Boiler won’t stop heating water!?

[kissinger]

We have an old back boiler that’s worked fine for the past 6 months since we moved into our house.

For the past couple of days the boiler seems to constantly heat the water, even when the switch is set to ‘timed’ or ‘off’. The heating still works as normal. The only way I can get it to stop is to turn the whole unit off.

Anyone know what might be wrong?

 

[Seb101]

Might be a stupid question, but how do you know it‘s just heating the water and not running the central heating?

 

[CBW]

Sounds like a failed motorised valve, resulting in the end switch firing up the boiler.

 

[kissinger]

Might be a stupid question, but how do you know it‘s just heating the water and not running the central heating?

The rads stay cold unless I turn in the thermostat dial.