Plumbing Gaff

PoGee

I hope a plumber can help. Long story - gas CH is not working, waiting on a spare part. A lightbulb came on in my head and thought 'wonder if the REALLY old immersion heater still works', so that I could get hot water while doing dishes. Then heard a mini waterfall.
There's water gushing out the round bit (i think it's the immersion heater bit) in the water tank that's in an airing cupboard. I thought the water leak might be old water built up in pipes so opened all the taps (sinks + bath) and switched water off at mains. Dripping stopped but started gushing again once I switched water on at mains. I could hear water going through the pipes when I never did before, before I switched the hot water immersion switch in kitchen, I mean. Kitchen immersion switch is off.
The tank is part of the central heating system. How bad is this? Home emergency been called.

Myser

Can you post a photo of the hot water tank and where the water was leaking out?

PoGee

Thanks Myser. It's leaking from where the immersion copper heater enters the tank. The seal around the round part of the heating element (black round bit). Apologies for not providing a photo, I have a cheap mobile phone that doesn't take good pics and son who has a good phone went out with his mates. Direct Lind said they'd send someone out tonight but have gone back on their word. Would something like FLOMASTA EXTERNAL LEAK SEALER or Fernox LS-X Leak Sealer 50ml  stop the leak?

Do you think switching the immersion switch on (the one in the kitchen), did this? It's never leaked before and I've never switched that switch on before either.

Myser

Assuming the switch you have operated is wired to the immersion heater, if the seal has been damaged or if it wasn't fitted properly in the first place, then expansion from the heat may have caused a gap and therefore the leak.

Are you sure the switch isn't wired to a pump as you mentioned a sound of water going through pipes?

If the tank is partially drained you could try using Flomasta or LS-X (both are good) and allowing it to work for a couple of hours or so.

Is it a standard hot water tank with a jacket or an unvented cylinder?  An unvented cylinder will have a tundish beside it:

Myser

If the leak is within the black cap where the electrical connections are housed, you will probably need to remove the black cap first and see where water is leaking through. Be careful as there will be live connections in there, so switch off first.

There will be a small screw/nut to remove the cap.

PoGee

Hi Myser. It's a standard water tank with a jacket. I don't know if the switch is connected to a pump but if it was connected to a pump, I was hoping switching it off would stop the pump. 
I know that the centarl heating boiler has a pump under the kitchen floorboards. I'm sure it's not that sound. 
I've attached a picture of the element. I know I don't see the copper bit - the leak is at the black round portion where it protrudes the tank.

PoGee

Myser said:

If the leak is within the black cap where the electrical connections are housed, you will probably need to remove the black cap first and see where water is leaking through. Be careful as there will be live connections in there, so switch off first.

There will be a small screw/nut to remove the cap.

The leak is not within the black portion but where it exits the tank. I'm going to Screwfix tomorrow am. Fingers crossed. Many thanks for your help Myser.

PoGee

p.s I don't think there is a pump connected to the hot water/ immersion tank but there is a large cold water tank above it, in the attic. I really hope there's no pump.

Bendy_House

We need a photo - even a carp one.

PoGee

Bendy_House said:

We need a photo - even a carp one.

I'll get a photo taken. Hot water tank is in son's room but he's asleep at moment. He has a bit of a hangover...There's a video on youtube that shows what's happening to our one. It's a video by Allen Hart titled Leaking Hot Water Cylinder. Date 22/01/2018.
So I think the sealant idea is not to be used as there may be a hole or two in the element.

Direct Line saying someone will be here this afternoon 'to have a look'. They'll then probably say that they don't have the part. They're reasonably priced; if I get one before plumber gets here, are they all the same diameter? I'll make sure it's the same wattage etc as I'm sure it had that info on the black round bit. 

FreeBear

PoGee said:

Bendy_House said:

We need a photo - even a carp one.

I'll get a photo taken. Hot water tank is in son's room but he's asleep at moment. He has a bit of a hangover...There's a video on youtube that shows what's happening to our one. It's a video by Allen Hart titled Leaking Hot Water Cylinder. Date 22/01/2018.
So I think the sealant idea is not to be used as there may be a hole or two in the element.

Direct Line saying someone will be here this afternoon 'to have a look'. They'll then probably say that they don't have the part. They're reasonably priced; if I get one before plumber gets here, are they all the same diameter?

If it is a real old system, the threads on the boss that the heating element screws in to could be slightly different. Before 1976, imperial threads were standard. After joining the E.U. metric became the norm, and suffice to say, metric & imperial fittings are not interchangeable.

Immersion heaters also come in different lengths - It might be marked on the label (if the old one still has it).