OEM Lennox Limit Switch — 10M75

The genuine OEM Lennox 10M75 limit switch is a critical high-temperature safety control in your Lennox gas furnace. It monitors the temperature in the heat exchanger and plenum, and if the air overheats — typically due to restricted airflow — it interrupts the gas valve to prevent damage and fire hazards. This normally-closed thermal switch is calibrated to open and reset at precise temperature setpoints matched to Lennox furnace models.

Common failure symptoms: The furnace short-cycles or shuts down on a high-limit fault, the burners light then quickly shut off, the blower runs but no heat is delivered, or the furnace repeatedly trips into lockout. A limit switch stuck open blocks heating entirely, while one stuck closed defeats a vital safety function.

Why OEM matters: The 10M75 is trip-temperature and reset-temperature specific — using a switch with the wrong rating can allow dangerous overheating or cause constant nuisance trips. The OEM Lennox part guarantees the correct temperature calibration, terminal configuration, and mounting fit for safe, code-compliant operation. Don't compromise on a safety device; install the factory-authorized limit switch.