THIS WATER LEVEL CONTROLLER IS FULLY AUTOMETIC , IT HAS TWO MODE AUTO AND MENUAL, IN AUTO MODE - WHEN WATER LEVEL IN THE UNDER GROUND TANK IS SUFFICIENT AND WATER LEVEL IN OVER HEAD TANK BECOMES LOW , MEANS WATER LEVEL GET DOWN FROM MIDDLE SENSOR, MOTOR GET SWITCH ON AUTOMETICALLY AND THE OVER HEAD TANK STARTS FILLING UP .WHEN WATER LEVEL REACHES TO THE HIGHER LEVEL , THE TOP LEVEL SENSOR SENSE, THE MOTOR AUTOMETICALLY GET SWITCHED OFF. AND WHEN WATER LEVEL IN UNDER GROUND TANK IS NOT AVAILABLE ,MEANS WATER LEVEL GET DOWN FROM THE MIDDLE SENSOR AND ALSO OVER HEAD TANK WATER LEVEL GET DOWN FROM MIDDLE SENSOR THAN IN THIS CONDITION MOTOR WILL NOT START AUTOMETIC AND PROTECT FROM DRY RUN . IN MENUAL MODE- YOU CAN ALSO START AND STOP MOTOR BY START AND STOP BUTTON