OEM Lennox Limit Switch — 38M68
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The genuine OEM Lennox 38M68 limit switch is a high-temperature safety control that safeguards your Lennox furnace against overheating. Positioned near the heat exchanger, it senses plenum temperature and interrupts the burner circuit whenever the furnace exceeds its safe operating range — typically the result of poor airflow from a clogged filter, a weak blower motor, or closed and blocked registers.
Common failure symptoms: The furnace repeatedly ignites and then shuts down after a short run, heating short-cycles, the system delivers no heat, or the blower will not stop running. When the 38M68 fails open it locks the furnace out of heating; when it fails closed it can no longer protect the heat exchanger from cracking under excess heat.
Why OEM matters: The Lennox 38M68 is set to the precise trip and reset temperatures engineered for your specific model. Aftermarket switches with incorrect ratings risk unsafe overheating or endless nuisance trips. Installing the factory-spec part ensures accurate calibration, a proper mechanical and electrical fit, and dependable protection for your family and your Lennox system.
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