I have a Worchester 350 which is 15 years old. I keep my pressure gauge at 1bar when the boiler is off and the boiler has been running fine, recently the pressure goes up to 3bar on the gauge when the boiler is running then the pressure regulator opens and dumps water, when the boiler goes off the pressure on the gauge is now 0.5bar. Is this ok ?

John Carson, November 2009

Yes, check your expansion vessel - I had exactly the same problem and re-charged the vessel with a car foot pump and all is sorted. Don't know where the original air went to though................?

Johnjohn, November 2009

check your expansion vessel

sean, November 2009

your heat exstager is leting water from hot water side to heat side so replace it.

gas man, November 2009