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Lennox

OEM Lennox Switch Blower Prove Sp Open 10mA@5V — 18L89

SKU: LNX-18L89 Brand: Lennox
$89.95 $129.95

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Texas CMBL #19328542014
SAM.gov Registered
Govt POs Accepted

The Lennox 18L89 is a genuine OEM blower prove switch rated at 10mA at 5V with a normally open single-pole configuration, designed to verify that the blower motor is operating correctly before allowing the full system to energize. A failed blower prove switch can result in your Lennox system refusing to start, displaying blower fault codes, or shutting down unexpectedly due to an unconfirmed blower status signal. This replacement part is built to Lennox OEM specifications to restore safe and proper system sequencing in compatible fan and blower applications.

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 Fan Motor fit my Lennox OEM Lennox Switch Blower Prove Sp Open 10mA@5V — 18L89?
Yes. This is the factory-specified OEM fan motor for the Lennox OEM Lennox Switch Blower Prove Sp Open 10mA@5V — 18L89. 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 fan motor on my Lennox OEM Lennox Switch Blower Prove Sp Open 10mA@5V — 18L89?
Difficulty: Medium-Hard (1–2 hrs)
Step 1: Turn off breaker. Step 2: Note motor specs: HP, RPM, voltage, rotation direction. Step 3: Remove old motor from mounting. Step 4: Transfer fan blade to new motor. Step 5: Mount new motor, reconnect wiring. Step 6: Restore power, verify rotation direction.
My AC fan isn’t spinning. What part do I need?
Fan not spinning, spinning slowly, or making grinding/squealing noises = motor failure. Grinding = bearings failed. Squealing = bearings dry. No spin + hum = check the motor capacitor first before replacing the entire motor.
Is this fan motor 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 fan motor?
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
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