Air in combi boiler hot water system

Hallo Pete The combo boiler, works on higher pressure, and is sealed. If air is trap into the system normally you can feel a "Watering" noise where the air is trapped. Normally the pump inside the boiler is capable to circulate the air around, and about 1-2 days, this air should be able to reach the top of some radiators, which you should "Bleed" with a radiator key. Very often, when the boiler is commissioned, some air could get trapped into the pump, but normally the pumps are fitted with an automatic air vent (which looks like a bicycle valve) where the little screw cap should be released. The other place where air tend to be trapped is into the Sludge Filter, (Magnaclean Type) but you can released the air from this device in the same way that you would do for the radiators. I hope this will help you. If not feel free to contact me. Tiziano Perera MA4 Plumbers