I have a 3 year old Ferroli combi gas boiler. A couple of years ago it stopped responding to commands from the room and radiator thermostats. It just kept on pumping out heat. In addition when it was supposed to be heating water it was also warming the radiators. This went on for a few days and then corrected itself. Now it has started the same behaviour again. Any clues to what maybe at fault.

It was serviced about 4 months ago.

Mikeycollins, March 2009

Thanks for your reply. Do you mean the room or boiler thermostat is faulty?

Mikeycollins, March 2009

Thanks for your reply. Do you mean the room or boiler thermostat is faulty?

Mikeycollins, March 2009

the divertor valve will have a bit dirt stuck in it letting heat pass to the rads. the TRV (thermostatic radiator valves) do not affect the boiler itself just the radiator, the room stat overides the boiler which it sounds faulty. replace the thermostat.

boiler bill, March 2009