On Wed, 28 May 2008 21:48:56 +0100, A.Lee wrote:

Pressure was a little low, so fill up to the recommended 1 bar. Tap is
shut off.
Heating comes on fine. 20 minutes later, I'm outside and hear water
running - the pressure relief/overflow from the boiler is spewing out a
bit more than a trickle, but less than a hosepipe, of hot water.
Back inside, turn off heating. Notice pressure guage now at 4 bar, hence
the pressure relief.
First thought, air in system, though bleeding all the rads doesnt
produce much air - typical of what I'd expect after not being done for 6
months.
Pressure now down to 2 bar when it is cool.

http://wiki.diyfaq.org.uk/index.php?... sure_dropping

(or go to
http://wiki.diyfaq.org.uk/index.php?...Heating_Repair
and navigate to section "system pressure dropping")

--
John Stumbles

I used to think the brain was the most interesting part of the body
- until I realised what was telling me that