Copper Pipe With HT Fittings

[Alcyen]

I’m using the non-pro hard tube fittings with 1/2 copper pipe (house plumbing) which has a 15.875mm OD and I have an air leak somewhere. I’ve tested my solder joints and those are good so I’m suspecting that air is leaking past the o-rings. The reason I think it’s the fittings is because I can pull on the tube and it starts to slide out of the fitting when fully tightened.

Has anyone experienced this and if so, did you use the extra o-rings (red/blue/yellow) to get a better seal or was it fine with the black ones? What order did you stack them in? For example: metal collar-plastic collar-red o ring-black o ring.

The o rings in the threaded part of the fittings are in the groove and undamaged if anyone is thinking that the problem is there. I appreciate the help.

 

[Eddy]

Using tubes that are almost 0.25 mm smaller with 16 mm hard tube fittings cannot work well. Even if 0.25 mm does not sound like much, it is simply too much.
The included O-rings are for the bottom part of the fitting, meaning the thread, not for the inner O-rings. They are completely different in size
What you are trying to do simply will not work properly. Unless you can expand the tubes to 15.95–16 mm. However, the edges must be deburred very cleanly, otherwise you will cut the O-rings.

 

[Alcyen]

Using tubes that are almost 0.25 mm smaller with 16 mm hard tube fittings cannot work well. Even if 0.25 mm does not sound like much, it is simply too much.
The included O-rings are for the bottom part of the fitting, meaning the thread, not for the inner O-rings. They are completely different in size
What you are trying to do simply will not work properly. Unless you can expand the tubes to 15.95–16 mm. However, the edges must be deburred very cleanly, otherwise you will cut the O-rings.

Thanks for the reply. I wasn’t using the other o-rings in the grooves; just stacking on top of the other o-ring under the collar to try and seal it up better. It still didn’t pass the pressure test so I’m going to buy new o-rings that are 15.8mm ID and replace the ones in the grooves.