It is imperative that your controller/timer has a pump start relay terminal if you are using a pump. This enables you to coordinate the pump with your entire irrigation system. A pump start relay is a device that lets your timer communicate with your pump. When choosing a location to mount the pump start location you must find an area that is 15 feet from the timer and pump, this avoids electrical interferences that can cause malfunctions. The pump start relay is easily connected to your timer in two locations, using normal irrigation valve wire. It is connected to the master valve and to the COM terminal on the timer. Once you are connected to those two locations you then connect the pump to the pump start relay, using wire appropriate to your pump.