Hot water tank overflowing

[Claralou]

Hi all, I'm looking for some advice & hoping you can help.

We have a sealed central heating system with boiler in the kitchen, hot water tank and expansion vessel in the airing cupboard. This morning I noticed the floor under the hot water tank is very wet and there are trickles of water coming from the top of the tank. There is no sign of water coming from the overflow pipe (tundish?). This was whilst the boiler was off, presumably it'll be worse when it's on?

Am I right in thinking that in order to stop the constant trickle of water I'll need to turn off the supply of water to the tank and therefore be without heating and hotwater? We can't get an engineer out for 4 days...

Thanks

(Don't know if it's relevant but expansion tank was replaced 18mths ago. We have a leak somewhere as pressure can drop from 1bar to 0.2 within 48hrs but have been unable to find it)

 

[oldbuffer]

Couple of pictures of the airing cupboard would be useful, one to show as much as possible of the contents, one to show top of hot water cylinder. Also useful to know what make and model of boiler you have.

 

[JohnD]

I think you mean hot-water cylinder. What colour is it? how old?



some photos would be helpful.

 

[Claralou]

Thanks both.

The system is 17yrs old, fitted by developers & seemingly neglected by previous owners...

Boiler is a Potterton Suprima - it has been rewired & had a new circuit board & a valve replaced 2.5yrs ago after a pipe above it burst. Has worked perfectly since but we know it'll have to be replaced next time something goes wrong on it.

Hot water cylinder is a Megaflo - water is trickling from under the plastic lid (for want of a better word) and seeping from around the outlet on the top.



Hope that helps

 

[Madrab]

Oh dear, sounds like it has gone at the HW outlet tapping. It may mean a new cylinder. You can turn off the hot water on the programmer and keep the central heating on, it should run on a separated circuit from the boiler.

For safety's sake though, you should shut the unvented HW off until it can be looked at by a qualified engineer. Make sure the engineer visiting has his UHW/G3 qualification, he should have a card proving it.

 

[Claralou]

Thanks Madrab

I've done as you suggested & will keep an eye on it. At least we don't have to huddle round the oil radiator! Although 4days of cold showers sounds hellish...

 

[Madrab]

If you find it's still leaking, an unvented HW cylinder is supplied with mains water pressure, then there will be a stop tap just before the cylinder that can be shut off therefore isolating it. Open up a hot water tap and that should relieve the pressure in the cylinder and therefore reduce or stop the leak.

Time for lots of kettles and shallow baths

 

[gassymark]

Just a thought looking at your pic,s I would check for a leak around the bottom of you expansion vessel it may be dripping on to the top of the cylinder and running into the Center around the DHW outlet
Cheers Mark

 

[Claralou]

Thanks Mark, hadn't thought of that!

A second call to the engineer has resulted in them reclassifying it as urgent (due to the electrics for immersion & pump being close to the leak) so should have an initial visit either tonight if first thing tomorrow.