According to IrrigationTutorials.com, properly turning on your sprinkler after winter is just as important as winterizing your irrigation system before freezing temperatures. During the winter, pests and animals can crawl into your pipes, tubes and sprinklers. It is essential to flush out these pests before preparing your sprinkler system for its normal irrigation routine. In addition, you should examine the heads of the sprinklers to check on any winter damage. Failure to do so can cause an uneven spray of water.
Open the ends of the drip tubes of your sprinklers. The drip tube is the long black tube that transfers the water from the valve. Allow the water to flow out of the drip tube for at least 15 minutes to ensure that if there is anything stuck inside, it will be pushed through.
Reattach the drip tube and run the system. Walk over to each nozzle to see if it is running properly. Check to see if the nozzles are leaning to one side or not functioning properly. Straighten the nozzles by pushing on them, so they are upright.
Remove broken nozzles and replace the entire nozzle with a brand new one. You must use the same brand and model of sprinkler nozzle in order for them to function correctly.
Replace the backup battery if it is not fully charged or is a couple of years old. Generally, irrigation controllers have 9-volt backup batteries that are found behind the front panel of the controller.
Walk across your lawn after a week of running the sprinkler system. Check for dry areas or places of standing water.