How to Start a Lawn Sprinkler System in Spring

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Because an irrigation system is not usually needed during the winter, it is turned off, and the system is usually drained. Come spring, however, you'll need to refill and start up your lawn sprinkler system to help your grass and flowers prepare for their busy growing season. Though it may seem intimidating, the spring start-up of your irrigation system can be a lot easier than it appears.

As long as you wait until the ground and weather are warm enough, the spring start-up of your lawn sprinkler system can often be completed quickly and with just a few tools, including a flathead screwdriver and a pair of pliers. If you are located in a Northern climate, it's important to wait at least a couple of weeks after the date of the last frost to avoid ending up with frozen and broken pipes in your sprinkler system. To be safe, you can make sure the ground is not frozen by using a shovel to dig down a foot into the soil before beginning your spring start-up.

Turning On an Irrigation System for Spring

Step 1: Turn the Control Panel to Manual

Locate the control panel and turn it to the manual cycle. This will allow you to manually run water through the system and test to make sure there are no leaks and everything is running correctly later on in the process. Make sure that each irrigation zone is turned off at the control panel.

Step 2: Inspect the Sprinkler Heads

Do a visual check of the sprinkler heads throughout your lawn sprinkler system, making sure they are not covered with plants, mud or debris and do not have any visible damage. Clear away any obstructions and replace any damaged heads.

Step 3: Close the Drain Valves

Close any open drain valves located at the end of each zone. These valves will be located in a ground box.

Step 4: Locate the Backflow Preventer

Locate the backflow preventer, which is usually installed inside the house but can also be installed outside. The backflow preventer prevents chemicals such as pesticides and fertilizer on your lawn from flowing back from the irrigation system into your potable water supply and is drained along with the rest of the system in the fall.

Locate and tighten any test cocks on the backflow preventer, which will require a flathead screwdriver. Make sure the ball valves are turned to the on position by turning the handles until they are parallel with the pipe. There should be a ball valve on the inlet side of the backflow preventer and one on the outlet side.

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Step 5: Locate the Main Valve

Find the system's main shutoff valve, which will be located between your home's main line and the irrigation system's backflow preventer. If there is a bleeder cap (a small metal cap that's twisted on the main valve), it was likely loosened or removed in the fall to make sure all water was drained from the system. Tighten the bleeder cap before turning on the water.

Step 6: Turn On the Water

Slowly open the main valve to the irrigation system. It is very important that you turn on the water slowly and do not start by opening the valve fully. Opening them quickly can lead to water hammer, which is a rush of air and water through the pipes that can cause a vibrating, or hammer, effect that can result in broken pipes, valves and sprinkler heads. Turn the valve slightly a little at a time until you hear the water stop running, signifying that the system is full. If water can still be heard running after several minutes, there may be a valve open somewhere, or there could be a leak in the system.

Step 7: Test Each Zone Manually

Run a manual test of each zone as part of your spring start-up. This will allow the air to be purged from the lines of each zone while they fill with water. As each zone runs, you will get air from the sprinkler heads. This may last a few minutes and is normal. Once the air has cleared from the lines, the zone is full of water and should begin working correctly.

Let the water run for approximately five minutes for each zone while you do a visual inspection. Watch the sprinkler heads to make sure the spray strength and pattern are correct. If any sprinkler pattern is off and needs adjusting, adjust the heads until you have the correct trajectory. For some types of sprinkler heads, you will need to turn off the water to the zone before making any changes. With these heads, it's best to find all issues and make repairs all at once if needed rather than one at a time.

There are several types of sprinkler heads with different adjustments, but most can be adjusted with a flathead screwdriver and pliers. Another thing for which to watch while doing a start-up of each irrigation system zone is low water pressure. A reduction in water pressure, particularly in one zone compared to others, can indicate a breakage in the water line. A soaked area of the lawn can also be due to a water line break. If you do suspect a break in the water line, shut off your irrigation system and repair the break or have it fixed by a professional.

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Step 8: Check the Valves

Inspect the valves in each ground box in your lawn sprinkler system to make sure that there are no leaks, including loose bleeder valves. Recheck the irrigation system water line inside the house, including the main valve and the backflow preventer. Look over all connections, particularly the bleeder caps, to ensure that there are no leaks.

Step 9: Set the Controller

Set the timer on the control panel to set up the watering times for each zone. When first starting the timer, set up the watering times for when you can observe them, such as in the morning or early evening, because it will allow you to see any problems that can potentially arise with your lawn sprinkler system. After a couple of cycles, you can set it for whatever time is most convenient. Setting up the controller correctly is important and can be a bit confusing if you are not experienced with doing so. Refer to your controller's instruction manual if needed. If you no longer have the instructions, contact the company or find the manual online and print a copy.

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Gary Sprague

Gary Sprague

Gary Sprague is a retired master plumber who now works as a writer. He lives with his family in Maine.