Heating won't turn off

[Courtyboy]

Hi - woke up today to a house at 26 degrees. Thermostat not clicking when turned up and down. Set heating and hot water both to off on the panel under the boiler, and went and bought a replacement thermostat from B&Q. However when I got home the house was still boiling even though I had turned the heating off.

The only way to stop it was to actually turn off the boiler at the wall.

What could be causing this? Thanks in advance for any help.

 

[Agile]

Maybe motor valve jammed on!

 

[RidleyRumpus]

Do you mean the valve in the new motarised valve or a different valve?

 

[Courtyboy]

I think it's more like the boiler is ignoring input from the thermostat or even the heating control next to the boiler and just heating and heating and heating. Setting the heating control to off, seems to be being ignored.

If the valve was sticking that would cause the pump to run, but wouldn't trigger the boiler to come on - is that right?