Fill the pit that the sump pump is mounted in with water from a garden hose to a depth of 14 inches. Use a ruler to gauge the depth of the water. If the sump pump does not turn on and start pumping automatically, follow subsequent steps.
Hold the float rod -- the long metal piece that connects the switch on the motor to the pump at the bottom of the device -- with a pair of pliers to keep it from turning.
Slide the rubber grommet on the float rod upwards until it makes contact with the motor switch. Slide the grommet upwards slightly until the motor turns on. Remove the pliers.
Allow the pump to shut off automatically.
Fill the sump pit with water. Ensure the pump turns on when the water level reaches 14 inches. Slide the grommet on the float rod as needed so that the pump switches on when the water level reaches 14 inches.