pat
: when the swimming pool is filling the electric water heater pipe makes a hammering sound. Ive already installed 2 arresters on both the hot & cold water washing machine outlets. The only way to stop the hammering noise is if I turn off the cold water intake valve on the water heater or run the hot water. Ive tried draining all the drains to release air pockets, moved the arresters to various spots, and so on. Could the water heater be faulty ( only about 1 year old) or could I install some sort of check valve on the line going into the cold water line on the water heater?? Thanks for any help you can offer.This sounds like a velocity problem. If your piping is copper tubing and you do have excessive FPS than your going to cause premature failure of your piping system especially on hot water. Normaly the velocity should be designed to be around 8 FPS and on HW not to exceed 5 feet per second. When the H/W temperature exceeds 140 degrees this will cause noise and erosion problems. Try using a globe valve to throttle down the volume passing through and the noise should stop. Respectifully Sylvan
