OEM Lennox Limit Switch — 27K79
OEM Guaranteed
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30-Day Returns
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The genuine OEM Lennox 27K79 limit switch is a critical safety control installed on Lennox gas and electric furnaces. It continuously monitors the temperature inside the heat exchanger or plenum and automatically shuts off the burners if the unit overheats, protecting your furnace and home from damage caused by restricted airflow or a failing blower. This factory-spec component is engineered to trip at the exact temperature threshold your Lennox system was designed around.
Common failure symptoms include a furnace that short-cycles (turning on and off repeatedly), no heat output, a blower that runs continuously, or a system that locks out entirely. A limit switch that has drifted out of calibration or failed open will interrupt the ignition sequence and leave your home cold, often accompanied by a fault code on the control board.
Why OEM matters: Aftermarket limit switches frequently trip at incorrect temperatures, causing nuisance shutdowns or, worse, failing to protect against a genuine overheat condition. The Lennox 27K79 is calibrated to precise factory specifications, guaranteeing correct operation, proper fit, and full compatibility with your Lennox furnace's safety circuit.
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