Sorry about bumping an old thread. Just joined here and have the same question. I currently have a late 1990’s vintage Rainbird 6-zone controller with an external 24VAC wall wort plugged in next to it. The other 115VAC outlet in that spot is running a refrigerator. I just want to replace the Rainbird so I can get to it from my phone outside the house. I’m trying to figure out which Opensprinkler 3.0 power option I should be buying? To me it seems like buying the 24VAC version is my best bet for a simple replacement. Have I missed something? (Wanted to add that I’d probably buy another 24VAC power supply anyway since the one I have is old at this point.)