Bad Joint on Lock Valve?

[Fitz]

Taking a newish rad off on Saturday for decorating purposes. I've done this on two other rads (installed at the same time) without any problems. Installed along with new boiler 2 years ago.

This time I closed the lock valve, applied pressure to the nut to turn, bracing the pipe as usual and a small jet of water suddenly started shotting out from the compression joint securing the lock valve to the supply pipe.

Oh bugger thinks I. Sealed combi fed system. First instinct is to wrap something round it, this proves to be entirely inefectual as you'd expect on a leak at around 1.5 bar.

So my second instinct is to sticka towel round it and take the pressure out of the system. So I turn the boiler off then suddenly realise that I have no idea whether there is any kind of pressure release valve I can just open, so opt for opening a bleed valve on the hall rad. Enduring the scalding hot water and capturing the resultant high pressure spray in a bucket I gather my wits a little and pass bucket duty over to the wife.

I go back to the ofending valve and thinking 'kill or cure' nip up the compression joint a bit more. Joy of joys the spray turns into a trickle. Another screeching, elbow poppin nip and the flow stops.

So I plug up the other rad and check teh pressure, seems to be as near to 0 bar as the gauge on the boiler can cope with.

So now three options: ~ Emergency plumber - costly, and I may have fixed it anyway. ~ Wait until the week and book a plumber - No hot water or heating for a few days and I might have fixed it anyway. ~ Repressurise system slowly and see what happens - if it holds consult the diy newsgroup on Monday.

It's monday so it doesn't take a genius to work out which option I went for.

I re-pressurised the system very slowly, gradually bleeding air out of various rads and slowly adding more until it was up to 1 bar. Normal cold pressure for my system.

The dodgy joint has started weeping. By now I'm feeling very cavalier so give it another tweak. I now notice that the entire joint rotates on the pipe. I'm sure that's not right.

Only one more tweak was required once the system was fully heated and back up to 2 bar.

So I'm having a plasterer in tomorrow and I'll be wanting to fit the rad back on in a week or 10 days. So I'm mulling my options?

1) Drain system, re-make compression joint 2) Find plumber - throw money at him and ask him to sort it out. 3) Give it a final tweak and if it holds leave it and hope it doesn't suddenly fail just as I've got all teh decoration and new carpets fitted.

And to assist in the decision, our first child is due on the 13th March, so I'm racing to get everything finished.

Also, this part of the installation is only two years old. We had a one year warranty on the parts and workmanship. Does the rotating valve indicate poor workmanship or do they all do that? I'm surprised given that I can't really turn it any more, it's as tight as I can get it. In this case if it is demonstrably poorly installed I might see if I can pursuade the installer to do the work as a goodwill gesture.

Sorry for the long post, I do ramble.

thanks in advance

[John Rumm]

Sounds like the way to go...

First step is to drain down enough (i.e. if this is an upstairs rad there is no need to drain the whole system, just drain to below it)

Take the valve off an look for obvious problems like scores or nicks on the mating faces of the valve and the olive. If it still looks ok you may get a water tight seal simply by wrapping a few turns of PTFE tape round the pipe an olive olive and remaking the joint. Using PTFE on the thread of the compression fitting will also make it do up more smoothly.

If there is any damage to the mating faces, then replace the valve and olive (given that lockshields are cheap, I would be inclined to do this anyway). Be careful when taking the old olive off not to damage the pipe. Partly cutting through it with a mini hacksaw, before breaking it of with a twist of a screwdriver in the slot you cut usually works well.

When you remake the joint, do it up tightly, but don't muller it until bits of metal start falling off. That way you have the option of giving it another quarter turn should it be needed to fix any weeping.

Also since you will have drained down (at least partly) twice, it would be well worth adding some more inhibitor to the system after you are sure you have fixed the problem. To save having to drain down again to do this, turn off both valves to another upstairs radiator when the system is empty. When you test the system leave this rad closed off so that it does not fill with water. When you are happy the leak is fixed, take one of the top plugs out of this rad (either the bleed valve or the blanking plug), and put pour the inhibitor into it and replace the plug. That way when you open the valves on that rad and bleed it, the inhibitor will added to the system.

You could, depending on how interested plumbers are in small jobs in your area, but this is a simple enough problem to fix yourself if you feel up to having a go.

Could do, but given it has not responded to the tweaking up solution, it suggests there may be a problem with the joint like a damaged olive, or a bit of swarf being stuck in it. It may have been overtightened in the past resulting in a deformed olive.

Congratulations!

(if you think plumbers are expensive, wait until you get one of them!)

Not necessarily... depends a bit on how easily you can turn it. If it spins freely by hand then there is something wrong with it. If you can only turn it with a spanner on it then that is less of an issue.

You can try, but I don't hold out much hope. Also the hassle involved would be more than than involved in fixing the problem.

[Roger]

The message from "Fitz" contains these words:

One possibility is that the pipe was cut off a bit short and the olive is squeezing down on the end rather than biting into the pipe a short distance from the end. I am not saying that is necessarily the case but it fits with the fitting starting to leak badly as soon as you started to mess with it but if that is the case there is now a faint possibility that the pressure will push the valve right off the pipe now you haven't got a radiator holding it in place.

Given that the radiator position is fixed the only cure (unless you are very lucky and do have some slack) would be to cut back the too short pipe and fit a slightly longer length. Don't go to the other extreme though. If the end of the pipe is hard up against the valve before the nut is tightened then much of the force exerted on the nut will be dissipated in forcing the olive along the pipe rather than into it.