Loud banging from airing cupboard and crunching sound from radiators

What type of boiler has your system got? It it a combi? Is there a hot water cylinder in the airing cupboard? It it a sealed system (with a pressure guage)? What pressure is it showing?

We need more info...

It sound as though the water in the system is boiling and trying to vent. Perhaps the boiler thermostat is not operating properly or the boiler temperature is set too high. The noise could perhaps also be a zone valve sticking or trying to open/close.

My heating system had symptoms like that - it seems that the plumber we had paid to (among other things) add anti-freeze to the system, had turned off the water to the expansion tank while doing the work, and had neglected to turn it back on when done. The tank was lidless - and about 18 months later, most of the water had evaporated. It was the middle of winter, my young daughter and I were alone, and it sounded like the system was about to explode!. After running the hot tap and turning off the heating, I checked the tank in the loft, saw it was empty, found the valve, which was carefully hidden by insulation, and turned it on. The tank now has a lid, and I called a different plumber the next time I needed work done....

Hello Alan

The boiler is a Maxol HomeWarm 600 (Combi).

Yes

Hope this helps.

Kevin

Hello

The boiler is not a Combi, sorry about that, do not know what I was thinking.

Thanks in advance

Kevin

Hello

Thanks for the reply.

I have checked the expansion tank and as far as I can tell everything is correct, however I am unable to locate a valve in the loft.

This problem has me confused, plus everytime we have British Gas come out the noise does not happen which does not make diagnosing the problem any easier.

Thanks in advance

Kev>>