Can anyone help me, newbie to forum I have recently changed the bathroom basin taps and since then I have appeared to to have developed what they tell me is water hammer, but this also occurs when the tap is open and water is flowing, not just on turning tap off, if I turn bath tap on I can stop the banging but just the basin tap has to be right open to stop it. This only occurs on the hot tap. I have no clue on what to do next. For info I have a combi boiler hot water system