How can I stabilise my Worcester Bosch 35CDi combi boiler pressure?

my boiler is losing pressure from under neath the boiler but only when it is running. the water is coming out a white plastic piece and a enginner said there was a part missing

steve edwards
November 2009

first check there are no leaks on your system. do this by shutting off the isolation valves on your flow and return under the boiler. note the pressure and leave for an hour. if the pressure drops during this time you have a leak at your boiler. if there's no drop open the isolation valves and if it drops then you know the leak is on your system. if you had to top up your old boiler once a month I THINK THE LEAK IS ON YOUR SYSTEM.

PAULGASMAN
November 2009

I have exactly the same issue and my boiler is only 4 years old. I am constantly losing water out the overflow pipe an can't stop it

steve, kent
October 2009