OEM Lennox Limit Switch — 87H90

The genuine OEM Lennox 87H90 limit switch is a critical safety control that monitors heat exchanger temperature in your Lennox furnace. If the unit overheats — typically from restricted airflow or a failed blower — this switch interrupts the burner circuit to prevent damage to the heat exchanger and reduce fire risk. It is a factory-specified component engineered to trip at the exact temperature threshold your Lennox system requires.

Common failure symptoms: Watch for a furnace that short-cycles (burner lights then shuts off quickly), no heat output despite a call for heat, or a blower that runs continuously. A limit switch that has weakened or drifted out of calibration will trip prematurely or fail to reset, leaving you without reliable heat.

Why OEM matters: Aftermarket limit switches often trip at incorrect temperatures, which can cause nuisance shutdowns or, worse, allow dangerous overheating. The OEM Lennox 87H90 is calibrated to factory specification, guaranteeing correct trip and reset points, proper terminal fit, and full compatibility with your furnace's control sequence. Protect your heat exchanger and your warranty with the exact part Lennox engineered for the job.