OEM Lennox Burner Box Assembly — 43W05
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The Lennox 43W05 burner box assembly (factory drawing LB-66958) houses and positions the furnace burners, delivering a stable, correctly aligned gas-air flame to the heat exchanger. Precise burner placement within the box is what ensures clean, safe combustion and even heat transfer throughout your Lennox furnace.
Common failure symptoms: delayed ignition or rollout, a yellow or lazy flame, sooting, rust and scale inside the box, warped or cracked housing, unusual combustion noise, and repeated flame-sensor or ignition lockouts. Years of heat cycling and corrosion can distort the assembly and misalign the burners.
Why OEM matters: the genuine Lennox 43W05 is engineered to hold the burners at the exact orifice spacing, orientation, and clearances your furnace was certified for, protecting flame quality and combustion safety. Aftermarket assemblies often misposition burners, disrupt the air-fuel mixture, and increase rollout risk. Installing the authentic OEM burner box restores factory-spec combustion, efficiency, and safety for your Lennox equipment.
Shipping Information
- Orders placed before 3PM CST ship same business day
- Standard delivery: 2-5 business days
- Express shipping available at checkout
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Return Policy
- 30-day returns on unused parts in original packaging
- Electrical parts (capacitors, contactors, control boards) are final sale once installed
- Email info@nationalhvacparts.com to initiate a return
- Refunds processed within 5-7 business days