When my boiler is used just on hot water in the summer the boiler pressure remains constant. But as soon as i use hot water and central heating the pressure falls and i am having to top up every evening to ensure i have heating the following morning.
Any suggestions would be appreciated

Peter, December 2009

Thanks, just checked and valve is leaking going to order one now.
Many thanks for your help

peter, December 2009

if you need to top it up every morning. this will be either you have your bioler pressure above 1.5bar and when the central heating is turned on the expansation vesal pressure rises and above 3bar. releasing pressure outside. Or more likely the safety valve is opening eariler than 3Bar and dumping water outside. TEST turn the central heating on full view the pressure on the gauge and need to go outside where the overflow for the central heating is view. if this dripping Replace safety valve.

S.Khan., December 2009