Hi folks, new to the forum but if you can help.I have had my Lynx 2 for 15 years and it’s always had a slight leek, never found it. I top it up occasionally but the gauge always sits on the border between green and red at about .5 bar. Recently I have had a problem, only with CH not HW, sometime immediately when the boiler start the pressure gauge goes through the roof. The boiler sound like its having a fit, some banging, and then I get a whooshing sound and the gauge drops. Then amazingly the boiler starts. I think the PRV is kicking in but not sure and I don’t know what causes the rise. Also the fault is intermittent. However I have found a way of replicating the fault. Turn boiler on from cold CH, then turn off after 30 seconds, turn on again and the gauge rises to above 3 (within ten seconds) then then drops and then the boiler kicks on. Naturally this plays havoc with the gauge pressure. Recently I topped it up to 1 and ran the boiler, the same thing occurs, even bigger whoosh and no the gauge is not registering any pressure at all, nothing! But boiler functions normally. This only happens on cold start and not when the boiler is running. Any help appreciated.