| American Standard Error Code | What this means |
|---|---|
| Green light on, slow flashing, or fast flashing | Unit is operating normally |
| Amber light on | Unit requires refrigerant |
| Red 1 flash | Communication error |
| Red 2, 3, and 4 flashes | Defrost fault |
| Red 5 flashes | Fault with the ambient temperature sensor |
| Red 6 flashes | Fault with the coil temperature sensor |
| Red 7 flashes | Low-pressure problem |
| Red 13 flashes | Fault with the external temperature sensor |
| Red 17 flashes | High-pressure problem |