Lennox 74W76 Limit Switch

The Lennox 74W76 Limit Switch is a critical safety component designed for precise thermal regulation within residential and commercial Lennox HVAC systems. As a veteran-grade furnace high limit switch, this OEM part is calibrated with a 200F cut-out temperature to prevent heat exchanger damage and ensure safe operational cycles. This auto-reset switch (Part #102135-11) is engineered for high-demand environments, offering reliable continuity for blowers and burners. It serves as a direct drop-in replacement for numerous models across the Allied Air, Armstrong, Concord, and Ducane families, maintaining system integrity when airflow restrictions or blower failures occur. Using genuine Lennox 74W76 components ensures the HVAC limit control matches original factory specifications, avoiding the calibration drift common with substandard aftermarket alternatives. Whether you are addressing an E250 error code or performing preventative maintenance, this 200-degree limit switch provides the heavy-duty performance required by professional contractors to maintain system safety and efficiency.

• Precision Thermal Safety: Features a 200°F (93°C) fixed temperature setpoint to protect the heat exchanger from overheating.
• OEM Compatibility: Replaces old part numbers 102135-11 across Lennox, Armstrong, and Ducane equipment for a seamless fit.
• Automatic Reset Logic: Resumes normal operation once the plenum temperature drops below the differential threshold, minimizing system downtime.
• Industrial-Grade Construction: Built with high-grade materials to hold tight tolerances under repetitive thermal cycling.

• What causes this switch to trip frequently? Most trips are caused by restricted airflow, such as a clogged 20x25x1 filter, a failing blower motor, or obstructed return air ducts.
• How do I test a Lennox 74W76 for failure? Use a multimeter to check for continuity across the terminals when the switch is cool; an "open" reading at room temperature indicates a failed component.
• Can I use this in an Armstrong or Ducane furnace? Yes, this part is cross-referenced as 102135-11 and is fully compatible with several Allied Air brands.

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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.