If the pressure has totaly dropped and preventing boiler to fire again after the boiler has been in use, The problem indicates that there are expansion issues with your boiler, when the pressure has dropped to 0 look down the back of the boiler and you will see a red expansion vessel, (you will have to go in from the top) remove the cap and check the pressure with a tyre pressure gauge. if the pressure in the expansion vessel is not 1bar- around 14psi then the vessel will req re-pressurising with a foot pump to 1bar- an indication of this problem is the pressure relief pipe outside the house will run when boiler in operation
chris, February 2007
