CH radiator problem

[allanb]

Each year when we turn on the central heating after the summer, one or two of the thermostatic valves fail to work.  Until now it's always been possible to fix them quite simply by removing the thermostat, then cleaning and wiggling the little pin until it moves freely.

This year we have a couple of problems:

(a) On two or three radiators, even though the pin (after treatment) can be moved in and out easily by hand, it doesn't returnto the "out" position by itself.

(b) On one radiator I must have pulled too strongly during the "wiggle" and the pin came out completely, allowing a dribble of water.  I can put it back in to stop the dribble, but I can't make it work as it should.

The pins appear to be spring-loaded, so I assume the springs are jammed or broken.  My question is: what do I have to do to get at them?  It seems obvious that I have to remove the hex nut that contains the pinhole, but as soon as I move it, water escapes.  Can I isolate each radiator in turn and work on it without disturbing the rest of the system?  If so, how?

[Le Plombier]

Thermostatic radiator valves should always be set in the fully open position for the summer

If they stick thay are easily freed by just closing the valve when you want to use the system in the winter

Do this and you will have none of the problems you describe

As they are at the moment when you push the pin in if it does not spring back by itself immediately then the valve is still stuck

A tap with a hammer or a replacement valve is probably the available choice

You can strip out the valve body but and clean but from a professional point of view it is quicker and cheaper to replace if you are going to pay someone

Le Plombier

[allanb]

I think I'd prefer to replace the valves: they are quite old.  But what would I have to do to close off the water to the radiator while I'm doing it?  I can't see anything that might be a shutoff valve. 

[AnOther]

I used to experience the same thing in UK but without individual taps to isolate the individual radiator you'll probably have to drain the system to do anything permanant about it. As a quick fix for one radiator you could get one of those aerosol freezers which you use to freeze the pipe locally.

Whilst a PITA try looking on it as an opportunity to give it a pre-winter going over with new valves and a refill with inhibitor [;-)]

[Le Plombier]

You need to drain the system

Do not go for the pipe freezing option, it might be ok for a single valve but is not an option for changing multiple valves

Le Plombier

[BIG MAC]

For a quick 'fix' tapping with a pin hammer on the end of the pin can sometimes free these off , other wise just change 'em pretty much as le plombier has said.

[allanb]

Thanks for all the advice.  Unfortunately nothing has worked - not even hitting the pins with a hammer - so I'm resigned to having the system drained and the valves replaced: what Ernie called the PITA solution.

I wouldn't feel so bad about the expense if only I got the winter fuel allowance.  I wonder if I could persuade G. Brown that I'm a special case?

[Bugsy]

[quote user="Le Plombier"]

Thermostatic radiator valves should always be set in the fully open position for the summer

[/quote]

I didn't know that, so thank you.