gas central heating - single radiator stopped working

hi all

the radiator in my living room has gone stone cold. every other radiator in the house is working fine. any idea what could be wrong?

cheers

Reply to
dustie
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Have you tried turning it on - or even bleeding the air out of it as a start?

Reply to
Unbeliever

I'm not completely stupid. It's always "on" - just like all the other radiators in the house.

Tried a bleed key and water came out but no air.

Reply to
dustie

You have an air lock; I have a radiator where it happens. Turn the pump up to full blast and go round and shut all the other radiators so that all the water is being forced through that single radiator, you may have to turn off the hot water and close the bypass if you have one. You should hear the water start to gurgle and hiss through this radiator and you should feel it begin to warm up. Then the airlock will be cleared and it will work OK until the next time!

Reply to
jhleslie

Two possibilities - its full of gas and needs bleeding, or it has a thermostatic radiator valve that hos got stuck in the closed position. Sometimes removing the thermostatic head will reveal a pin - this is normally !"up" in the open position. If it is stuck down, sometimes a it can be pulled free with pliers, or failing that a sharp tap on the side of the valve with a hammer may also help.

Reply to
John Rumm

Another possibility is a thermostatic radiator valve which has got stuck off. If you have a TRV on that radiator, unscrew and remove the head, and make sure the pin under it can be pressed in (you'll need something like a teaspoon to act as a thimble). If it won't, then it's probably already stuck down. You can sometimes free up by pulling it up with pliers, but people have managed to pull it right out by doing this and end up with water coming out, so you might not want to try freeing it up if you find it's stuck.

Reply to
Andrew Gabriel

ah, slight snag there in that most of the radiator valve heads (is that what they're called? the bits where you can chang ethe heat setting...) have long since broken off so all the radiators are technically fully "on" all the time. I can't actually shut them off anymore!!

Reply to
dustie

Or a sharp tap downwards on the pin, counter-intuitive though it might seem.

Reply to
newshound

Funnily enough, I had to do that many years ago as the radiator also went cold back then - I took the valve head off, gave it a tap with a hammer and it popped up and has worked ok since (I was never able to the valve head back on though as it broke so I just left it as it was).

Looking at it all now, the valve/pin does seems to be stuck down as it doesn't go in any further when pressed.- however, using some pliers, it lifts up very easily so it's obviously not jammed down like it was before. It's a little watery round that area too - is this anything to worry about?

I should also point out that this whole area of the radiator (the valve?) has been making a whistling noise for quite literally years. Tonight is the quietest I've ever heard it! Maybe it's been on its way out for years? ;)

Reply to
dustie

Worth noting that air locks are only likely to happen on vented systems, and quite unlikely on a sealed system. Sinec we don't know what system the OP has its not possible to state with any certainly.

Reply to
John Rumm

I didn't imply that you are "stupid". As you gave so little information, I merely advised a check for the simple problem (what I usually call an 'idiot check') - it is quite easy to turn a valve off and then forget about it.

Fair enough, but it would have helped if you had given that information in your original post.

Now the indications point to the fact that you either have an airlock in the radiator (or a pipe to it) or a blockage - the advice for clearing those has been given elsewhere in this thread.

If those methods fail, then simply take the radiator off, use a hose pipe to reverse flush the radiatior to clear any blockage or sludge, refit it, refill and bleed - ensuring that that central heating pump has been turned off first,

To check the pipes leading to the radiator for blockages - whilst the radiator is off, put a container under each valve and then open it (not both together by the way). It will then be obvious if the pipes are blocked or free flowing.

Also check that the bleeding nipple on the radiator is level, or higher than the other end - as this can create the conditions for an airlock.

These check ate not exhaustive, but are the simpler ones to make.

Unbeliever

Reply to
Unbeliever

The OP (me) doesn't actually know!! Can you possible clarify the difference between the two? :)

Reply to
dustie

Vented system (older/traditional style systems usually) has a feed and expansion tank somewhere high up (usually in the loft) that is connected to the system. This allows water to flow into the pipework and rads under the force of gravity. As the system heats up and the water expands, the small tank provides space for it to expand into.

A sealed (or pressurised) system is a closed loop that is not open to the air at any point. Water is introduced from the cold mains via a filling loop, and there is a pressure gauge to read off how much is in there. Somewhere (often in the boiler) there is also an expansion vessel to allow the expanding water somewhere to go (otherwise the pressure would rise significantly).

See Ed's FAQ for more details:

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Reply to
John Rumm

It should be sprung up - such that you have to push it down, and when you let go, it should string up again. It may be that the valve is seized but the pin is not actually attached to it - so pulling it up moved the pin but leaves the valve in the same place.

Also suggests the valve is knackered alas.

Some TMVs whistle when on the return rather than the feed - so it might just be it is on the wrong end of the rad.

If you shut the valve at the other end of the rad completely, and then bleed it - does water still come out and continue to do so, or does it quickly fade away to a dribble? If the latter, it would suggest no water is getting through the valve regardless of the pin position. Assuming the percussive maintenance option does not fix it, then its new valve time at that point.

Reply to
John Rumm

its full of air. Bleed it.

Reply to
The Natural Philosopher

hes tried that and water comes out you must have missed that post

Reply to
Kevin

yes..I do these things in post order.

Having read the rest, sounds like an airlock.

Reply to
The Natural Philosopher

TRV's Thermostatic Radiator Valves.

Sounds to me like you need to bite the bullet & change all the TRV's. It must be costing you a fortune for heating.

Reply to
The Medway Handyman

Just had that problem when I tested the system. Radiator bunged up. Needed flushing.

Reply to
Alang

hi all

Problem fixed! My stepdad (who's a plumber) advised me to hit the valve/pin with a hammer a couple of days like I did years ago when the pin first got stuck. I did so and it didn't make any difference as previously posted. He just came round and REALLY HIT IT! It's working now. Words fail me...

Thanks for everyone's advice. :)

Reply to
dustie

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