OEM Lennox Pressure Switch — 44W31

The genuine OEM Lennox 44W31 pressure switch is a safety control that confirms the draft inducer is moving combustion air before the furnace ignites. Sensing negative pressure through a hose connected to the inducer or collector box, it closes to prove airflow and signals the control board that it is safe to open the gas valve and energize the igniter.

Common failure symptoms: a furnace that runs the inducer but never lights, ignition lockout after several attempts, or a flashing fault code indicating an open pressure switch. Failures often show up as a switch stuck open, contacts that no longer close, or a diaphragm that has lost its calibration — all of which prevent the burner from firing.

Why OEM matters: pressure switches are calibrated to a specific trip point (measured in inches of water column) for the exact furnace model they protect. The correct Lennox 44W31 guarantees the switch trips at the factory-specified pressure, so it reliably proves draft without nuisance tripping or unsafe operation. Substituting a switch with the wrong setpoint can allow the burner to fire without adequate venting. Use the OEM part to keep this critical safety interlock working as designed.