The boiler heats water and heating okay but will not turn off at selected time on timer or if 'off' is selcted on timer. Boiler continues to heat but no heat to rads is supplied. I have to switch off at mains to turn off boiler. Have asked engineers to check but they seem to have no idea. We can't leave it on as it is using up gas and obviously if we switch off from the mains we have no heat first thing in the morning. Its a pain in the neck!

Helen, February 2011

C# - I continued to use your advice and have been fiddling with this system for the last week. We had an electrician look for faults and could find none. Last week I noticed that the pressure has dropped by a bar so thought that there must be a leak somewhere. To cut a long story short and ignore the bit where I nearly killed my husband, a small leak was discovered coming from a rad without a thermostat. One rad also needed bleeding. Bob's your uncle...problem solved. Let this be a lesson to all. Make sure the rads are not leaking especially if you have an unvented pressurised system, bleed the rads regularly, top up pressure and life should be worth living again. Thank you C# for the clues.

Helen, March 2011

Thanks for these suggestions but the boiler is not a combi. The model is an ESS condensing. I couldn't find anything to do with an actuator. When the thing is running it doesn't heat the water or the rads. Bizzare. And it is intermittent and usually when we get an engineer in it behaves itself.

Helen, February 2011

...and you can check it thinks there is permanent hot water demand by seeing if the hot water temperature control now controls the radiator temp as well.

c#, February 2011

...and you can check it thinks there is permanent hot water demand by seeing if the hot water temperature control now controls the radiator temp as well.

c#, February 2011

Your boiler thinks that there is permanent hot water demand, presumably because the microswitch that tells it there is a hot tap running is broken (and stuck on indicating demand). Microswitches are cheap, but it could be the actuating mechanism is stuck on 'dhw demanded'. Should be a quick cheap fix.

c#, February 2011