Don't run into this very often but I'm prepared when I do. Had a leaky low head on an old system so I was expecting the worse. Turned out to be a 35 year old wmtic 2" valve with a worn solenoid port. Had the replacement part on the truck.Took a pic of the diaphragm which had been replaced at one time since it was no longer black. What do you think of all that blistering? It was still working though but I replaced it anyway. Got into my wmtic diapragm bag and noticed one was coming apart at the seams Not sure if it from was sitting in a nasty tool drawer for several years or what.