{"product_id":"oem-lennox-heat-exchanger-assembly-36m71","title":"OEM Lennox Heat Exchanger Assembly — 36M71","description":"\u003cp\u003eThe genuine OEM Lennox \u003cstrong\u003e36M71\u003c\/strong\u003e (interchange R20431903) heat exchanger assembly is the core combustion component of your Lennox gas furnace. It transfers heat from the burning gas to the air circulating through your home while keeping combustion byproducts safely separated from the breathable airstream. This assembly is engineered to the exact tolerances of the original Lennox furnace it was designed for, ensuring proper airflow, correct temperature rise, and rated efficiency.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCommon failure symptoms:\u003c\/strong\u003e A failing or cracked heat exchanger often shows up as a flickering or shifting burner flame, rust or corrosion streaks on the metal, soot buildup, unusual odors, or the furnace short-cycling on the flame-rollout or limit switch. A cracked exchanger can also allow carbon monoxide to enter the airstream — making prompt replacement a safety priority.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy OEM matters:\u003c\/strong\u003e Because a heat exchanger is a safety-critical, combustion-sealed part, only a genuine Lennox \u003cstrong\u003e36M71\u003c\/strong\u003e guarantees the precise fit, metal gauge, and weld integrity your furnace requires. Aftermarket substitutes risk poor sealing, premature cracking, and voided warranties. Choose the factory part for a safe, code-compliant, long-lasting repair.\u003c\/p\u003e","brand":"Lennox","offers":[{"title":"Default Title","offer_id":63081064202611,"sku":"LNX-36M71","price":399.95,"currency_code":"USD","in_stock":true}],"url":"https:\/\/nationalhvacparts.com\/products\/oem-lennox-heat-exchanger-assembly-36m71","provider":"National HVAC Parts","version":"1.0","type":"link"}