York S1-025-41320-000 Limit Switch

The York S1-025-41320-000 Limit Switch is a critical safety component designed for precise thermal regulation in York, Luxaire, and Coleman furnace models. This L140-40F limit switch functions as a high-limit protection device, set to open at 140°F and automatically reset at 100°F. Engineered for high-cycle reliability, this OEM replacement part monitors the heat exchanger plenum temperature to prevent overheating, which can lead to cracked heat exchangers or hazardous operating conditions. It is a direct fit for HVAC high limit switch applications in units such as the TG8S, TM9V, and TMLX series. For technicians, this auto-reset temperature control ensures the system stays within safe thermal parameters by breaking the 24V circuit to the gas valve if airflow is restricted by a clogged filter or failing blower motor, while the 40-degree differential provides stable operation without premature nuisance tripping.

• Precise Thermal Calibration: Calibrated to an opening temperature of 140°F with a 40°F differential for accurate system protection.
• Direct OEM Compatibility: Specifically designed to replace York furnace part S1-025-41320-000 without the need for mounting modifications.
• Automatic Reset Functionality: Eliminates the need for manual intervention once the plenum temperature returns to the safe closing point of 100°F.
• Safety Compliance: Prevents furnace short cycling and potential fire hazards by reacting instantly to excessive internal heat.
• Durable Construction: Built to withstand the constant thermal fluctuations typical in residential and light commercial fan-limit control circuits.

What causes a York L140-40F limit switch to trip frequently?
Repeated tripping is usually a symptom of restricted airflow. Check for a dirty air filter, blocked return grilles, or a failing blower motor capacitor. If the limit switch stays open even after the system cools down, it likely has no continuity and requires replacement.

Is the S1-025-41320-000 compatible with other brands?
Yes, as an OEM part for the Johnson Controls family, it is the standard replacement limit switch for many Luxaire and Coleman air handlers and furnaces that specify an L140-40 sensor.

How do I test if this high limit switch is defective?
Using a multimeter set to the lowest Ohms setting, check for continuity across the terminals at room temperature. A functioning switch should show approximately 0 Ohms when cool. If you see infinite resistance (OL), the internal bimetal disc or contacts have failed.

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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.