Lennox 19L57 Pressure Switch WC SPST Normally Open - 0.25

The Lennox 19L57 is a pressure switch designed for HVAC applications, providing reliable control based on air pressure differentials. This switch activates at 0.25 inches water column (WC), making it ideal for monitoring low-pressure conditions in furnaces, air handlers, and ventilation systems.

Key Features:

• Pressure activation point: 0.25" WC (inches water column)
• SPST-NO configuration (Single Pole Single Throw - Normally Open)
• Genuine OEM Lennox replacement part
• Precision-engineered for reliable pressure sensing
• Designed for residential and light commercial HVAC equipment

This pressure switch is commonly used as a safety interlock to verify proper draft or airflow before allowing equipment operation. The normally open contacts close when the specified pressure threshold is reached, completing the control circuit. Ideal for furnace draft proving, vent pressure monitoring, and airflow verification applications.