compression fittings on plastic pipe

[andyv]

I've got a T junction under my sink which has a slight weep.

Two plastic pipes with plastic stiffening end inserts fit into a conventional brass compression fitting with olives. There's a T off to a washing machine in copper pipe.

Is it usual to run plastic pipes into a regular compression fitting like this? If so are there any tips for making it seal properly?

[Mike Halmarack]

The plastic may be displaced a little from the olive area over time, despite the inserts. Perhaps half a turn or so on the compression nut would fix it?

[Christian McArdle]

Yes, no problem at all. Some inserts are better than others. I prefer the Speedfit ones, which have a secondary sealing mechanism using a couple of O-rings to supplement the olive.

When doing them up, the nuts need more turning than with copper.

Christian.

[andyv]

I think I've got it now.

I decided to cut a new clean end and give it a fresh olive. Fingers crossed.

Thanks guys.

[chris French]

In message , andyv writes

The instructions for Hep2O suggest wrapping a few turns of PTFE tape around the olive before making the joint. I've followed this advice on a plastic/compression joint and it has worked well (I know that you don't normally use PTFE ona compression joint)

[Doctor Drivel]

Speedfit have two types of inserts. The double seal for plastic pushfits and one without for brass compression joints.

I prefer metal inserts when using brass compression joints. Speedfit are plastic.