Was losing pressure overnight and the outside pipe was dripping. I changed the PRV and it seemed to work for around a week. The pressure did drop to 0.7bar(green light) and the system still worked. After charging it will lose pressure overnight and go down to 0.6bar (red light)
Can someone let me know how to check the expansion tank side of the system, or anything that im not doing right - appreciate it

Alec, October 2009

generally vessels are charged around 1 bar / 10psi. they have a valve to connect foot pump too same as car tyre valve and if you press the needle you should get air(could be low/flat) not water out. water means split diaphragm. if flat you would charge to around 1 bar with pump while holding prv open. remove pump and close prv top back up system to 1-1.5 bar.

Before doing this you could just observe how it performs- top to 1 bar. set heating away and check pressure and prv in 30mins time. whats it risen to with expansion? 1-2 good 2-2.5 could be bit undercharged check again in 30 mins more, just monitor it. normal home with 8 rads i would expect from 1 bar cold a rise up towards 2 bar hot as a rough example.

ste, October 2009