Oil level detection system for deep fat fryer

A detector configured to indirectly monitor a level of liquid within a container, comprising:

• a temperature sensor;
• a heat producing element proximate to the temperature sensor;
• and
• a shell disposed around the temperature sensor and heat producing element, the shell configured to be disposed within a container and to provide a barrier between liquid disposed within the container and each of the temperature sensor and heat producing element,
• wherein the heat producing element is configured to transfer heat generated therein to the shell, and the sensor is configured to measure a surface temperature of the heat producing element.

A method of controlling a level of liquid within a cooking vat, comprising:

• providing a vat configured to receive a volume of liquid;
• providing a liquid level detector within the vat, the liquid level detector comprising a heat producing element and a temperature sensor disposed proximate to the heat producing element and configured to provide a first output signal representative of a surface temperature of the heat producing element;
• providing a controller that selectively energizes and deenergizes the heat producing element, and receives the first output signal;
• energizing the heat producing element;
• deenergizing the heat producing element after the first output signal reaches either a predetermined value or a substantially steady state value;
• measuring the rate of change of the first output signal after the heat producing element is deenergized;
• comparing the measured rate of change of the first output signal with a reference value range;
• and
• determining the presence or absence of liquid proximate to the liquid level detector based upon the comparison between the measured rate of change of the first output signal and the reference value range.