leaking radiator valve

daveshipway

Hi,

One of the radiators in our house has a valve that seems to have a slight leak. Water is dripping very slowly from the spindle at the top of the valve. Here is a picture of it:



I am wondering if this is something I can attend to myself or if I need to get a plumber in. I have tried tightening the nut at the top of the valve, but this doesn't seem to make any difference. I have read that it is possible to undo the nut at the top of the valve and wrap PTFE tape around the thread inside - is this correct ? If I do this do I need to drain down the radiator ? Incidently the name on the top of the cap
(which I removed for the photo) is "Belmont" if that makes any difference.

Many thanks in advance,

Dave

ariba10

What you need to do is slacken the smallest top nut.

Raise it up the spindle and put one or two turns of P T F E tape around the spindle (Wrap it around in a clockwise direction) and then replace the nut.

You will get a little water leakage while you do this but not a lot.

ariba10

Follow up-- Make sure you hold the larger bottom nut in place while you slacken the small top nut.

Wayne3765

If you're confident of draining down the system I'd say replace the valve.

They can be bought for less than £2 at screwfix , toolstation or an independant plumbers merchants otherwise B&Q type places for £4 to £5.

andrew-b

Looks very well corroded to me. Any idea of how old it is out of curiosity? Ideally i'd go along with wayne's suggestion of replacing. Though is that 15mm pipe or is it an imperial sizing? If it's imperial it may take a bit longer tracking down a replacement.

If your picture is anything to go by then you may well need to replace much more of the heating system than just a leaky valve.

Broadsword

Just sorted a leak. In brief:-

Assuming you have a gravity fed system switch off heating. Locate header tank. Probably in loft near cold water tank but much smaller. It has a valve and float like the cold water tank. Turn off water supply to this tank (probably stopcock near the tank). If you cannot find stopcock tie up ball valve into elevated position- as if it's floating high. Clear out any crud from header tank and remove muck by scooping contents and water out into bucket. Discard the bucketful down toilet. Open air valve on rad at high point on system (as next para)

Open drain valve on system. Could be anywhere but ideal when it pokes through an outside wall at lowest point on ground floor. It has a small square head set in a round brass body. Undo anti clockwise and drain the entire system until it runs dry. If it drains to an unsuitable place fit a piece of hose over the end. Open air valve on top of radiator with faulty valve. It's a small square headed thing or maybe a flat screw head at the top of the rad (left right or rear)

Replace valve, cleaning up pipe carefully and use PTFE tape on the threads. With luck the copper ring on "up" pipe to rad will not be damaged as they come off with great difficulty. Do not overtighten nut on "up" pipe. If unsure undertighten and then if it drips tighten a little more after testing

Close all valves previously opened, turn on stopcock into header tank and add anticorrosive solution into tank as it fills (any DIY shed has them). Brands include Fernox). Check for leaks particularly around valves you replaced. Wait until system has refilled (no more water flows into header tank)

Turn on heating, bleed system by opening each air valve in turn until hissing stops and water flows out cleanly. Have a towel handy as you open these air valves. As system warms up, check for leaks.

You'll need a bucket, rad (air valve) key from DIY shed, pliers, adjustable wrench for replacing valve, PTFE tape and towel for drips as well as a new valve. If this valve is the "in" valve- gets hot first when heating on, you could replace it with a thermostatic valve (about £7-10)

Canucklehead

Hi

It looks like it has been ignored for some years.These valves are servicable. Depending on it's age it will need two red or green 'o' rings at huge expense, about £1 each maybe more, the spindle comes out and seals the water in the same way as the old 'Supataps' except in c/h systems crud stops the seal and it usually lets by . I carry a spare so can swap it and clean up the old one for the next time.
Or just change the valve as above.

Corgi Guy.

debbie42

I posted about a leak a year ago (didn't realise it was that long!), in this thread.
The ptfe ribbon did the trick for me (thanks again to all who helped), and it hasn't leaked since. Mind you, my valve didn't look as bad as yours...

maintenance_man

it looks as if the top packing glad is gone and there is no more left to tighten it down. ideally u need to replace the value. if u where compendent u could do it live, if not u need to drain ur system down and replace the valve. refill and bleed the system again

27col

Going on the ancient appearance of the valve, you might find that it is worth a few quid if you get it valued on the Antiques Road Show.:D

Pssst

I concur with Canucklehead. This is a Belmont valve. They use o ring seals and they can be replaced without draining the system.. It pays to know what your doing though or you will get wet!