we have been getting highpitched noise from our loft when using shower etc just looked and found overflow tank empty apart from some sludge at bottom is this normal?
I think you mean the header tank, Terry...in your loft there could be 2 tanks - one large one is the domestic water supply to the hot taps, the other small one is the flow and expansion tank for the central heating. Anyway, the large one should be full - the smaller one should have about 4" of water in it. I guess the ball valve in the large tank has stuck shut.
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