Radiators heating up when on Hot Water only

[tessatiley]

Hi, I have the same problem as paul 1010, but my boiler is a combi boiler. It's a Potterton, was installed with the central heating system about 6 years ago and I have had nothing but problems with it - every few months something else would fail, and it's had practically everything replaced by now, and is still failing periodically. It also makes loud groaning noises whenever it's on, and I'm constantly worried that it will blow up! Is there a possibility that anything dangerous could happen?

I'd like to know whether the problem I have would be caused by the same components as in paul1010's non-combi boiler? Or do they work completely differently? And does anyone know why a boiler should keep failing like this? I'm thinking now that it's not worth repairing any more, and that I should look for a new one, but 1) I can't afford it, and 2) I'm concerned that maybe the problems were caused by the company who put the central heating in not doing it properly, and if so, would it just ruin the new one as well?

Any info gratefully received.

Tessa