Bosch 715ES Service Bulletin page 2

18 | G3-29 | 715ES, 2400ES, 2700ES
(to be discarded)
Attenuator Attenuator
Replacing the attenuator
1. Install replacement attenuator to the fan without o-ring.
(Fig. 3, pos. 1).
2. Secure the attenuator to the fan assembly with three Phillips
head screws. (Fig. 2, pos.2).
Adjusting fan speed (LP models only)
Note: Upon replacing the attenuator, if the water heater is a liquid
propane model, the fan speed should be adjusted using the
following the procedure.
1. Plug in power supply cord.
2. Press and hold the program (
Off button to the On position. (Fig. 4)
Data subject to change without notice | Printed in the USA | 02.2008
Figure 3
o-ring
Fan Fan
) button while pressing the On/
Figure 4
3. Release the program (
display. The display should read 'P2'. If not, repeat process.
(Fig. 4)
4. Press the ( ) button on the control panel until the display reads
'P1'.
5. Press the program ( ) button once and the display should show
the numeric value of the fan speed.
6. Use the ( ) and ( ) buttons on the control unit to select the
new fan speed for your model. The P1 fan speeds should be set
to the following:
Model GWH 2400 ES: P1 fan speed = 37
Models GWH 715 ES and GWH 2700 ES: P1 fan speed = 42
7. Press and hold (± 5 sec.) the program (
display flashes. The selected value is now memorized.
8. Press On/Off button on water heater to Off position. Press On/
Off button again to turn water heater back on.
9. Replace combustion cover only.
Adjusting CO₂
1. The water heater requires a CO₂ adjustment after the installation
of the replacement attenuator. Refer to Service Bulletin G3-12
for detailed instructions on this process.
2. After adjusting CO₂, replace front cover.
3. Press On/Off button on water heater to Off position. Press On/
Off button again to return water heater to normal service.
Service bulletin
) button when '188' appears on the
) button until the
Bosch Thermotechnology Corp.
50 Wentworth Avenue
Londonderry, NH 03053
Tel: 1-866-642-3198
Fax: 1-603-584-1681
www.boschpro.com
Bosch Thermotechnology Corp.