How It Works

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An irrigation controller is a device to operate automatic irrigation systems such as lawn sprinkler. Controllers have means of setting the frequency of irrigation, the start time, and the duration of watering.
While most sprinklers have a fixed duration of watering (e.g. 5 minutes per zone, as defined by the user), the RainMachine automatically adjusts your base watering duration by lowering it on rainy or colder days and increasing it on hot summer days.
Because the system dynamically adjust the watering duration the RainMachine not only saves water but it also protects your plants.

Base Watering Duration

The Base Watering Duration is the duration of watering required for each zone, during a normal, summer day, as defined by the end-user.
Calibration efforts using complex formulas that take in consideration soil type, inclination and hypothetical solar irradiation amounts coupled with perfect water distribution among all sprinkler heads is possible but not practical nor accurate in gauging what’s best for your garden.
Given a Base Watering duration per each zone, as decided by you, the RainMachine will then dynamically adjust this duration, up and down, as needed. These adjustments are the result of Evapotranspiration calculations that use feedback from meteorological data such as:

● Forecast Temperature from National Weather Service.
● Quantitative Precipitation Forecast from NOAA’s National Weather Service.
● Solar Radial Levels adjusted to Earth’s rotation and inclination during the year.

Note: See Appendix 1 for a detailed explanation of the Evapotranspiration (ET), Quantitative Precipitation Forecast (QPF) algorithms.

Protecting your plants – Hi and Low temperatures

While saving water is one of the RainMachine’s main goals, growing a healthy lawn or garden is equally important. RainMachine protects your plants against extreme weathe conditions, like freezing temperatures or unusually hot days.

Navigate to Setting -> Hi/Lo Temps and you can instruct the RainMachine to avoid watering when the minimum temperature drops below a certain level, or to add more water in extreme hot conditions. In addition, you can select individual months of the year when the controller prevents starting of any watering cycle.

Note: By setting up freeze protect you instruct RainMachine to not start watering cycles under a specified temperature or on specific months. That does not protect your pipes or other parts of the system against freezing. If you live in a zone where freezing occurs, please winterize your system.

Missing Internet weather data

The RainMachine can properly work even when your Internet connection temporarily goes down. The controller downloads forecast data for up to 7 days; therefore, it can continue normal operation several days with intermittent Internet failures.

Note: You need a working Internet connection when you setup the controller for the first time.

In addition, RainMachine uses a historical database with your local weather conditions, and, if no Internet weather data is available, it stills saves you some water by using a locally stored historical averages table.

Note: Using Forecast data and/or Historical averages can be disabled for any specific zone.

If both Forecast data and Historical averages are disabled for a specific zone, the RainMachine will act as a regular sprinkler controller, watering the amount you programmed (the Base Watering Duration) for each zone, without any adjustment.