HC HepO2 pipe with crazy expansion warping

[slowlybutsurely]

I had to made a repair to the flow side of a pair of HC copper pipes. A solder junction was leaking - it was also *right* on the edge of the joist and I think was being squeezed by the floorboard over it. Several feet away (along the copper pipe) there was a compression fitting which also was being flexed by the floorboard that was over it. So I chopped the whole lot out and replaced it by 15mm HepO2 plastic push fit.

Unluckily for me I left the floorboard up for a few days (to check for leaks obviously) and was staggered by the amount of bend that this new section of pipe experiences when hot. See photos.

Please ignore the pipe foam - that's not causing this. The 2m section of plastic warps up, or sideways, by 6cm++ - this can't be good ? Sure I can just nail the floorboard down and try to ignore this - but I'll know that twice a day this crazy warping will be going on. Something's gotta fail right?

Any idea what I can do?
Or what I should have done?
Or what will fail/or be okay?

Thanks

 

[picasso]

Always helps if we can see what your on about...

 

[dilalio]

There is only one comment a plumber would make, to seeing a repair/replacement like that.

Who the f**k did that?!

If you'd "paid" a plumber to make that repair, would you accept it?

DIY should be rebranded as DAYL (Do As You Like).

That should be done, in copper, with soldered joints, period.

 

[picasso]

To answer the ops question check the expansion vessel is charged correctly and actually joins on to the pipework that is moving.

 

[dilalio]

Ahem! Sorry! Been a rough day on the forum

Yes OP, you really should do that in copper with soldered fittings as it's more rigid and has lengthy proven history in hidden runs.

In my own house, I have no problem with hep pipe and fittings because I can afford to risk it and have nobody to blame but myself if it fails down the line, due to the product!

 

[oldbuffer]

Coefficient of thermal expansion of Hep2O is 0.13mm per metre per degree Celsius. So a 1 metre run, on heating from 10 degrees to 70 degrees would expand by (0.13 x 1 x 60) = 7.8 mm. The amount it would move sideways would depend on clipping, obstructions, unconstrained length allowing movement.