York S1-3500-3151/A Limit Switch

The York S1-3500-3151/A Limit Switch is a critical safety component engineered for precise thermal regulation within HVAC furnace units and air handling systems. This specific high limit safety control operates with a fixed temperature range of 55-155°F, acting as a primary safeguard against heat exchanger overheating. Featuring automatic reset functionality, the switch restores the electrical circuit once the internal temperature drops safely below the 55°F threshold, ensuring a return to normal operational cycles without manual intervention. As a critical OEM replacement part, this component ensures the system adheres to the original equipment manufacturer’s specifications for airflow safety. For service technicians, this switch is the standard solution for resolving lockout codes related to over-temperature faults. Its robust construction is designed to withstand the rapid thermal cycling typical of high-efficiency residential and light commercial equipment, providing accurate HVAC system protection and long-term reliability in the field.

• Automatic Reset: Eliminates the need for manual restarts after the system cools to safe parameters.
• OEM Precision: Direct replacement for York systems ensures compatible mounting and electrical termination.
• Thermal Accuracy: Factory-calibrated 55-155°F range prevents heat exchanger fatigue and potential safety hazards.
• Durable Contacts: Built to handle the inductive loads of furnace control circuits and ignition sequences.

What causes this limit switch to trip repeatedly? Frequent tripping is usually a symptom of restricted airflow, often caused by a heavily soiled air filter, a failing blower motor, or undersized ductwork causing the heat exchanger to exceed 155°F.

How do I verify if my York S1-3500-3151/A is faulty? Use a multimeter to check for continuity across the terminals when the switch is cool. If the switch remains open at room temperature, the internal bimetal disc has failed and requires replacement.

Does this switch require a specific mounting orientation? For optimal sensing, it should be mounted using the existing factory bracket to ensure the sensing element is directly in the path of the discharge air as specified by the equipment manual.

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.