Controlling an electric water pump, to keep a container full of water. Just as in a washing machine, the depth of the water can be sensed from a hose connected to the base of the container.The advantage over a float switch is that the level is easily adjustable. Providing a low water level warning eg, the switch could be used to activate a buzzer or light if the liquid level in a tank drops below an adjustable point.
These switches also look a lot like washing machine pressure switches, except they have multiple electrical terminals (six or even nine) and don't have external level adjustment. However, some have screwdriver adjustment for both the trip levels and the hysteresis. When extracting the pressure switch from a washing machine, be careful that you don't also inadvertently