Frost damage to underfloor heating pipes.

[Francis.]

This is on my self build project.
6 loops of 120M each were laid on insulation in 100mm concrete screed.
The manifold was installed & pressure tested before the concrete was laid & held for a long time after.
That was over two years ago & the building has had no heating in all this time.
Just installed a new ground source heat pump & immediately found a split pipe at the manifold.
On repairing this pipe we have tried pressuring the system & found major leaks on 3 out of the 6 circuits, one so bad that no pressure at all reads with the filling loop fully on.

my options 1. resign myself to only running 3 loops... not good as the room with the canbus temp sensor won't be heated.
2. try leak sealer products .... doubt they'd be much good at the flow rate I'm loosing.
3. listen for the sounds of the leaks & dig them up ... not good spent a fortune on granite tiles.
Major delay on heating partially from ICE energy going bust & taking my deposit with them..
More than a bit depressing right now....

 

[townfanjon]

Concrete ? , or screed ?

 

[Francis.]

CEMEX evolution liquid concrete.. basically 10mm aggregate loads of plasticiser & flowable.
The pipe is Wunda 16mm pe-al-pe cable tied to 50mm squared galvanised mesh.
The pressure test went to over 10 bar... set at 6 but the heat of the cure sent it off the gauge, was still all good a month later though..
Should have blown all the test water out... Should have used better quality pipe..
Up a creek without a paddle on this one...

 

[king of pipes]

Very unusual mate what brand of underfoor piping did you use hard to believe the leaks were caused by frost in the screed above ground maybe any pictures ? Cheers kop

 

[SimonG]

Can't see it being frost damage in the concrete. Nowhere for pipe to expand and split. Leak sealer is a no go.

If it's that bad then either dig it all up and start again or stick some radiators in to boost the three loops.

 

[Francis.]

photos of installation.... I'm going to try digging up some floor after listening to the leaks.. the sound does travel a lot.
The pipes are sleeved for about 600mm between room slabs. really odd no sign of water anywhere & its all on a dpm as well.

 

[snowhead]

I'd agree, the only solution is to dig it up and start again or re-lay on top of the failed floor if there's sufficient height.

I wouldn't trust using any of the non leaking loops.

 

[king of pipes]

Cant see to much wrong there really mate bit of a mystery that one , the most cost effective way would be to put a overlay system on the top its to much work to dig it all up , but i guess the project has moved on a bit since the pictures best of luck with it cheers kop.

 

[Francis.]

It's fair to say the floors don't look the same, getting the heating up & running has been left to last in a long list of work.
Anyone got a time machine ???
Blowing air through the faulty lines might give me a clearer sound to trace, a serious amount of water has gone somewhere under the slab & not even a trace of damp, not that I really want to soak the place..
More photos to show what I'm up against as regards starting in with a jack hammer.

 

[king of pipes]

nice looking place mate you are well and truly stuffed though don't dig up you will wreck the place and if you find a leak and do a repair it will just find the next weakest point and leak there take the hit replace it have a look at uheats website on here and price up a overlay system all that needs doing is trim the doors and plinths then I know you will have to replace your tiles but it will still work out cheaper and cause less disruption and be guaranteed no leaks , you should not put the heating loops under the kitchen units or bathroom furniture . cheers kop

 

[king of pipes]

there is one thing you could try get a 150m coil of 10 mm pex pipe disconnect one of the flow and returns from the manifold and feed the 10mm through the 16mm under floor loop apply a little lubrication ideal yellow 77 wire and cable pulling lubricant will help available from screwfix I cant guarantee it will work but worth a try tape the end of the 10mm pipe 16mm to 10mm adaptors are available best of luck kop

 

[Francis.]

You could be right, It's impossible for the pipe to split whilst encased in concrete.
I've found two leeks so far & both split where the pipe is in ducting between slabs.

What is the best repair, compression joints are easy, but what about reinstatement with concrete around them?

 

[snowhead]

What's the depth of cover over the pipework in the floor and has anything been screwed down to the floor and if so did the fixer(s) know there was U-Floor pipework?

 

[king of pipes]

Compression is what i have used in the past then wrapped with denso tape to protect from corrosion , it can be welded with electrofusion fittings but costly as you will need the equipment to do it ie hire cost ect , try what i suggested what you got to loose try it in the room with the expensive granite tiles the pipe is not dear you can always put it back if it fails but pretty sure it will work could save you alot of heartache bud .cheers kop

 

[Francis.]

Thanks King of pipes, your help has been top notch.
I had a fair idea of what to do but having someone with knowledge & experience for guidance has been a great help.
The screed is 100mm thick it also contains fibres & is about 70 Newton to breaking it up carefully without damaging pipes is proving hard work, but progress is being made & a problem is only a problem till it's fixed.
I replaced the roof with vaulted trusses over winter two years ago. I assumed that the floor was pretty much bomb proof ... any one else doing a similar project would be well advised to blow out all the circuits or add antifreeze.
Many thanks again..

 

[magicno1]

What a nightmare for you!
You can buy 16mm to 15mm adaptors that you use on a standard comp coupling. Most underfloor sites have them. I have some on board where are you?