My Potterton Prima F30 starts up from cold ok but then after say ten mins or so it reverts back to just the pilot light remaining my hot water and my radiators have not reached thermostat temperature, the flame looks a good colour too what could be sending the signal to the main flame gas valves to stop, any one any suggestions, it must be a thermosat musnt it?

Paul Smith, Warrington, November 2009

Thanks Ian, not considered that although i have just replaced the main thermostat in the boiler before getting a reply and the gas flame stays on now and thankfully goes out on room thermostat or hot water thermostat or zero on boiler thermostat so it must have been that. Is there something else im not aware of then regarding the gas valve? been working fine now for two days.

November 16th 2009

Paul Smith, Warrington, November 2009

the gas valve is faulty. it's allowing the pilot to stay alight when it shouldn't. this prevents the boiler from firing again as it detects the pilot when there shouldn't be one. new gas valve required.

Ian, November 2009