OEM Lennox Ignition Control Board — 34M66
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30-Day Returns
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The genuine OEM Lennox 34M66 ignition control board is the electronic brain that manages your furnace's startup and safety sequence. It coordinates the inducer motor, igniter, gas valve, and flame sensing while continuously monitoring safety inputs like the pressure switch and limit controls, ensuring each ignition cycle runs in the correct order and shuts down safely if a fault is detected.
Common failure symptoms: A failing 34M66 can cause no ignition, intermittent or delayed starts, blower or inducer that won't run, error codes flashing on the diagnostic LED, or a furnace that locks out unpredictably. Heat damage, cracked solder joints, failed relays, and power surges are typical causes of board failure.
Why OEM matters: The ignition control board must match your furnace's exact wiring, timing, and safety logic. A non-OEM board can misread sensors, mistime the gas valve, or fail to enforce critical safety interlocks. The 34M66 is the factory-engineered control your Lennox system was designed around, restoring correct ignition sequencing, accurate diagnostics, and full safety 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