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Installation Instructions
10.2 Electrical Connection to J-box
Field-Supplied Electrical Box on Furnace J-Box Bracket
See Fig. 35 on previous page.
1.
Remove cover from furnace J-Box.
2.
Attach electrical box to furnace J-Box bracket with at least two field-
supplied screws through holes in electrical box into holes in bracket. Use
blunt-nose screws that will not pierce wire insulation.
3.
Route furnace power wires through holes in electrical box and J-Box
bracket, and make field-wire connections in electrical box. Use best
practices (NEC in U.S.) for wire bushings, strain relief, etc.
4.
Route and secure field ground wire to green ground screw on J-Box bracket,
OR FURNACE WILL FAIL TO OPERATE.
5.
Connect line voltage leads as shown in Fig. 37.
6.
Reinstall cover to J-Box. Do not pinch wires between cover and bracket.
Electrical Box on Furnace Cabinet Side.
See Fig. 36 and Fig 37.
WARNING: FIRE OR ELECTRICAL SHOCK HAZARD
If field-supplied manual disconnect switch is to be mounted
f
on furnace cabinet side, select a location where a drill or
fastener cannot damage electrical or gas components.
1.
Select and remove a knockout hole in the cabinet where the electrical box is
to be installed.
Check that duct on side of furnace will not interfere with installed
electrical box.
2.
Remove the desired electrical box hole knockout and position the hole in
the electrical box over the hole in the furnace cabinet.
3.
Fasten the electrical box to cabinet by driving two field-supplied screws
from inside electrical box into cabinet steel.
4.
Remove and save two screws holding J-Box. (See Fig. 35.)
5.
Pull furnace power wires out of 1/2-inch diameter hole in J-Box. Do not
loosen wires from strain-relief wire-tie on outside of J-Box.
6.
Route furnace power wires through holes in cabinet and into electrical box.
7.
Pull field power wires into electrical box.
8.
Remove cover from furnace J-Box.
9.
Route field ground wire through holes in electrical box and cabinet, and into
furnace J-Box.
10.
Reattach furnace J-Box to furnace cabinet with screws removed in Step 4.
11.
Secure field ground wire to green ground screw on J-Box Bracket.
12.
Complete electrical box wiring and installation. Connect line voltage leads
as shown in Fig. 37. Use best practices (NEC in U.S.) for wire bushings,
strain relief, etc.
13.
Reinstall cover to J-Box. Do not pinch wires between cover and bracket.
4 0 |
10.3 Power Cord Installation in Furnace J-box
Power cords must be able to handle the electrical requirements listed in
Table 17. Refer to power cord manufacturer's listings.
1.
Remove cover from J-Box.
2.
Route listed power cord through 7/8-inch diameter hole in J-Box.
3.
Secure power cord to J-Box bracket with a strain relief bushing or a
connector approved for the type of cord used.
4.
Secure field ground wire to green ground screw on J-Box bracket.
5.
Connect line voltage leads as shown in Fig. 37.
6.
Reinstall cover to J-Box. Do not pinch wires between cover and bracket.
10.4 BX Cable Installation in Furnace J-box
1.
Remove cover from J-Box.
2.
Route BX cable into 7/8-inch diameter hole in J-Box.
3.
Secure BX cable to J-Box bracket with connectors approved for the type of
cable used.
4.
Secure field ground wire to green ground screw on J-Box bracket.
5.
Connect line voltage leads as shown in Fig. 37.
6.
Reinstall cover to J-Box. Do not pinch wires between cover and bracket.
10.5 24-V Wiring
Make field 24V connections at the 24V terminal strip (See Fig. 36.). Connect
terminal Y as shown in Section 10.8. Use only 18 AWG, color-coded, copper
thermostat wire.
The 24V circuit contains an automotive-type, 3-Amp. fuse located on the control.
Any direct shorts during instaIlation, service, or maintenance could cause this fuse
to blow. If fuse replacement is required, use ONLY a 3-Amp. fuse of identical size.
10.6 Accessories (Field Supplied)
1.
Electronic Air Cleaner (EAC)
For connection to an Electronic Air Cleaner (if needed), use ¼-inch female
quick connect terminals to engage with the two ¼-inch male quick connect
terminals on the control board marked EAC-H and one of NEUTRALS. The
terminals are rated for 115 VAC, 1.0 amps maximum and are energized
when blower motor is in operation (see Figure 36).
2.
Humidifier (HUM)
Connect an accessory humidifier using the ¼-inch male quick connect
terminals marked HUM and one of NEUTRALS, respectively, on the control
board. The HUM is energized when gas valve relay is energized. The
terminals are rated for 115VAC, 1.0 amps maximum (See Figure 36).
10.7 Grounding
The furnace must be electrically grounded in accordance with local codes or, in
the absence of local codes, with the National Electrical Code, ANSI/NFPA 70, if an
external electrical source is utilized.
Bosch 96% AFUE Condensing Gas Furnace - BTC 770503101 J (06.2023)
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