modena 80e central heating circuit once operated turns off heating within two min. with gurgling noises from boiler. i have renewed the circuit board and the flow valve. I think it may be air trapped in the boiler. I have emptied the radiators and refilled them and bled them but still the boiler cuts off on central heating the hot water side works fine can you help please?

john watt, October 2009

faulty pump or scaled heat exchanger

Ian, October 2009