To troubleshoot an Orbit sprinkler, you must first identify whether the problem is located in the misting nozzles, a sprinkler head or the timer. For instance, if the misting nozzles seem plugged, remove the entire nozzle, and soak it in a cleaning solution.
If a sprinkler head seems to be leaking continuously, a diaphragm in a control valve is probably damaged. There are several potential causes, so check one at time. After you eliminate one possibility, move on to the next.
To begin troubleshooting the sprinkler head, check the valve to see if it is installed in the correct direction. Then take out the solenoid to see if the plunger is missing or stuck. Next take off the cover assembly to see if the diaphragm or lower valve body diaphragm is torn or blocked.
For the timer, start by determining the exact issue. If the timer runs without stopping or adds cycles, you have programmed overlapping start times. Clear them all, and set a new time. If you input any other cycles, they must have different start times. If the timer often blows a fuse or trips the circuit breaker, an electric control valve has a short in a solenoid or in the wiring. Use a multimeter or volt meter to check for shorts, and replace the defective component.