Lennox 57W79 Pressure Switch

The Lennox 57W79 Pressure Switch is a critical OEM safety component engineered for precise inducer draft monitoring in Lennox gas furnaces. Calibrated to a 0.70" WC activation setpoint, this green pressure switch ensures the combustion blower is establishing sufficient static pressure before allowing the ignition sequence to proceed. As a direct furnace pressure switch replacement, it resolves common fault codes related to airflow verification and pressure switch stuck open or closed errors. This genuine Lennox 57W7901 equivalent is cross-compatible with R101432-14, IS20102-3137, and R45695-004. Designed for high-cycle reliability, it protects the heat exchanger by preventing operation under restricted venting or obstructed flue conditions. For service technicians, utilizing this OEM furnace part ensures exact electrical specs and mounting alignment, maintaining the factory-certified safety string integrity of the HVAC system.

Key Benefits for HVAC Professionals

• Precise Pressure Calibration: Factory-set at 0.70" WC to ensure exact differential pressure sensing and prevent nuisance tripping or unsafe firing.
• OEM Compatibility: Serves as the official replacement for part numbers 57W7901, R101432-14, and IS20102-3137, ensuring a drop-in fit for Lennox-built units.
• Enhanced Safety Logic: Continuously monitors the draft inducer motor performance to ensure combustion gases are properly vented.
• Durable Construction: Built to withstand the high-temperature environment of the furnace vestibule for long-term operational stability.

Common Questions

What are the signs that a Lennox 57W79 pressure switch has failed?
Common indicators include the furnace failing to ignite, the inducer motor running continuously without flame, or the control board flashing a diagnostic code for "pressure switch stay open." Technicians should verify the 0.70" WC setpoint using a manometer before replacing.

Can I use a universal pressure switch instead of the Lennox 57W79?
While universal switches exist, using the genuine Lennox 57W79 is recommended to maintain the specific safety tolerances and OEM furnace part specifications required for your specific model's combustion air requirements.

Is the 57W79 compatible with all Lennox furnaces?
No, this switch is specifically calibrated for units requiring a 0.70" WC Green Switch. Always verify the part number in the service manual or match the rating on the existing switch's label before installation.

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.