Reznor 207178 Pressure Switch 0.20" WC for Gas Unit Heaters

The Reznor 207178 is a genuine OEM 0.20 inch water column (WC) pressure switch designed for use in Reznor gas-fired unit heaters and HVAC equipment. This critical safety component monitors combustion air pressure to ensure proper venting and safe operation of the heating system.

Key Features:

• 0.20" WC pressure setpoint for precise air flow monitoring
• OEM replacement part ensures exact fit and reliable performance
• Safety device that prevents burner operation if proper venting flow is not detected
• Compact, durable construction for easy installation
• Compatible with multiple Reznor unit heater models including ADF, ADFH, RDF, DV, DFAH, and DFAV series
• Part of pressure switch replacement kit 193806

This pressure switch serves as a combustion air proving switch, verifying that both the venter motor has established proper airflow before allowing the gas valve to energize. During the ignition sequence, the control system energizes the venter motor, goes through a prepurge cycle, and verifies the pressure switch is in the closed state before proceeding with ignition. If restrictions in the flue or excessive vent length cause sensing pressure to fall outside the switch setpoint, the switch will shut off the main burner until proper conditions are restored.

Installation Note: Pressure switch tubing connections should be verified during installation. Units may have positive and negative tubing connections or a single tubing connection depending on the model. Always ensure tubing is secure and properly connected to the appropriate sensing ports.