Wiring.. why no need for 24V AC and ground?


I’m new the sprinkler wiring and our contractor disconnected the old sprinkler control panel without taking a picture so I’m not 100% sure which wires are which… I thought the old control panel had a 24V line? is there a way to tell by looking at the sprinkler solenoids themselves which wires are which??



If the old system used “standard” sprinkler wiring then the wires will be color coded. You can then match the wire color at the solenoid. Common wires are usually white and power wires black. There should be a transformer plugged in somewhere if there is still a 24v power wire. find it, unplug it, and remove those wires. The Iro comes with a new power supply that plugs into the unit.

If your wires are not color coded, you can just plug in what you have and do the setup. During that process the Iro runs each zone, so when the sprinkler comes on you now what gets watered on the zone. May not put the zones in the “logical” order, but at least will identify what wire goes to which sprinkler.


thanks for the quick reply, this is the part I’m confused about… where would the solenoids get the power from if the Iro doesn’t need a 24V line? All I need are the zone and the common wires? What do you mean when you say the Iro has a “new power supply that plugs into the unit”? As in the AC adapter for the Iro?

appreciate the help! sorry I’m such a n00b!


Exactly. That adapter provides the 24v AC for the system.


if there is an existing 24v power source, where would I find it? Near the solenoids?


Near a power source, e.g. an electrical outlet.


awesome, thanks!

last question, how do I know if I have a master/pump valve?


I don’t really know the conditions where there might be a master pump. But I would speculate that it would have to be at the base of the piping for your watering system. A master pump adds pressure to the system or possibly draws water from a reservoir. If you are simply connected to the water mains it is unlikely you would have one.