How to replace an automatic air vent?

Thanks JD. If I succeed with the replacement, is it normal to set them by opening them up slightly?

Roger
January 2009

well if it was me id bung the header tank, if its an open vented system, should be a small black tank in attic or highlevel somewere, if you dont have bungs then turn the valve of to the tank and drain system down, to below the level the air vents, you may have top open the motorised valves manually, to drain the system, once u repair the air vents, turn the tank back on and allow the system to fill back up, you will most likely have to bleed the radiators, let the new AAV's do there job

jazz drummer
January 2009