OEM Lennox Furnace High-Limit Switch — 26H6501

The genuine OEM Lennox 26H6501 high-limit switch is a critical safety control mounted on the heat exchanger or blower housing of your Lennox furnace. It continuously senses plenum temperature and opens the burner circuit if the furnace overheats — typically from restricted airflow or a failed blower — protecting the heat exchanger and preventing dangerous conditions. It is calibrated to the precise trip and reset temperatures Lennox specifies for its furnace platforms.

Common failure symptoms: A worn 26H6501 can cause the furnace to short-cycle on heat, shut down mid-cycle, fail to fire at all, or trip repeatedly even with clean filters and good airflow. A switch stuck open produces no heat, while one that has drifted out of calibration may nuisance-trip or fail to protect against genuine overheating.

Why OEM matters: A limit switch is a safety device, and off-spec aftermarket units may trip at the wrong temperature or fail to open when they should. The factory-original 26H6501 delivers the exact calibration, mounting fit, and terminal configuration your Lennox furnace requires — safeguarding the heat exchanger and keeping the system within its rated operating limits.