Using just hot water there is no problem and central heating working fine but each time I switch the heating off the boiler pressure drops to zero and I have to repressure before being able to use heating again or get hot water.. Getting to be a bit of a pain now its getting colder and the heating is on often. Please help.

mairi bell, December 2007

Try recharging expansion vessel, look for any leaks on system.

Big A, December 2007