York S1-024-27636-001 -0.85″ W.C. SPNO Close on Fall Pressure Switch

Description

The York S1-024-27636-001 is an OEM replacement pressure switch engineered for use in York HVAC systems. Designed with a Single Pole, Normally Open (SPNO) configuration, this switch closes its contacts when system pressure falls to the -0.85″ W.C. set point — providing reliable low-pressure detection and equipment protection.

How It Works

This “Close on Fall” pressure switch monitors negative pressure within the HVAC system. When pressure drops to or below the -0.85″ W.C. threshold, the normally open contacts close, signaling the control board to take the appropriate action — such as enabling the draft inducer or triggering a safety lockout. This ensures safe, efficient furnace or air handler operation by confirming proper airflow and venting conditions.

Key Features

• OEM York replacement part — direct-fit for compatible York equipment
• Set point: -0.85″ W.C. (inches of water column)
• Switch action: Single Pole, Normally Open (SPNO)
• Function: Close on Fall — contacts close when pressure drops to set point
• Designed for draft pressure monitoring in furnaces and air handlers
• Helps protect equipment from unsafe operating conditions due to blocked venting or inadequate airflow

Application

This pressure switch is commonly used in York gas furnaces and HVAC systems to verify that the draft inducer is operating correctly before allowing ignition. It is a critical safety component that prevents unsafe combustion conditions.

Specifications

• SKU: S1-024-27636-001
• Brand: York
• Set Point: -0.85″ W.C.
• Switch Type: SPNO (Single Pole, Normally Open)
• Action: Close on Fall