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Lennox

OEM Lennox 100679-21 Valve-Expansion (R410) — 42W34

SKU: LNX-42W34 Brand: Lennox
$59.95 $84.95

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Texas CMBL #19328542014
SAM.gov Registered
Govt POs Accepted

The Lennox 42W34 (OEM reference 100679-21) is a genuine factory-original R410A thermostatic expansion valve that controls the flow of refrigerant into the evaporator coil to maintain proper system superheat and efficiency. Common signs of a failing expansion valve include inconsistent cooling, frost buildup on the evaporator, or unusually high or low suction line pressures. This OEM Lennox part is manufactured to precise specifications to ensure a direct, reliable fit for compatible Lennox R410A systems.

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 Valve fit my Lennox OEM Lennox 100679-21 Valve-Expansion (R410) — 42W34?
Yes. This is the factory-specified OEM valve for the Lennox OEM Lennox 100679-21 Valve-Expansion (R410) — 42W34. 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 valve on my Lennox OEM Lennox 100679-21 Valve-Expansion (R410) — 42W34?
Requires licensed HVAC technician. Gas valve work involves gas lines that must meet local building codes. Improper installation risks dangerous gas leaks. Buy the part yourself to save 40–60% on markup, then have your technician install it.
What symptoms mean I need a new valve?
Common symptoms: unusual noises, intermittent operation, complete failure, or visible damage. Visit our diagnostic hub for symptom-based troubleshooting.
Is this valve 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 valve?
Always use OEM. Gas valves must match exact pressure ratings, port configurations, and safety certifications. Non-OEM gas valves can create safety hazards and may violate building codes.
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
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