[danman]’s sprinkler system has four 12V AC valves that need wrangling, and no data cables, necessitating the wireless setup. Initially, his control box contained a 240V AC to 12V AC 50VA ...

It's common for the valve to be in a box just under the ground or inside ... Attach its hose to the sprinkler zone control valve. Use an air pressure setting of 40 to 80 pounds per square inch ...