i can use the hot water all day long and pressure stays same... i put central heating on and it works perfect, pressure rises slightly which i believe is normal but when i turn heating off the pressure drops to nil within half hour and i have to put pressure back into it to make it work... what does this mean?
I know i will need to get someone out but would like a rough idea of why its doing it and how much its going to cost?

christine, October 2012

Look for leak if OK see no water drip from pressure valve if OK than pressure vessel need pump up to .75 bar when empty or refer to boiler manual

ltd, October 2012