OEM Lennox Limit Switch — 75M32

The genuine OEM Lennox 75M32 limit switch is a high-temperature safety control that protects your Lennox furnace from overheating. Mounted on the heat exchanger or in the supply air stream, it continuously monitors temperature and opens the circuit to shut off the burners if heat rises above the safe threshold — for example, when airflow drops due to a dirty filter, failing blower, or blocked ductwork. This safeguards the heat exchanger and helps prevent unsafe operating conditions in your home.

A failing limit switch typically causes the furnace to short-cycle, shut down on a limit fault, or in some cases fail to fire at all. If the switch opens prematurely or won't reset, you'll experience intermittent heat and repeated lockouts even when airflow is normal. A switch stuck closed removes a critical layer of overheat protection.

OEM is essential for safety limits because each switch is calibrated to a specific trip and reset temperature matched to the furnace design. A generic switch with the wrong set point can nuisance-trip or fail to protect the system. The Lennox 75M32 is factory-matched to your equipment's exact specifications for reliable, safe operation.