On 31 Jan 2005 03:04:36 -0800, "kmillar" wrote:

I've just had a completely new system installed. The boiler is a BAXI
'System' 35/60 with pump and expansion vessel built in. We have 6
Radiators plus indirect cyclinder and a 3 way valve.

Its not critical but your sealed system should be about 1 bar or so
when cold and between 1 and 2 when up to full temp. If there are no
leaks present then the key might be that its a new system. When new,
the system has been filled with oxygenated fresh water,,obviously
there is some settlement and so the pressure drops back a bit,,top it
up when cold to read 1 to 1.3 bar. Observe it over a few weeks and
ensure that the cold pressure remains the same. If not,you probably
have a very small leak somewhere.

By the way,the pressure varies with temp simple because hot water
expands and occupies a greater volume. As yours is a sealed system,it
has nowhere to expand to apart from into. The expansion vessel takes
up most of the expansion but some pressurisation does occur....

joe