Expansion vessel unvented cylinder

[Matt887]

If you go to a prv dripping and cold water expansion vessel has no charge. Do most people recharge? We have to depressorise and remove to do that. So it it easyier to just fit a new vessel ?

 

[Madrab]

Nope - dead quick and easy to re-pressurise with the correct type of pump, though if it is a remote EV (not an in cylinder baffle type) then it should really be done at service time by a qualified Unvented chap.

 

[Matt887]

Thanks yes I have my G3. Have a pump etc. is a remote vessel yes. It needs removing ideally to repressure it

 

[Madrab]

It needs removing ideally to repressure it

As long as you can get the connector from the pump to the top of it then it should be able to be done in situ, I have a stirrup type pump that has a 3m hose on it for exactly that kind of thing. if not then it's a drain down and remove.

Don't forget to balance out the pre-charge to the mains pressure and expansion etc.

 

[Matt887]

Would be 3 bar, as 3 bar pressure relief

 

[Johntheo5]

A stainless steel UV cylinder with its pressure reducing valve set to 3.0bar (or a recommended 2.8bar) and a EV sized to 10% of the UV cylinder's capacity will have a final pressure of just over 4.0bar if fully heated from 5C to 65C, its expansion relief valve might be typically set to 6.0bar and its T&PRV set to 8.0bar, example, below, of final pressure.