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Lennox

OEM Lennox Heat Exchanger LB-79081X — 54K42

SKU: LNX-54K42 Brand: Lennox
$39.95 $54.95

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Texas CMBL #19328542014
SAM.gov Registered
Govt POs Accepted

The genuine OEM Lennox 54K42 heat exchanger component (factory reference LB-79081X) is a precision-engineered part for your Lennox furnace's combustion system. It plays a direct role in transferring burner heat into the circulating air while helping keep flue gases safely separated from your home's air supply. Using the correct factory part protects both the efficiency and the safe operation of your equipment.

Common failure symptoms: visible cracking, corrosion, or warping, an erratic or yellow-tipped burner flame, soot accumulation, unusual ignition noises, odd smells during heating, or a carbon monoxide detector warning. Signs of a compromised heat exchanger call for prompt replacement.

Why OEM matters: the 54K42 is manufactured to the exact specification, materials, and dimensions Lennox designed for your unit. Generic alternatives may not seal or fit correctly, undermining heat transfer and long-term reliability. The genuine OEM part guarantees correct fit, rated performance, and dependable service life.

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 LB-79081X — 54K42?
Yes. This is the factory-specified OEM heat exchanger for the Lennox OEM Lennox Heat Exchanger LB-79081X — 54K42. 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 LB-79081X — 54K42?
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