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The genuine OEM Lennox 82M33 pressure switch is a critical safety device that confirms proper draft and venting before your furnace is allowed to ignite. It monitors the negative pressure created by the inducer motor and closes only when airflow is sufficient to safely carry combustion gases out of the home. If adequate draft isn't detected, the switch keeps the gas valve closed to prevent unsafe operation.
Common failure symptoms: the furnace inducer runs but ignition never occurs, repeated lockouts, error codes indicating an open or stuck pressure switch, short cycling, or a furnace that fails to start on cold mornings. A cracked hose, blocked port, or worn diaphragm are frequent culprits.
Why OEM matters: Lennox pressure switches are calibrated to a specific trip point measured in inches of water column, matched to your furnace's inducer and venting design. Installing a switch with the wrong setpoint can cause nuisance lockouts or, worse, allow operation under unsafe draft conditions. The OEM 82M33 guarantees the correct calibration and fit for dependable, safe Lennox performance.