Tabby ) wibbled on Monday 14 February 2011 15:23:

40mm compression fitting, an elbow, keeps popping off, but I cant find
anything wrong with it. It gets done up firmly each time, but still
comes off. The only thing I suspect about it is that the pipe that
comes out is restrained about 8 feet away, so perhaps it pushes
sideways (not in & out) in the compression fitting when it warms up.
That's really the only idea I have. The fitting is most likely from
screwfix, toolsatan or wickes.

Any ideas?


NT

I'm assuming the olive slides off the pipe[1]? If so...

You should be doing it up enough for the olive to bite into the pipe.

Not excessively (as in crush the pipe to buggery) but just enough so that if
you undo the fitting, and shine a torch over the olive, you will just be
able to see the pipe surface curve down a fraction next to each side of the
olive like a tiny mercury meniscus

( http://media.tiscali.co.uk/images/fe...y/meni0001.jpg )

Are you using copper olives on chromed pipe? If so, switch to brass.

Copper olives I find, whilst easier to do up, do not give the same feedback
a brass olive does (the latter starts the "creak" when (IME) it is right) -
but are OK on copper once you get the hang of the amount of welly to give
it. On chrome they will be a lot less effective as the chrome skin is pretty
hard.

Either way, sounds like you need to give the nut a pip more welly - the
olive should not be able to come off other than by cutting, or extreme
pulling force.

Cheers

Tim

[1] Th only other way is for the threads to slip - that would of course be a
very knackered fitting or nut!

--
Tim Watts