York S1-024-35274-000 -0.2/-0.4 SPNO Close on Fall Pressure Switch

Description

The York S1-024-35274-000 is an OEM single-pole, normally open (SPNO) pressure switch engineered to close on a fall in pressure. With set points of -0.2″ and -0.4″ W.C., this switch is designed to monitor negative pressure (draft/vacuum) conditions in York heating systems, proving proper inducer or combustion airflow before allowing burner operation. It is a direct OEM replacement, ensuring precise fit and reliable performance in the systems it was designed for.

Key Features

• OEM York replacement pressure switch — direct fit for compatible York systems
• Single-pole, normally open (SPNO) contact configuration
• Close-on-fall action: contacts close when pressure drops to the set point
• Set points: -0.2″ W.C. and -0.4″ W.C. (negative pressure / vacuum range)
• Designed to prove inducer draft and combustion airflow for safe burner ignition
• Helps prevent burner operation under unsafe or insufficient draft conditions
• Durable construction for long service life in residential and light commercial applications

Application

This pressure switch is a critical safety and control component in York furnaces and air handlers. It monitors the negative pressure generated by the draft inducer blower. When the inducer establishes adequate draft (pressure falls to the switch set point), the SPNO contacts close, signaling the control board that it is safe to proceed with ignition. If draft is lost during operation, the contacts open, shutting down the burner to prevent unsafe conditions.

Specifications

• Part Number: S1-024-35274-000
• Brand: York
• Contact Type: SPNO (Single Pole Normally Open)
• Switch Action: Close on Fall
• Set Points: -0.2″ / -0.4″ W.C.
• Application: Draft-proving / inducer pressure sensing