OEM Lennox Limit Switch — 12L38
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The genuine OEM Lennox 12L38 limit switch protects your Lennox furnace from overheating by monitoring the temperature in the heat exchanger or plenum. When air temperature climbs above the safe threshold — typically from restricted airflow or a blower issue — the switch opens and shuts off the burners, preventing heat exchanger damage and unsafe operating conditions.
A failing or tripped limit switch commonly causes short-cycling, where the furnace heats briefly then shuts down, no heat output, or the blower running continuously to shed excess heat. A dirty filter, blocked ducts, or a weak blower motor can cause the switch to trip repeatedly, so those conditions should be checked alongside the switch itself.
The OEM Lennox 12L38 is manufactured to the precise trip and reset temperatures your furnace's control sequence depends on. A generic limit with a different set point can allow overheating or cause nuisance shutdowns. Choose the factory-matched part for reliable, safe temperature protection.
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