i have a baxi 105e and even with the boiler turned off, it keeps overpressurising and lifting the safety valve. ive checked the expansion tank and the bladder pressure is 0.5 bar, which is correct according to the manual. it was suggested that it may be the hot water plate heat exchanger but i cant see how water gets into the heating circuit, could someone please enlighten me. much appreciated.

joshua maher, May 2009

CHECK THAT YOUR FILLING LOOP IS NOT LETTING WATER BY.IE MAKE SURE THAT THE LOOP IS DISCONNECTED

BRIAN, May 2009

un do your filling loop and c if it is passing water from the mains into the heating circuit if it isnt it will be deffinetly your plate heat exchanger

plumbbob, May 2009