Problem #1: Watering at Indefinite and Unwanted Times
Solution: The problem lies with the timer circuit. Multiple start times may have been set. Check the program and set only one start time. However, if you do not have proper expertise, it is better that you contact a person who understands the programming code, to check it.
Problem #2: No Watering at All
Solution: There can be several reasons for this. First of all, check if the sprinkler has been plugged into the power supply. Next, check whether the timer is switched on or not. If that is not the case then, there is probably some issue with one of the electronic components. Check the fuse. In case of a blown-out fuse, replace the same.
If you are facing this problem of fuses getting blown regularly, then you need to replace the valve solenoid. Other components like faulty sensor devices or transformers could also be the reason. In either case, you need to replace them. Also, check for faulty or damaged wires.
Problem #3: Flooding
Solution: If the garden area is getting flooded, there are two possible reasons: Either the nozzle is not working or missing, or the head is faulty. In either case, replacement is the only solution.
Another reason might be that, the water pressure is not sufficient to rotate the sprinkler. In such cases, you have to either replace or simply split the entire zone into two parts. Before you go for the replacement, check if there is any debris stuck in the equipment. If found, simply clean it with a brush.