York S1-025-28670-003 Limit Switch

The York S1-025-28670-003 Limit Switch is a critical safety component designed for precise thermal monitoring within York gas furnaces and residential air handlers. This automatic reset limit switch is engineered to operate within a specific 90-110F temperature range, ensuring the heat exchanger and plenum do not exceed safe operating parameters. When the sensed temperature hits the upper threshold, the internal bimetal disc opens the circuit to the gas valve or ignition control, then closes automatically once the system cools to the lower differential. For contractors servicing OEM York HVAC equipment, this high-limit control provides a direct-fit solution to resolve furnace short-cycling issues caused by drifted sensors. Its robust terminal construction ensures reliable continuity and rapid response times during high-static or restricted airflow conditions. Maintaining the integrity of the limit circuit is essential for preventing structural equipment damage and ensuring correct blower motor sequencing during the heating cycle.

Key Benefits for Technicians

• Exact OEM replacement part ensures full internal specification compatibility with York, Coleman, and Luxaire furnace models.
• Automatic reset functionality eliminates the need for manual intervention after the system reaches safe temperatures.
• Calibrated 90-110F thermal range provides accurate safety cycling to prevent overheating.
• Standard two-pin terminal configuration allows for a fast drop-in installation during service calls.
• Reliable bimetal sensing technology provides consistent performance across thousands of cycles.

Common Questions

How do I diagnose a faulty York S1-025-28670-003?
Use a multimeter to check for continuity across the terminals while the switch is at room temperature. An open circuit during a cold state typically indicates the internal disc has failed or the switch has migrated out of its calibrated range.

Does this switch require a manual reset button?
No, this is an auto-reset switch designed to automatically restore the electrical circuit once the sensed temperature drops back down to the 90-degree Fahrenheit reset point.

What causes this limit switch to trip frequently in a furnace?
Frequent tripping is usually a symptom of airflow restrictions, such as a clogged pleated filter, restricted return air ducting, or a failing blower motor, rather than a failing switch itself.

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.