My yard's irrigation has a total of 8 zones (two irrigation boxes of 4 zones each). After turning on the irrigation this year, I noticed that one whole irrigation box (4 zones) all won't turn on, while the other does. I have had one zone fail before and I've had to replace a solenoid, but never all 4 fail. I tested the electrical wires on each valve and confirmed each one is getting 24 volts. Next, I tested the resistance of each solenoid and confirmed they were each 25 ohms. Also, I can turn the solenoid a quarter turn, or open the bleed screw, and each valve manually turns on.

Now I'm at a loss at what to do next. I would assume that it's likely not a valve problem, as all 4 valves won't open. It seems more likely to be an electric problem, but the proper voltage seems to be getting to the box. What else can I check to diagnose the problem?

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    It sounds to me like you have two common wires (typically white), and one it damaged / broken / poorly spliced. I agree with @pnuts about first switching the 4 valves at the controller, as it could also be an issue with your controller. – Ben May 18 '17 at 11:37
  • That makes sense. I'll test the valves by switching wiring at the controller first. If that doesn't work, would this help determine the problem: Take the wires at one of the valves, disconnect from the solenoid, then connect them directly together. Then at the controller, test the resistance of that circuit. This should be a closed circuit now and there should be almost no resistance. If there's high resistance, then it verifies there's a damaged or broken wire. – Sam Baird May 18 '17 at 20:09
  • Some irrigation controllers have a fuse. That is the first thing I'd check... does your controller have a fuse and is it intact. – andrewbuilder May 18 '17 at 21:30

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