Pressure goes up by about 0.8 bar when the heating is on. No signs of leaks from radiator tops that I can see. pressure drops much more slowly whan boiler isn't used but I think it still drops a tiny amount. The other day the PRV was dripping at a pressure of 1.5 bar and the bloke who replaced...
I got charged £100 to get the pressure release valve replaced last week because we were losing 0.2 bar pressure per day. It's still dropping 0.2 bars a day!! One corgi registered plumber said it's most likely a problem with the expansion vessel and another has said it could be a leak but might...