Location of External Expansion Vessel

[DarrenSL]

Hello all.

My combi boiler EV is bust (water coming out when valve is pressed and pressure building until prv releases). I'm planning to install an external EV but just need to be sure I am installing correctly.

I will be cutting into the flow return (left most pipe in photo) and installing a tee just beneath the boiler. Ideally I would fit the EV lower than the Tee but as you can see there isn't enough room for a 12ltr tank. If I fit it on the wall next to the boiler I expect there will be air trapped between the EV and the system. Does this need to be avoided?

Thanks

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• DarrenSL
• 2 Dec 2012
• 1

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[CBF]

it is normally fitted on the ret if that where the pump is, not the flow

 

[The831Bunny]

Have you tried re pressurising the vessel?

 

[DarrenSL]

I've assumed that because water is coming out when I press the valve that the diaphragm has gone. It might work for a short while if there is just air in the EV but I expect it'll need replacing at some point.

Yes, the pump is on the return which is the left most pipe.

My concern is whether the EV will work if there is trapped air on the water side of the tank. I suspect it'll be ok but just want to check with the forum first.

Thanks.

 

[denso13]

I suspect it'll be ok

Yes that's ok.

 

[neiltheplumber]

I would still try re-pressurising the vessel first, just because water comes out doesn't mean it's knackered. It can be condensation in the bladder, there could easily be one litre of water in there caused by condensation!