OEM Lennox Pressure Switch with Bracket — 12W49

The genuine OEM Lennox 12W49 pressure switch ships complete with its mounting bracket for a direct, factory-correct fit. This safety component monitors negative air pressure created by the draft inducer to confirm that the flue is clear and combustion gases are venting properly before the furnace allows ignition. It is a critical link in your Lennox furnace's safety chain, preventing operation under unsafe venting conditions.

Common failure symptoms: A faulty 12W49 pressure switch often causes the furnace to short-cycle, lock out after a few seconds, or fail to ignite entirely. You may also see a specific fault code flashed on the control board or hear the inducer run without the burners lighting. Corroded contacts, a cracked diaphragm, or a blocked pressure port are typical culprits.

Why OEM matters: Lennox calibrates each pressure switch to a precise trip point matched to your furnace model. Generic or aftermarket switches with the wrong set point can cause nuisance lockouts or, worse, allow unsafe operation. Installing the OEM 12W49 ensures the exact pressure calibration, bracket alignment, and connector fit your Lennox equipment was engineered for.