York S1-025-27747-009 Limit Switch

The York S1-025-27747-009 Limit Switch is a critical OEM furnace safety control designed to maintain thermal integrity within high-performance heating systems. Engineered with a 140°F trip point, this manual reset limit switch serves as the primary safeguard against heat exchanger overheating and potential cracked cells. As a genuine Source 1 replacement part, it ensures factory-standard calibration for York, Luxaire, and Coleman gas furnaces, preventing the unsafe cycling often caused by airflow restrictions or blower motor failure. For service technicians, utilizing this single-pole single-throw (SPST) safety component is essential for restoring the rollout protection circuit and ensuring the HVAC high limit control meets manufacturer specifications. Built for high-cycle durability, it provides a precise thermal cutout to protect both the equipment and the structure, fulfilling the rigorous demands of residential and light commercial furnace repair and maintenance.

Key Benefits for Contractors

• OEM Precision: Guaranteed compatibility with York heating equipment, eliminating the liability risks associated with universal aftermarket components.
• Manual Reset Safety: The M/R design requires a technician to inspect the system before restarting, ensuring the root cause of overheating is identified and resolved.
• Standardized Calibration: Pre-set to 140 degrees Fahrenheit to align with furnace high limit switch safety parameters.
• Durable Construction: Engineered to withstand the thermal stresses of the heat exchanger cabinet environment without premature fatigue.
• Direct Fitment: Standard mounting footprint and terminal spacing facilitate rapid field replacement during emergency service calls.

Common Questions

What causes a manual reset limit switch to trip?

In most York furnaces, this switch trips due to restricted airflow, such as a clogged 1-inch filter, a failing inducer motor, or a blocked secondary heat exchanger. It acts as a safety barrier to prevent the unit from operating under dangerous temperature conditions.

Can I replace a 140°F M/R switch with an auto-reset model?

No. Replacing a manual reset limit switch with an auto-reset version is a safety violation. The manual reset requirement ensures that a qualified HVAC technician evaluates the system to prevent repeated overheating which could lead to equipment failure.

Is this switch compatible with other Source 1 brands?

Yes, the S1-025-27747-009 is the correct OEM replacement for various models under the Johnson Controls umbrella, including Coleman and Luxaire furnaces that specify this part number.

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.