One For The Plumbers

[needawin]

Central heating joint (nut) has a very slight seepage. When heat is not on a little water would seep and form at the top if the nut. When the heat is on it evaporates.
This is ok at the moment as I can see the joint but a new kitchen is going in and the joint will be behind the units.
Is there some sort of sealant spray that would stop this seep. I have tried to tighten the nut but seems at its tightest.

[The Builder]

Sounds like a compression fitting, Needy. Certainly best to fix it now, before it's hidden away.

The simple way is to wait for the water to cool down... then unscrew the backnut... wind a few turns of PTFE tape around the olive ..... then screw back up. No need to be overtightened.

The best DIY method is to drain down (if it's on the heating circuit) or turn off the water if it's on the Hot Water side.

[The Builder]

......... it's not on one of the rad tails is it? That would be a little more involved.

[needawin]

No on a pipe midway joint. Would not fancy draining system. Have seen sprays advertised. Anyone ever used them?

[buildersmate]

No, do not rely on sprays. You have to get into the gap between the metal fittings and make it smaller so that water cannot pass through, not stick something akin to a plaster on top.
Sometimes these joints do seal themselves as the salts in the hot water evaporating on the leak surface fill the gap I'm talking about but you can't rely on it.

[murraymints]

The plumbers tape as described by builder should do...I had similar problem in bedroom and simply put some tape on and screwed valve back down...

[needawin]

Thanks all

[dekkypoo]

Agree with all, no chance of a "spray-on" product working but their is another way if you don't fancy draining down e.t.c Fernox have a product called FP4 Leak-sealer which I have used a few times to good effect. Possibly another solution would be, if you're having "people" in to fit the new kitchen, ask their plumber to sort it for you for a few bob extra of course.

[dekkypoo]

That should be "there is"