Why would a JG fitting fail after 6 months?

[happypeter]

Hi,
I noticed our boiler pressure started dropping and traced it to a leaky John Guest elbow fitting. It looked like it had almost completely unscrewed itself with the pipe still fully inserted. It has been fine since installation 6 months ago.

I took it apart, inspected it, put it back together and reconnected.

I’m worried because I couldn’t find anything wrong with it and concerned it may fail in another 6 months (Nice clean cut plastic pipe, fully inserted, pipe insert etc)

What could be the cause?

thank you

 

[Swwils]

If it leaked you should ideally re cut it, making sure it's exactly perpendicular.

Also give it a pull test to see if it did securely meet.

Possible that it's a knock off JG fitting?

 

[Madrab]

Given it's a mechanical fitting then unlikely it has unscrewed itself unless the pipe was under stress/pressure due to it being at an angle, on a bend, not properly clipped etc. Or if the pipe/insert and fitting aren't matched. JG are usually pretty good.

If you're worried then you can get collets that will 'lock' the fitting once it's tightened.

 

[happypeter]

the pipe was under stress/pressure due to it being at an angle,

It is on a angle/bend (bottom pipe in pic). Maybe the clip is too close to the fitting? I will get some collets.
thanks

 

[Madrab]

The pipe setting out could have been the issue, especially if the pipe twists. You wouldn't normally use copper saddle clips like that with plastic pipe as they have the potential to cut the pipe if it's under pressure.

See it all the time with copper pipe and the copper clips are used to clip the pipe tight to a wall but clipped pipe should really be raised off of the clipping surface. Saddle clips come with bases that should be used but invariably aren't.

 

[happypeter]

Ok thanks for the info. I'll have another look and maybe add another elbow to remove the bend
Cheers

 

[oldbutnotdead]

Thats not JG tube either- make sure you're using the proper inserts for that tube (OD of all of them will be 15mm, ID varies).
Also check you've pushed the tube all the way in (25mm. JG tube has marks so you can see as well as feel).

 

[happypeter]

Thats not JG tube either

Blimey you have a sharp eye! You're right its a pex universal from toolstation, I used the same universal inserts. Maybe I should have stuck to all JG

 

[oldbutnotdead]

The universal will be fine with the correct inserts & pushed in all the way. It seems to be much stiffer than jg, bit of a mare to get it straight.