When I turn on the hot water or heating on, the boiler switches on but after couple of minutes or so the boiler starts to make loud banging noises and eventually shuts off. The pump keeps running even after hours the boiler was shut off and it looks that the pump has become slower even set at top speed. Someone please help me to diagnose what could be the problem.

Sam, October 2009

sounds like the pump, it may be running but not quick enough to force the water around the heat exchanger & the water is kettling (boiling like in a kettle!) which is what the banging noises are

bamba, October 2009

sounds like a faulty pump or a heavily sludged up system.

Ian, October 2009