Lennox 57W76 Rollout Switch

The Lennox 57W76 Rollout Switch is a critical safety component designed for precise thermal monitoring in residential gas furnaces. Engineered to actuate at a fixed setpoint of 185 degrees F, this manual reset rollout switch serves as a high-limit flame sensor that interrupts the heating cycle if it detects excessive heat or flame rollout conditions outside the combustion chamber. Featuring a Single Pole Single Throw (SPST) configuration, the circuit opens on temperature rise to provide immediate system shutdown, protecting both the heat exchanger and surrounding furnace components from thermal damage.

This genuine OEM 57W76 thermal switch (Part # R37520B018) is built for long-term reliability in demanding HVACR environments. It utilizes 90-degree quick connect terminals for straightforward integration and is housed in a purple ID color coded casing for rapid identification during field Service. As a non-recycling safety limit, once the 185°F threshold is breached, the manual reset button must be engaged by a technician after the underlying cause of the rollout has been diagnosed and mitigated. This switch is frequently utilized across a broad range of Lennox, Armstrong Air, and Ducane furnace models, ensuring OEM furnace part compatibility and meeting strict factory specifications for safety and performance.

Key Benefits:

• Thermal Protection: Precisely calibrated to 185°F to prevent furnace overheating and potential fire hazards.
• Manual Reset Mechanism: Ensures the system is inspected by a professional before operation resumes after a trip.
• Direct OEM Replacement: Guaranteed fit for Lennox 57W76 and cross-referenced R37520B018 thermal limits.
• Industrial Build Quality: Features 1/4-inch terminals and a 5/8-inch insertion length for high-vibration furnace environments.

Common Questions:

What causes a Lennox rollout switch to trip?
A trip typically indicates a blockage in the flue, a cracked heat exchanger, or improper gas pressure causing flames to back out of the burner intake. This 185F M/R SPST rollout switch is designed to catch these specific safety failures.

Can I replace this switch with a higher temperature limit?
No. You must always use the 185°F specified limit to maintain the original safety certification and design parameters of the heating equipment.

Are these terminals compatible with standard furnace wiring?
Yes, the 57W76 features universal 90-degree quick-connect terminals designed for standard 1/4-inch female spade connectors used in most HVAC control circuits.

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.