Ao-Smith Tankless-Water-Heater Error Codes | Service Manual Source
Available Models
Section titled “Available Models”| Model | Error Codes | Details |
|---|---|---|
| nnlp-110-h-ng | 5 | View |
| nnlp-150-h-ng | 5 | View |
| nnlp-199-h-ng | 6 | View |
Total Error Codes: 16
Section titled “Total Error Codes: 16”Common Ao-Smith Tankless-Water-Heater Error Codes
Section titled “Common Ao-Smith Tankless-Water-Heater Error Codes”Troubleshooting Tips
Section titled “Troubleshooting Tips”When you encounter an error code on your Ao-Smith tankless-water-heater:
- Note the exact error code displayed on the panel
- Find your model in the table above
- Click the error code for detailed troubleshooting steps
- Follow safety warnings - some repairs require professional service
Last Updated: March 2026