Central Heating Noise/Vibration

[imhotep]

Please help, we are being driven mad by our noisy heating. We have a Vaillant combi boiler just over 2 years old i.e. just outside warranty. With the heating on all is fine until a hot tap is turned on then off, then after a few seconds there is a loud regular vibrating noise from pipework upstairs. It is difficult to isolate the exact spot but I estimate it is about 3 metres from the boiler. The only way to stop the noise is to switch the heating off, it stops when the pump stops. We do not get the noise when just heating or just hot water is required only after hot water has been demanded with the heating on. Phoned Vaillant technical help who said that it MAY be the diverter valve. I can feel a very very slight vibration from the upper pipe of the diverter valve when the noise is present.
If anyone could confirm or deny this I would feel much better about the £95 plus parts that they want to come and look. I'd hate to call them out to be told there's nothing wrong with the boiler.

 

[gme106]

Hi Imhotep, don't know if my rambling will help but I was having a similar problem. Had a Baxi boiler installed about 1& half years ago. after a few months I started to experience the same problem. As soon as any taps were put on there was a rumbling coming from the boiler.

Anyway after much investigation I traced it back to 1 specific pipe coming from the boiler to the storage tank in the loft. What was happening was as the hot water was being used the bolier must have been requesting more cold from the storage tank to heat, to me this seemed plausable. However the problem was the installers had forgot to clamp down this feed pipe and it was rattling against another pipe and one of the joists causing the almighty noise.

Might be an idea to check this out.
Sorry if this doen't help