Technical Service Bulletin:
Resetting the Watervalve
Models: 830ES, 940ES-ESO, C950ES, C1050ES, 1210ES-ESC, T9800/T9900 SE(C)
A qualifi ed service technician is recommended to perform the work.
Problem
Tankless water heater that doesn't activate, and doesn't show an error code.
Possible Cause
The watervalve may be clogged or needs to be reset.
Overview
Sometimes a tankless water heater doesn't start up when water is turned on (above
activation rate), and also doesn't give an error code. This can be due to the impeller
in the watervalve being stuck or clogged, the water valve being closed, or even just
a clogged inlet fi lter. Some of the models have an inlet fi lter accessible from outside
the machine, which you can inspect for debris fi rst. Other models have it directly
in line with the watervalve, in which you will have to disconnect and remove the
watervalve for access.
Procedure
1.
Drain the machine down of any water on both the hot and cold sides.
2.
Remove the inlet and outlet water clips and remove watervalve from the
machine. After it is removed, disconnect all wiring to the watervalve.
Inspect the screen for any blockage and clean if necessary.
3.
Remove the 2 Phillips head screws that hold the watervalve engine to the
watervalve body (Fig. 1).
Data subject to change without notice | Printed in the USA | BTC 740002333 A | 05.2018
All manuals and user guides at all-guides.com
Figure 1
4.
Remove the 2 Phillips head screws that hold the watervalve engine to the
watervalve body (Fig. 1).
5.
Separate the 2 the watervalve body and the watervalve engine.
6.
On the valve side, locate the brass gear. Rotate the gear counter clockwise
(towards the "0") until it stops (Fig. 2).
Figure 2
Bosch Thermotechnology Corp.