Fitting external expansion vessel to sealed system

[Paul E]

Hi, I have an Ideal Combi 30, and my expansion vessel internal membrane has failed (CH is sealed system, and pressure drops overnight to zero, and water leaks from Schrader valve ) I have also discovered this boiler's internally fitted 8 litre EV is underrated for my 12 rad system.
When I fit the external EV (18 litre includes new filling loop, PRV and pressure gauge kit).

Should I blank off the union that originally connected to the faulty EV, or leave the vessel in the system as it is only leaking internally? I would prefer to blank it off if ok to do so.

I will leave the original PRV and pressure gauge in situ.

Thanks for any suggestions.
Paul.

 

[muggles]

You shouldn't be removing the front cover of your boiler, as it forms the safety room seal that prevents carbon monoxide escaping into your room, and the regulatory 26:9 checks need to be carried out by a Gas Safe Registered Engineer before the boiler is operated again.

You shouldn't need to cap off the internal boiler vessel unless it's actually leaking, but as mentioned above this is GSR territory on this boiler anyway.