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Lennox

OEM Lennox Return Air Duct Zone Sensor Non-Communicating — 56L81

SKU: LNX-56L81 Brand: Lennox
$24.95 $34.95

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Texas CMBL #19328542014
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Govt POs Accepted

The Lennox 56L81 is a genuine OEM return air duct mount zone sensor engineered for non-communicating zoning applications, delivering industry-leading temperature accuracy of +/-0.36°F to ensure precise zone-level climate management in your Lennox system. If you notice temperature inconsistencies within specific zones, unresponsive zone control, or inaccurate readings reported back to the zone controller, this sensor may require replacement. Designed as a direct OEM replacement, the Lennox 56L81 is fully compatible with applicable Lennox zoning systems and installs easily into standard return air duct configurations.

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 Sensor fit my Lennox OEM Lennox Return Air Duct Zone Sensor Non-Communicating — 56L81?
Yes. This is the factory-specified OEM sensor for the Lennox OEM Lennox Return Air Duct Zone Sensor Non-Communicating — 56L81. 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 sensor on my Lennox OEM Lennox Return Air Duct Zone Sensor Non-Communicating — 56L81?
Difficulty: Easy (10–15 min)
Step 1: Turn off power/gas. Step 2: Open furnace panel. Step 3: Locate flame sensor rod near burners. Step 4: Remove single mounting screw. Step 5: Clean rod with 400-grit sandpaper until shiny (or replace). Step 6: Reinstall and tighten. Most common furnace repair — saves $150–$300 vs technician.
My furnace lights then shuts off after a few seconds. Why?
Furnace lights then shuts off after 3–10 seconds = dirty flame sensor in 90% of cases. The sensor can’t detect flame through oxidation buildup. Fix: clean with 400-grit sandpaper (free, 15 min). If cleaning doesn’t work, replace the sensor.
Is this sensor 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 sensor?
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