How to Winterize Your Sprinkler System

how to winterize your sprinkler system, How to Winterize Your Sprinkler System

Estimated reading time: 6 minutes

Even though the likelihood of deep freezing temperatures and heavy snow is usually very small in North Texas, it is still a good idea to winterize your sprinkler system by the time winter arrives. This will help avoid any damage to your system just in case unusually cold weather hits. If water is left in your irrigation lines or valves, it could freeze and expand, causing them to split or burst. When that happens, you may be in for a nasty surprise come spring when you turn your system on. Burst pipes can cause flooding, significant same to your home’s plumbing system, and much more.

Where to Start

Maybe you’ve never wondered how to winterize your sprinkler system, but a major threat to your sprinkler system during winter is freezing. As residual water inside the pipes, valves, and other components freeze and expands, it can rupture or deform sprinkler components and lead to major problems or leaks in the spring. Some homeowners assume that buried sprinkler pipes are insulated from freezing by the latent warmth of the earth at a certain depth, known as the “frost line.” In many parts of the country, though, the frost line is located as deep as three or four feet below the surface. Since most sprinkler pipes are installed at a shallower depth, they become vulnerable to freezing and the resulting damage.

In order to winterize a sprinkler system, it is important to first know what type of system you have. In this article, we will touch on both the most basic steps of sprinkler winterization and the more specific methods based on your system type.

How to Winterize Your Sprinkler System

Turn Off the Supply

how to winterize your sprinkler system, How to Winterize Your Sprinkler System

First, cut off the water to the entire sprinkler system. A properly installed system should have a main water shutoff valve in a sheltered location to protect it from freezing, such as a basement or crawl space. However, if the shutoff valve is outdoors and exposed to freezing temperatures after the water is turned off the valve should be insulated for the winter. This can be done by covering it with a plastic bag, then wrapping it with foam insulation tape.

Set the Controller

There are two options to winterize the system controller. Many controllers have a rain mode that essentially stops the signals to the valves. While in rain mode, the controller will still have the correct date and time and keep track of all the programmed settings. The only difference from regular mode to rain mode is that your valves don’t turn on – everything else stays the same.

As an alternative to leaving the controller in rain mode all winter, simply unplugging the power to the controller will also stop all valve activity. When spring arrives, however, you’ll need to reprogram the controller for the correct date, time, and settings.

Remove the Water

The next step is to drain the water from your sprinkler system, which may include one of the following methods

  • The system may be drained manually. In this method, manually operated drain valves (usually located at the lowest points of the system as well as at the termination point) will be opened by hand and water allowed to drain. The backflow device will also be drained by opening the test valve. Finally, water in the span between the main sprinkler shut-off valve and the backflow device will be drained through a separate valve.
  • If a system incorporates automatic drain valves, these valves typically open when pressure in the system drops below 10 p.s.i. After shutting off the main water valve, a sprinkler contractor will activate a single sprinkler to relieve residual system pressure. The drain valves will automatically open and empty the lines.
  • Blowing water out of the pipes with compressed air is another method, usually reserved for more complex systems where water cannot be fully removed through drains. This option requires high-pressure air compressors specifically designed for this use. The process can be hazardous for people who aren’t trained and should be handled by a qualified sprinkler contractor. Spans of pipe in a sprinkler system must be blown out in a specific sequence according to the overall layout, in order to ensure total removal of water.

3 Methods to Winterize Your Sprinkler System

Manual Drain Valve Method

For systems with a manual drain valve:

  1. Turn off your sprinkler system from its mainline shut-off valve.
  2. Open one of the system’s control valves to relieve pressure on the mainline. This can be done manually or from the system’s control box.
  3. Open the manual drive valve.
  4. Repeat for all manual drain valves on the mainline.

You will need to remove any remaining water from the valves. This can be done by taking the valves apart and drying the parts or blowing compressed air through your system. Replace any valves you may have removed and leave them all in the open position to prevent the system from repressurizing during the winter.

Automatic Drain Valve Method

For systems with an automatic drain valve:

  1. Turn off your sprinkler system from its mainline shut-off valve.
  2. Open one of the system’s control valves to relieve pressure on the mainline. This can be done by hand, or from the system’s control box.
  3. Open the manual drive valve.

The automatic valves automatically remove water when your sprinkler system shuts off. However, you will still need to take apart the valves or blow compressed air through the system to remove any water that may still be in the valves.

Blow-Out with Compressed Air Method

Unless you know what you are doing, you may want to have a professional winterize your sprinkler system if it needs to be done with the compressed air blow-out method. Doing this incorrectly could cause damage to your sprinkler system, so if you have any doubts about doing it yourself, contact a professional outdoor contractor in North Texas.

  1. Begin by shutting off the main sprinkler valve.
  2. Release pressure in the system by slowly opening one of the manual shut-off handles.
  3. Attach your compressor hose to the system’s blow-out adapter.
  4. Set your compressor to 50 psi, but do not turn your compressor on.
  5. Open the zone valve to be blown out and then turn the compressor on.
  6. Increase the pressure slowly until all sprinkler heads for that zone pop up.
  7. Allow the air to blow through for no more than two minutes.
  8. Turn off your compressor to allow air to purge from the irrigation line.
  9. Close blown-out valve.
  10. Repeat the above steps twice for each zone in your sprinkler system.
  11. Disconnect your compressor and turn the power off to your sprinkler system.

Taking the time to properly winterize your sprinkler system before winter arrives can help you avoid expensive repairs in the spring.

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