Plumbing leaking radiator valve.

[Bazzer Smith]

Hi, Upstairs radiator has started leaking slightly from the ftom the top of the valve which switches it on and off (twist down for on up for off, fairly basic stuff).

I am wondering what to do, I suppose I will have to buy as similar valve, old one is compression about 14mm pipe?

Or is it just a washer?

Suppose I have to drain them by tying up the ballcock in the hot water tank? Or is that just for the hot water? Are the rads on a different circuit? Fairly standard setup Glow worm boiler 25 years old ish.

Any help or advice appreciated. Can't do anything now as it's too late at night, I tried to stop the leak by tieing a bit off bicycle innertube over the valvehead and binding it with string to the pipe then tieing it up above the head but that didin't work well. I also have some 'plastic padding' leak fix, stuff you mix and it sets in ten mins, I guess I could have tried using some of that with the inner tube thing?

Looks disconcertingly like one of these-

[Bob Minchin]

Try tightening the gland nut. this is the small hex nut under the plastic knob.

[Roger Mills]

It will be a 15mm pipe.

A lot depends on the construction of the valve. When you remove the white cap to reveal the spindle which has to be turned to turn it on and off, is there a nut - about 1/2" across the flats - surrounding the spindle? If so, under the nut is some compressible material which is supposed to form a seal, and stop water from leaking out. Tightening the nut a bit may be sufficient to stop the leak. If that doesn't work, turn the valve off and then remove the nut. Then wind a bit of thin string round the spindle and replace the nut - pushing the string down into the nut's housing, and tighten the nut onto it. That should fix it.

If there isn't a nut - and some more recent valves don't have gland nuts - you can't do that, and the whole valve will have to be replaced. If that is the case, the radiator and some of the pipework will need to be drained. Whilst this can be done by a competent DIY-er, some of your questions suggest that you may not have the necessary skills, in which case it may be safer to pay a plumber to do it.

[Bazzer Smith]

Yes I noticed one there, I tried to turn it using a mobile wrench but it seemed fairly stiff so I didn't try too hard, I need to try with a proper spanner or I will bugger the nut.

I will have a go at that, tomorrow, I've got most of the water leaking into a bowl upstairs now, just a small drip into the kitchen so it should be fine untill then. Thanks for your help.

I don't really have much skills but I have done a few bits and bobs myself before. Anyway my brother is a gas fitter I will give him a call if necessary.

[John]

If it won't tighten then follow the previous instructions about using string (although I would prefer twisted PTFE tape).

[Bazzer Smith]

Well I decided to 'bite the bullet and have a look at it tonight. I had left the valve open which I decided was a bad idea so I need to remove my cycle innertube and string bandage anyway. I though I would have a go at loosening that nut as I now had the right spanner, I figured I would be OK not draining the system with the valve closed so there was not too much water. Anyway I got it off and had a look at it as it was seeping water. Fortunately I remembered my brother had left me some PTFE tape! I had never used the stuff before so it was a but weird, not sticky as I expected but anyway I wrapped it around the spindle a bit as instructed and put the nut back on and tightened it up. Much to my relief it stopped leaking!! Seems as dry as a bone now and there is no leak in the kitched. I have left the valve closed for now I will try opening it tomorrow I hope/expect it will be OK. I'm lucky the weather is a bit better as I can leave the radiator off for now. Magic stuff that ptfe tape! Saved me a trip to B&Q I hope!

Thanks very much to everyone for their help, much appreciated!!

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[Bazzer Smith]

Thanks very much for your help it seems to be sorted now as explained in my my reply to John. I did have some PTFE tape and it seems to have done the trick!!