my combi boiler makes a very loud droning noise most of the time it is on and you can hear it all around the house, i believe it is an airlock but the radiators in the upstairs rooms have no bleed points only the 2 in my living room... am i right for this to be an air lock or is it something else? and how would i get the airlock out?

katy, December 2008

depends on model - does it make a drone during hw demand? If so there is probably air trapped in the boiler - check to see if there is an automatic air relief valve that may be jammed

peppered, December 2008

most combi boilers have automatic air vents fitted which release air whenever it passes through them. Very often they sieze and it becomes very difficult to remove the air from the system without the vent working correctly. IF your problem is related to an air lock, you will probably need a new air vent

gasmandave, December 2008