Weeping cylender connections

[John Durham]

I am part way through installing a pumped shower and bat. it all started with a broken bath tap but that grew... Cut a long story short I am exhausted and struggling to stop tow weeping connections into the hot water cylinder (which I have replaced). I fitted the coupling into the tank before placing in the airing cupboard as there is only 4 inches or so clearance around these connection. I several turns on PTFE (in the correct direction so it didn't unwind when I wound it on). Why is it always the hard to get to joints which leak?! Anyway, needless to say I am getting dampness around them enough to glisten on my finger a few seconds after wiping dry.

I have tried nipping up the compression joints but gut feel is it is the inner joint onto the tank that is to blame. I am nervous to tighten much more in case I damage the tank (and I am guessing it is in as far as it can go.

(All connections are new rather than reused and are made with PTFE)

We are in a very hard water area - am I being too hopeful to consider that it might seal it self over the next few days?

Any help or suggestions would be greatly appreciated.

Many thanks and sory for the length of this post.

John

[BillV]

These connections are difficult to get weep free as the threads are so sloppy. The fernox stuff in the small yellow tube usually works for me . And yes, hard water does help with self seal... mind you the water is very hard round here.

[John Durham]

Thanks - so at least I can go to bed now and know that I am not alone!

Is the fernox stuff an additive that goes in in addition to the inhibitor (5 litre container)? Does it do any harm to pumps and things?

Thanks again.

John

[John Durham]

[please excuse if this is a duplicate message]

Thanks - nice to know I am not alone. The leaks are on water feed and supply pipes rather than the heating coil side - so can I use/ will the fernox stuff have any effect?

Any idea of how long it will take hard water to solve the problem (we are in a VERY hard water area) if I rely on that?

Thanks again.

John

[G&M]

After having the same problem I eventually used a form of silicone sealant that was okay at high temperatures. Still took two attempts.

And today the boiler did the same thing.

I HATE BSP connections !!!!!!!

[OldScrawn]

Agree with this post, but the other life saver is the "plumbers" epoxy putty which comes in a stick. You cut off a length and then knead it like plasticene which mixes the hardener (in the core) with the resin (on the outside, or vice versa). The mixed goo really does stick to wet surfaces, in defiance of intuition, and will very often recover an otherwise really awkward problem. While I always feel I should attach a notice saying "It wasn't me, it was the previous bloke" I can't actually see anything wrong with this as long as you are trying to make what should really be a permanent installation (e.g. a hot water cylinder, rather than a radiator or tap).

[Harry Bloomfield]

If I am understanding this correctly, there is no need for PTFE tape on the threads, because the seal is supposed to be achieved between the two faces. I usually find little 'Boss White' smeared on the faces provides a good seal, providing the faces are tightened up reasonably square to each other.

[John Rumm]

The other poster is probably refering to the small tubes of jointing compound that fernox do - it sets rather like a clear soft(ish) silicone rubber.

[adder]

I don't bother with PTFE tape anymore - I use boss white or jointing compound too.