A liquid level control module comprising an elongated tubular housing immersible through a surface of a liquid and into a bulk volume of the liquid, and first, second, and third electrical switches, and first and second floats movable along the tubular housing. The first electrical switch is disposed within a lower portion of the tubular housing, the second electrical switch is disposed within an intermediate portion of the tubular housing, and the third electrical switch is disposed within an upper portion of the tubular housing. Each of the switches has an open state and a closed state. Motion of the first float relative to the first switch changes its state. Motion of the second float relative to the second switch changes its state, and motion of the second float relative to the third switch changes its state. Thus a two-float module may provide three level control signals.

An overflow detection system for a grease trap or other receptacle is provided. The overflow detection system includes an overflow sensor. The overflow sensor can include a switch and a processor. The switch can include a float configured to float in a fluid in the receptacle, a surface that is separate from the float, and a resilient member coupled between the float and the surface. The switch can generate a signal in response to the float being within a predefined distance of (e.g., contacting) the surface. The processor can receive the signal from the switch and, in response, transmit a notification to a user device that is remote from the receptacle. The notification can indicate a high fluid level in the receptacle.

A fluid level detection device comprising an elongated shaft having a plurality of sensors and associated switches on a distal end thereof. The distal end of the shaft extends into a liquid reservoir with the switches configured to detect multiple predetermined fluid levels. The first fluid level detected is a warning level indicating that the level of fluid in the reservoir is low and results in a warning indication. The second fluid level detected is for a shutoff threshold that results in shutdown of the device using the fluid in the reservoir and a shutdown indicator.

An overflow detection system for a grease trap or other receptacle is provided. The overflow detection system includes an overflow sensor. The overflow sensor can include a switch and a processor. The switch can include a float configured to float in a fluid in the receptacle, a surface that is separate from the float, and a resilient member coupled between the float and the surface. The switch can generate a signal in response to the float being within a predefined distance of (e.g., contacting) the surface. The processor can receive the signal from the switch and, in response, transmit a notification to a user device that is remote from the receptacle. The notification can indicate a high fluid level in the receptacle.