there is a clicking as if there was thin sheet metal knocking against something behind the fire where the boiler sits. The pilot light stays on. I turned the heating down (thermostat) and it stoped. It started again when the heating went on. The noise is not constant its spasmodic. It started 2 days ago. The thermo was on high - could that be the problem. Is this anything to worry about. It has been serviced.

clare, March 2011

i would guess that it is the heat expansion usually a ticking sound it will probably happen on hot water only and is fairly common and won't cause any damage

brian, March 2011