@nate: you said “If i connect the common and one of the solenoid’s wires to a AA battery they fire just fine” — I don’t quite understand: how can AA battery fire the solenoid? If this is 24VAC solenoid, it would require at least 17 to 20V to energize. Also, OpenSprinkler 2.0 is 24AV only (there is no DC version of OpenSprinkler 2.0) So I am trying to understand the setup you have.