York S1-024-35979-000 Pressure Switch

The York S1-024-35979-000 Pressure Switch is a critical safety component engineered for York, Coleman, and Luxaire residential and commercial furnaces. This OEM furnace pressure switch is calibrated to a specific set point of -0.15" WC (Water Column), featuring a Single Pole Normally Open (SPNO) configuration that is designed to close on a fall in pressure. As a veteran technician knows, this switch monitors the negative pressure generated by the draft inducer motor, ensuring that exhaust gases are safely vented before the ignition sequence begins. If the inducer fails to reach the proper RPM or if there is a vent blockage, the switch remains open, preventing the gas valve from energizing and protecting the heat exchanger from dangerous flue gas buildup. This high-reliability HVAC safety switch is crucial for resolving the common 4-flash error code on York control boards, ensuring consistent airflow verification and system uptime during peak heating cycles.

• Precise Calibration: Factory-set at -0.15" WC for accurate sensing of vacuum pressure, preventing ignition under unsafe venting conditions.
• Direct OEM Replacement: Engineered specifically for compatibility with Source1 equipment, including popular ACP, CP9C, and 2EE furnace models.
• Enhanced Safety: The SPNO (Close on Fall) logic acts as a primary fail-safe against inducer motor failure or obstructed flue pipes.
• Durable Construction: Built with industrial-grade materials to withstand the high-temperature environment of the combustion chamber.

What does the 4-flash code mean on my York furnace?
This typically indicates a pressure switch fail-to-close error. It means the control board is not seeing the S1-024-35979-000 close when the inducer starts, often due to a clogged port, cracked pneumatic tubing, or a failing inducer motor.

Can I use a switch with a different WC rating?
No. Pressure switches must match the manufacturer's specified inches of water column exactly. Using a switch with a higher or lower rating can lead to premature shutdowns or, more dangerously, allow the furnace to run with insufficient venting.

How do I test if this switch is faulty?
Using a manometer and a multimeter, verify that the inducer is pulling at least -0.15" WC. If the vacuum is sufficient but the SPNO switch fails to show continuity across the terminals, the internal diaphragm or electrical contacts have likely 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.