OEM Lennox Limit Switch — 86H72

The genuine OEM Lennox 86H72 limit switch is a high-temperature safety control that monitors heat exchanger and plenum temperature in your Lennox furnace. When temperatures climb past a safe threshold — usually from restricted airflow — the switch opens and shuts off the burners to prevent overheating and heat exchanger damage. This precision-calibrated switch is a direct factory replacement engineered for your Lennox equipment.

Common failure symptoms: A faulty 86H72 can cause the furnace to short-cycle on the limit, shut down mid-cycle, fail to fire the burners, or throw a limit-open fault code. Nuisance tripping when airflow is actually fine, or a switch that fails closed and never trips, both point to a limit switch that has drifted out of calibration and needs replacement.

Why OEM matters: Limit switches are set to the exact open and close temperatures required for your specific Lennox furnace model. The OEM 86H72 guarantees the correct trip point and mounting fit, preserving the factory-designed safety margin. An aftermarket switch with the wrong temperature rating can allow dangerous overheating or cause endless nuisance shutdowns. Protect your furnace and family with a genuine Lennox part.