Plumbing: Are those white push-fit end-caps reliable on 15mm copper pipe?

[Al]

Are those cheap (B&Q, etc) white plastic push-fit end-caps reliable on

15mm copper pipe in a gas-fired domestic central heating system? I just removed a radiator and used these to cap off the feed and return pipes. I was alarmed when I saw how easy they push on and pull off by hand. Has anyone known one to work loose? The pressure of my system goes up to 2 bar.

Thanks..

Al

[Ian Stirling]

1 bar = 1Kg/m^2 of pressure. 2 bar = 2Kg/m^2 of pressure. 15mm pipe has an area a bit more than 1 square centimeter, so you're probably looking at a force of around 3Kg. Obtain a 3Kg weight, and compare the forces.

[Andy]

I think you mean 1 bar = 1kg/cm^2, non?!

Andy.

[Ian Stirling]

Yes. I'd claim a dodgy c key, but it was simply not thinking while typing.

[Mr Fizzion]

Did you push them on far enough? I'm currently replumbing a load of radiators using hep2o

and you certainly can't pull those connectors off by hand, but it takes a bit of effort to push the pipe far enough into the connectors.

Being able to pull plumbing apart by hand doesn't sound right to me!

Mr F.

[Christian McArdle]

No problem with them on copper. However, if you can pull them off again, then you either aren't pushing them on enough, or the joints have been misassembled, so the grab ring is ineffective.

Christian.

[Lurch]

On Sun, 11 Sep 2005 21:04:41 GMT, [e-mail] (Al) scrawled:

They generally do pull on and off easily by hand when there is no pressure behind them. IME, once you refill the system the endstop is unmoveable as the pressure locks it into place.

[Al]

Thanks to all who responded. After reading your comments I found I could push them on a further 5mm than I had realised. Hopefully they will now hold! Many thanks!

Al

[Christian McArdle]

You'll probably find the first "click" is the O-ring, which provides the seal. The second "click" is probably the lock ring going onto the copper, which stops it coming apart.

Christian.