Unvented 6 bar Relief Valve Running

[arran197]

I'm a bit confused with this. Recharged the vessel to 3 bar, still leaking. Cleaned prv seat, still leaking. Replaced seat, still leaking. Piped in a secondary prv, ok for an hour. Then started leaking again. Reduced pressure on pressure reducing valve. Still dripping. What is wrong with it? The temp and pressure relief is not dripping, it's just cold water coming out. The zone valve shuts on temp rise. The only other thing I can think is that the reducing valve is allowing the pressure to build up as it only leaks after a bit and if a tap is opened it's fine. Pressure is high at first opening the tap, then reduces.

Anyone got any other suggestions? Advance Appliances cylinder.

 

[Simon F]

is there a needle valve anywhere to read what pressure it gets up to?
or somewhere to fit one?
seems that swapping the pressure valve is next.

 

[Chalked]

Either the pressure reducing valve isn't working, or b@@@dy pressure relief valves!!! One they start dripping, no end of tinkering eill stop them. Only remedy is new pressure relief valve.:cuss:

 

[Rabbitman]

I seem to think i had something Simaler a long while ago where they'd taken a cold supply off before the pressure reducing valve to a bathroom mixer, because of the higher pressure it was passing/mixing back thro the hot and causing the valve to lift and pass, but i may be getting confused lol.......

 

[townfanjon]

^^^ yep i have had that, its a sod when it happens, you think you are going mad.

 

[Ryanmuz01]

Change the PRV, then that dismisses that. Then you have the nuisance of finding out what caused it, if it still passes

 

[Kevin D]

Is the diaphragm in the expansion vessel OK? Has it got mostly water on the air side? But I bet Rabbitman has nailed it.

 

[Millsy 82]

I seem to think i had something Simaler a long while ago where they'd taken a cold supply off before the pressure reducing valve to a bathroom mixer, because of the higher pressure it was passing/mixing back thro the hot and causing the valve to lift and pass, but i may be getting confused lol.......

Yeah I had something similar. I wasn't a happy bunny stood there with a new PRV in my hand and I still had water coming out of the hot tap when the water was isolated to the cylinder.

I should of guessed it as well as she kept saying the water didn't seem as hot as it was before.

 

[arran197]

I've piped in a secondary prv after the original as they don't make the same ones any more. So it now goes through the old prv and in to a new 6 bar prv I bought from the cylinder manufacturer. So it eliminates the prv being the issue. There wasn't any water in the schrader valve when I pumped up the vessel. When I turn off the cold feed to the cylinder, the hot stops running apart from a few drips. They have recently had a new bathroom. I wonder if anything is amiss in there? I need to find out if turning the pressure reducing valve down has stopped it. There's no gauge fitted anywhere, I would like to fit one.

 

[arran197]

Ok I've just had a call from the customer, it's leaked again badly. Wtf is the problem with it?

 

[townfanjon]

Arran , is the balenced connection used ?? The prv , do you mean the expansion valve ?

 

[arran197]

No, there's no balanced connection, the pressure reducing valve is downstairs on the cold mains for the whole property. No gauge. It's been fine for 15 years, I did some work on the cold and turned off the main, but that's all. They had a new bathroom, then the pressure relief valve started leaking. I recharged the expansion vessel. Put a new pressure relief valve in and re piped the pipework as it was poorly done. I turned the pressure reducing valve down and the leak slowed, but pressure is just too low.

 

[townfanjon]

Is the expanssion vessel connection definatly taken from the correct port ?
If its a flexi hose to the vessel, is it clear of debris, hard pipe in 22 is the best.
Is the check valve working correctly in the inlet control set, I have had them missing , jammed shut / jammed open .

Good luck

 

[arran197]

This is it.

 

[arran197]

Only the bottom pipe out the manifold now has a second prv and the discharge pipe is different.

 

[arran197]

So from left to right. Cold fill for cylinder, bottom is 6 bar pressure relief valve, top is expansion vessel, right is cold mains.

 

[townfanjon]

Have you looked inside the valve arran , that would be the next step for me,

 

[arran197]

In all honesty no I haven't, but to me it just looks like a block of brass.

 

[townfanjon]

Have a look in it pal, as said, check its there lol , and working. While the waters off check the route to the vessel for crud etc .

 

[arran197]

Ok. I think I have fixed it. I went via Screwfix and picked up a Honeywell pressure reducing valve. Took the old one out and looking inside, the rubber seat was all broken up. Fitted the new one, set the pressure and no more leak. Although the pressure on the top floor was not great compared to before, but it must have been 6 bar obviously! The new valve has a manometer on it so at least I can see what pressure we have in the property.
Anyway, I'm going to check back with the customer to make sure it's ok over the next few days. They're a family friend though so not much of an issue. I've learnt something new anyway.