What could be causing my Potterton Performer 28i to lose pressure?

you have a pressure relief valve prv which may be dripping and causing boiler pressure loss look outside the house somewhere near the boiler there should be a15 mm pipe with an open end which will be wet or dripping if im right you willneed a prv id call an engineer you may also need the pressure vessel pumped up and you may also have crossleakage beetween the heating and hot water

john
January 2010

look outside and check the pipe isnt dripping

b
January 2010

The pressue goes to around 2.5bar as when on heat but when the heating switches off the pressure drops to 0bar meaning it won't turn on again automatically.

nick
January 2010

does the pressure go over 3 bar

b
January 2010