A rain sensor communicates with an irrigation system controller through a wired or wireless connection to prevent irrigation cycles from occurring when there is rainfall. The two main types are cork-disk and catch basin types. Cork-disk types expand with moisture to turn off the watering cycles, and catch basins operate by the water weight or electrode position to delay an irrigation cycle. Testing your rain sensor for proper operation is an integral part of your irrigation system to conserve water and your costs.
Cork-Disk Rain Sensors
Turn on the watering zone closest to your rain sensor on your irrigation controller. You may wait until it is close to the time schedule for an irrigation cycle or turn it on manually at any time.
Observe your sprinkler heads in the zone you turned on. They should start emitting water onto the lawn
Press and hold the button on the top of your rain sensor. The water should stop flowing from the sprinkler heads.
Release the button on top of the sensor. The sprinkler heads should start irrigation on your lawn.
Catch Basin Rain Sensor
Place three empty, shallow cans on your lawn when you expect it to rain. These serve as alternate catch basins for measuring rainfall.
Set your catch basin rain sensor to 1/4 inch. Depending on the model, there is a plastic piece calibrated in inches that turns or slides up and down to set it.
Allow the cans to collect rain. Pour all three cans together and divide by three to get the average of rainfall in your lawn.
Turn on your irrigation controller manually when the average rainfall from the cans is 1/4 inch or more. The sprinkler heads should not initiate irrigation.