Whistling radiator after fitting HR92

[DJBenson]

I posted this in another thread but didn't receive a reply so please forgive the new post...

I replaced all but two (a decorative panel radiator in the dining room and a small radiator in the downstairs toilet) of my manual TRV's with HR92s and everything was fine. I then ordered another HR92 and fitted it to the panel radiator in the dining room (which previously had a manual Honeywell TRV) and the valve is whistling so much it's almost constantly turned off. The valve did not whistle with the manual TRV so there's something about the HR92 that's upsetting the system.

The only difference between this one TRV and the rest in the house is that this one appears to be a European model (i.e. the display is upside down) but apart from that I believe there is no physical difference (it responds to the controller absolutely fine).

The one remaining radiator with no TRV's at all is the closest one to the boiler (which is in the garage next to the downstairs toilet) and that is always left fully open as I was of the understanding one radiator should be used for the bypass and it seemed logical to use the one closest to the boiler (and the one frankly which is most appreciated when left on full )

Any idea's folks? I've tried balancing the rad by opening/closing the valve on the opposite side of the radiator but it made no difference. Would replacing the actual valve make any difference?

[emmeesse68]

I posted this in another thread but didn't receive a reply so please forgive the new post...

I replaced all but two (a decorative panel radiator in the dining room and a small radiator in the downstairs toilet) of my manual TRV's with HR92s and everything was fine. I then ordered another HR92 and fitted it to the panel radiator in the dining room (which previously had a manual Honeywell TRV) and the valve is whistling so much it's almost constantly turned off. The valve did not whistle with the manual TRV so there's something about the HR92 that's upsetting the system.

At a friend of mine, building regulations imposed new TRVs (they didn't have them at all), and now some rads whistle even with a manual TRV head. So it's not easy to blame the HR92 for that; since it's the TRV body that whistles, the problem mostly likely arises because the HR92 is driving your valve almost completely close, while probably that didn't happen with your manual TRV.

The only difference between this one TRV and the rest in the house is that this one appears to be a European model (i.e. the display is upside down) but apart from that I believe there is no physical difference (it responds to the controller absolutely fine).

Yes, they differ in the display orientation only.

The one remaining radiator with no TRV's at all is the closest one to the boiler (which is in the garage next to the downstairs toilet) and that is always left fully open as I was of the understanding one radiator should be used for the bypass and it seemed logical to use the one closest to the boiler (and the one frankly which is most appreciated when left on full )

If you happen to appreciate that particular radiator to be always open, that's fine; otherwise, I think it's better to choose the farthest as a bypass, and maybe choke it a bit with the lockshield, not to make a short-circuit for hot water (that would reduce flow in all the other radiators and cause an useless work for the circulation pump).

Any idea's folks? I've tried balancing the rad by opening/closing the valve on the opposite side of the radiator but it made no difference. Would replacing the actual valve make any difference?

Might, but it's not that black or white. If the whistle appears with the HR92 open at a particular % only, you could try tightening it onto the valve body (closing the vale a bit more) or loosening it, to release the pin a bit. Sometimes it's a matter of less than one millimeter...

[rotor]

When I installed my Evohome system, I found out that one TRV valve was stuck open, and one was stuck closed (I ended up replacing every TRV in the house). It's the sort of thing you don't discover until the HR92s start really exercising those TRVs to a very fine degree (closing really tightly and opening them wide-open, and many tiny increments in between).

[G4RHL]

When I installed my Evohome system, I found out that one TRV valve was stuck open, and one was stuck closed (I ended up replacing every TRV in the house). It's the sort of thing you don't discover until the HR92s start really exercising those TRVs to a very fine degree (closing really tightly and opening them wide-open, and many tiny increments in between).

I had one HR92 that would fire itself off the TRV. Sitting quietly enjoying the comfort all of a sudden the HR92 would shoot off the TRV. It was fixed to a Dyson TRV with the supplied plastic adaptor and the HR92 when closing the valve must have been finding the pin too long and when it reached the last element of closing, off it would fire. The plastic adaptors are not very good but I cured it by simply not screwing the HR92 all the way on but backing it off ever so slightly.

I have one other radiator with a Dyson TRV and this problem never arose. I understand Dyson TRVs can have varying sizes of pin in what appear to be the same models. Hence my problem. A colleague fitted Dyson TRVs (he does not use Evohome) and found that several would never fully open or fully close. Dyson's initial response was they must be forgeries! He cured the problem by adapting the pins - shortening them in fact and now all fully close and open.