OEM Lennox Furnace Heat Exchanger Assembly — 14D70

The genuine OEM Lennox 14D70 heat exchanger assembly (also cross-referenced as 612998-21 and 610280-10) is the core component that transfers heat from the combustion process to the air circulating through your Lennox furnace. As combustion gases pass through its sealed passages, the surrounding airflow is warmed and delivered to your home while flue gases are safely vented — keeping the breathable air separated from the products of combustion.

Common failure symptoms: A failing heat exchanger often shows visible cracks, rust, or corrosion, an unusual smell during operation, soot buildup, or a flickering burner flame that moves with the blower. In many cases a cracked heat exchanger will trip the flame sensor or safety limit, causing the furnace to short-cycle or lock out. Because a compromised heat exchanger can allow carbon monoxide to enter the airstream, replacement should never be delayed.

Why OEM matters: Lennox engineers the 14D70 to exact tolerances for its specific furnace models, ensuring proper sealing, correct gas flow, and rated combustion efficiency. Aftermarket substitutes can warp, leak, or fail to seat correctly, voiding warranties and risking safety. Choosing the OEM 14D70 assembly guarantees a precise fit and restores your furnace to factory performance.