Rought cost to replace an expansion vessel

[playford]

Hi All,

I'm hoping you could help me out.

I'm having an issue with a plumbing insurance company. We have had a leak for a couple of months now, they have been out and replaced a TPRV as the leak was coming from the tundish. we have now realised that the expansion vessel is broken and the engineer thinks is may have a puncture so needs replacing.

We have been told that the quote for the replacement is £300 for the replacement part and labour, this includes a drain down. When the TPRV was replaced, the engineer said it doesn't need a drain to replace the TPRV and the expansion vessel is higher than that. Does this sound like a very expensive quote to you, it's a 12 litre vessel that I beleive can be purchased from Screwfix for around £50 to £65.

Apologies for the typo in the title, I can't change it

Many Thanks
Mark

 

[snb]

You can only work on unvented cylinders if you hold a current G3 qualification.

 

[MeldrewsMate]

TPRV? Temperature and pressure relief valve? This would be fitted to your unvented hot water cylinder, so would not require a heating system drain-down.

The fitter will have to collect the vessel and bring it to you, and that won't be for free.
Following the (partial) drain-down the fitter will have to top-up the inhibitor concentration in your system. That doesn't come for free.
His/her labour won't be for free, neither will the cost of any call-backs if there are any minor problems, post-repair.

You have given no details of your boiler, nor of your system. We have no details of the expansion vessel that you wish to replace. Is it enclosed within the boiler? Is it external and visible?

Was TPRV also a typo? TRV? PRV? Each puts a different slant to the story.

PS: An expansion vessel does not need replacing if it MAY be punctured, only if it IS punctured.

 

[playford]

Apologies, I wasn't sure how much info you would need for a vessel replacement.

The boiler is a viesmann boiler but only runs on one part of it, the central heating part.

In the pic is the vessel and the bottom left is the TPRV, this is what the plumber told me when he replaced it. He said he thought the vessel was punctured and he would replace it. I can't see any markings on the vessel but I know it's a 12 litre one

many thanks
Mark

 

[Mottie]

If it’s an insurance job, why worry about the cost?

 

[playford]

The issue is they are saying they won't pay out for it as it was only a recommendation to replace the vessel even though the plumber left with water leaking out the top at a good pace.

 

[MeldrewsMate]

That white vessel is a bit camera shy, but the photo clears up many questions.
It's a potable water expansion vessel, they are more expensive than the red heating expansion vessels.
There is no need to drain down neither the cylinder nor the heating system.

The fitter will still have to source and collect the vessel.
It'll take less than an hour to replace it.
You're in Central London, so it'll cost more, but £300 seems like a high price. Only you can say if it's excessive.

 

[MeldrewsMate]

The issue is they are saying they won't pay out for it as it was only a recommendation to replace the vessel even though the plumber left with water leaking out the top at a good pace.

Was it the water leaking at a good pace, or the plumber leaving at a good pace?

 

[ianmcd]

The white expansion vessel is for the unvented HW cylinder, nothing to do with the heating, nothing needs draining, simply the water supply is isolated at the cylinder and the lowest hot tap opened, that is IF the expansion vessel needs replacing, most just need charged correctly

 

[MJN]

A punctured vessel diaphragm will manifest itself in water leaking out of the valve (schrader valve on the top). Press the stem in the middle - if water comes out then it is indeed punctured, if nothing comes out then the air has leaked out, if some air comes out then it might still need repressurising (with a bike/foot pump). To do this, turn the water off and open a hot tap (keep it open even after water has stopped coming out). The instructions for my cylinder say to pressurise it to the static water pressure less 0.2 bar. In my case that's 1.8 bar.

 

[ianmcd]

water comes out then it is indeed punctured,

really ?

 

[MJN]

really ?

Yes, but given your post count I'm assuming you don't need it explaining to you! Perhaps you could elaborate on your question/concern?

 

[ianmcd]

could just be condensation within the vessel, the correct way to test is, remove system pressure with a drain point left open, close the drain point when nothing more comes out, remove shraeder valve insert , re-pressurise system until all water and air stops ,install a new schraeder valve insert then open drain point and re-pressurise vessel, you will know instantly if the diaphragm is punctured, pressing in the insert tells you nothing

 

[MJN]

I can't imagine a scenario whereby condensation could accumulate in such a quantity as to be mistaken for a ruptured diaphragm but I bow to your experience (I just have a expansion vessel - I don't work on them or anything related!) so if your method is the correct way then Mark should heed that advice, even if it does seem a bit long winded to me.

 

[ianmcd]

I can't imagine a scenario whereby condensation could accumulate in such a quantity as to be mistaken for a ruptured diaphragm but I bow to your experience (I just have a expansion vessel - I don't work on them or anything related!) so if your method is the correct way then Mark should heed that advice, even if it does seem a bit long winded to me.

I have a contract of flats with Un-vented HW cylinders and whe I am there , I do 10 a day servicing them and this is part of the service, this is the service procedure that the manu insists on, who am I to argue ?