This water level controller is used to control two water pumps, achieving the transfer of water from a well to a high-level water tank through a relay system between the two pumps.

Under normal circumstances, a simple water level controller operating a single pump can automatically draw water from the well into the tank.

However, when there is a significant elevation difference between the tank and the well, it becomes challenging to lift water using only one pump. Therefore, an intermediate tank and an additional pump can be added—first, Pump 1 draws water from the well to Tank 1, and then Pump 2 lifts water from Tank 1 to Tank 2. This way, the lifting height for each pump is effectively halved, making operation smoother and more efficient.

This water level controller monitors the water levels in both tanks and controls the operation of the two pumps to automate the water transfer process: "Well → Tank 1 → Tank 2." It maintains appropriate water levels in both tanks while preventing dry running and frequent starts of the pumps, thereby protecting them.