Carrier 59SC2A - J-Box Installation; 24-V Wiring

J-Box Installation
CA UN Le
FIRE OR ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury, death, or property damage.
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 is used when field line voltage electrical connections are
made to the furnace wiring harness inside the furnace casing. The
J-Box is not required if a field-supplied electrical box is attached to
the outside of the furnace casing and the box is grounded to the
green ground wire of the main wiring harness and the earth ground
of the field electrical supply.
The J-Box cover, mounting bracket and screws are shipped in the
loose parts bag included with the furnace. The J-Box can be
mounted on the left or right side of the casing, as viewed from the
upflow position. See Fig. 32.
Remove the J-Box cover and mounting bracket from the loose
parts bag. Select a 7/8-in. (22 mm) knock-out on the desired side
of the casing. Remove the knock-out from the casing. Drill two (2)
1/8-in. (3 mm) pilot holes in the casing dimples by the desired
7/8-in. (22 mm) knock-out.
Align the J-Box mounting bracket against the inside of the casing
and secure the mounting bracket with the screws. See Fig. 32.
Electrical Box on Furnace Casing Side
NOTE: Check that duct on side of furnace will not interfere with
installed electrical box.
1. Fasten a field-supplied external electrical box to the outside
of the casing by driving two field-supplied screws from in-
side electrical box into casing. See Fig. 33.
. Route field power wiring into external electrical box.
Ww
. Pull furnace power wires through 1/2-in. (12 mm) diameter
hole in J-Box. If necessary, loosen power wires from strain-
relief wire-tie on furnace wiring harness.
4. Connect any code required external disconnect(s) to field
power wiring.
5. Route external field power wires through holes in electrical
box and casing.
6. Connect field ground wire and factory ground wire to green
ground screw on J-Box mounting bracket as shown in Fig.
32.
7. Connect field power and neutral leads to furnace power
leads as shown in Fig. 35.
8. Attach furnace J-Box cover to mounting bracket with
screws supplied in loose parts bag. Do not pinch wires
between cover and bracket.
9, Complete external disconnect wiring and installation. Con-
nect line voltage leads as shown in Fig. 33. Use best prac-
tices (NEC in U.S.A. for wire bushings, strain relief, etc.,
CANADA: Canadian Electrical Code CSA C22.1)
Power Cord Installation in Furnace J-Box
NOTE: Power cords must be able to handle the electrical
requirements listed in Table 11. Refer to power cord
manufacturer’s listings.
1. Install J-Box mounting bracket to inside of furnace casing.
See Fig. 32.
2. Route listed power cord through 7/8-in. (22 mm) diameter
hole in casing and J-Box bracket.
3. Secure power cord to J-Box bracket with a strain relief
bushing or a connector approved for the type of cord used.
4, Pull furnace power wires through 1/2-in. (12 mm) diameter
hole in J-Box. If necessary, loosen power wires from
strain—relief wire-tie on furnace wiring harness.
5. Connect field ground wire and factory ground wire to green
ground screw on J-Box mounting bracket as shown in Fig.
32.
6. Connect power cord power and neutral leads to furnace
power leads as shown in Fig. 35.
7. Attach furnace J-Box cover to mounting bracket with
screws supplied in loose parts bag. Do not pinch wires
between cover and bracket. See Fig. 32.
BX Cable Installation in Furnace J-Box
1. Install J-Box mounting bracket to inside of furnace casing.
See Fig. 32.
. Route BX connector through 7/8-in. (22 mm) diameter
hole in casing and J-Box bracket.
bo
3. Secure BX cable to J-Box bracket with connectors ap-
proved for the type of cable used.
4. Connect field ground wire and factory ground wire to green
ground screw on J-Box mounting bracket as shown in Fig.
32.
5. Connect field power and neutral leads to furnace power
leads. as shown in Fig. 35.
6. Attach furnace J-Box cover to mounting bracket with
screws supplied in loose parts bag. Do not pinch wires
between cover and bracket.
24-V Wiring
Make field 24-v connections at the 24-v terminal strip. See Fig.
36. Connect terminal Y as shown in Fig. 35 for proper cooling
operation. Use only AWG No. 18, color-coded, copper thermostat
wire.
NOTE: Use AWG No. 18 color-coded copper thermostat wire for
lengths up to 100 ft. (30 M). For wire lengths over 100 ft., use
AWG No. 16 wire.
The 24-v circuit contains an automotive-type, 3-amp. fuse located
on the control. Any direct shorts 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. See Fig. 36.
Accessories (See Fig. 34 and 36.)
1. Electronic Air Cleaner (EAC)
Connect an accessory Electronic Air Cleaner (if used) using
1/4-in. female quick connect terminals to the two male
1/4-in. quick-connect terminals on the control board
marked EAC-1 and EAC-2. The terminals are rated for
11SVAC, 1.0 amps maximum and are energized during
blower motor operation.
2. Humidifier (HUM)
The HUM terminal is a 24 VAC output, energized when the LPS
closes during a call for heat.
Connect an accessory 24 VAC, 0.5 amp. maximum humidifier (if
used) to the '%4-in. male quick-connect HUM terminal and
COM-24V screw terminal on the control board thermostat strip.
NOTE: If the humidifier has its own 24 VAC power supply, an
isolation relay may be required. Connect the 24 VAC coil of the
isolation relay to the HUM and COM/24V screw terminal on the
control board thermostat strip. See Fig. 34.
Alternate Power Supplies
This furnace is designed to operate on utility generated power
which has a smooth sinusoidal waveform. If the furnace is to be
operated on a generator or other alternate power supply, the
alternate power supply must produce a smooth sinusoidal
waveform for compatibility with the furnace electronics. The
33
59SC2A