DIYbanter - View Single Post

wrote:
Hello,

Can anyone think if a reason as to why the hot water coming from my hot
water tank has suddenly got very hot? Even though I have turned the
thermostat right down the water is scalding hot. In fact, adjusting
the thermostat does not seem to have any effect at the moment.

Is there a boiler involved ( indirectly heated hot water storage
cylinder) and/or is there an electric immersion heater.

The contacts on electric immersion heaters can weld themselves
together, so that they fail in an On/unsafe condition. If you have an
immersion heater in the tank, I'd suggest you turn it off.

This will either;

a) stop the water heating altogether (new immersion heater thermostat
required)
or
b) will have no effect (the problem was in the boiler controls).

In either case, it will render the main hazard safe. Do that &
report back for further suggestions if needed.