Hi, Went downstairs last night and noticed water on the floor. It was dripping from the bottom of the boiler. Took cover off and identified the source of the problem. The black plastic piece that attaches to the auto-air valve and supplies the hot water to taps has a tiny hole in it and a very fine spray of water is coming out. The hole is in the body of the plastic and not at a joint. Has anyone seen this before? The boiler is about 4 years old and I don't know what the deal with the warranty will be. To me, a fixed piece of plastic shouldn't develop a leak - it's almost as if the plastic has corroded from the inside. All our water is off at the moment. Can anyone advise on how much it would be to replace the part (I don't know specifically what it's called - as I said above, it's black plastic in the bottom left of the boiler and supplies the connection on the manifold with a picture of a tap). Also, can anyone advise if this should be under warranty? Many thanks in advance.