C.H. Combi Boiler Expansion tank u/s

The expansion tank on my sealed system combi has failed (water comes out of the air Schrader valve when pressed). Also the pressure changes massively depending on temperature; classic symptoms.

So I have the choice of having an engineer change the boiler expansion tank , behind boiler so he'd probably have to remove boiler from manifold to get to it. £££+

Or I could fit another remote expansion tank at a much easier location (pro bably under floor boards).

Question is would it be okay to leave the u/s exp. tank connected to the sy stem as its now full of water? Are there any side effects of fitting anothe r exp. tank and keeping the old one connected?

Its a Worcester 24i Junior non-condensing boiler.

Thanks

Reply to
simon mitchelmore
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of the air Schrader valve when pressed). Also the pressure changes massivel y depending on temperature; classic symptoms.

nk, behind boiler so he'd probably have to remove boiler from manifold to g et to it. £££+

robably under floor boards).

system as its now full of water? Are there any side effects of fitting anot her exp. tank and keeping the old one connected?

The existing one can be removed or abandoned and a new one fitted at a more convenient place.

It is theoretically better to remove the old one but people sometimes don't bother.

You will need access to the new one to put air in at some point in the futu re.

Reply to
harry

Don't know about that model, but replacement of the vessel was a real PITA on one of my previous combis (didn't even have decent access for testing).

I can't see *any* downside in leaving the old one in place and full of water, except perhaps that in the long term it could corrode through from the inside?

I've positioned my replacement underneath the boiler, in the relatively dead space just in front of all the main pipework. I fitted mine on a flexible hose so that it can be moved out of the way if required for access to stuff. I think it is worth having a service valve in the feed, and a drain valve, so that they can easily be isolated and drained for repressurisation without depressurising the rest of the system, as long as you remember to open it afterwards!

Reply to
newshound

...and ideally, connect it into the system as near to the pump inlet as you can, as the pump benefits from the pressure smoothing effect of the pressure vessel on it's input side.

Reply to
Andrew Gabriel

I've done this to another Worcester boiler (are they particularly poor pressure vessels?) with no problems. As for internal corrosion of the old one, I'm assuming that the inhibitor will protect, just as it does with the rads?

Charles F

Reply to
Charles F

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