OEM Lennox Limit Switch — 47W64

The genuine OEM Lennox 47W64 limit switch is a critical high-temperature safety control found in Lennox gas and electric furnaces. It continuously monitors the temperature inside the heat exchanger and blower compartment, opening the circuit to shut down the burners if the unit overheats. This protects the heat exchanger from cracking and prevents dangerous conditions caused by restricted airflow, a failing blower motor, or a clogged filter.

When the 47W64 fails, you may notice the furnace short-cycling, the burners igniting and then quickly shutting off, no heat despite the thermostat calling, or a limit-related fault code on the control board. A switch that trips prematurely or fails open leaves your system without proper safety protection.

Choosing an OEM Lennox part matters because the 47W64 is calibrated to the exact trip temperature and reset point specified for your Lennox furnace. Generic substitutes may have incorrect temperature ratings or mounting dimensions, leading to nuisance trips or inadequate protection. Install the factory-engineered replacement to restore safe, reliable heating performance.