10-05-2005, 12:37 PM
New house. Incoming water line goes to a tee. Off one side of tee there is a ball valve, pressure regulator then the entire hot and cold water system for the house. Of the other side of the tee is a ball valve, pressure regulator, about 50' of PVC line, backflow preventer, solenoid valves, lines to sprinkler heads. When the solenoid valves close, we get loud noise in lines in crawl space - water hammer. Installation of a new backflow preventer didn't have an effect (I thought it may limit a reverse pressure wave/surge in the PVC line and stop/reduce the water hammer). I saw an earlier suggestion I believe at your website to rebuild the solenoid valves but these are brand new valves. Does anyone make slow close solenoid valves? Will a tank with an internal rubber bladder absorb enough shock to reduce/prevent the noise? Do I need to install a larger diameter PVC line to reduce water velocity upstream of the backflow preventer and solenoid valves? How do I fix this?