leaky cylinder joints

30 Dec 2003
Reaction score
United Kingdom
Ive just replaced an old hot water cylinder with a new foamed jobby. Used loads of PTFE tape on all the threads but some leaked. Drained it all down, put more PTFE tape on but the dam thing is still weeping, especially around the immersion and top blanking lug.

Would a drop of LS-X help to stop my weeping cylinder?
Sponsored Links
I always just use jet blue jointing compound on the threads of the immersion and the fibre washer supplied with the immersion. Did you make sure you cleaned all the bits of foam off the metal surface that the fibre washer pulls against?

Just use ptfe or loctite 55 on other threads.
I did try to make sure that all the foam was removed before attaching the fittings.

I must admit that I didnt thing you were supposed to use a jointing compound, but cant really see how else to get a good leak free connection!
Sponsored Links
A friend had exactly the same problem and was told that using gas grade ptfe rather than standard plumbing ptfe would fix it. Apparently gas ptfe is much thicker and makes a much more reliable seal. He tried it and says it did the job perfectly.
firegazer, did you sort out your leaky problem?
I have just had the same problem with the hot water in coupling. Loads of PTFE but still leaking.
Did you try the gas grade PTFE, jet blue or the loctite 55 on the joints and what was the outcome?


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