Stopping Water Hammer

When shock waves pass through the water in the domestic system as the flow is turned off and on, this may cause a distinctive and irritating sound known as water hammer.  It can be caused by a number of things, including the water flowing too fast in the system, worn jumper units in taps or stop valves, faulty ball valves or loose spindles.

An initial step in getting rid of water hammer is to close the main stop valve slightly.  If this has no effect, another cause of the water hammer might be the float of a ball valve bouncing up and down on the water as a cistern fills up.  You can easily correct this problem by fitting a damper to the float arm in the cistern; even an empty yoghurt pot hung in the water with its open end uppermost would be ideal.

If the case is severe, the rising main could be continued above the level of the storage cistern ball valve and ended in a capped-off pipe to form a shock-absorbing air chamber.

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