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Lennox

OEM Lennox Heat Exchanger Assembly — 57L31

SKU: LNX-57L31 Brand: Lennox
$399.95 $549.95

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Texas CMBL #19328542014
SAM.gov Registered
Govt POs Accepted

The OEM Lennox 57L31 heat exchanger assembly moves heat from the furnace burners into the circulating air while sealing combustion byproducts away from your indoor air. Manufactured to exact Lennox tolerances, it fits and seals correctly in compatible furnace platforms so your system heats efficiently and safely.

Common signs that the heat exchanger needs replacing include cracks or corrosion on the exchanger surface, a burner flame that pulls or flutters when the blower runs, soot deposits, strange smells during operation, or repeated limit-switch shutdowns. Any of these can indicate a breach that risks carbon monoxide exposure, making prompt replacement essential.

OEM is the only safe choice for a combustion component. The genuine Lennox 57L31 uses the correct metallurgy and forming to survive constant heating and cooling cycles and to mate perfectly with the burner assembly. Off-brand parts may not hold the seal or the thermal load, jeopardizing safety, efficiency, and your Lennox warranty.

Shipping Information

  • Orders placed before 3PM CST ship same business day
  • Standard delivery: 2-5 business days
  • Express shipping available at checkout
  • Free shipping on orders over $75
  • Tracking number emailed upon shipment

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

Frequently Asked Questions

Does this Heat Exchanger fit my Lennox OEM Lennox Heat Exchanger Assembly — 57L31?
Yes. This is the factory-specified OEM heat exchanger for the Lennox OEM Lennox Heat Exchanger Assembly — 57L31. It is a direct drop-in replacement that fits without modification. Always verify the model number on your equipment nameplate before ordering.
How do I replace the heat exchanger on my Lennox OEM Lennox Heat Exchanger Assembly — 57L31?
Refer to your equipment service manual for model-specific steps. General approach: turn off power, photograph connections, remove old part, install new part, restore power and test. For gas components, hire a licensed technician. Email info@nationalhvacparts.com for guidance.
What symptoms mean I need a new heat exchanger?
Common symptoms: unusual noises, intermittent operation, complete failure, or visible damage. Visit our diagnostic hub for symptom-based troubleshooting.
Is this heat exchanger compatible with Bryant or Payne too?
Many Lennox parts are cross-compatible with Bryant and Payne since all three brands are manufactured by Carrier Global Corporation. The same physical part is often used across brand labels with different model numbers. To verify: check your Bryant or Payne equipment service manual for cross-compatible part numbers, or email info@nationalhvacparts.com with your model number.
Should I use OEM or aftermarket for my Lennox heat exchanger?
OEM recommended for reliability and warranty compatibility. OEM parts match exact factory specifications for proper fit, performance, and safety. While aftermarket alternatives cost less upfront, the risk of improper fit and reduced lifespan usually makes OEM the better value long-term.
How fast does National HVAC Parts ship?
Orders placed before 3:00 PM CST ship the same business day. Standard delivery is 2–5 business days anywhere in the continental United States. Express shipping available at checkout. We ship from Houston, TX to all 50 states. 30-day return policy on all parts.
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Mike Rivera
HVAC Parts Specialist — Online