Lennox 66J78 310-350F Auto Limit Switch

The Lennox 66J78 is an Auto Limit Switch 310-350F, a safety device mainly used in furnaces and heating units in HVAC systems. This auto-limit switch is programmed to keep track of temperature inside the system and therefore is a safeguard device that ensures that the system is not over-heated. If the temperature soars over 350 degrees Fahrenheit, the switch opens and interrupts the circuit to ensure that the heating component is shut off by keeping off harm. Whenever the temperature drops below the safe working limit of 310 degrees Fahrenheit, the switch gets reset and the heating system continues.