I set the water pressure on my brittony combi se at 2 bar and when the heating is on the water pressure expands over the blow off limit of 3 bar . When the CH is off the water pressure settles below 1 bar which wont allow the boiler to function, and new water has to be added to get above 1 bar and start up the boiler. The gas fitter I use has within the last couple of months fitted 2 new water pressure release valves but to no avail . Anyone any ideas?

Peter Lawn, November 2006

no pressure in expansion vessel. open the schrider type valve (if spelt correctly!!) on the vessel, if water comes out then new vessel needed, if air comes out then needs pressurising.

gavgas, October 2007

check the expansion vessel!!

me, December 2006