Odd radiator noise

kaktus · 22 Nov 2020 at 02:08

Hi guys

Bit of an odd one, but living room radiator has started making a very strange tapping noise and I can't figure what is causing it.

Here is a video of the noise https://vimeo.com/482339776

I have tried bleeding the radiator (and all radiators) like 20 times and it is making no difference. Water comes out immediately so it doesn't appear to be a trapped air issue.

Sometimes the sound comes when the heating is switched off, sometimes it comes when heating has been on for a while. Sound comes intermittently and doesn't seem to follow any particular pattern. Boiler pressure has been varied from 1bar to 3.5bar so that doesn't seem to have any effect either.

Kinda at my witts end atm

kaktus · 22 Nov 2020 at 02:10

I should add that this is the first time in 6 years since renovating the house that something like this has happened.

rodders · 22 Nov 2020 at 09:59

Clearly someone is trapped and you need to let them out!

That's very odd, I was going to ask if you had thermostatic valves, as mine make a little noise when opening. But nothing as loud as that, or irregular.

Wonder if a pipe has come loose and tapping and sound amplifying though that rad.

Simon42 · 22 Nov 2020 at 10:35

Does it happen when the radiator is warming up and cooling down? Is so then does holding the pipes (when not too hot) or the rad itself reduce the noise/can you feel anything?

I had one rad on an all new system make a creaking/taping noise and it was the wall brackets slightly twisting the rad and a missing plastic slider on one bracket due to careless plumbers. As the rad expanded and contracted it caused a series of creaks as it grated along the bracket, but replacing the slider and loosening one screw resolved it.

If its not making noise when there's no flow it can't be a piece of debris that's stuck against the internals or one of the valves which was another thought. I've heard some TRV headers make a noise but that's easy to test by removing/switching.

200sols · 22 Nov 2020 at 11:00

Sometimes over time all the heating and cooling can warp the pipes, if they are tight against another material like wood it can cause knocking
/creaking as the pipes move.

pp111 · 22 Nov 2020 at 16:03

Sounds to me like one or more of the pipes is tight against the hole in the floor. it's alwayus a good idea to leave a little room around a pipe to allow for expansion.

kaktus · 22 Nov 2020 at 18:00

Simon42 said:
Does it happen when the radiator is warming up and cooling down? Is so then does holding the pipes (when not too hot) or the rad itself reduce the noise/can you feel anything?

It is completely intermittent. It happens when the radiator is cooling down, heating up, been on for hours or been off for hours. It doesn't seem to have any discernable pattern to it.

I have tried holding the radiator, the mounting brackets, the valves, the pipes everything when it happens and it doesnt make any difference. The sound seems to be coming from the lock shield area but we all know that the sound could be originating somewhere else and traveling there.

kaktus · 22 Nov 2020 at 18:27

https://vimeo.com/user127695047/review/482339776/d03cb557dc

pp111 said:
Sounds to me like one or more of the pipes is tight against the hole in the floor. it's alwayus a good idea to leave a little room around a pipe to allow for expansion.

So the radiator is connected like this:

Everything appears to be tightly fitting, no movement of any kind as far as I can tell. If the pipe has come lose, it isn't from what is visible as the exposed part of the pipe and radiator have no movement whatsoever.

pp111 · 22 Nov 2020 at 21:00

kaktus said:
https://vimeo.com/user127695047/review/482339776/d03cb557dc

So the radiator is connected like this:

Everything appears to be tightly fitting, no movement of any kind as far as I can tell. If the pipe has come lose, it isn't from what is visible as the exposed part of the pipe and radiator have no movement whatsoever.

Ok so it's not the floor then. Everything expands as it gets hot and yours has nowhere to go. I am wondering if the noise is coming from the wall brackets where the radiator is resting. The radiator should be sitting on some silicon mounts that go between the radiator and the wall bracket. I wonder if they are missing?

kaktus · 23 Nov 2020 at 01:12

So i just got into bed and my wife and I noticed the sound coming from the radiator. So I went downstairs to check it out and put my ear really close to it. With everything turned off including TV etc.

This is going to sound nutty, but I could swear it sounded as if something was inside the radiator scratching. It would start, make that noise then die down. Then start up again and in between there was the slightest, ever so slightest, sound of a bit of ruffling. I don't know if I just imagined it but I could swear it sounded like something was scratching the inside of the radiator.

I banged on the radiator and the sound stopped.

Am i going mental or is it possible for something to be inside the radiator and survive even when the heating has been on full blast for hours at 82c water temp. Or could it even be something outside the radiator but scratching a pipe and that sound is filtering in? I don't know anymore, this is driving us bonkers.

I know we have had a pest problem (we suspected mice) in the kitchen recently, but we havent actually seen what the pest is. We just stopped putting food waste under the sink where it/they appeared to be coming from and thinking about it, this is about the same time this sound from the radiator started. Maybe the pest has been moving searching for food and has somehow gotten into the radiator??

Wtf is going on

JBuk · 23 Nov 2020 at 01:29

What is behind the wall where the pipes go? Do they drop down into joists ?

it’s possible if there’s a cavity you could have a rodent knawing away at the pipes

my parents had a rat find the tiniest of cracks in the mortar of their extension which eventually led into the wall cavity and up into the flat roof

kaktus · 23 Nov 2020 at 01:52

JBuk said:
What is behind the wall where the pipes go? Do they drop down into joists ?

it’s possible if there’s a cavity you could have a rodent knawing away at the pipes

my parents had a rat find the tiniest of cracks in the mortar of their extension which eventually led into the wall cavity and up into the flat roof

As far as I know, nothing. It's a 1900 victorian terrace which didn't have cavity walls and this particular radiator is underneath the windows of the living room. Behind that wall should be nothing but gypsum skim, plasterboard, cement and then brick. Underneath the floorboard however, is a suspended floor with the heating pipes running to the boiler.

I have just ordered a whole bunch of mouse traps from amazon and they should be arriving on Tuesday. Will see what I catch, if I catch anything, and see if that stops the sound. If it does (hopefully) then at least I know it's a rodent problem and not a plumbing problem. Actually come to think of it, I'm not sure the rodent problem is the one to be hoping for!!

pp111 · 23 Nov 2020 at 08:29

Take a look with a torch behind the radiator to see if the plastic pieces are in place. They sit on the wall bracket ( tiny things ) and the radiator in turn sits on them.

Here they are ..

https://www.ebay.co.uk/itm/PACK-OF-...627429?hash=item27dd4e66e5:g:54AAAOSwCEhcMGVM

there are twelve in that picture. You should have one on each of the wall brackets between the bracket and the radiator.

If they are missing the radiator can make exactly the noise you are experiencing.