there are several reasons for pipe hammer the obvious one being the pipework is loose. The water pressure should be checked to see if there is a variation in pressure both with water running and static. If there is a big variation are the stopcock's open fully. you could try fitting a pipe rester but a plumber should be able to locate the real reason,is your water pressure abnormally high in which case the pressure reducing valve will do
toptrish, August 2013
