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4 0 | Bosch 96% AFUE Gas Furnace
10.2 Electrical Connection to J-box
Field-Supplied Electrical Box on Furnace J-Box Bracket
See Fig. 34 on previous page.
1.
Remove cover from furnace J-Box.
2.
Attach electrical box to furnace J-Box bracket with at least two fi eld-
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 fi eld-wire connections in electrical box. Use best
practices (NEC in U.S.) for wire bushings, strain relief, etc.
4.
Route and secure fi eld 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. 36.
6.
Reinstall cover to J-Box. Do not pinch wires between cover and bracket.
Electrical Box on Furnace Cabinet Side.
See Fig. 35 and Fig 36.
WARNING: FIRE OR ELECTRICAL SHOCK HAZARD
If fi eld-supplied manual disconnect switch is to be mounted
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 fi eld-supplied screws
from inside electrical box into cabinet steel.
4.
Remove and save two screws holding J-Box. (See Fig. 34.)
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 fi eld power wires into electrical box.
8.
Remove cover from furnace J-Box.
9.
Route fi eld 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 fi eld 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. 36. 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.
Data subject to change
10.3 Power Cord Installation in Furnace J-box
Power cords must be able to handle the electrical requirements listed in
Table 16. 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 fi eld ground wire to green ground screw on J-Box bracket.
5.
Connect line voltage leads as shown in Fig. 36.
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 fi eld ground wire to green ground screw on J-Box bracket.
5.
Connect line voltage leads as shown in Fig. 36.
6.
Reinstall cover to J-Box. Do not pinch wires between cover and bracket.
10.5 24-V Wiring
Make fi eld 24V connections at the 24V terminal strip (See Fig. 35.). Connect
terminal Y as shown in Fig. 36 for proper cooling operation. 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 EAC-N. The terminals
are rated for 115 VAC, 1.0 amps maximum and are energized when blower
motor is in operation (see Figure 35).
2.
Humidifi er (HUM)
Connect an accessory 24 VAC 0.5 Amp. maximum humidifi er using
the ¼-inch male quick connect terminals marked HUM-H and HUM-N,
respectively, on the control board. The HUM is energized when gas valve
relay is energized (see Figure 35).
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.
Installation, Operation & Maintenance
04.2019 | Bosch Thermotechnology Corp.
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