Recessed nut on hot water tank

[Tony]

I hope someone can offer me some advice.

My hot water tank is factory-lagged. There is a leak at the point at which a pipe goes into the coil, half way up the tank, and I want to undo the joint there to see if I can seal it by using new PTFE or something without having to call a plumber.

The problem is that the nut is recessed into the lagging with a gap around it of about 10mm, and I cannot get at a purchase on it with any of the tools that I have.

What sort of cranked/offset spanner should I be looking to borrow or buy?

[Bob Minchin]

Just cut away the insulation - usually only soft foam.

Bob

[Tony]

Thank you, but I'd thought of that, but didn't really want to do it. In any case, whoever installed it must have had the tool that I am after....

[Andrew Gabriel]

but do bear in mind that the copper tank has just about the same resistance to a sharp knife as does a sheet of bacofoil.

[R]

You'll need a spanner like Ebay item 250402511107

Works a treat

[EricP]

As does the tank, to someone turning the nut in a determined way!

[newshound]

Agreed. If it were mine I would be seriously looking at that plumbers two part epoxy putty which, contrary to all normal expectation, sticks fine on wet surfaces.

[YAPH]

First off I'd cut away some of the lagging to get a better look at it and see exactly where it's leaking. Use a mirror (handbag size is ideal) and torch. Depending on where the bushes are located you may find that it's leaking higher up, at the immersion heater bush, and running down inside the lagging and becoming evident at the lower bush.

If it is actually leaking at the central heating coil connection then you need to find out if it's coming from the cylinder itself or the CH side. If you drain down the CH and the leak stops then it's just the fitting into the cylinder and, as long as it's a compression fitting, you may be able to either tighten the fitting or undo it, seal it with Boss White and refit it to cure the leak.

If it's actually leaking from the cylinder you've very little chance of fixing it but you've got nothing to lose so drain the cylinder, cut away foam around the leak and apply your choice of epoxy, glass fibre, resins, whatever to try to patch it. Good luck!

[Tony]

Many thanks to all who replied. I've fixed it with Evo-Stick 'Plumbers mait'.

[Pete Verdon]

And here's me thinking that that number would turn out to be an angle-grinder :-)

Pete

[Grimly Curmudgeon]

We were somewhere around Barstow, on the edge of the desert, when the drugs began to take hold. I remember YAPH saying something like:

I've tried patching a copper cylinder with a leak, using f/glass, epoxy putty, Isopon, etc. It works for a few days or even several weeks, but it always leaks again. I presume it's the thermal movement, but Icbw.