OEM Lennox Limit Switch — 73W19
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The genuine OEM Lennox 73W19 limit switch is a temperature-activated safety control that protects your furnace from overheating. Mounted on or near the heat exchanger, it continuously monitors plenum temperature and interrupts the burner circuit if heat rises above a safe threshold — typically when airflow is restricted. This exact-fit component is engineered to the precise trip and reset temperatures your Lennox furnace was designed around.
Common failure symptoms include short cycling on the burners, the furnace shutting down mid-cycle, blowing cool air, or the unit failing to fire at all. A limit switch that trips prematurely or fails open is a frequent culprit behind intermittent no-heat calls, especially when paired with a dirty filter or blocked ductwork.
Why OEM matters: aftermarket limit switches often use different trip points and mounting geometry, which can compromise the safety function your Lennox system relies on. Installing the factory-specified 73W19 ensures the correct temperature calibration, proper fit, and reliable protection of your heat exchanger — safeguarding both performance and warranty coverage.
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