Expansion Vessel Replacement - is it easy?

[skenk]

I have had a plumber round to look at an expansion vessel for an unvented cylinder in a rented flat I look after for a friend. It's leaking from and around the pressure release valve.

I thought it would a fairly simple job to replace and re-charge but he's telling me the part is obsolete for that model and he's not been able to find it so far. It just looks like a normal cylinder with an expansion vessel mounted on top to me.

The current EV looks like this: http://www.screwfix.com/prods/43809...-and-Accessories/COMAP-Expansion-Vessel-25Ltr

Is he trying to pull a fast one or are EV's for Heatrae Sadia Cylinder's hard to come by? (sorry don't have a model no).

The cylinder does feed a bath so I thought maybe the EV should be white, although the current one is red?

Any pointers/advice would be greatly appreciated

 

[Boilerman2]

No the vessel you have found is only suitable for Heating or Cooling water applications if this vessel id fitted to an Un-vented HW cylinder the vessel MUST be suitable for POTABLE water they are usually White in colour these days, however only a competent person with a G.3 Unvented certification should work on one of these installations

 

[powell30]

G3 installations need to be serviced annually by a G3 certified engineer.

These things can be bombs if not maintained/installed correctly.

 

[skenk]

The guy is gas-safe don't know if he has his unvented ticket but from reading on here i'd have thought he'd be competent enough to swap an EV. I will tell the landlady it needs an annual service in future. Is there a website which lists 'G3' qualified folk, like the gas-safe website for gas guys?

Guess it needs something like this? http://www.advancedwater.co.uk/prod-634-147-0252.html

Is there any reason an off-the-shelf EV like this would not be suitable?

I'm just trying to get an idea of the complexity so if he hit's me with a huge quote I can tell him where to go. He's already fitted a hob for me and wanted to silicone it it because he didn't want to use the plasticine so i'm a bit wary of him. I've used another GSR plumber before but he's away at the moment for a family funeral . . .

Sorry for all the questions thanks for the help so far

 

[ChrisR]

It's leaking from and around the pressure release valve.

But that isn't part of a pressure vessel, it's a separate bit.
If the old PV is red, are you sure it's not on the heating? Could well be.
Is a picture possible?

I've never seen an original PV on an unvented which was red either.

I can recommend Rannoch Services, based Bearsden.

 

[OLLIE20]

The red vessel is for CH not Domestic side as said by the lads, do you deffinately have another one for you cylinder, is it not a bubble top??? Did he try 2 recharge the vessel, or check if the PRV or T&PRV were passing, as this is not uncommon, as far as i am aware aslong as its suitable size and type (white) for domestic its ok to fit, they all work the same

 

[skenk]

Ok so just had a look and it seems I do have a photo on my phone

View media item 26854
Turns out it's not red, it's blue On the top (of the blue thing) there is a big dimple with a valve - looks like a car tyre valve. This is leaking from the actual valve and also from the base/seam where it joins the vessel (is this dangerous?).

This is the only cylinder in the property and the only source of hot water. Heating is all electric underfloor.

I guess it doesn't look quite like a normal cylinder, only just realised I had a photo. I was leaving it to the plumber to sort it out but reckons he can't get the part??

 

[OLLIE20]

Yeah that is your doemstic exp vessel, if its leaking from the schrader valve (car tyre like one)

you can remove it with a special schrader remover tool and replace it,

if its leaking from there, vessel mat have gone, but they do get condensation in them and it can be an awful lot litres of the stuff

If its leaking from connection just remove and seal using ptfe or washer depending on connection

If you take scrader valve out empty water out of it, fit new valve and recharge to what it says on the pressure reducing valve or just under as 0.1 bar under , refit and test

If it works, sorted if not replace entire vessel, they're not that dear

I take it its all electrical

 

[skenk]

thanks Ollie

Yes, no gas in the building.

So, as I thought, the worst it gets is replacing the EV. I swear he (the plumber) was on about having to mount the EV elsewhere because it wouldn't fit but not even being able to find one as it wasn't made anymore. . Is there any way to easily check if it is just condensation? If I put a pressure gauge on the valve it should read about 3bar, correct? I've no intention of swapping the EV over myself and don't really want to start messing with the valve either. I don't have a pic of the top but I'll be back at the flat next week. Is there any immediate danger from this? The tenants are still using the hot water.

 

[OLLIE20]

Well an expansion vessel is an expansion vessel mate, aslong as its for the domestic he can fit it, it looks likea standatd 3/4" tapping from the pic, so i cant see a problem with fitting a new one

3bar is correct if thats what it says on your pressure reducing valve on the incoming cold main 2 the cylinder

Its not dangerous to keep using, unless someone is stood under your pressure relief pipe out side, then they might get wet and burnt, other than that, no

The guy from what i can see in the pic and what youve said, eother doesnt know what he's talking about, or is going down the line of talking you into a new cylinder, is he qualified makesure he is, and if poss just get someonce else to do it, your paying, if you aint happy with him, blurt him

 

[skenk]

Thanks again mate, will be contacting someone else for the job

cheers
tim