American Standard AUH1B080A9H31A Error Code 2 Flashes: System Lockout (Retries or Recycles Exceeded)
What Does Code 2 Flashes Mean?
Code 2 (2 Flashes) on the American Standard AUH1B080A9H31A indicates a system lockout — the furnace has exhausted all ignition retry attempts and will not fire until manually reset. This means the furnace tried to ignite several times and could not establish or maintain a flame.
During each ignition attempt, the inducer motor starts, the hot surface igniter heats up, the gas valve opens, and the flame sensor looks for flame. If the sensor does not detect a flame, or if the flame is established but then lost, the control board counts it as a failed attempt. After exhausting all retries, the system locks out.
The most common cause is a dirty flame sensor. Over time, carbon buildup on the sensor rod reduces its ability to detect the flame's electrical signal, causing the control board to think there is no flame even when the burners are lit. Other possible causes include a failed hot surface igniter or a gas supply interruption. You can try resetting by turning the power off, waiting 30 seconds, then turning it back on.
Common Causes
| Cause | Likelihood | DIY? |
|---|---|---|
| Dirty flame sensor causing repeated ignition failure | Most common | ✗ Call a pro → |
| Failed igniter | Common | ✗ Call a pro → |
When to Call a Professional
Contact a licensed HVAC technician if:
- Code 2 returns after cleaning the flame sensor
- The igniter does not glow red-hot during the ignition sequence
- You smell gas but the burners do not light
- The flame lights briefly then goes out repeatedly
- The flame sensor rod appears cracked or damaged
✓ Verified against manufacturer service manual — March 2026