Noisy TRVs

[Norman]

Hi I have a problem with noisy TRVs.

I Have a Baxi combi boiler supplying 6 radiators with Caleffi thermostatic valves and a towel rail with plain locksheild vales (fully open flow and return). When any of the radiators reach the point where the are satisfied for heat the valves make a loud noisy that changes in pitch till it stops this can take 10 minuets. It sounds like a hammer drill and is loud enough for my neighbours to ask about it. Not good in a morning as you have to get up when the heating comes on or get up to a cold house.

Some one told me I need to have a Differential Bypass Valve fitted; what does this do and why don't these need to be fitted to all heating systems?

Cheers Norman

[EricP]

Sounds like your flow and return is going the wrong way.

[Norman]

No checked that !! Flow is hotter than return, valves fitted on flow side but according to Caleffi's web site valves are suitable to be fitted on both.

[Paul Saunders]

[-=Scozia=-]

Had the same problem a few months ago.

You'll probably find it's only 1 or 2 that's actually noisy. the problem with my TRV's were they were on their last legs, once i had replaced them no more noise.

-=Scozia=-

[Andy]

Fitted back to front! Look for the flow arrow..

AE