URGENT Do I need a expansion vessel fitted to my system

[Paul Jay]

I have just had a water meter fitted and since been told I need a small expansion vessel fitted to my domestic hot water system as the meter will have a NRV in. I have also been told no I don't as my boiler is over 10meters away from the meter and any expansion will be taken up within the pipework, aproxx distance boiler is from meter is 20 meters. Boiler is a Worcester Greenstar Cdi combi. I would be grateful for any help with this question as i am now regretting having this meter fitted, Thanks.

 

[Chuck]

It's in the WB installation instructions under 'Water Supply', e.g.:

"Where the mains water supply has a non-return, back flow prevention valve fitted, a mini expansion vessel (A) should be connected to the mains water inlet pipe (B) between the non-return valve (C) and the boiler (D) as shown opposite."

To reduce the potential for damage and leaks caused by overpressure, I suggest you don't use the 'pre-heat' function on the boiler until you have a mini EV installed.