How Do I Connect a Float Switch to a Solar Pumping Machine?

Solar energy pumps are favored for their energy-saving, eco-friendly, and off-grid adaptability, making them a top choice for off grid water well pumps and rural water supply. For users of submersible pumps or other solar pumping systems, a float switch is an essential accessory to ensure stable operation—here’s a concise guide to its role and connection method.

What Does a Float Switch Do?

A float switch is a core component for automatic water level control. It detects water level changes to automatically start or stop the solar energy pump: when the water level drops to the lower limit (e.g., in wells or tanks), it triggers the submersible pump to start pumping; when the water level rises to the upper limit, it shuts the pump down. This not only prevents the pump from dry running (avoiding motor burnout) but also avoids overflow, reducing energy waste and maintenance costs.

Step-by-Step Connection Guide

1. Power Off First: Disconnect the solar pumping machine’s power supply to ensure safe operation .

2. Identify Terminals: Float switches typically have three terminals (NO: normally open, NC: normally closed, COM: common). For water supply scenarios (e.g., filling tanks), connect the COM and NC terminals; for drainage, use COM and NO .

3. Connect to Controller: Link the float switch wires to the corresponding terminals on the solar pump controller (instead of direct connection to the pump motor for high-power models) .

4. Fix the Float Switch: Mount it in the water tank, ensuring the float moves freely without obstruction. Keep the upper limit 10cm below the tank top and the lower limit 20cm above the bottom .

5. Test Operation: Restore power, adjust the water level manually, and check if the submersible pump starts/stops automatically.

Proper connection of the float switch maximizes the efficiency of your solar energy pump, whether it’s an off grid water well pump or a submersible pump. Follow these steps to achieve hassle-free automatic water level control.