On Mon, 08 May 2006 05:59:05 -0700, Redeye wrote:

after a rather more eventful weekend than i was hoping for, i'm hoping
somebody can explain this....

i finished plumbing in everything in my new bathroom a couple of weeks
ago. no real problems and all went quite well. so, i was a bit
surprised to be woken at 1am on saturday to the sound of water running
and a hysterical girlfriend. it appears that one of the compression
joints has spontaneously exploded, allowing mains pressure water to go
everywhere. fortunately no real damage done, just a lot of mopping up
to do downstairs.

the bit i don't understand is why this joint went so suddenly. here's
the facts :

1. the pipe had just slipped straight out leaving the olive in the
service valve that the pipe had escaped from.
2. the joint hasn't leaked at all in the last 2 weeks.
3. the pipe was running from a service valve horizontally about 4"
across then going to a flexi-hose which connects vertically to the
adapters which go up to the mixer tap.
4. the pipe wasn't supported by pipe clips, although it's a short run
and hardly moves at all anyway.
5. i'd put a couple of wraps of PTFE tape over the olive as i'd been
advised that this can help stop small leaks (was this my downfall?)
6. all the other compression joints i've made are absolutely fine and
have been for 2 weeks.

i'd quite like to understand why this joint has failed so spectacularly
before i go trying to fix it.


Either the pipe was not inserted past the olive (it may have been but then
pulled out before tightening), in this case the tightening tends to roll
the olive over the end of the pipe and tends to expel the pipe.

The fitting was in noway adequately tightened.
If the pipe/fitting are in good alignment and everything is clean then the
back nut will "finger spin" up to the "bite point". After that I would say
you are looking at adding 2-4 'flats' (1/3 to 2/3 of a turn to tighten
most fittings).

HTH


--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
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