Bosch 715ES User manual

Models: 715ES, C800ES, C920ES, C920ESC, 2400ES, 2700ES
Cleaning and replacing ignition group
Service Bulletin G3-23
Introduction
The ignition group consists of two ignition electrodes and one
ame sensing rod. These components may need to be cleaned
or the entire group replaced if the heater has frequent EC or EA
error codes or fails to produce a spark.
Tools needed:
Phillips head screwdriver
 8mm wrench or small adjustable wrench
Fine steel wool for cleaning
Preparation
1. Unplug water heater and turn off gas to heater using installer
supplied manual shut off valve.
2. Loosen two Phillips head screws located at bottom rear of cover.
(Fig. 1, step 1, pos. 1).
3. Lift front cover upward and remove. (Fig. 1, step 1, pos. 2 & 3)
4. Remove combustion cover by unclipping two upper and two
lower clips securing cover. (Fig. 1, step 2)
Step 1 Step 2
S
tep
1
S
tep
2
Figure 1
3
3
Removing the ignition group
1. Locate ignition group. (Fig. 2, pos. 1).
2. Disconnect two large yellow ignition wires from ignition group.
(Fig. 2, pos. 2)
3. Disconnect small black ame sensor wire from ignition group.
(Fig. 2, pos. 3).
Figure 2

Data subject to change without notice | Printed in the USA | BTC710002310 A | 01.2009 Bosch Thermotechnology Corp.
Service bulletin
18 | G3-23 | 715ES, C800ES, C920ES, C920ESC, 2400ES, 2700ES
Bosch Thermotechnology Corp.
50 Wentworth Avenue
Londonderry, NH 03053
Tel: [phone]
Fax: [phone]
www.boschhotwater.com
|
4. Remove two 8mm nuts from ignition group. (Fig. 3, pos. 1).
5. Remove ignition group and gasket from the water heater. Leave
the observation window in place.
Figure 3
Cleaning ignition group
1. If the ignition group gasket is discolored or torn, replace with a
new gasket. (Fig. 4)
2. Using steel wool, gently polish all metal surfaces of the ame
sensor and the ignition electrodes. (Fig. 4)
Figure 4
Gasket
Flame
sensor
Ignition
electrodes
Replacing ignition group
1. Gently place ignition group gasket over left bolt stud for 8mm
nut. The stud will hold the gasket in place.
(Fig. 3, pos. 1)
2. Carefully feed tips of ignition group into heat exchanger ensuring
that the ame sensor rod is on the far left.
3. Ensure a proper seal between the heat exchanger and ignition
group.
4. Replace and tighten two 8mm retaining nuts. (Fig. 3, pos. 1).
5. Reconnect two large ignition wires to the right and center igniter
terminals. (Fig. 2, pos. 2).
6. Reconnect small black ame sensor wire to the left terminal.
(Fig. 2, pos. 3).
7. Ensure that all three wire connections t securely on the
terminals.
8. Replace combustion cover and front cover. (Fig. 1).
9. Plug in water heater‘s power cord and press On/Off button to
"ON". Reset any error that is displayed.
10. Open manual gas shutoff valve.
11. Return water heater to service.
!WARNING
FAILURE TO PROPERLY SEAL THE
IGNITION GROUP WITH GASKET MAY
CREATE A HAZARDOUS CONDITION
CAUSING SEVERE PERSONAL INJURY
OR DEATH.