Lennox 33W18 2-Stage Pressure Switch Assembly 0.20"/1.32" WC

The Lennox 33W18 is an OEM 2-stage pressure switch assembly designed for use in Lennox gas furnaces and HVAC systems. This genuine replacement part monitors combustion air pressure and controls furnace operation by activating at two distinct pressure set points to support dual-stage heating operation.

Key Specifications:

• Manufacturer Part Number: 101599-02
• Low Pressure Set Point: 0.20" W.C. (water column)
• High Pressure Set Point: 1.32" W.C. (water column)
• Contact Rating: 5 Amp Resistive at 24 VAC
• Configuration: SPST-N.O. (Single Pole Single Throw - Normally Open)
• Weight: 0.5 lbs

Function and Benefits:

• Monitors air pressure changes in the combustion air system to ensure safe furnace operation
• Automatically turns the furnace on or off based on detected pressure levels
• Protects against unsafe operating conditions by preventing ignition when proper airflow is not detected
• Designed for two-stage furnace applications for improved efficiency and comfort
• Engineered to match Lennox manufacturer specifications for perfect fit and reliable performance

This pressure switch assembly is a critical safety component that should be installed by a qualified HVAC technician with properly calibrated combustion test equipment. Cross-reference part numbers include BA20230 and Honeywell 1913/316192.