or unbroken electrical
ground. The controls used in this furnace require
an earth ground to operate properly. Acceptable
methods include electrical wire or conduit
approved for ground service. Do not use gas
piping as an electrical ground!
Table 5. Wire Length & Voltage Specifications
FURNACE
MODEL
NUMBER
FURNACE
INPUT
(BTUH)
CABINET
WIDTH
(IN.)
NOMINAL
ELECTRICAL
SUPPLY
MAXIMUM
OPERATING
VOLTAGE
MINIMUM
OPERATING
VOLTAGE
MAXIMUM
FURNACE
AMPERES
SC-038D-T23A1
38,000
14 ½
115-60-1
127
103
6.9
SD-038D-T24B1
38,000
17 ½
115-60-1
127
103
9.3
SC/SD/SM-054D-T24B1
54,000
17 ½
115-60-1
127
103
9.3
SC/SL-072D-T24B1
72,000
17 ½
115-60-1
127
103
9.3
SC/SD-072-T35C1
72,000
21
115-60-1
127
103
9.3
SM-072-T35C1
75,000
21
115-60-1
127
103
12.0
SD-090D-T35C1
85,000
21
115-60-1
127
103
12.0
SM-090D-T35C1
85,000
21
115-60-1
127
103
12.0
SC-090D-T35C1
90,000
21
115-60-1
127
103
12.0
SC/SD-108D-T45D1
108,000
24 ½
115-60-1
127
103
12.0
SD-120D-T45C1
115,000
24 ½
115-60-1
127
103
12.0
SC-120D-T45D1
120,000
24 ½
115-60-1
127
103
12.0
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.
