OEM Lennox Integrated Furnace Control Board — 12J99
OEM Guaranteed
Same-Day Ship
30-Day Returns
Secure Checkout
The Lennox 12J99 is a genuine OEM integrated furnace control board (IFC) that serves as the brain of your Lennox gas furnace. It coordinates the entire heating sequence — monitoring the thermostat call, sequencing the draft inducer, igniter, gas valve, and blower, and running continuous flame-sense and safety-limit checks. This board is a direct factory replacement engineered to match the exact firmware, relays, and connector pinout of your Lennox system.
Common failure symptoms: furnace that won't ignite or has no response to a heat call, blower running constantly, intermittent lockouts, error/fault codes flashing on the diagnostic LED, cracked solder joints, or scorched relay contacts. Electrical surges, moisture, and repeated hard cycling are typical causes of board failure.
Why OEM matters: A factory Lennox 12J99 board guarantees correct ignition timing, blower speed logic, and safety interlocks that aftermarket boards often can't replicate. Using an OEM control board protects your furnace's warranty and ensures reliable, safe operation season after season.
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