I think there is a small leak somewhere in piping. Usually gradual reduction in pressure, but not used Heating since April/May. Have had the system flushed\ with a sealant about 3 years ago by a plumber.
The repressurising knob no longer works, it has lost any grip to turn and open the valve (The Main key is still OK) Can I get this unit replaced or is there a way arounfd the problem. The pressure gauge is currently zero so I'm not using the central heating at the mment. Thanks