Boiler water light is on when not drawing water + radiators are warm *VIDEO*

[boolie]

The thermostat is off but the radiators are warm. At the boiler the 'tap' light is on but all the taps are off. So there should be no demand for anything.. but the radiators are warm and the tap light is flashing! The hot water pipes are cold so no demand for hot water whatsoever. Any idea what the problem is?

See video

 

[CBW]

If your boiler has a preheat function, then it’s likely the diverter is passing into the central heating circuit , and rarely being satisfied. If you can turn off the preheat, then it’ll only happen when you run hot water, but at least it’ll stop firing for preheat until your sorted.

 

[boolie]

I'll do a more scientific test. My wife may have put the central heating on before - which may have resulted in the warm radiators

Its a main eco elite (~6 years old). In the meantime I've turned the DHW knob all the way to the minimum - I believe that turns off pre-heat according to this

.