What control devices are used to start and stop pumps?

Floats are devices that detect the level of liquid in a tank or basin and are commonly used to control the operation of pumps. When the liquid reaches a certain level, the float will either rise or fall, depending on its design. This movement activates or deactivates a switch that starts or stops the pump. This automatic control helps maintain the desired liquid level, preventing overflow or dry running of the pump.

The other options, while potentially related to pump operation, do not serve the primary function of starting and stopping pumps as effectively as floats. Timers can schedule pump operation but rely on time rather than liquid level, which may not be responsive to immediate conditions. Pressure gauges monitor pressure but do not directly control pump activation. Remote switches allow for manual operation of pumps from a distance but do not automatically adjust based on liquid levels, unlike float switches. Thus, floats are critical in ensuring automatic and safe control of pump systems in various applications.