Had an a new vaillant ecotec fitted about 9 months ago since it was fitted i get a puddle of water on my patio pretty much daily which is dripping out from the flue, anybody know why this is? I have a black telescopic flue which comes out from the wall then bends up to come away from the guttering, next door have a standard White flue that comes out from the wall an does not drip at all, thanks