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Lennox

OEM Lennox 100679-66 Thermal Expansion Valve 5 Ton R410A — 17G77

SKU: LNX-17G77 Brand: Lennox
$59.95 $84.95

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Texas CMBL #19328542014
SAM.gov Registered
Govt POs Accepted

The Lennox 17G77, also identified as OEM part number 100679-66, is a genuine thermal expansion valve (TXV) rated for 5-ton R410A cooling-only applications without an integrated check valve, designed specifically for compatible Lennox air conditioning systems. A failing TXV can cause symptoms such as poor cooling performance, frost buildup on the evaporator coil, inconsistent superheat readings, or the system short-cycling. This direct OEM replacement ensures accurate refrigerant metering and optimal system efficiency for your Lennox cooling equipment.

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 100679-66 Thermal Expansion Valve 5 Ton R410A — 17G77?
Yes. This is the factory-specified OEM valve for the Lennox OEM Lennox 100679-66 Thermal Expansion Valve 5 Ton R410A — 17G77. 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 100679-66 Thermal Expansion Valve 5 Ton R410A — 17G77?
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
HVAC Parts Specialist — Online