OEM Lennox Spark Electrode Ignitor — 21L98

The genuine OEM Lennox 21L98 spark electrode ignitor delivers the high-voltage spark that lights the burners on spark-ignition Lennox furnaces. Positioned precisely at the burner, its electrode gap creates the arc that ignites the gas at the start of every heating cycle, while the ceramic insulator keeps that spark isolated and consistent.

Common failure symptoms: When the 21L98 electrode wears, cracks, or its gap drifts out of spec, you'll often see weak or intermittent sparking, delayed ignition with a small "whoof," repeated ignition attempts, or a furnace that fails to light and locks out with no heat. A cracked ceramic insulator can also cause the spark to ground out before it reaches the burner.

Why OEM matters: Lennox builds the 21L98 to an exact electrode gap, rod length, and bracket alignment matched to its burner assembly and ignition control. An OEM electrode sparks in the correct location for fast, clean light-off; aftermarket substitutes frequently sit at the wrong gap or angle, causing hard starts and premature lockouts. Installing the OEM 21L98 restores dependable ignition and proper fit for compatible Lennox, Armstrong, and Ducane furnaces.