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 freezes and expands, it can rupture or deform sprinkler components and lead 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.
Learn how to winterize your sprinkler system, and get the winterization process started by following these steps:
Turn Off the Supply
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 power to the controller will also stop all valve activity. When spring arrives, however, you’ll need to reprogram the controller for 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.