'Tapping' Radiator
 

Evening all,

Anybody got any ideas how to stop a radiator from making a 'tapping' sound.

It's like a metalic tapping, there's no specific frequency to it, sometimes it's louder than others. I think it only occurs when the system's running though.

It's not air in the system, I've bled all the radiators and that isn't the problem.

Any thoughts?

Re: 'Tapping' Radiator
 

Is there enough water in the system. bleeding it is one thing, topping it back up is another

Re: 'Tapping' Radiator
 

Yep, just checked and the boiler pressure is bang on what it should be.

Re: 'Tapping' Radiator
 

if you havent already you should "desludge" your system using the approate chemical addative (then draining out the system as per the addatives instructions). Once this is done a inhibitor should bee used. After doing this (if the noise is still present) you can use a noise redusing addative.

Its not generally advised to use the noise reducer on a sludged system also for an efficient system it should bee desludged/inhibbited once ever year or 2, hense the desludge/inhibitor steps though you could go straight for the noise addative.

heres links to the approate addatives on screwfix (though most diy shops also sell them)

desludger - http://www.screwfix.com/prods/89458/...Sludge-Remover
inhibitor - http://www.screwfix.com/prods/46974/...nhibitor-500ml
noise reducer - http://www.screwfix.com/prods/44452/...centrate-500ml

I beleave the ones in the links are for pooring direct into the central heatings header tank (not the cold water tank, bee sure you get the right one ;)). If your system dosnt have a tank you will need the "injectable" versions (which can bee added via the filling loop or direct into a radiators bleed valve) but these tend to bee more expensive.

You should also bee sure to check the addatives are suitable for your boiler (though they are in 99.9% of cases some types of boiler needs different addatives)

Re: 'Tapping' Radiator
 

You sure it's not just thermal expansion? Has it only just started making this noise? One of our rads makes a similar noise when it's heating up but it stops when it's hot.

Re: 'Tapping' Radiator
 

beeman,

Thanks. The system's not that long been drained and re-filled. The radiators are all less than 2 years old, and the boiler's only a couple of years old as well. The radiator in this room is new.
I would doubt very much that it's all gunked up, especially as the radiator in this room was put in only a couple of months ago. Will have a chat with the engineer (ex father-in-law) about the additives you've suggested though - thanks.

Osem,

Suppose it could be, if it is then it's the only radiator in the house that does it (and they're all the same make). It's driving me mad because it keeps doing it late at night either when I'm trying to sleep, or when I'm already asleep and then it's loud enough to wake me.

Need to get it sorted. Think I'm going to have to have a word with the ex father-in-law and see if he can recommend anything. Didn't really want to have to go down that route.

Thanks all :tu:

Re: 'Tapping' Radiator
 

RobM ..as Osem suggested it is most likely expansion ,one of the most common noises come from the contact point of the rad and the wall bracket .As the rad expands it moves on the bracket and can create a randome metalic noise as you are hearing .There are a few solutions ,one is to try and get the plastic bracket clips supplied with new brackets and as far as i know not sold seperately the other is to lift the rad off the brackets and rap some electricians tape around the strap on the back of the rad this will take up any slack and stop metal to metal contact

hope this helps

Re: 'Tapping' Radiator
 

It's odd you should say that because our works very well as an alarm clock - the heating fires up at around 7.00am and the ticking noise starts shortly thereafter... ;)

I guess it's likely to be worse when the rad's being heated from stone cold as the expansion involved will be greater. It's also possible that other rads may sometimes be making a similar noise but that it's less noticeable than is the case in a quiet bedroom at night.

Re: 'Tapping' Radiator
 

perhaps you have tiny man in there, and he's tapping out morse code to try and get you to release him?

Re: 'Tapping' Radiator
 

Just did a quick google and found an interesting post..

Next time it starts tapping run a hot water tap - if the tapping stops it means that its not expansion\contraction but something thats effected by the flow of water.

(perhaps that tiny man tapping out morse code?)

Re: 'Tapping' Radiator
 

The usual thing is, the walls not quite flat behind the radiator so the brackets are not quite in planar alignment with the brackets on the rad. This makes the rad tight on the wall brackets.

Initially plastic covers are fitted to the wall brackets where the rad slots on but, because the fit is tight, after a short while these wear through until meteal to metal contact occurs and you get that characteristic ticking sound.

Soloution is to pack out the offending wall bracket(s) until both are the same flat plane relative to the radiator brackets.

Other things I have experienced are:
Rads that were slightly bowed that caused the same thing. Luckily the same remedy fixes them.
Underfloor pipework that is tight in its notches or short on expansion bends can have a similar effect but it's more of a knocking noise as opposed to a ticking noise.

Re: 'Tapping' Radiator
 

I'd say they need balancing. I did mine once. it was an experience.

Re: 'Tapping' Radiator
 

Ok, thanks for the overnight advice guys.

It started at 0130 last night so I got up and turned the thermostat off. As soon as the water flow stopped the tapping stopped. At this point the existing hot water in the radiator was still causing it to heat slightly, but there was no water flow. So now I'm wondering if it's related to the water flowing through the radiator rather than the expansion.

I'll talk to ex father-in-law about the other solutions though, I've got to do something because it's driving me mad. I'm cold enough at night as it is without having to turn the damn radiator off :(

Re: 'Tapping' Radiator
 

Here it was caused by the copper pipework under the floorboards expanding and making a noise as it slipped against joists.

Re: 'Tapping' Radiator
 

To prove a point you could temporarily switch off the boiler and let the pump come on again. If the tapping continues with no heat then it's not an expansion problem and must be something loose inside.

If you move your hand about on it you may be able to feel the location. My guess it's coming from the TRV.