Hi All, Can anyone help. The water prssure gauge on my Greenstar 30Si continually goes to 0 prressure whenever the central heating stops. I've had the RCI installer return 2 times and he doesn't seem to be able to solve the problem. I am on normal water supply - Severn Trent in Birmingham. One time the Installer bled the system and introduced a sealant - that has not worked. He thought one of the rad may have a leak - they were all sound. Anyway if that was the case surely the sytem would run dry during operation. Anyone got any clues about what it could be - is there an issue inside the boiler mechansim and valve which could be causing the issue.