I've got a Rainbird system and recently noticed the pump cycling on and off during the time outside my normal watering schedule. I've checked the system pressure and noted the pump cycles on when the pressure drops (the way it's supposed to do when the system is in operation as commanded by the controller). This is occurring while the system is on, but not in operation. I'm wondering if one or more of the zone valves might be stuck in the open position and thus causing a drop in system pressure ...
