Water hammer after kitchen mixer tap change

[Andy165]

Changed a kitchen mixer tap (washer type) to customers new ceramic disc mixer tap and am now getting water hammer in cold mains supply pipe. Have installed "Hammer Arrester" close to mixer tap which has helped a little. Also put on a Pressure Reducing Valve but it made no difference. Existing pipes buried in kitchen wall behind units, stop tap in street quarter turn type. Any sugestions for remedy before customer drives me nuts. Have looked at other threads on water hammer but they offer no extra advice/ solutions.

[Elkato531]

If, as you say you've already fitted a hammer arrester the problem is probably due to the pipework being insufficently clipped where you can't get to it.

I assume that you've fitted the tap the customer wanted and done what you can to alleviate the hammer problem. The fault is not with the work you've done but with the pipework. Unless they want you to start pulling apart their kitchen, they may just have to learn to turn the tap off slowly.

[compheat]

Try turning down internal stop tap.
The pressure in my own house is approx 6bar and when stop tap is on full i get water hammer but if its turned down slightly its ok.

[Andy165]

Thanks for the replies. The internal stop top does not control the cold main pipe to the kitchen sink. The lead pipe branches off under the solid kitchen floor before the stop tap, and then somewhere behind the units joins onto copper.The kitchen tap cold feed has to be isolated by the roadside stop tap (quarter turn). Odd I know, but the house is about 70 years old.

[Whitespirit66]

I had this problem after changing a customer's tap once. Turned out it was the washer in the stop tap that had broken up. The metal stop tap jumper was moving and banging when a tap was turned on or off.

The stop tap washer must have broken up when I used it to turn the water off. Just a thought.

[JayJay1978]

Did you fit any isolation valves on the kitchen tap?

Trouble is they are not designed to reduce flow and increases the water 'hiss'.

I read somewhere that fitting a non return valve on the pipe underneath the tap would halt the 'shockwave' and stop the water hammer. Does anyone know if this is true?

Was the shock arrester like this one?

http://www.toolstation.com/shop/Plumbing/Valves/Potable+Water+Shock+Arrestor+12+MBSP/d20/sd2696/p93058

[Andy165]

Kitchen mixer tap came with its own non-return valves which were fitted, as well as large bore isolating valves. Water hammer arrester was long cylindrical type cost £24.99 from local merchants. The ball type one shown on your thread, PTS wanted £34 for it