OEM Lennox Flame Sensor — 51M14
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The genuine OEM Lennox 51M14 flame sensor confirms that your furnace burners have successfully ignited. Using flame rectification, this rod detects the presence of a flame and signals the control board to keep the gas valve open — an essential safety function that prevents raw gas from accumulating in the combustion chamber.
Common failure symptoms: A dirty, oxidized, or failing 51M14 is one of the most frequent causes of furnace lockout. Typical signs include the burners lighting for a few seconds then shutting off, repeated ignition attempts, or a furnace that cycles on and off without producing sustained heat. A coated sensor rod loses its ability to conduct the tiny micro-amp signal the control board needs.
Why OEM matters: The correct rod length, positioning, and alloy are critical for a stable flame-sense signal. The OEM Lennox 51M14 is built to factory tolerances so it seats properly in the burner assembly and delivers a reliable signal, eliminating the intermittent lockouts that generic sensors often cause in Lennox 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