why does boiler keep ejecting water from c/heating?

i assume you mean its coming out of the prv pipe, so whats the pressure gauge doing ? is it high cos its over filled ? or does it go from 1 bar to 3 bar rather quick ? if its the latter then the expansion vessel is at fault you might get away with just re pressurising it to 1.5 bar with a foot pump (once system is emty of course)

mark the gay boiler man
January 2009