make sure the pump keeps running after the boiler stops firing, it should continue to overrun for approx 2 mins, if this is happening make sure the system has a bypass as banging can be heat unable to get away from the boiler, try boiler noise silencer in your f and e tank but if you can get it straight into the primary pipe work it would be more effec tive
john
February 2010
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix home heating systems.