New Compression Joint Leaking - Help

18 Jun 2006
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United Kingdom
I'm not a plumber, but I have spent the last 4 days watching a mate of a mate (who is a plumber), fit my new bathroom bear with me please.

There is a short length of pipe that connects my cold water bath tap (gravity fed system, not mains) to a stopcock isolation valve. This copper pipe can be bent by hand as most of the length of it is ribbed. The tap, copper pipe and stopcock are all brand new.

When the plumber left at 6pm tonight, there were no leaks. In fact, he completed the bath fittings yesterday and the stopcock has been open all this time with no leaks. Well actually there was one leak when he first connected it but he fixed that one at the time.

However, at 9pm tonight, I noticed a few drips coming from the kitchen ceiling which is directly under my bathroom. I ran upstairs to find a leak in the compression joint that connects the 22mm copper pipe to the stopcock. It wasn't just dripping it was more of a gentle stream.

I switched off the stopcock and the leak stopped. It then started to drip, so I figured it was the existing water in the pipe, so I opened the tap to release the vacumn and the drips got faster until they stopped a short while later.

So my question is why would a compression joint that was working with no leaks suddenly start leaking many hours later ?

Was it not tight enough ?
Was it too tight ?
If it was too tight, can it be fixed by just fitting a new olive ?
Or do I have to replace the full section of bendy copper pipe in case it has a kink in it ?

Any advice welcome.

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Undo it, dry it off and put a thin smear of fernox lsx around the mating surface of the stoptap and olive and reassemble comfortably tight, then a slight tweak more.
Plumbers woudn't normally use those ribbed copper pipes because they split easily - and produce a small stream of water. Typically would happen if a compression fitting were tightened without supporting the pipe, so it would twist...
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Why should you have to mess with it, call the one who fitted the pipe (unless it was done for free- in which case friend of a friend of a friend..... may not come)

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