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915SB: Installation, Start-up, Operating and Service and Maintenance Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
24
A190079
Fig. 33 – Typical Single-Stage Wiring Diagram
A190279
Fig. 34 – Field-Supplied External Electrical Box on Furnace Casing
Table 10 – Electrical Data
115-V Wiring
Furnace must have a 115-v power supply properly connected and
grounded.
NOTE:
Proper polarity must be maintained for 115-v wiring. If polarity
is incorrect, control LED status indicator light will flash rapidly and
furnace will
NOT
operate.
Verify that the voltage, frequency, and phase correspond to that specified
on unit rating plate. Also, check to be sure that service provided by
utility is sufficient to handle load imposed by this equipment. Refer to
rating plate or
for equipment electrical specifications.
U.S.A. Installations
: Make all electrical connections in accordance with
the current edition of the National Electrical Code (NEC) NFPA 70 and
any local codes or ordinances that might apply.
Canada Installations
: Make all electrical connections in accordance
with the current edition of the Canadian Electrical Code CSA C22.1 and
any local codes or ordinances that might apply.
Use a separate, fused branch electrical circuit with a properly sized fuse
or circuit breaker for this furnace. See
specifications. A readily accessible means of electrical disconnect must
be located within sight of the furnace
J-Box Installation
The J-Box must be used when field line voltage electrical connections
are made to the furnace wiring harness inside the furnace casing. The
J-Box cover is not required if a field-supplied external electrical box is
attached to the outside of the furnace casing. The field ground wire and
furnace main ground wire are grounded when the J-Box bracket is
attached to the furnace and the field ground wire and factory ground wire
are secured to the bracket grounding screw. If the J-Box cover is not
used, the field and factory spliced connections must be located inside the
external electrical box. Do not leave splice connections unprotected
inside the furnace.
The J-Box cover, mounting bracket and screws are shipped in the loose
parts bag included with the furnace. See
for J-Box mounting
locations.
The J-Box mounting bracket and green ground screw is used as a
grounding point for all line voltage wiring options. The J-Box cover may
115-V FIELD-
SUPPLIED
DISCONNECT
AUXILIARY
J-BOX
24-V
TERMINAL
BLOCK
THREE-WIRE
HEATING-ONLY
FIVE WIRE
NOTE 1
NOTE 2
FIELD-SUPPLIED
DISCONNECT
CONDENSING
UNIT
TWO
WIRE
FURNACE
C
O
N
T
R
O
L
R
G
COM
W
C
R
G
Y
GND
GND
FIELD 24-V WIRING
FIELD 115-, 208/230-, 460-V WIRING
FACTORY 24-V WIRING
FACTORY 115-V WIRING
208/230- OR
460-V
THREE
PHASE
208/230-V
SINGLE
PHASE
BLOWER DOOR SWITCH
WHT
BLK
WHT
BLK
NOTES:
Connect Y-terminal in furnace as shown for proper blower operation.
Some thermostats require a "C" terminal connection as shown.
If any of the original wire, as supplied, must be replaced, use
same type or equivalent wire.
W
Y
GND
THERMOSTAT
TERMINALS
1.
2.
3.
COPPER
WIRE ONLY
ELECTRIC
DISCONNECT
SWITCH
ALUMINUM
WIRE
FURNACE
SIZE
VOLTS-
HERTZ-
PHASE
OPERATING VOLTAGE
RANGE
*
*. Permissible limits of the voltage range at which the unit operates satisfactorily.
MAXIMUM
UNIT
AMPS
UNIT
AMPACITY
†
†. Unit ampacity = 125 percent of largest operating component’s full load amps plus 100 percent of all other potential operating components’ (EAC, humidifier, etc.) full load
amps.
MINIMUM
WIRE SIZE
AWG
MAXIMUM
WIRE LENGTH
FT (M)
‡
‡. Length shown is as measured one way along wire path between furnace and service panel for maximum 2 percent voltage drop.
MAXIMUM FUSE
OR CKT BKR
AMPS
**
**. Time-delay type is recommended
Maximum
Minimum
30026E14
115-60-1
127
104
5.1
7.3
14
50 (15.5)
15
30040E14
115-60-1
127
104
7
9.7
14
38 (11.7)
15
36040E17
115-60-1
127
104
7.5
10.3
14
36 (10.9)
15
36060E14
115-60-1
127
104
7.1
9.8
14
38 (11.5)
15
42060E17
115-60-1
127
104
9.6
12.9
14
28 (8.7)
15
48080E17
115-60-1
127
104
10.8
14.4
14
25 (7.8)
15
60080E21
115-60-1
127
104
12.3
16.3
12
35 (10.7)
20
60100E21
115-60-1
127
104
12.9
17.0
12
33 (10.3)
20
66100E21
115-60-1
127
104
12.6
16.6
12
34 (10.5)
20
66120E24
115-60-1
127
104
12.4
16.4
12
35 (10.7)
20
66140E24
115-60-1
127
104
12.9
17.0
12
33 (10.3)
20
CAUTION
!
FURNACE MAY NOT OPERATE HAZARD
Failure to follow this caution may result in intermittent furnace
operation.
Furnace control must be grounded for proper operation or else control
will lock out. Control must remain grounded through green/yellow wire
routed to gas valve and manifold bracket screw.
WARNING
!
FIRE OR ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury, death, or
property damage.
High voltage field connections must be located in J-Box with furnace,
or in field supplied external disconnect mounted to furnace.
If field-supplied manual disconnect switch is to be mounted on furnace
casing side, select a location where a drill or fastener cannot damage
electrical or gas components.