Help with some plumbing

[tonkski]

I've been putting this job off for years. There's a leaking fitting on one of my central heating radiators and I'm not sure how best to go about fixin g it. I've got as far as cutting away the boxing to see what's going on. Se e photo at:

The telescopic fitting "B" leaks, despite various efforts at bodging it, an d needs replacing with something. The nasty bodge "A" also needs doing prop erly. Pipe "E" rises out of a concrete floor and is already quite short so I don't want to mess with it too much for fear of ending up having to repla ce a buried pipe.

My thought had been to cap off the top of T fitting "D", put a compression T fitting in pipe "F" and then bring a pipe from that up and around (throug h 90 degrees) into the radiator using a straight valve. My worry is that th ere might not be enough movement in pipe "F" to allow the T fitting in. Hop e this makes sense.

Any bright ideas please?

[Chris Hogg]

Seems like a lot of extra work just to stop the leak at B. Why not just remove valve C (disconnecting at B and the top of that short extension to T-fitting D, temporarily capping it off). Then remove the stub going into the radiator and the nasty bodge at A. Clean up all the mating surfaces, apply Plumbers mait where appropriate and re-assemble. Whatever you do, there'll be water draining out so be prepared.

[tabbypurr]

e of my central heating radiators and I'm not sure how best to go about fix ing it. I've got as far as cutting away the boxing to see what's going on. See photo at:

and needs replacing with something. The nasty bodge "A" also needs doing pr operly. Pipe "E" rises out of a concrete floor and is already quite short s o I don't want to mess with it too much for fear of ending up having to rep lace a buried pipe.

n T fitting in pipe "F" and then bring a pipe from that up and around (thro ugh 90 degrees) into the radiator using a straight valve. My worry is that there might not be enough movement in pipe "F" to allow the T fitting in. H ope this makes sense.

use a site that doesn't royally screw with browsers and you'd get more asss itance.

[Chris Hogg]

If you mean Tinypic, I did give up using it to post images, a while ago, because it no longer worked for me, although I've had no problems with it as a viewer and saw the OP's image easily enough.

[Brian Reay]

Returning to the topic.

If it were my problem, I'd drain enough of the system so I could strip the parts down.

The fitting which screws into the rad, and the lockshield valve, replace. Carefully remove the 'olives' from the other joints and replace.

Re-assemble, checking joints aren't stressed.

Refill, bleed the system, check for leaks.

[harry]

e of my central heating radiators and I'm not sure how best to go about fix ing it. I've got as far as cutting away the boxing to see what's going on. See photo at:

and needs replacing with something. The nasty bodge "A" also needs doing pr operly. Pipe "E" rises out of a concrete floor and is already quite short s o I don't want to mess with it too much for fear of ending up having to rep lace a buried pipe.

n T fitting in pipe "F" and then bring a pipe from that up and around (thro ugh 90 degrees) into the radiator using a straight valve. My worry is that there might not be enough movement in pipe "F" to allow the T fitting in. H ope this makes sense.

You may well find the radiator also needs replacing. Something like this should help.

[Andy Burns]

Hoping that someone hasn't overtightened and crushed them in an attempt to stop the leak

[Harry Bloomfield]

tonkski explained :

So far as I know, B does not telescope.

If that valve and its opposite number at the other end of the radiator can be persuaded to shut off enough, then you might manage the task with just that radiator drained down. Fit a new B, with a good smear of Plumbers Mait on the thread and the mating surface.

If the either valve fails to seal, then you will have to drain down, so may as well fit a replacement valve plus B. Don't forget to add inhibitor.

[tonkski]

Thanks Harry. I think I can shut the valves off sufficiently. I'm not sure what B is, but it looks like it has been bunged into the radiator rather th an using a proper screw-in fitting. I'm not sure a new B will fit in the sp ace allowed by the valve if done properly. The radiator is a replacement put in by a plumber a few years ago.

[John Rumm]

I would suggest replacing the valve completely, and if necessary get a stem extension to allow it to reach the rad from its current location.

You can replace the tail screwed into the rad with an extension tail - these normally have a rubber O ring that seals against the surface of the rad rather than the more traditional taper fitting that needs PTFE tape on the threads. That gives you a protruding stub of 15mm pipe. Most modern rad valves expect to seal onto a pipe (the supplied tails being nothing more than a threaded taper fitting fixed to a short length of pipe). So you can discard the short stub that comes with the valve, and use the longer one instead.

e.g.

and

[Harry Bloomfield]

It looks like the perfectly standard part, which comes with the valve, from what I can see in the photo.

[Manikin of mirth ...]

......should be fun trying that...tee hee

[Manikin of mirth ...]

[Andy Burns]

Not to me, It looks like a modern 'stem' that ought to screw into the radiator has instead been used backwards screwed into the union coupling of an old style valve, then 'sealed' into the radiator with gunge ...

[tonkski]

Thanks John. I hadn't realised that.

I think I'll drain down and replace the valve and tail as you suggest.

I'll replace olives if they are willing to come without a struggle or I can easily cut / split them without damaging the pipes.

Thanks everyone. I get great help on here every time.

[RJH]

Why replace the valve? If the problem is at the radiator tail - maybe just replace that? The existing tail looks most odd to me.

Not replacing the valve would save draining the system down . . .

[Harry Bloomfield]

Manikin of mirth ... was thinking very hard :

You make a saw cut across the olive, in line with the pipe, just deep enough to get a sharp screwdriver in. If made deep enough, twisting the driver breaks the olive. If not too tight, you might be able to get a pair of pliers behind the olive and tap it off with a hammer.

[Bimbo ...]

yip...hard work

[John Rumm]

The new valve will come with new olives. The only place there might be cause to reuse one is if you re-use the old backnut form the existing valve to fit the new one. Note however there is no guarantee that the thread will match, or the length of protruding pipe will not be too long for the new valve. So you may well have to pull or split that olive.

[John Rumm]

The main difficulty with the existing valve is it uses the traditional cone joint style of fitting. Most tail extensions won't have that fitting, and will expect the valve to have a 15mm compression fitting on the rad side as well as the pipe side.