Re: Leaking copper/plastic joint

[BigWallop]

My loo cistern has a plastic ball valve assembly. It is fed from a

> copper pipe. The joint is now leaking. Tightening the join doesn't fix > it. Reassembly of the joint has made the leak slightly worse. > > What does the team think is the likely cause? Suggested fixes? > > Thanks! > > Steve at netservs dot com

Turn off the supply. Remove the brass nut from the plastic tail. Wrap the tail with five turns of PTFE Tape to build up the thread again. Replace the brass nut on to the tail. Not to tightly, as this will strip the thread again. Make sure the brass nut is on the proper theard and not cutting across it. Then turn the water back on and check the seal.

[Steve Harris]

There doesn't seem to be a seal at all

Steve

[Dave Plowman]

It's usual to use a tap connector, and I reckon the standard fibre washer is often too hard for the maximum clamping pressure you can manage with a plastic thread. And wrapping the thread with tape will only work if the leak is above the washer - not if it's between the tap connector and the washer.

[BigWallop]

The wrap the end of the plastic tail with PTFE Tape (plumbers tape) and overlap it slightly over the end of the plastic tail, not enough over that it seals the end, and it will act as a washer and a thread seal at the same time.