Bosch C1210ES Reference manual

Technical Service Bulletin:
Replacing & Servicing The Condensing
Heat Exchanger
Models: C1210ES, C1210ESC
Introduction
 If replacing the copper heat exchanger (below the condensing
heat exchanger), refer to Technical Service Bulletin: Replacing
The Copper Heat Exchanger after the condensing exchanger has
been removed.
Tools needed:
 Phillips head screwdriver
 8mm nut driver with 6" extension
 4mm allen wrench
 Clean rag
Preparation
1. Unplug water heater and turn off gas to heater using installer
supplied manual shut off valve.
2. Remove front cover and combustion cover using instructions in
the installation manual.
3. Close installer supplied inlet isolation or shut off valve and open
a hot water tap to release pressure and drain. If water ows
continuously from the tap, a plumbing crossover is present and
must be corrected.
4. Disconnect inlet and outlet piping from the water heater to
facilitate draining. Have a bucket ready to catch water.
5. Place a clean rag over the water heater‘s control unit to catch any
residual water when removing pipe connections.
Removing the condensing heat exchanger
1. Remove Phillips head screw, gasket and exhaust temperature
sensor from center of condensing exchanger. (Fig. 1, pos. 1).
2. Remove overheat sensor/ECO wires from sensor on heat
exchanger. (Fig. 1, pos. 2). Ensure that wires are out of the way
for heat exchanger removal and reinstallation.
3. Remove clip from black condensate drain pipe connection and
pull drain pipe free. (Fig. 1, pos. 3).
Figure 1
4. Remove clips on copper pipe connecting upper and lower heat
exchanger and remove pipe (Fig. 2, pos. 1). Dripping water is
likely.
5. Remove clips from top of cold water pipe and remove pipe from
heat exchanger (Fig. 2, pos. 2). Dripping water is likely.
6. Remove the two Phillips screws and two 4mm hex head screws
from the top left and right of the exchanger (Fig. 2, pos. 3).
7. Remove the four 8mm nuts from the bottom front and top rear of
condensing exchanger. (Fig. 2, pos. 4). Note: two left nuts are
not visible in Figure 2.
8. Remove the condensing heat exchanger by pulling it forward and
out of the heater.

Data subject to change without notice | Printed in the USA | BTC 740002318 A | 07.2010 Bosch Thermotechnology Corp.
Technical Service Bulletin
18 | Replacing & Servicing The Condensing Heat Exchanger - C1210ES, C1210ESC
Bosch Thermotechnology Corp.
50 Wentworth Avenue
Londonderry, NH 03053
Tel: [phone]
Fax: [phone]
www.boschpro.com
5
5
Figure 2
Inspecting condensing heat exchanger
Note: If removing the lower copper heat exchanger, refer to
Technical Service Bulletin: Replacing Copper Heat Exchanger
now. If installing a new condensing heat exchanger, skip the
next section.
1. Using a ashlight, look through the rear inlet slot of the heat
exchanger so that the n coils inside are visible.
2. If there are any signs of soot, combustion byproducts or
corrosion, the condensing exchanger must be disassembled to
clean the n coils.
Disassembling condensing heat exchanger
1. Remove clips from copper "U" bend pipes on left and right side of
heat exchanger (Fig. 2, pos. 5). Remove copper "U" bend pipes.
2. Remove the four 4mm hex head screws from one side of the heat
exchanger. (Fig. 3, pos. 1)
3. Carefully separate one side of heat exchanger from main body by
prying evenly. Use caution to prevent damage to the aluminum
and gasket.
4 Please note o-ring positions when dissassembling. Smaller
o-rings (Fig. 3, pos. 2) t on n coil pipe ends. Larger o-rings are
placed on the outside of the heat exchanger sides
(Fig. 3, pos. 3).
5. Gently pull n coil tubes (Fig. 3, pos. 4) free from the exchanger
body. If necessary, the other side of the heat exchanger can be
removed to ease removal of n coils.
6. With n coils exposed, vacuum them clean with a soft bristle
vacuum brush. Then spray clean with water. Ensure drain hole
in bottom right of exchanger is clear of debris or corrosion.
Reassembling and installing condensing heat exchanger
1. Reinsert n coils (without o-rings) into exchanger body. (Fig. 3,
pos. 4).
Figure 3
2. Place side with gasket (Fig. 3, pos. 5) on to main exchanger body
and push rmly on sides to properly seat ncoils.
3. Install four 4mm hex head screws with washers to secure each
heat exchanger side (Fig. 3, pos. 1)
4. Place small o-rings (Fig. 3, pos. 2) on n coil ends and large o-
rings (Fig. 3, pos. 3) where "U" bend, and water pipes connect.
Use dish washing liquid to lubricate large o-rings and seat them
with connecting pipes.
5. Reinstall "U" bend pipes on each side of exchanger
(Fig. 2, pos. 5) Secure both pipe connections with clips.
6. If lower heat exchanger was removed, reinstall using bulletin G3-
22 before proceeding.
7. Place condensing heat exchanger back into heater. Ensure that
gaskets between upper and lower heat exchanger and between
condensing exchanger and ue gas collector are correctly in
place.
8. Tighten the four 8mm nuts at the bottom front and top rear of
condensing exchanger. (Fig. 2, pos. 4). Note: two left nuts are
not visible in Figure 2.
9. Install the two Phillips screws and two 4mm hex head screws
from the top left and right of the exchanger (Fig. 2, pos. 3).
10. Reinstall cold water pipe (Fig. 2, pos. 2) and connecting pipe
(Fig. 2, pos 1) with o-rings on heat exchanger. Secure with clips.
11. Reinstall condensate drain pipe to connector with o-ring and
clip. (Fig. 1, pos.3).
12. Reinstall exhaust temperature sensor with washer and screw
(Fig. 1, pos. 1).
13. Reconnect wire leads to overheat sensor/ECO (Fig. 1, pos. 2).
14. Turn on water supply and check for leaks.
15. Replace combustion and front covers.
16. Plug in power cord and return heater to service.