OEM Lennox High Altitude Pressure Switch — 15M22

The genuine OEM Lennox 15M22 is a high-altitude pressure switch that verifies proper draft and combustion airflow in your Lennox gas furnace before the ignition sequence begins. It is specifically calibrated for high-elevation installations, where thinner air changes the pressure the switch must sense. The 15M22 confirms the inducer motor is moving flue gases correctly and safely closes the circuit to allow ignition only when adequate draft is present.

Common failure symptoms: The furnace inducer runs but the burners never light, the unit short-cycles or locks out, or a pressure-switch fault appears at the control board. Failures often stem from a stuck diaphragm, cracked sensing tubing, or a switch that no longer closes at its rated pressure — leaving the furnace unable to prove draft.

Why OEM matters: Pressure switches are matched to an exact activation setpoint and elevation range. The high-altitude Lennox 15M22 is factory-calibrated for the correct pressure threshold, so substituting a standard or off-spec switch can cause nuisance lockouts or unsafe operation. Install the genuine OEM part for guaranteed calibration, proper fit, and dependable safety performance in your Lennox furnace.