24-V Wiring; Accessories - Carrier 58MTB Installation, Start-Up, And Operating Instructions Manual

ELECTRIC
DISCONNECT
SWITCH
Fig. 33—Disconnect Switch and Furnace
Use a separate, fused branch electrical circuit containing a properly
sized fuse or circuit breaker for this furnace. See Table 6 for wire
size and fuse specifications. A disconnecting means must be
located within sight from and readily accessible to furnace.
NOTE: Proper polarity and proper grounding must be maintained
for 115-v wiring. If polarity is incorrect, control LED status
indicator light will flash rapidly and furnace will NOT operate.
FIRE HAZARD
Failure to follow this warning could result in intermittent
operation or performance satisfaction.
Do not connect aluminum wire between disconnect switch
and furnace. Use only copper wire. (See Fig. 33.)
ELECTRICAL SHOCK AND FIRE HAZARD
Failure to follow this warning coud result in electrical shock,
fire, or death.
The furnace casing MUST have an uninterrupted or unbroken
ground according to NEC ANSI/NFPA 70-2002 and Cana-
dian Electrical Code CSA C22.1 or local codes to minimize
personal injury if an electrical fault should occur. This may
consist of electrical wire or conduit approved for electrical
ground when installed in accordance with existing electrical
codes. Do not use gas piping as an electrical ground.
→
Factory Installed J-Box Location
Install electrical entry hole filler plugs (factory-supplied in loose
parts bag) in unused power entry holes. (See Fig. 34.)
J-Box Relocation
1. Remove 2 screws holding auxiliary J-box. (See Fig. 35.)
2. Rotate J-box 180° and attach box to left side, using holes
provided.
→
3. Install electrical entry hole filler plugs (factory-supplied loose
parts Bag) in unused power entry holes. (See Fig. 35.)
ELECTRICAL SHOCK AND FIRE HAZARD
Failure to follow this warning could result in intermittent unit
operation or performance satisfaction.
If manual disconnect switch is to be mounted on furnace,
select a location where a drill or fastener will not contact
electrical or gas components.
COPPER
WIRE ONLY
ALUMINUM
WIRE
A93033
POWER ENTRY HOLE
FILLER PLUG (FACTORY-
SUPPLIED LOOSE PARTS BAG)
→
Fig. 34—Factory Installed J-Box Location

24-V WIRING

Make field 24-v connections at 24-v terminal block on furnace.
(See Fig. 37.) Connect terminal Y/Y2 as shown in Fig. 31 and 32
for proper cooling operation. Use only AWG No. 18, color-coded,
copper thermostat wire for lengths up to 100 ft. For wire lengths
over 100 ft, use AWG No. 16 wire.
The 24-v circuit contains an automotive-type, 3-amp fuse located
on furnace control. (See Fig. 37.) Any direct shorts of 24-v wiring
during installation, service, or maintenance could cause this fuse to
blow. If fuse replacement is required, use ONLY a 3-amp fuse of
identical size/type. The control will flash code 24 when fuse needs
replacement.

ACCESSORIES

1. Electronic Air Cleaner (EAC)
Two male quick-connect terminals marked EAC-1 and EAC-2
are provided for EAC connection. (See Fig. 37.) These
terminals are energized with 115-v (1.0-amp maximum)
during blower motor operation.
2. Humidifier (HUM)
Connect an accessory 24 VAC, 0.5 amp maximum humidifier
(if used) to the 1/4-in. male quick-connect HUM terminal and
C -24V screw terminal on the control board thermostat strip.
OM
The HUM terminal is energized when gas valve is energized.
(See Fig. 36 or 37.)
NOTE: A field-supplied, 115–v controlled relay connected to
EAC terminals may be added if humidifier operation is desired
during blower operation.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in unit component
damage.
DO NOT connect furnace control HUM terminal to HUM
(humidifier) terminal on Thermidistat™, Zone Controller or
similar device. See Thermidistat™, Zone Controller, thermo-
stat, or controller manufacturer's instructions for proper
connection.
27
FACTORY
INSTALLED
LOCATION
UNUSED 7/8-IN.
DIAMETER POWER
ENTRY HOLES
A05113
A05113