We have had a water hammer problem for a number of years and but i suspect it could be the proximaty of water and gas pipe running side by side down the inside of a conduit in a wall. I am thinking of placing an arrester to eliminate the problem, but where is the best place to place it??? I have ample room in the loft to place it anywhere, but I can't get at the area where i think the pipes are coming into contact. We have quite high water pressure and I have turned it down to reduce the hammer

Andy, March 2010

yes your right it will give a metalic sound cause it is probably hitting the gas pipe.
but it's the water pressure thats causing the pipe to move and bang against the gas pipe.

hi-spec plumbing & heating (essex), March 2010

The property is a 2 story maisonette and the pipework is inside some trunking alongside the gas pipe from the groundfloor to the loft. The stopcock is in a small groundfloor access panel approx 6 by 10 inch where the water pipe enters the property. From the loft, the pipe is secured to the rafters by clips and feeds the equipment in the kitchen and bathroom. The reason I assumed it was the gas and water piper coming into contact is the water hammer is a loud metalic sound when a tap or other 'water using' item is turned off. not sure how i can give any more info really as I am no way educated in plumbing matters..

Andy, March 2010

water hammer is not caused by pipes touching.
it's by high water pressure.
you won't stop water hammer by closing the stopcock
that only reduces the flow not water pressure which causes water hammer.

without knowing the layout or where the problem is can't say where to locate the arrestor.

hi-spec plumbing & heating (essex), March 2010