Question
I have a Hunter irrigation system and an ICC controller. When I turn on a zone manually, all of the zones come on. I checked and zone 1 was the only one to have 26 volts. When I switch it to zone 2, I get the same thing. All come on but with a weak water flow. Also, zone 2 had the correct voltage that time....same with the others when I tried them. I cut the power and unscrewed the solenoids thinking the heads should pop up, but none of them did. Three questions: 1. Should I replace the solenoids? 2. Why are they all coming on? 3. How do I fix the problem?

Answer
Hey Billy, #1 wait to change the solenoids. So the reason they are all coming on, is either the controller is defective, or your wires (wiring) is defective. Step one: in the back of the controller on the terminal strip, take off the wires hooked to valve #2, #3, #4 etc. until all the wires are disconnected except the wire to terminal #1 and the C (common) terminal, when you take each wire off, mark them #2, #3 etc. so you do not get them mixed up. Step two: Now turn valve #1 on manually from the controller. Step three: now check your voltage at the terminals, #1 should have voltage, but if #2, #3 or any of the other terminals have voltage, then the controller is defective and needs to be replaced. If the other terminals do not have voltage to them, then the controller is not defective, and you have an issue with the wires that run from the controller to the valves. What is happening, is that the wires have crossed each other somewhere, so all the valves have current running to them at the same time. You can only run one valve at a time, other wise there is not enough water pressure to pop-up the heads on more than one valve. If the wires are defective,  then you either need to find the problem in the wires, or run new wires. When you say you unscrewed the solenoid with the power off, but the valve did not turn on, indicates that you might have a master valve hooked up on the system, and water is not supplied to the other valves, until the master valve turns on. In the back of the controller on the terminal strip, see if you have a wire hooked to the MV (master valve) terminal or the PS ( pump start terminal). If you do, then you have a master valve hooked up to the system. This master valve must be turned on by the controller, before any water gets to the other valves. Good luck and have a great day.