OEM Lennox Flame Sensor — 98M87

The genuine OEM Lennox 98M87 flame sensor is a critical safety and ignition component in your Lennox gas furnace. It works on the principle of flame rectification — sending a small electrical current through the burner flame to confirm the furnace has actually lit. When the control board receives no signal, it shuts off the gas valve to prevent an unsafe buildup of unburned gas. This part is a direct factory replacement engineered to the exact tolerances of your Lennox equipment.

Common failure symptoms: A dirty, oxidized, or failing flame sensor is one of the most frequent causes of furnace short-cycling. You may notice the burners igniting and then shutting off after just a few seconds, the furnace locking out after several failed attempts, or intermittent no-heat calls — especially during cold snaps when the furnace runs most often.

Why OEM matters: Lennox control boards are calibrated to a specific microamp signal range. Aftermarket sensors often produce a weak or inconsistent flame signal that trips the safety lockout even when the furnace is running correctly. Choosing the OEM 98M87 guarantees proper flame rectification, reliable ignition, and full compatibility with your Lennox furnace's control logic.