OEM Lennox Heat Exchanger Assembly — 99M83

The genuine OEM Lennox 99M83 heat exchanger assembly is the core component that transfers heat from combustion gases to the air circulating through your furnace, keeping the combustion byproducts safely separated from your home's breathable air. Precision-engineered to Lennox factory specifications, it delivers the correct clamshell geometry and metallurgy required for proper airflow, rated efficiency, and safe operation in your Lennox gas furnace.

A failing heat exchanger typically shows up as visible cracks or rust, a flickering or lifting burner flame, soot buildup, a strong odor during heating cycles, or a furnace that repeatedly locks out on the limit switch. Because a compromised heat exchanger can allow flue gases — including carbon monoxide — to mix with your supply air, this is a safety-critical part that should never be run past its service life.

Choosing OEM matters on a component this important. The 99M83 is built to the exact dimensions, alloy, and pressure tolerances Lennox engineered for your model, ensuring a leak-free seal, proper fit against the burner box and blower, and full compatibility with the unit's safety controls. Aftermarket substitutes often vary in thickness and shape, risking premature failure and voided warranty coverage.