OEM Lennox Stainless Steel Heat Exchanger Assembly — 19A66

The genuine OEM Lennox 19A66 stainless steel heat exchanger assembly is the primary heat-transfer component in your Lennox gas furnace. Combustion gases pass through its stainless channels while the blower moves household air across the exterior, warming your home without ever mixing the two streams. Stainless steel construction gives this assembly superior resistance to corrosion, condensation, and thermal fatigue, making it well suited for high-efficiency and secondary heat-exchange applications.

Common failure symptoms: Look for visible cracks, rust, or scaling on the exchanger surface, a burner flame that distorts or rolls out when the blower starts, banging or popping noises during startup and shutdown, unusual combustion odors, or repeated high-limit lockouts. Because a compromised heat exchanger can leak carbon monoxide, any of these signs should be inspected without delay.

Why OEM matters: The 19A66 is built to Lennox's exact stainless-steel specification, weld pattern, and airflow geometry. Genuine OEM parts deliver the rated AFUE efficiency, correct temperature rise, and certified safety performance your furnace was designed to achieve — while keeping your equipment warranty intact. Non-OEM substitutes risk improper fit, reduced service life, and voided coverage.