On Sat, 31 Dec 2005 22:33:51 GMT, wrote:

If the pressure is rising rapidly when heating, then it is likely that the
pressure vessel has lost charge. It's easy to check but the system needs to
be cold and not pressurised. You will require a pressure guage (car type is
adequate) and a foot pump or similar to re-charge. About 10psi (0.7bar) is
normal.

Heh... That's actually the *first* thing I did!

It does pressurize quickly, so the amount of pressure in the expansion
vessel could be wrong, but there was plenty of pressure in there when
I tested it. I will try to find out what the pressure should be for
the boiler and make sure it is correct.

It also leaks when the pressure is well under 2 bar (the maximum it
gets to), and I believe for this boiler the pressure relief valve
opens (or rather should open) at around 3 bar.

I *think* it is slightly better since I tweaked the valve yesterday. I
shall try it again later, but I suspect it needs replacing anyway.

Thanks,

Andrew