{"product_id":"oem-lennox-bottom-burner-box-61m21","title":"OEM Lennox Bottom Burner Box — 61M21","description":"\u003cp\u003eThe Lennox \u003cstrong\u003e61M21\u003c\/strong\u003e (factory reference LB-100712D) is the bottom burner box that mounts and aligns the gas burners within your Lennox furnace. It establishes the correct combustion geometry and airflow so the burners ignite cleanly and channel heat into the heat exchanger safely and efficiently. This part is a direct OEM replacement for the original bottom burner box.\u003c\/p\u003e\u003cp\u003eA corroded, warped, or damaged burner box can cause flame misalignment, incomplete combustion, sooting, delayed ignition, or nuisance trips on the flame sensor and rollout switch. Symptoms such as yellow or lifting flames, unusual burner noise, or repeated safety lockouts warrant inspection of the burner box and its mounting.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy OEM matters:\u003c\/strong\u003e Lennox builds the \u003cstrong\u003e61M21\u003c\/strong\u003e to exact combustion tolerances for their furnace models. Aftermarket substitutes can disrupt flame travel, airflow, and burner spacing, undermining efficiency and safety. The genuine OEM box guarantees proper fit, rated performance, and adherence to Lennox specifications.\u003c\/p\u003e","brand":"Lennox","offers":[{"title":"Default Title","offer_id":63081128919411,"sku":"LNX-61M21","price":49.95,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0984\/1190\/5395\/files\/nhvac-burner-ribbon-LNX-61M21.jpg?v=1783759513","url":"https:\/\/nationalhvacparts.com\/products\/oem-lennox-bottom-burner-box-61m21","provider":"National HVAC Parts","version":"1.0","type":"link"}