New TRV's leaking

23 Jun 2006
Reaction score
United Kingdom
Can anyone offer any advice...

A couple of weeks ago I fiited a few new rads with normal handwheel valves. On the weekend I swapped them with Drayton TRV4's. I put a few turns of PTFE tape on both the tail and pipe ends threads then refitted them.

But when I re-filled the system both were leaking from both the tail and pipe ends, even when I did the nuts up as tight as I could without damaging them. I thought perhaps that the PTFE tape was stopping the nut from going on as tightly as requred and therefore not making a proper seal with the olive, so I drained the system down again and removed all the PTFE tape.

When I refilled the system for the second time, the leaks were still there but much less - 2/3 drops throughout the whole evening.

Have I knackered the valves/olives?

I've also got a rad thats leaking water down the thread where the rad tail screws in - despite haveing around 8 wraps of PTFE on there? Do I need more? The rad tail wont go in any further.
Sponsored Links
Ptfe is ok for the rad tail, I usually wind on about 10 times, but I now prefer to use loctite 55.

You shouldn't have any ptfe around the valve body threads, this will not stop a leak. The leak will be around the olive. The thread is just the mechanical devise to pull the olive and fitting together.

It is possible to crush an olive too far by over tightening. Try putting the ptfe just around the olive, about 2 or 3 turns.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local

Sponsored Links