Bryant 987MB Installation, Start-Up, Operating And Service And Maintenance Instructions page 27

987MB: Installation, Start-up, Operating and Service and Maintenance Instructions
VOLTS-
FURNACE
HERTZ-
SIZE
PHASE
115-60-1
42060C17
115-60-1
60060C21
42080C17 115-60-1
60080C21 115-60-1
115-60-1
66100C21
115-60-1
66120C24
*. Permissible limits of the voltage range at which the unit operates satisfactorily.
†. 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.
‡. Length shown is as measured one way along wire path between furnace and service panel for maximum 2 percent voltage drop
**. Time-delay type is recommended
WARNING
!
ELECTRICAL SHOCK AND FIRE HAZARD
Failure to follow this warning could result in personal injury, death, or
property damage.
The cabinet MUST have an uninterrupted or unbroken ground
according to NEC NFPA 70 or local codes to minimize personal injury
if an electrical fault should occur. In Canada, refer to Canadian
Electrical Code CSA C22.1. This may consist of electrical wire,
conduit approved for electrical ground or a listed, grounded power cord
(where permitted by local code) when installed in accordance with
existing electrical codes. Refer to the power cord manufacturer's
ratings for proper wire gauge. Do not use gas piping as an electrical
ground.
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 HAZARD
Failure to follow this warning could result in personal injury, death, or
property damage.
Do not connect aluminum wire between disconnect switch and furnace.
Use only copper wire, see Fig.
ELECTRIC
DISCONNECT
SWITCH
Fig. 33 – Field-Supplied External Electrical Box on Furnace Casing
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
OPERATING VOLTAGE
MAX UNIT
*
RANGE
* *
Maximum Minimum
127 104
127 104
127 104
127 104
127 104
127 104
33.
COPPER
WIRE ONLY
ALUMINUM
WIRE
Table 9 – Electrical Data
MODULATING
UNIT
†
AMPS AMPACITY
9.0 12.0
14.1 18.4
9.0 12.0
14.1 18.4
14.1 18.4
14.1 18.4
J-Box Installation
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.
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
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
be omitted when electrical connections are made inside an external
electrical box mounted external to the casing.
External Electrical Box on Furnace Casing
NOTE: Check to ensure that external electrical box does not interfere
with duct work, gas piping or the indoor coil drain. See
alternate electric entry through top panel.
1. Select and remove 7/8-in. (22 mm) knock-out on the desired side of
the casing. Remove the knock-out from the casing.
NOTE: If electrical entry through the furnace top panel is used, a 7/8-in.
(22 mm) hole must be drilled through the top panel.
2. Drill two (2) 1/8-in. (3 mm) pilot holes through the dimples in the
furnace casing near the 7/8-in. knock-out.
A190279
27
MINIMUM MAXIMUM
WIRE SIZE WIRE LENGTH
‡
AWG FT (M)
14 30 (9.4)
12 31 (9.5)
14 30 (9.4)
12 31 (9.5)
12 31 (9.5)
12 31 (9.5)
WARNING
!
Fig. 34
MAXIMUM FUSE
OR CKT BKR
**
AMPS
15
20
15
20
20
20
for J-Box mounting
Fig. 30 for