York S1-2985-3181 Limit Switch

The York S1-2985-3181 Limit Switch is a critical OEM safety component designed for high-limit protection in residential and light commercial furnace applications. This 160-190F Auto Limit Switch features a primary safety circuit that opens when the internal plenum temperature reaches its 190°F trip point, effectively de-energizing the gas valve or heating elements to prevent heat exchanger damage or hazardous overheating. As an automatic reset limit control, the internal bimetallic disc re-engages the circuit once the system cools to the 160°F threshold, allowing the unit to resume its heating cycle.

Engineered for high-duty cycle reliability, the York replacement limit switch is often cross-referenced with part number 208W47 and specifically fits York, Coleman, and Luxaire models like the 2970A766. When diagnosing intermittent shut-offs or furnace short cycling, technicians should verify this switch's continuity. If the furnace high limit switch trips frequently, ensure airflow is not restricted by a secondary heat exchanger blockage or a failed blower motor before concluding the sensor is out of calibration. This genuine Source1 HVAC part ensures precise thermal response and direct pin-to-pin compatibility for rapid field replacement.

• Precise Thermal Call: Calibrated with a 190°F open and 160°F close range for optimal system protection.
• OEM Standards: Direct York S1-2985-3181 replacement ensures proper fitment without the need for terminal modifications.
• Automatic Diagnostics: The auto-reset function simplifies troubleshooting for recurring thermal limit trips versus manual lockouts.
• System Longevity: Prevents terminal cracks in the heat exchanger by maintaining safe operating temperatures.

• Why is my York furnace short cycling with this limit switch? Frequent tripping usually indicates restricted airflow from a dirty filter, blocked vents, or a failing blower motor rather than a faulty switch.
• Can I use a 160-190F switch in place of a different temperature range? No. You must match the specific OEM temperature rating to ensure the safety circuit activates at the manufacturer’s specified safety limit.
• How do I test the S1-2985-3181? Using a multimeter, check for continuity across the terminals at room temperature. The switch should read as "closed."

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.