INSTALLATION INSTRUCTIONS
Gas Furnace: (F/G)9MVT, (F/G)9MXT, (F/G)9MXE
32
440 01 4001 05
Specifications subject to change without notice.
Figure 37
J
−
Box Bracket Installation
L12F025
J
−
BOX
MOUNTING
SCREWS
J
−
BOX
MOUNTING
BRACKET
GROUND
SCREW
J
−
BOX COVER
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 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
Figure 37
)
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 inside electrical box into casing. (See
Figure 38
)
2. Route field power wiring into external electrical box.
3. 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
Figure 37
.
7. Connect field power and neutral leads to furnace power
leads. as shown in
Figure 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.
Connect line voltage leads as shown in
Figure 38
. Use
best practices (NEC) ANSI/NFPA 70 in U.S.A. for wire
bushings, strain relief, etc., and Canadian Electrical
Code CSA C22.1.
Figure 38
Field
−
Supplied Electrical Box on
Furnace Casing
A10141
GROUND
NEUTRAL
LINE
VOLTAGE
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
Figure 37
)
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
Figure 37.
6. Connect power cord power and neutral leads to furnace
power leads as shown in
Figure 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.
BX Cable Installation in Furnace J
−
Box
1. Install J
−
Box mounting bracket to inside of furnace
casing.
2. Route BX connector through 7/8
−
in. (22 mm) diameter
hole in casing and J
−
Box bracket.
3. Secure BX cable to J
−
Box bracket with connectors
approved 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
Figure 37
.
5. Connect field power and neutral leads to furnace power
leads. as shown in
Figure 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
Figure 41
or
Figure 42
) Connect terminal Y/Y2 as shown in
Figure 35
for proper cooling operation. Use only AWG No. 18,
color
−
coded, copper thermostat wire.