Having a problem installing shower diverter (leaking!)

Are both of them dripping? Can you tell if it is from the 3/4" coupling or the 15mm compression end?

I would:
remove both, rewrap the 3/4" end with PTFE, thinner at the open end and thicker towards the centre. Tighten into the mixer, the connect the 15mm WITHOUT PTFE - it should not be necessary on a clean new joint, unless you have over-tightened the connection already.

kbdiy said:

Are both of them dripping? Can you tell if it is from the 3/4" coupling or the 15mm compression end?

I would:
remove both, rewrap the 3/4" end with PTFE, thinner at the open end and thicker towards the centre. Tighten into the mixer, the connect the 15mm WITHOUT PTFE - it should not be necessary on a clean new joint, unless you have over-tightened the connection already.

Click to expand...

its definitely from both 3/4 ends. I'll remove the PTFE from the 15mm (I only put it there as once this is in access isn't gonna be easy) and rewrap the 3/4 this evening and get back how that goes. How thick should I be doing the ends roughly? Thanks so much for any help or assistance. Wish I never started this and just saved until I could pay someone else to! Never again but just really want this done for Christmas!

Edit: just in case. It wouldn't need a washer or anything like that would it?

No washer needed. Just wrap with PTFE so it is a tight fit by hand, then tighten with spanner/grips until it feels firm. If it goes right in easily, you need more tape, so take it out and wrap again.

kbdiy said:

No washer needed. Just wrap with PTFE so it is a tight fit by hand, then tighten with spanner/grips until it feels firm. If it goes right in easily, you need more tape, so take it out and wrap again.

Click to expand...

right, just got home gonna take it apart and give it another go. Thanks a lot for the help I cant express my appreciation enough! Will let you know how I get on.

1) you don't shove ptfe tape around the thread for the nut / olive. It's unnecessary.

2) you only nip up the nut for the olive, it WILL leak if overtightened, especially if olive gets crimped onto the copper pipe.

3) cheap olives provided with fittings are sometimes rubbish! Best swap them for good quality ones.

4) if it's leaking from where the fitting screws into diverter and you are really having problems with it and getting enough ptfe tape on it to seal it, then try liberally using liquid ptfe which is more of a paste and spreads out around the thread. Be warned though sometimes that stuff can almost permanently bond it together making disassembly awkward after if required.

Seems to have worked on the hot still a slow drip on the cold, maybe I've just not been using enough PTFE this whole time? Will see how it goes once its redone and left overnight. At least I've replaced the flexis now though. Thanks for everyone's help