Lennox 49K61 Limit Switch

The Lennox 49K61 Limit Switch is a critical OEM replacement part engineered for precise thermal regulation in high-temperature HVAC applications. This 300F CO Auto Limit Switch is a normally closed SPST disc-style control that provides essential safety by opening the circuit upon a temperature rise to its 300 degree Fahrenheit set point. This high-limit protection prevents heat exchanger damage and ensures safe operational parameters for Lennox furnace systems, air handlers, and residential heating units. Professionals should note that the 49K61 is identical to 49K6101, offering full compatibility for legacy and modern equipment repairs.

Designed for seamless integration with ECB29 series electric heat sections and various gas-fired units, this automatic reset limit control (TOD Series 61F) eliminates the need for manual intervention after the system cools to safe threshold levels. Its robust 300 degree thermal rating is specifically calibrated for high-limit safety, preventing dangerous overheating conditions often associated with restricted airflow or blower failure. As a genuine Lennox HVAC part, it ensures the exact electrical specifications and mounting footprint required to maintain the system's UL certification and operational integrity.

Key Benefits

• Broad Compatibility: Directly replaces 49K6101 and fits multiple Lennox, Allied, and Ducane models including the ECB29 series.
• Automatic Reset Functionality: Features a self-resetting mechanism that restores circuit continuity once temperatures drop below the 300°F cutout.
• High-Temperature Safety: Engineered as a secondary limit for high-heat applications, preventing excessive thermal stress on heat exchangers.
• OEM Reliability: Genuine Lennox replacement part ensures correct SPST normally closed switching logic and calibrated temperature response.

Common Questions

• What causes a 300F limit switch to trip repeatedly? Frequent tripping usually indicates restricted airflow, often caused by a heavily soiled air filter, blocked return air ducts, or a failing blower motor capacitor.
• Can I use the 49K61 to replace a 49K6101? Yes, these part numbers are interchangeable. The 49K61 is the current production standard and is technically identical to the 49K6101.
• How do I verify if the limit switch is faulty? A technician should check for electrical continuity across the terminals at room temperature; since this is a normally closed switch, a lack of continuity when cool indicates a failed component.

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.