In article ,
"Bilbo Baggins" writes:
My question relates to the pressure vessel for the central heating system.
The vessel has a pressure gauge and a water feed attached and my plumber
recommended that I have it set at 1 bar pressure. When the system is idle
the pressure is currently 1 bar and when it's in demand it's nearly 2 bar.

Is this correct or should I have it running at 1 bar ?

That sounds correct. 1 bar when cold will ensure highest points
in the system stay pressurised as long as they aren't more than
30' above the height of the pressure guage. Pressure always goes
up when system heats up. For most systems, it mustn't get to 3
bar, or the pressure relief valve will operate (would indicate
the expansion vessel is too small, or lost it's pressure).

--
Andrew Gabriel