Question
I have a 24 zone clock. Zone 19, which controls 2 houses, sometimes comes on by itself and does not shut off - I have to physically shut the pump to make it stop. I replaced the solenoid, thinking it was bad. Same problem. I replaced the valve %26 solenoid, thinking it was the valve causing the problem. Same problem. I disconnected the solenoid to the valve yesterday, and today when the clock went on, zone 19 came on in its proper order but did not shut down. Could it be that the sprinklers are connected to a different valve? A wiring problem? How do I get to the bottom of this?

Answer
ZONES STICK ON FOR 2 MAIN REASONS (1) THERE IS DEBRIS IN THE VALVE CAUSING THE DIAPHRAGM TO STAY OPEN AND NOT SEAT DOWN, AND (2) IT MAY BE WIRED INCORRECTLY. I WOULD TRY A FEW THINGS: (1) CHECK THE WIRING AT THE CONTROLLER AND AT THE VALVES TO MAKE SURE THAT EACH ZONE HAS ITS OWN WIRE AND THAT THE COMMON WIRE IS IN THE PROPER SEQUENCE OF "DAISY CHAINING" TO ALL THE VALVES. MAKE SURE THAT YOU DO NOT HAVE A ZONE VALVE WIRED TO THE MV/PUMP POSITION ON THE CONTROLLER TERMINAL STRIP. GO TO THE VALVE(S) THAT ARE STICKING-ON AND REMOVE THE BONNET. LOOK FOR ANY DEBRIS THAT MAY BE KEEPING THE VALVE OPEN. ALSO CHECK THAT THE DIAPHRAGM HAS NOT BEEN TORN AND DOES NOT HAVE A HOLE IN IT (WHICH WOULD KEEP THE VALVE FROM CLOSING) BY HOLDING IT UP TO THE LIGHT AND INSPECTING IT. REPLACE THE PARTS AND RE-ASSEMBLE THE VALVE(S).

IF YOU STILL HAVE ISSUES PLEASE LET ME KNOW AND WE'LL FIGURE IT OUT.

GOOD LUCK!