OEM Lennox Limit Switch — 49L86

The genuine OEM Lennox 49L86 limit switch is a high-temperature safety device built for Lennox furnaces and heating systems. It monitors heat exchanger and plenum temperatures and automatically de-energizes the burners whenever the system runs hotter than its safe threshold — protecting against overheating, heat exchanger damage, and fire risk. Each switch is factory-calibrated to the specific trip temperature your Lennox model was engineered to use.

Common failure symptoms: A failing 49L86 often causes the furnace to short cycle, the blower to run non-stop, or the unit to produce no heat at all. When the switch drifts out of calibration, it may trip on normal operating temperatures — resulting in nuisance lockouts and inconsistent comfort throughout your home.

Why OEM matters: The safety function of a limit switch depends entirely on its precise calibration. Generic replacements frequently use different trip points that either compromise protection or trigger false shutdowns. Choosing the OEM Lennox 49L86 ensures an exact fit, factory-rated temperature setpoint, and guaranteed compatibility with your equipment — keeping your Lennox furnace running safely and efficiently.