York S1-024-35978-000 -0.67″WC SPNO Close On Fall Pressure Switch

Description

The York S1-024-35978-000 is an OEM replacement pressure switch engineered for reliable system protection in York HVAC equipment. With a set point of -0.67″ water column (WC), this Single Pole Normally Open (SPNO) switch is designed to close its contacts when system pressure falls to or below the calibrated threshold — a critical safety and operational function in furnace and air handler applications.

How It Works

This pressure switch operates on a “Close On Fall” principle: the electrical circuit remains open under normal operating pressure and closes when the monitored pressure drops to the -0.67″ WC set point. This configuration is commonly used to verify proper draft inducer operation, ensuring combustion gases are safely vented before allowing ignition to proceed.

Key Features

• OEM York replacement part — ensures proper fit and function
• Set point: -0.67″ WC (water column)
• Switch type: Single Pole Normally Open (SPNO)
• Action: Close On Fall — contacts close when pressure drops to set point
• Designed for draft inducer / combustion air pressure monitoring
• Direct OEM replacement for compatible York furnace and air handler models

Application

This pressure switch is a direct OEM replacement for select York gas furnaces and heating systems. It monitors negative pressure created by the draft inducer motor to confirm adequate venting airflow. If the inducer fails to generate sufficient negative pressure, the switch remains open, preventing ignition and protecting against unsafe flue gas conditions.

Why Choose OEM York Parts?

Using genuine York OEM components ensures compatibility, maintains equipment warranties, and delivers the performance reliability your system was designed for. The S1-024-35978-000 is the correct factory-specified replacement to restore safe, efficient operation.