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alan_m alan_m is offline
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Default Faulty Thermostat or faulty installation

On 18/04/2021 10:38, Chris B wrote:

When moving the thermostat manually there is about a 5C "backlash"
between switch on/off operations.

Is that just the normal hysteresis of 5 to 10C?

1) a thermostat that didn't like being moved and has failed due to the

It is probably a simple bi-metal strip with little to go wrong - except
in moving it the installer has created a high resistance electrical
connection - wire connected with screw through the insulation and only
just making electrical contact.

2) Lack of thermal connection between the new tank and the thermostat
(should there be any form of heat transfer compound between them)* - I
think this would be my first point of call if it was my tank)

The strap may not be tight enough to hold the thermostat tightly against
the tank. As far as I'm aware no compound is used between the tank and

3) Incorrect positioning of the thermostat

Where is it positioned? The position may only be relevant to what
temperature you set it to. Currently on by tank I have installed two
(Ebay special) temperature probes/displays. One half way down the tank
where the thermostat is fitted and one at the very top. While water is
heating from cold there is a approx a 10C difference in reading with the
top of the tank being hotter.

4) any other ideas.

He has the maintenance contact with BG so they will be called in to fix
it but he would like some confidence that the problem can be fixed.

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