Compression fittings and Plastic pipe - a cautionary tale

[NoSpam]

I came home last night to find a flood in one of the downstairs rooms and have spent the first half of today opening-up the floor above and fixing the problem.

When I re-plumbed the house a couple of years ago I used plastic pipe and Tectite fittings everywhere accessible; but where I couldn't avoid having joints under the floor I used compression fittings because I didn't totally trust push-fit. The joint that failed was a compression elbow on the end of a long straight DHW run - the pipe had completely pulled-out of the elbow. I presume it was thermal expansion of the long straight run and an inability of the other "limb" to bend sufficiently. I've replaced the compression elbow with a tectite elbow and arranged a longer "limb" on the other side so hopefully there's more flex.

Moral of the story: take expansion seriously and trust push-fit.

Dave

[Stuart]

So you used a pipe support ,then there is the olive crimped on to the pipe ,then the nut holding both to the body of the fitting .....I'm still trying to figure how the pipe got pulled out .???

Stuart

[NoSpam]

I recall double-checking the joint tightness before the ceiling went up (and I hadn't forgotten the sleeve). It's a straight run of about 6m, I assume that lengthways thermal expansion/contraction has "worked it out" over the last 2 years.

Dave

[Staffbull]

I like the yorkshire range of copper push fits, they seem to be made extremeley well, fitted to plastic pipe with inserts they seem fine.

[Ian_m]

Looks like you forgot the plastic pipe support then

The compression fittings on plastic I did in 2000 (with pipe supports) had to have the olives cut off and replaced they were so firmly wedged, when I recently rearranged the plumbing. Lot easier with the proper plastic fixings (Hep2O) just cracked them open, removed pipe, replaced grab ring and O-ring, pushed in new pipe, job done.

[NoSpam]

Nope, the stainless support was looking at me when I shone a torch at the joint, the pipe was pulled back about 5mm.

Dave

[Stuart]

So the pipe must have been pulled back through the olive 5mm ?

[Ian_m]

You certainly couldn't pull the pipe through the olive (or olive off the pipe or even get the pipe insert out) in all the compression on plastic I have taken apart. The olive has shrunk sufficiently to render it "stuck".