OEM Lennox Limit Switch — 33J38
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30-Day Returns
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The genuine OEM Lennox 33J38 limit switch is a temperature-activated safety control found in Lennox heating equipment. It monitors the air temperature around the heat exchanger and interrupts power to the burner or elements the moment the furnace runs too hot, safeguarding the heat exchanger and preventing hazardous overheating. The 33J38 is factory-calibrated to your Lennox unit's specific trip and reset points.
Common failure symptoms include repeated short cycling, heat that starts and abruptly stops, continuous blower operation, no warm air on demand, or a control board reporting an open-limit condition. A degraded switch may trip too soon, disrupting comfort, or stay closed and defeat an essential safety function.
Why OEM matters: because the 33J38 is a life-safety component, exact calibration and fit are non-negotiable. The Lennox factory part guarantees the correct temperature rating, terminals, and mounting for your furnace, avoiding the nuisance shutdowns or protection gaps that come with universal replacements. Install the OEM switch to keep your Lennox system operating safely and within spec.
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