Lennox 27K16 Limit Switch

The Lennox 27K16 is a heavy-duty automatic reset limit switch specifically engineered for Lennox furnace and air handler applications. This critical safety component features a factory-set thermal range designed to open at 175°F and automatically close at 145°F, effectively maintaining a 30°F differential to prevent heat exchanger overheating. As a genuine OEM replacement part, the 27K16 ensures seamless integration into existing Lennox HVAC systems, protecting sensitive electronics and internal components from thermal stress. The L27K16 limit control is built to withstand rigorous thermal cycling in both residential and light commercial environments. For technicians diagnosing a locked out furnace or system short-cycling, this switch provides the precise over-temperature protection required to restore safe operational parameters. Its robust construction and standardized mounting make it a reliable choice for maintaining system integrity and air handler safety.

• Precise Thermal Regulation: Factory calibrated to trigger at 175°F, providing a reliable safety cutoff.
• Automatic Reset Functionality: Closes the circuit once temperatures drop to 145°F, allowing the system to resume normal operation without manual intervention.
• Direct OEM Compatibility: Ensures a perfect fit and matched electrical specifications for Lennox furnace parts.
• Durable Construction: Engineered for high-frequency thermal cycling to ensure long-term stability in high-heat environments.
• Enhanced System Safety: Critical for preventing damage to the heat exchanger and surrounding furnace components.

How do I know if my Lennox 27K16 limit switch is failing?
Common signs of a faulty limit control include the furnace blower running constantly while the burners remain off, or the system shutting down prematurely before reaching the thermostat setpoint. If you encounter a High Limit Switch Open error code, testing the switch for continuity is the standard diagnostic step.

What causes a limit switch to trip repeatedly?
A trip is usually a symptom of restricted airflow. Technicians should check for dirty air filters, blocked return vents, or a failing blower motor that is not moving enough air across the heat exchanger, causing temperatures to exceed the 175°F threshold.

Can I use this switch in non-Lennox equipment?
While designed primarily for Lennox, this 145-175F auto limit switch may cross-reference with Allied, Armstrong, and Ducane models. Always verify the specific temperature ratings and mounting configuration against the original equipment manufacturer specifications.

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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.