Bosch 830ES Technical Service Bulletin

Resetting the watervalve

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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

Drain the machine down of any water on both the hot and cold sides.

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.

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

Figure 1

Remove the 2 Phillips head screws that hold the watervalve engine to the

watervalve body (Fig. 1).

Separate the 2 the watervalve body and the watervalve engine.

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.

Page 1 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 Figure 1 The watervalve may be clogged or needs to be reset.
Page 2 10. Plug the wiring back in, and reinstall the clips on both the incoming and outgoing side of the valve. Bosch Thermotechnology Corp. 65 Grove Street 11. Slowly turn on water supply to check for leaks, before powering up and...