In reply to message posted by Gary H:
Two values in our new house are located in the back and are plumbed through the house instead of having a pipe run to the main water line. We get a waterhammer noise when they come on and a noticable pipe hum in a bathroom shower while they run. Any suggestions where to start to isolate and fix this annoyance?
Whenever you use a solenoid valve or other quick closing valve there is always the possibility of hydraulic shock.
This can be avoided by use of a shock absorber or a properly designed air chamber or using a slow closing solenoid like we use on hydronics heating systems or process piping.
Also check your piping for proper supports as band iron is the work of jack legs and folks who have no clue to proper installations.
You may also want to check your pressure as excessive pressure can cause a host of serious piping failures.
Hearing the “water hammering” means someone certainly missed school that day with piping designs.
Plumbing should be seen not heard.
“Humming” sounds like a velocity problem check your pressure then get your pipe size and re post or contact me by E mail as we can find your actual velocity in FPS.