My central heating is a sealed system which seems to lose pressure. There doesn't appear to be dripping from the pressure relief valve outlet. When I add more water to the system the pressure increases, but drops again after a while - a few hours. I have used some Fernox F4 superconcentrate sealer but the situation persists. The central heating appears to work normally, sometimes with a bit of vibration noise from the boiler, but otherwise normally. There are no obviouse leaks anywhere. When the gauge indicates zero pressure the system seems to work normally.
The system has worked like this for some years. It was new in 1999. I top it up every so often from the inlet pipe in the airing cupboard. It was looked at in 2003 by a plumber when the pressure relief valve, pressure gauge and pressure vessel were all replaced.
Maybe this is an indication fault? But then why would it indicate increased pressure when water is added? Maybe there is a small weep leak from a pipe behind the plaster wall? This would drip down to the ground in the cavity between the plaster walls. The Fernox F4 (2 tubes) was added over a week ago so it should have taken effect by now.
Should I be bothered?
The system has worked like this for some years. It was new in 1999. I top it up every so often from the inlet pipe in the airing cupboard. It was looked at in 2003 by a plumber when the pressure relief valve, pressure gauge and pressure vessel were all replaced.
Maybe this is an indication fault? But then why would it indicate increased pressure when water is added? Maybe there is a small weep leak from a pipe behind the plaster wall? This would drip down to the ground in the cavity between the plaster walls. The Fernox F4 (2 tubes) was added over a week ago so it should have taken effect by now.
Should I be bothered?