The boiler is a Baxi Maxflow Combi WM gas fired wall mounted combination boiler with unvented hot water storage. I regulate the heating by the individual thermostat on each radiater. It seems that when I alter the thermostats or bleed a radiater which has a lot of air in it.the pressur drops, resulting in no heat or hot water.There are no leeks in the pipework. The boiler is about 4 years old.

Jo from Glasgow, January 2008

Hi Jo, the pressure in your boiler is regulated manually via the filling loop at the base of the boiler. Should you vent air from any radiator this pressure will drop according to the amount of air or water you take out of the system. This pressure has to be replaced via the loop.

Linwood BTU., January 2008