Water Hammer

Water Hammer or rhythic banging in a pipe system can be annoying and can even result in a ruptured pipe. Our experts offer a couple of opinions:-

Waterhammer. The advice offered concerning the 'turning down the stoptap' to stop water hammer is incorrect.

Modern water supply pressures are usually greater than that of yesteryear and chattering of ballvalves etc is normally due to high inlet pressures acting on shut off valves, which can lead to excessive resonance in pipework.

Contrary to the advice given, stoptaps are isolation valves only - not regulating valves! Only the water flow is affected by regulating the stoptap. The pressure in the outside water main is variable but once any taps or outlets are shut off in a property, water pressure will increase to the water mains standing pressure. It is this increase in pressure which can lead to water hammer (banging in the pipes)

The obvious answer is firstly to make sure that all mains service pipework is properly clipped and secured and secondly, an in line pressure reducing valve will cure the problem in a flash.

If you still have a problem contact a properly qualified plumber who will give you proper and professional advice.

Hope this helps and you can have this advice on me for free! -- Kevin Humphries

RE: Water Hammer.  Having read one of your tips on preventing water hammer of which the cause is usually a worn ball valve in cold water storage tank, the resultant hammering is caused by unsupported pipe work (cold feed) next to the storage tank. Usually the plumber can’t be bothered to do the job properly but a couple of 15mm pipe clips attached to suitable battens placed near the tank will stop the hammer. Additionally a new ball valve assy, make sure the rising main to tank is turned off first before changing ball valve.  .. peter wells