My ideal logic combi boiler has recently started making a swooshing noise when it I turn on the central heating. The noise can be heard outside from the flue and water pours out every intermittently. When the boiler reaches temperature this stops. It also happens when I turn on the hot water tap although not as much. Prior to this happening we had a blockage in the drainage pipe from the washing machine/sink and had to get a plumber out to unblock it. This is when the noise started. Since then I have had a heating engineer out twice and they have checked for a blockage in the condensing pipe. He said this seems fine and does not know what is causing the noise and the water from the flue. I understand water should not be pouring from the flue and there must be a problem with it. I would like to get to the bottom of this as I don’t want it getting damaged and breaking in the winter. Any advice would be much appreciated.
