Outside leak from hot water cylinder at the coil input area

FlyBoy

I have a slow persistent leak coming from the area around the outside of the indirect coil input pipe.
Now, I've read things in these forums about how easy to is to change an "Essex Flange". However.....
Is there really an Essex Flange at this point? I can see a nut close to the tank, and there is then a thread to another nut to hold on the input pipe from the motorized valve.
The leak is not coming from the second nut; its coming from the cylinder wall by the inner (Essex Flange?) nut. It look like an Essex Flange.
The leak appears to vary with temperature AND pump pressure in the coil. When pump is off or valve not directing flow to tank the leak reduces to almost zero.
I cannot tighten the inner nut because the insulation is in the way. But it looks like the inner nut area is leaking,
What's troubling me is that this has the coil behind it; do they fit an Essex Flange to the coil through the tank wall?
Copper indirect coil open vented. Outside nut is more than 1 1/2 inch in size (more than 32mm).
Would it be worth me removing insulation so I can get a wrench onto the inner nut? I can always use expanding foam to re-insulate.
ANY advice welcome.

Alex1983

You will not be able to repair that, you will need a new cylinder.

Le_Kirk

I would agree with Alex. You should arrange to have it done as soon as possible. I had to do mine due to a leak in a similar position. We had drained down the water systems and were undoing connections to the cylinder when the faulty pipe "let go" and we were left with wet feet.

firefox1956

I had the same thing happen.
It's knackered I'm afraid.
Get it sorted ASAP before you have a nasty flood at an inconvenient time !!
And don't forget that the old copper cylinder could be worth about £40.

FlyBoy

Thanks you Alex, Le Kirk & firefox. Grateful for your replies.
As all 3 of you gave the same answer, I should probably read the writing on the wall. However...

I there really no mileage in attempting to tighten the inner nut, the one flush with the side of the tank?

I have pictures but can't find a way to attach them.

DaftyDuck

To add my opinion, no. When these tanks begin to fail, the thin metal loses its intrinsic strength, and WHAM. Wet everything!


Replace it.

firefox1956

You try & tighten that nut you are going to have a big wet mess.
It will just twist out of the tank..........

Le_Kirk

Don't touch that nut with a bargepole, spanner, stilsons, monkey wrench or anything. You have been given the best possible, moneysaving, wet-feet saving answer!

FlyBoy

Okay.
Got it.
Understood.
Leave well alone.
Dry feet is the way.

Copper or SS replacement?

One other thing for the techies; when I view the forums NOT logged-in I see the new style, when I login I see the old style.

Alex1983

Stainless, it will be cheaper. Unless you have a gravity hot water system then you will need to fit a copper one.

FlyBoy

Alex1983 wrote: »

Stainless, it will be cheaper. Unless you have a gravity hot water system then you will need to fit a copper one.

I had a new Worcester Bosch boiler and a new energy efficient (button) pump fitted last year; no other changes.
I have a gravity fed, from 2 water tank in loft, open-vented heated and hot water system. Two tanks, two return pipes.
There's one big water tank and one small water tank in the loft, both with ball-cocks.
There is a return pipe to the big tank that goes no higher than just above the tank top cover.
There is a return pipe to the small tank that loops around very high in the rafters until it drops down into the top of the small tank cover.
I suspect that the small tank is for the radiators and the coil because that's the one that the engineers and I put inhibitor in. I last used X100 3 years ago.
The hot water cylinder has the usual one cold in at the back low down, top middle output hot water, and the pump in/out to coil on the side; looks standard to me.

I would be most obliged if you or anyone could please explain why I can't use SS for my new tank?
I have a background in aeronautics, physics and mathematics, so please be a technical as needed.