Lennox 49L86 Limit Switch

The Lennox 49L86 Limit Switch is a critical safety component designed for precise thermal regulation within residential and commercial HVAC systems. This OEM furnace limit switch operates on a normally closed SPST circuit, serving as a primary over-temperature protection device. Engineering specifications confirm a fixed 175 degree open temperature to interrupt the heating cycle if internal plenum temperatures exceed safety thresholds. The integrated automatic reset function closes the circuit once the system cools to 145°F, restoring standard operation without manual intervention. Featuring a 3-inch insert length (STILT type) and a distinct blue sleeve for easy identification, this switch ensures proper reaching into the airflow path for accurate sensing. This component is a direct replacement for Lennox part number 49L8601 and is compatible with an extensive range of equipment, including G40UH, G50UH, G60UH, and G61MP series units. Utilizing genuine Lennox HVAC replacement parts maintains system integrity and ensures electrical compatibility with existing control boards.

• Verified Compatibility: Direct OEM replacement for Lennox, Armstrong, and Ducane part numbers 49L8601, 1445058559, and 36T01B3.
• Automatic Thermal Cycling: Features a 30°F differential (175°F Open / 145°F Close) for reliable automatic reset limit switch performance.
• Standardized Fit: The 3-inch stilt design allows for seamless installation in high-temperature plenum environments.
• OEM Reliability: Built to original factory specifications to prevent premature tripping or mechanical failure in high-cycle applications.

How do I know if my Lennox furnace limit switch is failing?
If your furnace blower runs continuously while the burners shut off prematurely, or if the system exhibits rapid cycling, the Lennox 49L86 may be tripping due to restricted airflow or a weakened internal bimetal disc.

Can the 49L86 be used in place of a manual reset rollout switch?
No. This is an auto reset limit control designed for high-limit air temperature monitoring. Manual reset switches are typically reserved for flame rollout safety and should not be interchanged with automatic models.

What does the blue sleeve on the 49L86 indicate?
The blue sleeve is a visual indicator used by Lennox to signify the specific L175-30F temperature rating, assisting technicians in quickly identifying the correct HVAC thermal protection switch during field service.

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.