Goodman GMEC960803BN Error Code Red 8 Flashes: External Lockout (Recycles)
What Does Code Red 8 Flashes Mean?
Eight red flashes on the Goodman GMEC960803BN control board indicate an external lockout due to excessive recycles. Unlike the 7-flash code (where the flame was never detected), this code means the furnace successfully lit but then lost the flame signal repeatedly. After too many flame-loss events, the system locked out.
Each time the flame sensor loses its signal during operation, the gas valve closes for safety and the system attempts to relight. When this happens too many times in a row, the control board determines something is fundamentally wrong and enters a 1-hour lockout.
The most likely cause is a dirty flame sensor that is barely able to detect the flame — it works intermittently but cannot maintain a consistent reading. The sensor rod develops a buildup of oxidation and combustion residue over time that insulates it from the flame. Less common causes include intermittent gas supply problems, low gas pressure producing a weak flame, or a loose flame sensor wire connection.
Common Causes
When to Call a Professional
Contact a licensed HVAC technician if:
- The code returns after cleaning the flame sensor
- The furnace lights but the flame appears weak, yellow, or uneven
- Other gas appliances in your home have weak flames (possible low gas pressure)
- The flame sensor wire or connector is damaged
- The problem is intermittent and only occurs during very cold weather
✓ Verified against manufacturer service manual — March 2026