Goodman GMEC960803BN Error Code Red 8 Flashes: External Lockout (Recycles)
What Does Code Red 8 Flashes Mean?
Eight red flashes on the Goodman GMEC960803BN's Integrated Control Module indicate an external lockout from excessive recycles — the burners lit and the flame was proven, but the flame signal was then lost, over and over, until the board locked out. Each time flame is lost the board shuts the gas and recycles through a new ignition; too many recycles in a row triggers the lockout.
The key difference from red 7 flashes is timing: red 7 means the flame was never proven at all, while red 8 means it was proven and then dropped. That pattern points to a marginal flame-sensing signal (a dirty or corroded flame rod), an intermittent gas supply, low gas pressure producing a weak flame, or a front-cover pressure switch that drops out mid-cycle.
This lockout is frequently the destination of an ignored rapid amber (low flame sense) warning: as the flame signal weakens, the furnace goes from warning, to losing flame, to locking out. It is a high-severity fault, and the gas pressure, gas valve, and pressure-switch aspects must be handled by a technician.
What You'll Notice
- The burners light and run briefly, then go out, and the cycle repeats before an eight-flash lockout
- Heat that starts normally but cannot sustain a full cycle
- The furnace works some cycles and fails others as the flame signal drifts
- The problem often worsens gradually as residue builds on the flame rod
- The furnace finally locks out and stays off until reset and repaired
Common Causes
How This Is Diagnosed
Because the flame was proven and then lost, diagnosis focuses on why a good flame signal decays. A technician inspects and services the flame sensor and its wiring, verifies steady gas supply and correct manifold pressure (a weak flame from low pressure drops out easily), checks burner flame quality, and confirms the front-cover pressure switch holds during the cycle. Gas pressure, gas valve, and pressure-switch work are professional repairs.
When to Call a Professional
This code involves components that are not homeowner-serviceable, so have a licensed HVAC technician diagnose and repair it. Keep in mind:
- The burners light but keep going out until the furnace locks out
- The lockout returns after a power cycle
- The flame looks weak, yellow, or lifting rather than crisp and blue
- You suspect low or intermittent gas pressure
- Cleaning the flame sensor did not resolve the recycling
Frequently Asked Questions
What is the difference between seven and eight red flashes?
Seven flashes means the furnace never proved a flame during ignition, while eight flashes means it lit and proved flame but then lost it repeatedly. Eight flashes usually points to a marginal flame signal, weak flame, or intermittent gas.
Why does my furnace light and then shut off a few seconds later?
If the burners light but the flame signal is lost shortly after, the board recycles and eventually locks out with eight flashes. A dirty flame sensor or a weak flame from low gas pressure is a common cause and should be serviced by a technician.
✓ Verified against manufacturer service manual — March 2026