After having been so impressed with this website over replacing diaphrams I was hoping someone could also help on another issue. I have to top up my Ace High boiler every 2 or 3 wks so obviously have a minor leak somewhere (although where is anyones guess) have put bowl under overflow to check that. But even when I have topped it up to 1 bar within a few days the pressure is zero when off and rises to around 2.5 to 3bar when on. My question is would such large variations in pressure have anything to do with the expansion vessel? Hope some one has similar experiences, thanks in advance.

Rob P, January 2011

yes expansion vessel has lost pressure or diaphragm has split.try draining boiler down and pump up vessel to one bar.repressurise and run boiler in ch.if pressure still climbing above 2 half bar it will blow off through prv outside.if so new cex required

DEANO RGI, January 2011