Bosch 715ES Service Bulletin

Service Bulletin G3-24
Models: 715ES, C800ES, 2400ES, 2700ES
Replacing the control unit
Introduction
Tools needed:
Phillips head screw driver

Small flat head screw driver

Needle-nosed pliers

Note: Avoid touching printed circuit board as static discharge may
damage circuitry.
Preparation
1. Push power button to "OFF" and unplug power cord.
2. Loosen two Phillips head screws on bottom rear of front cover.
Pull cover bottom outwards then lift cover upwards to remove.
Removing control unit
1. Remove three Phillips screws on front of control unit. (Fig. 2,
pos. 1)
2. Turn control unit to expose the rear. (Fig. 2, pos. 2). Remove
hot water sensor from pipe to ease turning.
3. Locate and remove 6 Phillips head screws on back of control
unit (Fig. 2, pos. 3).
control unit front control unit front
4. Remove rear cover from control unit to expose circuit board elec-
trical connections. Slide wire restraints out of control unit.
(Fig. 3, pos. 1).
5. Remove two large electrical strip connectors by pulling them
away from board. (Fig. 3, pos. 2).
6.. Remove medium sized electrical strip connector by pulling it
outwards. (Fig. 3, pos. 3).
7. Remove small electrical strip connector by pulling it outwards.
(Fig. 3, pos. 4).
8. Remove two large yellow ignition wires by pulling them out-
wards. (Fig. 3, pos. 5).
9. Remove yellow/green striped ground wire spade connection by
depressing tab on connector and pulling it gently off the board.
(Fig. 3, pos. 6).
10. Loosen two small flat head screws on terminal block for power
cord. Pull black and white wires free from terminal block and
control unit. (Fig. 3, pos. 7).
11. Loosen Phillips head screw and remove green ground wire
connection for power cord. (Fig. 3, pos. 8).
Figure 2
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12. Remove control unit from the water heater.
13. Natural Gas heaters only: Remove jumper from JP6 connection
on control board. This jumper must be installed on replacement
control board. (Fig. 4 ).
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2
4
6
8
1
Figure 3
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5
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