Zone won't shut off - old valves

Hi there - hoping you can help.

I have a zone (pop-up sprayer/mist on a lawn) that will not shut off.

I triaged by unplugging the controller and the system still ran, so that leads me to believe this issue is mechanical and related to the valve or solenoid. I don’t think it’s the Rachio, which has been great. Just trying to take advantage of the friendly experts here.

The valves are about 20 years old and appear to be Superior Controls (Buckner). They’ve been running well for at least the last 8 years with no issue. The last 1 year with the Rachio smart controllers.

Pics are attached.


I removed the top of one of the valves and the diaphragm inside seemed to be in good shape. I turned the main back on and let some water rush through hoping that any debris or blockages might get cleared out. That doesn’t seem to have done the trick.

Solenoid replacement? And where would I begin to find such an old part.

Thanks for the guidance!

Amateur/home user learning about this stuff on the fly.