basically it's the start and finish pressure that matter the cold standing pressure should be 1-1.5 bar which will slowly rise to 2 bar approx. when the system is hot if when you try to fill the system or when you switch the boiler on the pressure rises very very quickly then more than likely you have a problem with the feed to the pressure vessel or the vessel it'self re the warrenty if it was from vailent they can't void it ring Trading Standards up and get their advice the service company may be breaking the law
brian
April 2011