"Christian McArdle" wrote in message .net...
As for the pressure gauge, the water in the system will expand considerably
when hot. This would cause a rapid pressure rise, but is absorbed by the
expansion vessel instead. This is usually sized to limit the pressure rise
to around 0.5 bar or less. When cold, the system should be pressurised to 1
bar. So, next time the system is cold, attach the filling loop hose and
increase the pressure to 1 bar. Don't forget to disconnect the hose
afterwards.

Christian.


Chistian,

Thanks for your comments. I suspected much of what you said as it
makes sense. I can easily refill the system to 1 bar, the plumbers
fitted a pipe with two taps under the boiler to make this easier.

Thanks
Andy