Plastic pipe joint fail - why?

bouicca21

A new heating system was installed by the previous owner. Just over 2 years later, after I bought the place, there was a massive leak under the floor caused by a faulty joint in the plastic pipes.

I was given to understand that this was because the joint is a push fit and then tightened and it had been inadequately tightened. There was extensive and expensive consequential damage, fortunately covered by insurance.

Fast forward just over two years later and the same joint has gone again. Insurance company unhappy as am I.

What would cause this to happen? Water pressure slowly forcing it apart? How can I ensure this never happens again?

neilmcl

Was the joint replaced after the first leak or simply re-tightened? Sounds like the seals in the connector have gone.

To ensure it doesn't happen again get a plumber round to replace the speedfit connector with a proper soldered joint.

bouicca21

neilmcl wrote: »

Was the joint replaced after the first leak or simply re-tightened? Sounds like the seals in the connector have gone.

To ensure it doesn't happen again get a plumber round to replace the speedfit connector with a proper soldered joint.

I don't know whether it was replaced or re-used as I had to move out during the repair works. Can you solder plastic?

It was a nightmare and the thought of facing it all again is another nightmare, especially as all concerned are probably going to quarrel over liability. The thought that it could actually happen a third time just makes me want to hide in a corner and cry.

societys_child

caused by a faulty joint in the plastic pipes.

replace the speedfit connector with a proper soldered joint

Bit awkward, that


Only plastic pipe joints I've known fail were caused by someone forgetting pop an insert into the pipe end whilst installing . . .

bris

You can however use compression fittings on plastic pipes with the steel inserts, if you want a proper fix use them.


It is a bit unlucky though they usually hold. After 2 years I doubt it wasn't fitted properly, I have seen them go after 2 minutes, 2 years is something else.

Davesnave

I would concur with the above. I've maybe two dozen 20mm plastic fittings here, mostly outdoors, buried and slightly more robust than the ones inside houses.

Over 10 years, only two fittings have given any trouble, both of them because of poor installation. It's incredibly easy to make quick joints with them and I suppose that makes people lazy, either by forgetting to put the insert in, or just not checking the pipe is home all the way before tightening.

None of the plastic joints in the indoor system, all installed by the same plumber, has given us a problem.

bouicca21

The first time it was a slow and gradually increasing leak. This time it seems to have gone all at once.



I think it has somehow worked loose. But how and why?


A friend mentioned the possibility of fitting a pressure valve; does one get the compression plus steel insert as well or instead? I can't remember seeing a steel insert when the floor was up.

neilmcl

bouicca21 wrote: »

I don't know whether it was replaced or re-used as I had to move out during the repair works. Can you solder plastic?

It was a nightmare and the thought of facing it all again is another nightmare, especially as all concerned are probably going to quarrel over liability. The thought that it could actually happen a third time just makes me want to hide in a corner and cry.

Sorry, I hadn't read that it wasn't just the pipe connector that was plastic but the whole pipe. If it's just at the joint then your best bet is to completely replace it.

societys_child

The first time it was a slow and gradually increasing leak. This time it seems to have gone all at once.

That suggests there is no insert in the end of the pipe.

A small hard plastic or alloy insert prevents the end of the pipe 'compressing' over time, which leads to a leak. The fact it has leaked much quicker, could be because the pipe has already been compressed once, and is much weaker now. I could be wrong and you would expect that it was checked last time, but who knows . . .

Small plastic inserts, look like this

tacpot12

I'd also check that the pipes are adequately/correctly supported in the area of the joint that is failing.