Hello all, I have a residential sprinkler system that I installed myself last year. From browsing the forums here, I can see that I will take some flak for using Rainbird parts from HD. I will claim ignorance, I thought they were all the same quality parts. I didn't know any better. Despite that, the system works well and has good coverage on my 1/4 acre lot. I am having trouble with waterhammer when switching zones. I have 1" PVC feeding the valve boxes, and some of the runs are pretty long from the source to the valve boxes. My zones use 12 to 14 GPM depending on which one is running, static water pressure is 62 PSI. I did not install a master valve on the system, and I'm wondering if that might help? The pipe runs basically the length of the house before exiting outside, so I wonder if a master valve would be a good idea even if it dosen't help with waterhammer? Just wondering if anything can be done to get the hammer under control before something bad happens! Thanks, Joe M.