Navien Water Heater Error Code 005: How to Fix It

Q: What does error code 005 mean on a Navien water heater?

Error code 005 indicates the burner thermal fuse has activated due to overheating. It's a safety shutdown.

Q: How do I reset error 005 on my Navien?

Turn off power to the unit for 10 minutes to allow the thermal fuse to cool and reset. If it doesn't clear, check for blockages.

Q: Can a dirty air filter cause Navien error 005?

Yes, but Navien units don't have traditional air filters; however, blocked air intake or exhaust can cause overheating and trigger error 005.

Q: How much does it cost to fix Navien error 005?

DIY fixes are free. Professional service typically costs $150-$300 depending on the cause.

Q: Is Navien error 005 dangerous?

It indicates overheating, which could pose a fire risk if ignored. Always address the root cause.

Abstract

Error code 005 on your Navien tankless water heater means the burner thermal fuse has activated. This safety device shuts down the heater if the burner chamber overheats. Usually caused by restricted combustion air or exhaust, or a faulty fan motor.