Very low pressure but boiler appears to work fine

[pinn73]

My Baxi 105he consistently loses pressure, despite me having a plumber into check radiators and repair a leaking valve. The pressure drops to about 0.3 and remains there. The CH and water all work fine, albeit the boiler is lightly noisier.

Is this harmful to the boiler or not?

Thanks

 

[bellairaphon]

Check the expansion vessel. And yes the system pressure needs to be around 1.5 bar.