Relays are automatic switch units. They are responsible for switching on and off the pump in an irrigation system.
There are more brands and types of them are commonly used hence there is no general instructions to operate and use them.
Operation, test and maintenance
When the controller starts a zone, it also send a signal to the relay and switch the power on for the pump this way. When the program is finished, the power will be switched off by the relay, based on the controller signal.
Simple relays cannot be tested separately, as they don’t have any options to it. When a zone is fired up, the relay must click and switch the power on for the pump. The click might even be heard when there is no high voltage for operating the pump.
More advanced relays might have their own signal lights about power supply, water level insufficiency, and other pump faults. User manual is always supplied by the installer with these kind of units.
Most simple test of a rely is to start a zone and see if it’s started. When any issues occured, call an irrigation engineer for further investigation.