The codes are usually explained on a wiring diagram that is on the back panel.
Check yours, it might be different! For me, a continuously blinking light is normal.
- Flashing slow: Normal – no call for heat
- Flashing fast: Normal – call for heat
- Continuous on: Replace IFC (circuit board)
- Continuous off: Check power
- 2 Flashes: External lockout (retries or recycles exceeded)
- 3 Flashes: Pressure switch error
- 4 Flashes: Open limit device
- 5 Flashes: Flame sensed when no flame should be present
- 6 Flashes: 115 VAC power reversed polarity or poor grounding
- 7 Flashes: Gas valve circuit error
- 8 Flashes: Low flame sense signal
- 9 Flashes: Check igniter