Is the rain dial sprinkler controller broken, or is it a sprinkler valve problem? Basic Troubleshooting Steps

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Sometimes people suspect the rain dial sprinkler controller is bad.  Before sending it in to get it repaired, or even worse, putting in a whole new system, test to see if the problem is with the valves.  We do this by disconnecting the controller from the system and manually connect the valve wires to the transformer power.

Bypass the timer and check that the 24VAC transformer can turn on the valves directly by doing the procedure below.  You basically touch the valve wires directly to the 24V transformer outputs instead of going through the timer:

    1. Unplug the timer’s ribbon cable from the back of box so it can’t control anything.
    2. Disconnect one of the valve wires (e.g., connected to terminal #1 screwed into the back of the controller box; just loosen the valve’s connection screw and slide out the wire)
    3. Take the wire and hold it directly on the right-most of the two 24VAC screw terminals (touch it for 10-15 seconds, long enough to notice if the valve 1 turns on or not)
      (Note: don’t touch it to both 24VAC terminals at the same time. )
    4. If the Rain Dial Transformer and valve are good, the valve should turn on within a few seconds of touching the wire to the 24VAC terminals.  If it doesn’t come on, it’s most likely a valve or wiring problem, not a problem with the rain dial controller.
    5. Additional things to try, just to be very thorough:
      1. Try repeating the process by touching the wire to the other 24VAC terminal instead.
      2. To eliminate the back-connector board from question, connect the wire going to the VC terminal to the left 24VAC terminal and the valve wire to the right 24VAC terminal.  (You can put two wires under the screw and tighten it down.)  If the valve comes on, the wiring and valves are good, contact us about repairing the controller.
      3. It’s also worth noting, that if you’re having trouble, try disconnecting every valve wire except one, this will help simplify things while troubleshooting.

Note, it is extremely rare for a valve to stay stuck “on” because of a bad controller.  Valves stuck on are usually due to a valve problem, or a programming problem caused inadvertently by the user.  If a  sprinkler valve is stuck on, try disconnecting power to it, or disconnecting the Rain Dial’s ribbon cable from the back-connector board. If the valve stays stuck on, the controller is certainly not the problem.  You can probably fix this by purchasing new “guts” (diaphragm, washers, etc.) for your valve from a good irrigation supply store.  Tell them the RainDialDoctor sent you, and let them know we repair Irritrol RainDial timers.  We’d appreciate it!

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