York S1-024-35269-000 .55/1.3″ WC SPNO Close On Fall Pressure Switch

Description

The York S1-024-35269-000 is an OEM replacement pressure switch engineered for York heating systems. Designed as a Single Pole Normally Open (SPNO) device with a Close On Fall action, this switch monitors negative pressure produced by the draft inducer blower to verify proper venting before allowing the burner to fire — a critical safety function in modern gas furnaces.

How It Works

This pressure switch operates on the principle of differential pressure sensing. When the inducer motor runs and creates the correct level of negative pressure, the switch closes its contacts, signaling the control board that it is safe to proceed with ignition. If adequate pressure is not achieved — indicating a blocked flue, failed inducer, or restricted vent — the switch remains open and lockout occurs, protecting the heat exchanger and occupants.

Key Features

• OEM York replacement part — ensures proper fit and function
• Set points: .55″ / 1.3″ water column (WC)
• SPNO (Single Pole Normally Open) configuration
• Close On Fall action for draft-proving safety control
• Compatible with York furnace models requiring this pressure switch
• Supports reliable ignition sequencing and heat exchanger protection

Application

• York gas furnaces requiring draft inducer pressure proving
• Direct OEM replacement for failed or out-of-tolerance pressure switches
• Suitable for use by qualified HVAC technicians during routine maintenance or emergency service

Installation Notes

Always verify the pressure switch set points match the original equipment specifications before installation. Use a manometer to confirm inducer performance and rule out blocked flue or condensate drain issues prior to replacing the switch. Refer to the unit’s wiring diagram and service manual for proper connection procedures.