I have an ASCO solenoid (with an extra coil) that make a fairly loud buzzing sound when energized. Is this normal? Also, what solenoids does everyone else use for their pneumatic props? I need a 3 or 4 way solenoid as I have double acting cylinders.
For double acting solenoids, use 4 ways. Three ways are more for single acting and for cylinders where you want the rod in more than two positions on the stroke. Many times, trying to use a 3 way on a double will cause the rod to "creep" when the solenoid isn't charged. Me, I use these but that's only because I use what I sell.