Hope someone can help me - just having the bathroom re done and the rad replaced - now leak coming from valve directly behind pressure gague with a red cap on it, seems to leak alot more over night when heating is off - turn on heating and pressure is up to 3 bar, have read alot here about recharge expansion vessle - but have no idea what this is or where or how to do - manual gives no instructions or idication or help, any assistance would be greatly appreciated.

Hellsbells, February 2008

Thank you Tony - I have printed out and will have a go!! thanks a mill.

Hellsbells, February 2008

On a system boiler such as a prima the system presure when cold need only be 0.5 bar the leak you have is from the presure release valve due to system over filled or as you mention expansion vessel requires re presurising ,you also have the problem now that the presure release valve is now leaking and will probably required replacing as they do not reseal very well
so firstly purchase new presure release valve which if right behind presure gauge may be combined fitting but not that expensive at any rate
Than turn off system and open existing presure release valve letting out system presure and water keep this valve open , go to your expansion vessel this is usually the red tank you will see on top maybe on bottom a connection that a car tyre pump can fit onto ,it may be covered by a plastic cover
Fit foot pump and pump up to 1 bar whilst doing this make sure presure release valve is still open this allows vessel to be reprimed correctly indeed as you pump it up you may find water being pumped out presure release valve
once this is done remove pump replace cap and replace presure release valve unit refill system to 0.5 bar only and away you go

tony, February 2008