Leaking Radiator - Gland Nut?

debbie42

I've a slight leak coming from the small nut above the valve on my radiator. From what I've read it's called the gland nut? I've tried tightening it, but feel that it's pretty much at its limit now. I have read that you can undo it and put some packing in it to help tighten it.

I've a few questions before I decide to get some professional help in:
Is the packing just ptfe tape, or something else?

Can I do this without draining the system (or getting a big mess!) I've just laid a wooden floor, so am very wary of any spillage.

How do you isolate the valve? The other end of the rad has a thermostatic valve, but this end (outlet?) is more basic. I can't see how I'd switch this off, though guess you must be able to, as the rad was taken off a few months back. (It's leaked a very small amount since it was reconnected.) The top of it is like a rod thing: does that turn? I'm not that knowledgable about the terms, I'm afraid!

Canucklehead

Hi

Does the leaky valve have a name on the cover cap ?

Corgi Guy.

alanobrien

Firstly is it a TRV or a lockshield valve ? Assuming its a lockshield and newish it will most likely be sealed with an O ring these days. If that is the case you may get away with replacing the O ring but unfortunately sometimes the valve stems wear so you may have to replace the valve.

If its older it would be sealed with what is called a one piece packer - i know this i used to work for the company that made millions of the things each year . If this is the case all you need to do is add more material to the packing chamber and tighten the gland nut, it will then seal against the valve stem even if its worn. Graphite tape is the best material for this, you can use PTFE cord but it does have a tendancy to extrude hence manufacturers do not use it as a packing material.

Note; The original one piece packers were graphite based, the newer versions are rubber based usually silicone or nitrile.

debbie42

Canucklehead wrote: »

Hi

Does the leaky valve have a name on the cover cap ?

Corgi Guy.

No cap on it at all.

debbie42

alanobrien wrote: »

Firstly is it a TRV or a lockshield valve ? Assuming its a lockshield and newish it will most likely be sealed with an O ring these days. If that is the case you may get away with replacing the O ring but unfortunately sometimes the valve stems wear so you may have to replace the valve.

If its older it would be sealed with what is called a one piece packer - i know this i used to work for the company that made millions of the things each year . If this is the case all you need to do is add more material to the packing chamber and tighten the gland nut, it will then seal against the valve stem even if its worn. Graphite tape is the best material for this, you can use PTFE cord but it does have a tendancy to extrude hence manufacturers do not use it as a packing material.

Note; The original one piece packers were graphite based, the newer versions are rubber based usually silicone or nitrile.

TRV or what? You've lost me there! It is at least 18 years old, as we've never replaced it, though have changed the thermostatic valve (hmmm.. is this what TRV stands for??) at the other end. I'll try and get a pic posted.

alanobrien

debbie42 wrote: »

TRV or what? You've lost me there! It is at least 18 years old, as we've never replaced it, though have changed the thermostatic valve (hmmm.. is this what TRV stands for??) at the other end. I'll try and get a pic posted.

Yes TRV = Thermostatic Radiator Valve. The "Lockshield" valve is the one at the other end. If its 18 years old its very likely to be graphite/fibre packed so you should be able to add material to it. A picture would help though.

Canucklehead

Hi

Peglar make Belmont rad valves ,these are serviceable without draining the system .That's why I ask.

The grey cap or hand wheel is the give away.

Otherwise the aforementioned advice about ptfe tape is the way to go.

Corgi Guy.

debbie42

Taken a photo, first time via photobucket, so hope it works.



btw, the photo looks worse than it does in real life. Must be the flash.

silvercar

We had a leak in one of those. The engineer managed to fix it without draining down the system. He did say it was knackered somewhere and now that radiator can't be turned on or off.

I know he used a wrench, more than that I couldn't say. We lived with a bowl under the leak for a few weeks until he was here doing another job!

alanobrien

Looks like an old terrier or belmont valve so i suspect it can be repacked.
Try your local plumbers merchant for a repacking kit.

Canucklehead

Hi



Looks like one for the ptfe tape as previously described.

Corgi Guy.