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Irrigation/Zone 1 Valve stays open


Hello, I hope you can assist me.  I have a Rain Bird ESP-8LXi+ controller with CP-100 valves.

I had not utilized the system for a few years and gor the system started back up the other week.  As soon as I turned on the water main to the system, Zone 1 began flow, without the pump running.  When I put the system into test mode, and ran each station/zone for 2 minutes each, Zone 1 powered up with the pump as normal, but continued to flow when all the other zones cycled through operation.

I disconnected power from the controller completely and was troubleshooting the system.  I was about to check the bleed screw to potentially release debris that may be blocking the diaphragm from closing.  In order to do that I turned on the water main, and noticed there was no water flowing from the heads in Zone 1.

I shut off the water again, and reconnected power to the controller.  When I turned on the water again, Zone 1 was flowing.  I then disconnected power...the water stopped.

Based on the Rain Bird troubleshooting guidelines, and common sense, it is NOT the solenoid or the valve, but rather somehow the controller is telling the valve to open even if that station or ALL stations are OFF.

I am not at all sure what to do next.

Can you advise?

Thanks in advance,

Hey Wade, so either the controller is defective and is allowing power to the #1 terminal, thus turning on zone #1, or there is an issue with the wire to valve #1 hooked up wrong. First take the wire off of the terminal marked #1, next Take a volt/ohm meter, and put the positive lead on the terminal marked #1 and the negative lead on the terminal marked C (common). With the controller off, but the power on to the controller, see if you are getting a voltage reading, if you are, then the controller is defective and needs to be repaired or replaced. Also, with the wire from the #1 terminal being disconnected, the #1 valve should not be on. If the #1 valve is on with the wire being disconnected, then the #1 valve is not hooked to the #1 terminal and you need to find which wire the #1 valve is hooked to, possibly the pump start or master valve terminal. Good luck and have a great day.


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Jim Schaefer


Any question regarding sprinking systems,installation,repair, and trouble shooting.


I have been installing and repairing sprinkling systems since I was 15 years old. Have owned my own sprinkler system contracting business for over 26 years. It is basically the only job I've ever done, except for being a paper boy when I was young.

High School diploma and 3 years college credits.

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