Winterize a Smart Sprinkler System: When, Why and How to

Winterizing a smart sprinkler system protects it from winter freeze damage. It should be done in October or early November and is accomplished by manual draining, automatic draining, or blowing out the system with an air compressor.

If you live in an area that experiences below-freezing winter temperatures, it’s essential to winterize your smart sprinkler system to protect your investment. So, let’s talk about the why, when, and how!

Why Winterizing A Smart Sprinkler System is Important

Winterizing a smart sprinkler system is critical in areas that experience below-freezing temperatures. It protects the underground components like heads and lines from irreparable damage due to freezing and your wallet from expensive repair bills.

But why is winter so dangerous for a smart sprinkler system?

Simply put, when winter temperatures roll around for the season, the ground and any water in it can freeze (even water inside your sprinklers). When water freezes, it expands by about ten percent. This amount may not seem like much, but when this water freezes in 1-2” irrigation pipes or sprinkler heads, this expansion puts tremendous pressure on these components.

With little room in sprinkler heads and supply lines to accommodate expansion, this pressure causes plastic to crack or burst, or the heads can pop off completely. Plus, when it’s cold these materials are more brittle and therefore, more susceptible to cracking or breaking.

Winterizing removes the water from your smart sprinkler system so there is no chance of it freezing and creating expansion pressure. This preventative maintenance reduces the chances of broken pipes, heads, and valves, helping you avoid expensive repairs.

When To Winterize A Smart Sprinkler System

The exact timing will depend on your system type and your local climate. In general, most systems are winterized between October 1 and Thanksgiving.

If you have above-ground components like a backflow preventer or exposed pipe, you will want to err on the side of caution and get it done earlier in that time frame. If your system is entirely underground, you can wait until later.

Colder climates should winterize earlier in the season compared to more temperate zones where the first seasonal frost happens later.

The goal with timing winterization is to keep your sprinklers running until the grass growth slows for the season. However, get them winterized before the temperatures drop and the area experiences regular hard freezes at night or consecutive days of below-freezing temperatures.

Step-By-Step Instructions For Winterizing Your System

There are three methods for winterizing sprinklers, each with the goal of purging water from the entire system:

  • Manual drain
  • Automatic drain valve system
  • Air blowout

Winterizing by manually draining the water or using an auto-drain valve system is straightforward. However, most landscaping contractors recommend the air blowout method to winterize a sprinkler system. Air is forced through the valves, supply pipes, and sprinkler heads to rid the system of water completely.

An air blowout can be a DIY-project, but you’ll need a compressor with specific volume and pressure outputs. Chances are, the compressor you have in the shop or garage is too small for the job, but you can rent one from a local equipment rental yard.

1. Shut Off the Water Supply

It shouldn’t be surprising that the first step is turning off the water at the main valve. Shutoff valves are usually buried in a valve box near the mainline or water meter, in the basement, or in a crawl space.

If your system has backflow valves, shut them off, too. Typically, two valves lead into the backflow device; both must be shut off. Systems that run on non-potable water might not have a backflow preventer.

2. Turn Off the Irrigation Programs

Once the water is off, access the digital controller and turn off the scheduled watering programs. At this point, you don’t want to shut off the digital controller completely. You may need it to activate zones to drain water from the lines.

3. Drain the Water From the System

How you drain the water depends on your system’s components. For the best results, drain the water manually or use the auto-drain valves (if applicable), then blow the system out with air.

Manual Draining

Some sprinkler systems have shut-off valves at low points in the lines or at the ends. These valves can be opened manually to drain the water.

Locate the shut-off valves and slowly open them one at a time to let the water run out. The water supply in the system is under pressure, so exercise caution when opening them and wear eye protection. Close them once they are fully drained.

Open the test cocks on above-ground backflows to drain all the water into the house or below-ground. Ensure the ball valves are left in the 45° position to avoid splitting.

Using the Automatic Drain Valves

Other systems have auto-drain valves installed that automatically drain the water when the water pressure drops below a specified pounds per square inch (psi) threshold. Some systems drain every time the sprinklers shut off; others need the main valve shut off to release the water.

First, follow the manufacturer’s directions to open and engage the auto-drain valves. Then you’ll need to drain the residual water that may be trapped in the valves.

Each valve has a solenoid on it—a plastic cap that has thin electrical wires coming out of the top. Locate the solenoid on each valve and loosen it. This allows air to flow into the valves and pushes the water out.

Blowing Out the System with Air

Using air to blow out an Irrigreen smart sprinkler system is the most effective method, as it ensures the water is removed completely. But it does require specialized equipment.

To blow out the system with a 2” or less mainline, you’ll need an air compressor with a rating of 50-100 cubic feet per minute (CFM). The air pressure should never exceed 50 pounds per square inch (PSI) for poly pipe and 80 PSI for PVC pipe.

    1. With the water valve on the backflow preventer and the compressor valve closed, attach the air compressor hose to the backflow blowout port using a quick coupler or other connection fitting.
    2. Open your Irrigreen 2 app, and on the dashboard, select “Zones” at the bottom of the screen. Click on the digital zone furthest from the compressor and “Edit” under “Program Zone Shape” to activate the zone and open the valve inside the sprinkler head.
    3. Slowly open the valve on the compressor to introduce air into the sprinkler system and pop up the sprinkler head.
    4. Allow air to run through the zone until you can’t see water spraying from the head(s). On average, this takes two or three minutes.
    5. Once the zone is purged, shut the compressor valve. You don’t want to continue blowing air through the lines as it can cause heat and friction, potentially damaging the components.
    6. Exit zone edit screen, going back to the main screen listing the digital zones.
    7. Continue this process, moving closer and closer to the compressor until all the zones are blown out with air.
    8. When finished, disconnect the compressor from the system.

4. Insulate the Above-Ground Components

After the water is purged from the system, it’s time to insulate everything above-ground from the cold. Wrap the main shut-off valve and any exposed pipes and backflow preventers in insulated tape or protect them with foam covers.

Make sure not to block the air vents of drain outlets on the backflow preventers.

5. Turn Off the Digital Controller

After fully purging the water and all components are insulated, you can shut the controller off. Doing this ensures the system won’t try to turn itself on and run.

Most systems can safely be powered off without losing programmed information or settings. You can turn it back on in the spring, and it should resume working normally.


Do Auto-Drain Systems Need to be Winterized?

Even though they are called “auto-drain” systems, they should still be winterized to protect the system from damage. The system is designed to drain all the water from the lines and heads when the pressure drops below a certain threshold but doesn’t get rid of water trapped in the valve. This trapped water can still freeze and damage the valves.

Will a Hard Freeze Damage My System if it hasn’t been Winterized Yet?

You don’t need to panic if you see an early-season freeze warning for your area and haven’t winterized your sprinkler system yet. The season's first freeze isn’t enough to damage underground components (or freeze the water in them because the soil acts as an insulator), but it can damage anything above ground. Insulate any exposed pipes or backflow devices with old towels or blankets until you can get the system winterized.

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