I've just replaced the fan assembly and auto release air valve and pressure relief valve on my boiler and cannot get the pressure to remain constant since filling the boiler back up! I've bled the radiators, but am still having problems. I've filled it so it is just over 1 bar, then on use it can go up into the red area indicating the pressure is too high. Then when the heating is off, the pressure drops back down - any advice on what to check next would be appreciated?

Angela, January 2006

Cheers for the advice Mike

Seems to be running ok now - wonder whether it was air in the system that has managed to find it's way out via the automatic air vent?

Angela, February 2006

so long as your boiler pressure isnt going above three bar of pressure when running this is perfectly normal if your pressure drops back down to 1 bar when it goes off and stays at 1 bar then this is ok the pressure rises when the boiler is operating because when you heat water it expands thus giving a greater pressure in the heating system hence your gauge going up when it cools it contracts back to its original state hence the drop back down in ( a nut shell your boiler should be ok )

mike, February 2006

Andy - you offered advice about the pressure vessel - excuse my ignorance, but what do I need to do with it???

Thanks Angela

Angela, January 2006

expansion vessel.

andy, January 2006