CK
Never heard that one before. Usually it happens because a pipe is improperly supported, ie loose, when pressure is increased or decreased the pipes have a tendency to move and bang. Have you checked your piping to see if such a situation exists? If you find a spot or two try reaffixing the pipe or placing a piece of plastic between the pipe and the wood it is banging on, if you cant get plastic in there try a little dab of silicone. An expansion tank on the water heater should do the same thing. Your hot water heater will create a banging noise, if it is scaled up, when the water is being heated, just like an old kettle. You can open the drain valve on the bottom of the tank and flush the sediment out through there. Tip if the valve clogs, just hook up a hose to the drain and force some water into the tank to clear the blockage, then resume draining……….Lou
