Lennox 22W68 Limit Switch

The Lennox 22W68 Limit Switch is a critical safety component engineered to monitor internal plenum temperatures and prevent heat exchanger damage. This OEM Lennox replacement part is calibrated with an L165-40F temperature rating, meaning the circuit opens at 165°F to interrupt the heating cycle and automatically resets once the temperature drops by 40°F. Designed for high-demand HVAC furnace repair and commercial rooftop units, this 165F high limit switch ensures the system operates within safe thermal parameters, protecting both the equipment and the structure from overheating conditions.

A failing furnace limit control often results in short-cycling or a complete system lockout. For technicians performing Lennox 22W68 troubleshooting, this 100079-01 switch provides a precise thermal response and direct compatibility with series such as the 48HH, 48TJD, and LGE/SGC commercial systems. Utilizing genuine Lennox parts like the 22W68 maintains the manufacturer's specified airflow safety margins and ensures reliable integration with existing wiring harnesses and mounting brackets without the need for field modifications.

Key Benefits:

• Precision Thermal Monitoring: The L165-40F calibration provides a reliable 165°F cutout to prevent thermal stress on the heat exchanger.
• OEM Compatibility: Specifically designed as a direct 100079-01 replacement for seamless fitment in Lennox-manufactured furnaces and RTUs.
• Automatic Reset Function: Features a 40°F differential that allows the system to resume safe operation once optimal temperatures are restored.
• System Protection: Acts as a primary fail-safe against restricted airflow, dirty filters, or blower motor failures.

Common Questions:

What are the symptoms of a bad Lennox 22W68 limit switch?
Common indicators include the furnace blower running continuously while the burners stay off, or the system "short-cycling" where the heat kicks off before the thermostat is satisfied. If the switch remains open, the control board will typically flash a specific diagnostic code indicating a primary limit circuit fault.

Is the 22W68 compatible with other brands?
While this is a Lennox OEM part, limit switches are specified by their temperature ratings (L165-40F) and mounting style. However, to maintain the safety certification and performance of your Lennox unit, using the factory-specified 22W68 is required by most contractors to ensure the correct trip point and differential.

Can I bypass the limit switch for testing?
Jumpering a limit switch should only be done briefly by a qualified technician for diagnostic purposes to verify the circuit. Operating a furnace with a bypassed high limit control is extremely dangerous and can lead to catastrophic equipment failure or fire.

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Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.