Lennox 57W75 Limit Switch

Precision is critical in furnace safety circuits, and the Lennox 57W75 Limit Switch is the standard-grade solution for managing thermal thresholds in high-efficiency systems. As a 250F CO M/R Limit Switch, this component is engineered to interrupt the burner circuit when temperatures reach the 250-degree Fahrenheit cutoff, requiring a manual reset to ensure a technician inspects the underlying cause of the overheat. This OEM part is the direct replacement for 31J95, offering a seamless fit and electrical match for a wide range of furnace and packaged units. Constructed for longevity in demanding environments, the 57W75 rollout switch maintains a normally closed state and features a 90-degree quick-connect terminal configuration for efficient field replacement. Whether you are addressing an E250 error code or replacing a tripped flame rollout, this switch provides the exact thermal response curve required by original equipment specifications to protect the heat exchanger from damage due to restricted airflow or blower failure.

Key Benefits for HVAC Contractors:

• Direct OEM Compatibility: Engineered as the specific Lennox 31J95 replacement, ensuring proper mounting and calibrated trip points.
• Enhanced System Safety: The 250F manual reset prevents the furnace from cycling automatically after a high-heat event, protecting the heat exchanger.
• Broad Application Range: Compatible with Lennox, Armstrong, and Ducane furnace models and packaged residential rooftop units.
• Professional Build Quality: Features high-grade pink ID color-coding and durable contacts designed for consistent normally closed operation.

Common Questions & Technical Support:

What causes a Lennox 57W75 to trip frequently?
Repeated tripping is usually a symptom of restricted airflow, often caused by a dirty air filter, a failing blower motor, or obstructed return ductwork. Always verify static pressure and temperature rise across the heat exchanger during troubleshooting.

Can the 57W75 replace an older 31J95 switch?
Yes, the Lennox 57W75 is the factory-authorized functional and physical successor to the 31J95 limit switch. It maintains the same 250°F trip settings and manual reset functionality.

How do I resolve a furnace E250 error code?
An E250 code typically indicates an open limit or rollout circuit. After the heat exchanger cools, press the manual reset button on the 57W75 switch. If the code persists or the switch trips again immediately, check for flame rollout or secondary limit issues.

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.