Testing valves/solenoids (and transformer/power)

You can prove that the Irritrol Rain Dial controller/timer is the likely the problem and not the valves (or power/transformer) by bypassing the timer with this simple test.

Important: Make sure the water it turned on to the valves.  People often spend hours troubleshooting the system, only to find out that the water had been turn off to it.  Typically, there are valves near the back-flow near where the water enters your house.  

You basically connect one valve wire directly to the 24VAC screw terminals.

    1. Unplug the timer’s ribbon cable from the back of box.
    2. Disconnect (unscrew) one of the valve wires (e.g., connected to screw terminal #1 of the back of the connector board that sits behind the control module)
    3. Touch and hold it directly on the right-most of the two 24VAC screw terminals (touch it for a several seconds, long enough to notice if the valve 1 turns on or not, but not too long.  You don’t want the transformer to be damaged by trying to turn on a solenoid that’s shorted).
      (Note: do not let it touch both 24VAC terminals at the same time.)  This will connect one of the valve wires directly to 24volts.
    4. If the Rain Dial Transformer and valve are good, the valve should turn on within a few seconds.  If it doesn’t, try moving the wires from the VC screw terminal to the left most of the 24VAC terminals.  This will connect the other wire of the valve directly to 24volts.  Then repeat step C above.  When you touch the wire to the terminal, both wires will be connected directly to 24volts.
    5. If it comes on, you know that the valve and wiring to it are good.  You also know the power to the transformer and the transformer is good.   Thus, the timer and/or back connector board are likely the problem; send it in for repair.
    6. If it does not come on, you likely have a problem with the fuse, power to the transformer, or the transformer has failed.

A note about the fuse: See the Checking the Fuse page for more info.  Note that the controller will still receive power, even if the fuse is bad (open).   The fuse only protects the common terminal to the valves.  You can always move the VC common wire to the left-most of the two 24VAC terminals, and then repeat the test above.  Be wary though, the fuse may have blown for a reason, and you’re bypassing the protection it provides. (see disclaimer at the top of this page).

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:-)