Navien Tankless Water Heater Error Code 003: How to Fix Flame Failure

Q: What does error code 003 mean on a Navien water heater?

Error code 003 indicates a flame failure. The burner did not ignite or lost flame during operation, often due to gas issues, dirty components, or ignition problems.

Q: Can I reset Navien error code 003 myself?

Yes, try turning the unit off, waiting 5 minutes, then turning it back on. If the error persists, follow the troubleshooting steps above.

Q: Why does my Navien keep showing error 003 after cleaning?

If cleaning doesn't help, the issue may be with the gas valve, control board, or flame rod. These components require professional testing and replacement.

Q: Is it safe to use my Navien with error code 003?

No, the unit will not operate safely. Attempting to bypass the error can lead to gas leaks or fire hazards. Fix the issue before use.

Q: How much does it cost to fix Navien error 003?

DIY cleaning costs nothing. If a technician is needed, expect $150-$300 for service call plus parts (e.g., flame rod ~$20-$50, control board ~$200-$400).

Abstract

Navien error code 003 indicates a flame failure, meaning the burner failed to ignite or lost its flame during operation. This is often due to gas supply issues, ignition problems, or blocked components. Follow these steps to diagnose and fix the issue safely.