{"product_id":"oem-lennox-heat-exchanger-assembly-lb-65729d-43j44","title":"OEM Lennox Heat Exchanger Assembly LB-65729D — 43J44","description":"\u003cp\u003eThe genuine OEM Lennox \u003cstrong\u003e43J44\u003c\/strong\u003e heat exchanger assembly, also cataloged as \u003cstrong\u003eLB-65729D\u003c\/strong\u003e, is the primary combustion-to-air transfer component in your Lennox furnace. As the burners fire, this assembly absorbs the heat and releases it into the moving air stream while safely venting flue gases away from your home. It is built to the exact Lennox specification for surface area, clearance, and fit.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCommon failure symptoms:\u003c\/strong\u003e Look for rust flaking, visible cracks along the seams or bends, a yellow or wavering burner flame, soot accumulation, and loud popping, rumbling, or booming during startup. A compromised exchanger can also cause the limit switch to trip, short-cycle the system, and set off carbon monoxide alarms.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy OEM matters:\u003c\/strong\u003e The heat exchanger is the barrier between combustion gases and your breathing air, making it one of the most safety-critical parts in the furnace. Only the genuine Lennox \u003cstrong\u003e43J44\u003c\/strong\u003e \/ \u003cstrong\u003eLB-65729D\u003c\/strong\u003e guarantees the factory-grade steel, weld quality, and dimensions required to fit correctly and vent safely. Replacement should always be performed by a licensed HVAC technician.\u003c\/p\u003e","brand":"Lennox","offers":[{"title":"Default Title","offer_id":63081064464755,"sku":"LNX-43J44","price":399.95,"currency_code":"USD","in_stock":true}],"url":"https:\/\/nationalhvacparts.com\/products\/oem-lennox-heat-exchanger-assembly-lb-65729d-43j44","provider":"National HVAC Parts","version":"1.0","type":"link"}