On Jan 19, 3:30*pm, AmateurRob
wrote:
Thanks for all the replies - I'll try to address most of them with this
reply:

- System has not been emptied recently (other than a isolating a couple
of radiators when I've re-PTFE'd the rad tails) and I've been getting
rid of air for a few months now - can't believe there's that much air in
there!

- No leaks from pressure relief valve near expansion vessel - there's a
pipe that goes to a drain that's been dry the whole time.

- I've assumed expansion vessel is fine since (a) no water from air
inlet (b) only a small rise in cold-hot pressure change (0.1bar).

- Pressure holds all the time - it only loses pressure when I bleed the
air out.

- Got some inhibitor to add, but I wanted to make sure I'd sorted the
leaks before I added it (and then diluted it with refills). *Might add
that to eliminate the 'hydrogen' gas possibility.

- I suppose boiler leak is a possibility - I'm going to get it serviced
and will find out then.

- I'll re-bleed all the rads again to eliminate as much as possible.

- Can someone tell me what gauge pressure (in the cellar) I should set
so that my ground floor, 1st floor and 2nd floor rads are at the right
pressure (plus it's a Victorian house so the ceiling/height of each
floor is 9 or 10feet)

Thanks,
Rob.

--
AmateurRob

question....is the system ALWAYS under pressure?...even when idle?

it's hard to understand how new air could enter the system if all of
it is under positive pressure all the time?

Mark