OEM Lennox Limit Switch — 49L03

The genuine OEM Lennox 49L03 limit switch is a critical safety control that monitors the temperature inside your furnace's heat exchanger and plenum. When temperatures climb too high, the switch shuts off the burners to prevent overheating and potential damage, while also signaling the blower to run and dissipate excess heat. Built to Lennox factory specifications, it is a direct replacement for compatible Lennox furnaces.

A failed or out-of-calibration limit switch causes frustrating and unsafe behavior. Common symptoms include the furnace short cycling, the blower running constantly, no heat output, or the unit shutting down repeatedly on high-limit faults. Because this component is a primary safety device, a faulty switch should always be replaced promptly with the correct part.

Installing the OEM Lennox 49L03 ensures the exact trip temperature and reset points match your furnace's engineered design — a precise match that generic switches cannot reliably provide. Using the authentic factory part protects your heat exchanger, ensures safe operation, and maintains your Lennox warranty. Restore dependable, safe heating with this genuine replacement limit switch.