How Can I Identify the Common Wire(s)

I’m upgrading from a Hunter Pro C using 12 zones. There was nothing connected to the Common terminal and nothing connected to the P/MV terminal. There were two wires (green and white) connected to the ground terminal. So, how do I locate this mysterious Common Wire(s)? I’ve tried search for a way to identify the common but it seems it’s so obvious there’s no need to explain which one it is. Thanks, Jeff

Many controllers have an internal connection between Ground and Common, most likely your common is the white wire connected to the GND terminal. If you have a multimeter, you can verify that this is common by disconnecting it from everything and measuring resistance between the white wire and one or more of your zone terminals. In case it is common you should see a reading somewhere between 60 and 300 Ohms (depending on the model of your valves).

In addition to the above test, common wire will likely resemble your zone wires (have the same wire and insulator thickness), in case zone wires are bundled together into one cable, common will likely also be part of that bundle.

At the end of the day, you can simply try it. Connect the white wire to commons (on your old controller, or your new) and try running any of the zones.



Thanks so much. I’m setting up the system tomorrow and will let you know how it went. Jeff

I followed your advise and made both the green and white commons and voila, I’m up and running with the first set up attempted. This product isn’t idiot proof but if you take your time and follow instructions you’ll be fine. I’m more than pleased. Thanks Again, Jeff