Vibrating Central heating

[charmed240]

Help… My central heating system keeps intermittently vibrating. Have had system flushed as never been done and was very sludgy, all radiators have been bled but it is still doing it. I have tado system fitted and notice it happens when 1 or 2 radiators upstairs are off and not receiving any flow, as soon as I remove or turn on the TRV for those rads the vibration stops. Can also hear gurgling water through one of them when I do this. Is it trapped air, pressure problem and or pump problem?

 

[Harry Bloomfield]

That is vibration from a TRV fitted to the wrong end of a radiator, the return end, rather than the flow end. Some TRV's can be fitted either in flow, or return.

 

[charmed240]

Thanks for your response, the TRVs have always been on that side though, system been fitted for over 20yrs?

 

[Jurassicspark]

First approach would be to bleed a rad.
Has the pump speed been changed recently?
Inspect any TRV's for looseness.
Has any work been done recently?

 

[Harry Bloomfield]

Thanks for your response, the TRVs have always been on that side though, system been fitted for over 20yrs?

Yep, they can not cause a problem for years, then suddenly the noise begins. To check which is the flow....

With system cold, start the heating up, whilst feeling the two pipes. The first to become warm, is the flow..

 

[charmed240]

Ok, I’ve checked one of the problem radiators and that seems to be the case, it looks like they TRVs are bidirectional so in theory should be OK? What would I need to do to stop the noise as it can get quite loud at times?

 

[charmed240]

First approach would be to bleed a rad.
Has the pump speed been changed recently?
Inspect any TRV's for looseness.
Has any work been done recently?

Radiators all been bled, pump speed not changed it’s set to max. TRVs aren’t loose, finger tight currently. Only had system flushed but that was because of noise so was happening before

 

[Harry Bloomfield]

Radiators all been bled, pump speed not changed it’s set to max.

Even the bi-directional ones, are less likely to chatter, when on the flow. You said your pump speed is set at maximum - rarely is maximum flow necessary, and it will put a TRV under more pressure to be forced open. You might try turning the pump down a little.

The ideal speed for a pump, is no faster than is necessary to serve your system adequately. Some pumps have an automatic mode, so their speed is compensated to just maintain pressure.

 

[charmed240]

Yeah it’s a Worcester 24Si II and manual says should be at maximum but only feeds 5 rads so does seem excessive and not sure if to adjust or not

 

[Harry Bloomfield]

Yeah it’s a Worcester 24Si II and manual says should be at maximum but only feeds 5 rads so does seem excessive and not sure if to adjust or not

Ring WB, explain the problem, and seek their advice..

 

[charmed240]

Thanks for the advice I’ll do just that

 

[tincup]

It could be a pump problem.
Try dropping the pump speed back a bit

 

[gas112]

take the heads off the trvs for a few days and see if the noise goes away