For the system to lose pressure there has to be a leak of some sort within the presurised portion of the installation – there is no other alternative, especially if you have to bleed air out as well – for air to get into a closed system there has to be a source. Check all your valves etc, if that fails then call in an expert to test and locate the leak for you.
Selgas Services Ltd
Craftsman Gasfitters, Plumbers, Electrical Service Technicians