I keep getting air in one Radiator?

[jon.p.weaver]

For as long as I can remember, one of my radiators makes a racket... I bleed it and the noise goes away, but a few days later it comes back.

Every time I have tried to fix it (by keep bleeding it), the summer comes and I give up.

The problem is back now and I want to fix it.. I have bleed it 3 times this week already and again today, there is air in it?

What can I do? Where is the air coming from? Why is it always this one radiator?

Any tips would be appreciated

All the best

Jon

[Ian Stirling]

Ticking when cooling up and down, gurgling noises, James Blunts latest album?

[Andrew Gabriel]

You could look back over the several identical threads on this topic over the last months, and at least find out what minimum information you would need to supply in order to get any useful help, if not the answer.

[Roger Mills (aka Set Square)]

First off, you need to determine whether it *is* air - or hygrogen. The latter is caused by corrosion if there is insufficient (or no!) corrosion inhibitor in the system. Next time you bleed the rad, collect some this 'air' in an upturned jam jar and then apply a lighted taper to it. If it burns with a blue flame, it's hydrogen. If it *is* hydrogen, you need to flush and refill the system, and add an appropriate quantity of inhibitor to the water.

If it's air, it could be getting in for a variety of reasons. The most common ones are insufficient water in the fill & expansion tank, or 'pumping over' - where there is a constant flow of water out of the vent pipe into the F&E tank when the pump is running. [Both of these assume that you've got a vented - rather than sealed/pressurised - system]. If it *is* pumping over, try reducing the pump speed. If this doesn't fix it, there will almost certainly be an error in your pipework layout which will need fixing.

Whenever you get air - or another gas - in the system, it invariably settles in one particular place - probably because some particular feature of the pipework makes it easier for it to go there than anywhere else.

[Fatboise]

Can somebody please explain how to test for hydrogen as mentioned abov I'm afraid I don't understand the explanation - D'o

-- Fatboise

[Roger Mills (aka Set Square)]

If you hold a lighted match or taper in the stream of gas coming out of the bleed hole, you can tell whether it's air or hydrogen by its behaviour. If it's air it will have no effect, or may even blow the flame out. If it's hydrogen, the hydrogen itself will burn with a blue flame.

But it might also set fire to surrounding objects - which was why I suggested doing it in two stages. Because hydrogen is a lot lighter than air, it will rise - so if you hold a jamjar upside down, with the open part just above the bleed screw, any hydrogen will collect in the jar. If you then introduce a burning taper up into the jar, you'll see whether or not the collected gas burns. If it *does* it will do so in a more controlled way, without setting fire to the whole house!