Whistling radiator valve - Waves for PigletJohn please...

[HelloItsMeAgain]

Help. We have a whistling radiator valve. Taken me a while to work out where the fucking annoying sound was coming from.

Landing radiator - the thermostatic radiator valve is emitting a high pitch whistle.

Why? What can I do? Does it need replacing/fixing? How? I am sure I have seen something about this in here before but my digging around did not reveal anything.

Awaits a barrage of questions and hopefully some answers please... Thank you.

[PigletJohn]

turn it slightly down. Does the noise stop? Turn it slightly up. Does the noise stop?

When the TRV is turned to max, does this radiator heat up very quickly, compared to the others, or does it stay warm for a long time?

Feel the pipes at each end. Are they equally hot, or is one noticeably cooler than the other? Is the one at the TRV end cooler? Post a pic of the TRV, and the lockshield at the other end, or if you can't, note any make and model you can see.

Is there an arrow on the metal TRV body? Which way does it point?

[HelloItsMeAgain]

Thank you. OK some answers but not all.

Turned it up. It went away. I did this yesterday before I posted and hadn't realised had not included in OP. Whistling happened last winter and it went away when I just turned the radiator down to zero so forgot about it until it started up again. Turned to 2. Whistling started. Turned up to 4 - it went away. Cannot seem to make whistling come back at the moment. Would be happy to leave alone - but just want to make sure there is not something I need to do maintenance-wise to ensure longevity of CH.

Not sure about this radiator warming up quicker than the others. Never measure properly. Been out all day so will try and feel tomorrow.

Pipes at either end. The TRV side is slightly cooler than the other side - I think. Difference is not hugely noticeable. Have tried to tell the difference several times but could not be certain disclaimer, years spent in professional kitchens have hardened hands to any form of heat detection

Additional info - we have very high water pressure (chap who fitted the water softener said it was at 5 (or something) and any higher would have been too high for softener fitting and a megaflow system. Off to take photo and check arrows.

[HelloItsMeAgain]

OK - attaching photo - and double checked - this time non-trv def hotter than the valve end.

And

[PigletJohn]

If you turn down the valve at the other end, it will reduce flow through the radiator and noise will probably stop. The other valve might have a knob, but more likely a plastic cap retained by a small screw. You take the cap off, and use a very small spanner to wind the spindle down until fully closed, then open it one turn only. Go away for half an hour, then feel the two pipes. Is one of them hot? If not open it another half turn and check again in half an hour more.

One of the pipes is supposed to be noticably less hot than the other. If both of them are fully hot, close down the lockshield some more.

Your valve is a Pegler Bulldog, which is a good quality make. IIRC they are bidirectional, but look on their website for the installation instructions.

The side that heats up first is the Flow side, the other is the Return side. That just means the side where the got water runs into, and out of, the radiator.

TRVs can be noisy when they reach the pre-set temperature and they are nearly closed, when the water is squirting though the almost closed gap. That's why changing the setting a bit will temporarily stop the noise. The arrow shows the correct direction of flow for quiet operation.

Reducing the rate of the flow with the lockshield is correct, and should stop the noise.

If another radiator becomes noisy, turn that down too. Lockshields are not supposed to be fully open, they should all be nearly closed.

[HelloItsMeAgain]

Thank you. Will do over the weekend once not full of red wine and report back in case someone else ever has this problem.

Whilst playing around with the non TRV should the TRV be turned up to max - or does it not matter?

[PigletJohn]

You can. It needs to be open so you can feel the hot water pumping through.

[donajimena]

I almost wishing I had a plumbing problem so I can call upon piglet

[HelloItsMeAgain]

Tis done. The spindle was quite high up so is now 1 turn up and radiator still toasty warm.

Whistle was intermittent so not sure if fixed totally but at least I know what to "fiddle" with and how to solve it.

Again many thanks.

[cjrees]

Not a Mum, but this came up on a search for 'whistling radiator'. Thanks. FYI - I had to turn the lock shield down SIX turns to only about 1/2 turn on to stop the noise.

[Anniemoss11]

Piglet, if you’re still here I’m having the same issue with a whistling radiator (really high pitch like an alarm) AND interestingly the pressure on the boiler keeps falling to 0 instead of being around 2 where it should be. Do you think there’s a leak causing this whistle that’s causing the pressure to drop? I have to manually turn two knobs on the pipes in the boiler every 3-4 days to being the pressure back up.

[PigletJohn]

the pressure on the boiler keeps falling to 0

you have a leak.

Do you think there’s a leak causing this whistle

No.

[Emmmmmm]

Thank you pigletJohn, three years on and your feed is still helping people. 👌

[DisrespectfulAdultFemale]

Not in need of any help but I wanted to pop in to say "thank you" to PigletJohn for all of the helpful advice he has offered over the years.

[mrsmacmc]

Thank you @PigletJohn whistling radiator now silenced in our living room ❤️