Glossary

Rain Delay

Controller function used to suspend watering for a specified period without affecting watering programs.

Rain Shut·off Device Or Rain Sensor

A device which prevents the controller from activating the valves when a preset amount of rainfall is detected.

Riser

A length of pipe which has male nominal pipe threads on each end. Usually affixed to a lateral or submain to support a sprinkler or anti-siphon valve. May also be used underground to connect system components.

Rotor

A sprinkler with a water-propelled internal drive mechanism which causes the sprinkler to rotate and water the area in which it is installed. Other type of rotor: impact drive.

Run-off

Water which is not absorbed by the soil and drains to another location. Run-off occurs when water is applied in excessive amounts or too quickly for the soil to absorb.