Water level controller is a device that manages water levels on a variety of systems such as water tanks, pumps and swimming pools. The basic function of a water level controller is to regulate water flow and optimize system performance. The level controller uses a displacer connected to the controller to sense the liquid level. The displacer sits in the process fluid inside of the separator. When the liquid level increases and the displacer reaches a high set point, the level controller sends a pneumatic signal to open the control valve.

The operation of water level controller is based on the fact that water conducts electricity. As the water level rises or fall the sensing probes and circuits of the controller detect the same. These signals are used to switch on or switch off the pump motor as per requirements.