Hot water cylinder help

Lgas

You don't actually need to turn the main stopcock in the house off, just that yellow lever below the pressure reducing valve in your picture. That shuts off the cold mains to the cylinder.

I have a card that proves i'm unvented qualified, he should be able to show you his.

unclebulgaria

If its full of water Matelodave its knackered. RGI dont look at unvented cylinders, thats gas. You need a qualified plumber/heating engineer with the correct unvented qualifications. If the tundish is showing water then make sure the filling loop is turned off properly. Dont mess around asking questions on here ring a qualified plumber, if you admit not being conversant with any plumbing you shouldn't be messing. The leaking water is a safety feature so its doing whats its designed to do.

Lgas

Ah yes, I forgot to say that, it did cross my mind too that the filling loop may not be turned off! (tap on the end of the flexible hose should be at 90 degrees to the pipe)

MSaxp

I havent blown up yet, which is good news.

I never intended to fix this myself. I just wanted to know what I am talking about, so to first of all know if i am doing something wrong and am causing this.

and also know how bad the problem might be (pretty scary for a newly purchased house) and also know how to describe the problem to the plumber.

Anyway the plumber is on his way, so hopefully i'll know more about it soon. Not sure i fancy replacing the whole cylinder.

Two more points:

1) The pressure in the gauge under the expansion vessel is easily reduced. Just turned the valve next to it and it dropped. Not that it made any difference to anything, unfortunately.

2) I turned the yellow stopcock and the flow in the tundish didnt seem to be impacted. Not sure how that is possible.

ollski

The pressure, the red expansion vessel and the filling loop are entirely unconnected to your problem as they are all on the heating side. Although you may have given yourself a leaking prv on that side too now.
Almost always the mains water expansion vessel (cream / grey) will be flat and when you heat the water in the cylinder the pressure will rise to above 6bar and trigger the pressure valve to open. Chances are when the water pressure reduces the valve won't seat properly and will need replacing and will drip constantly. It will automatically repressurize itself as it is on the mains water which should be kept by the pressure reducing valve at 3bar

MSaxp

Just wanted to thank everyone for their contribution. It's much appreciated.

(The plumber replaced the 6bar relief valve to fix the leak and also replaced a 2 port valve that was the reason for getting no hot water unless the immersion heater was on. Seems to be fine now)

Danielle85

Hello,

I've just had a plumber out to fix a constantly leaking tundish which has started to leak outside my house.

Now, I know nothing about plumbing so I aren't sure whether he has ripped me off or not.

Basically, he thought he immediately knew what the problem was and suggested that the 12 ltrs potable expansion vessel had failed as it was leaning down and would cause the tundish to leak. He replaced that but it's still leaking through the tundish...

He now thinks the relief valve needs replacing - so if that's the case surely the expansion vessel didn't need doing?!? Also, concerned that he is going to try and fit the multi block control....

I can't see anywhere on any forum where this has been the solution!!!

Any help greatly received.

Dx