Navien Tankless Water Heater Troubleshooting and Error Code Definitions

South End Plumbing, Heating, & Air Expert Tips

Navien Tankless Water Heater Error Code Diagnostic
Navien Tankless Water Heater Error Code Diagnostic

Navien Tankless Water Heater Troubleshooting & Error Code Look-Up

Navien-error-codes
Navien-error-codes

If you have a tankless water heater in Charlotte, NC, you’ve made a wise investment that will deliver endless hot water for years with proper maintenance. Modern tankless water heaters need far less in the way of maintenance and servicing than traditional water heaters. They do still have that needed maintenance and will occasionally have errors that need attention. The Charlotte plumbers at South End Plumbing services all brands, but for this article we’re focusing on our house brand, Navien tankless water heater troubleshooting because the self diagnostics tool provides codes that makes it easier to diagnose problems.

There’s a reason we carry and install Navien tankless water heaters. Navien tankless water heaters are self diagnosing, meaning it is equipped with a self-diagnostic tool that continuously monitors if the unit is not functioning properly. When fault is out of tolerance, the unit displays an error code. Using the Navien this tankless water heater error code guide, you can quickly determine what the problem is and if you need a plumber to service the unit or if it can be fixed on your own. Interested in having a Navien water heater installation in Charlotte? Give us a call today!

Navien Tankless /Water Heater Error Codes

Error Code E003
What it Means: Ignition failure in your tankless water heater.
How to Fix: Confirm the main gas supply valve is open.

Error Code E004
What it Means: False flame detection.
How to Fix: Confirm properly grounded electrical cord.

What it Means: Flame loss.
How to Fix: Confirm properly grounded electrical cord. Inspect and clean intake air filter.

Error Code E016
What it Means: Overheated heat exchanger.
How to Fix: Turn off the water heater for 30 minutes and restart. Inspect and clean the filter in cold water inlet. Flush the heat exchanger.


Error Code E030
What it Means: Exhaust overheating. The unit will shut down when the temperature in the flue exceeds 149° Fahrenheit (65° Celcius).
How to Fix: Turn off the water heater for 30 minutes and restart. Inspect and clean the filter in cold water inlet. Flush the heat exchanger.


Error Code E046
What it Means: Abnormality in limit control.
How to Fix: Call technical support (800-519-8794).


Error Code E047
What it Means: Abnormality in exhaust thermostat.
How to Fix: Call technical support (800-519-8794).


Error Code E060
What it Means: Abnormality in dual venturi.
How to Fix: Call technical support (800-519-8794).

Error Code E109
What it Means: Abnormality in fan motor.
How to Fix: Inspect and clean the intake air filter.

Error Code E110
What it Means: Abnormality in air pressure.
How to Fix: Confirm there are no obstructions in the exhaust pipe. Inspect and clean intake air filter.


Error Code E407
What it Means: Thermistor open or short circuited (hot water outlet).
How to Fix: Call technical support (800-519-8794).

Error Code E421
What it Means: Thermistor open or short circuited (cold water inlet 1).
How to Fix: Call technical support (800-519-8794).

Error Code E432
What it Means: Thermistor open or short circuited (cold water inlet 2).
How to Fix: Call technical support (800-519-8794).

Error Code E434
What it Means: Abnormality in water adjustment valve.
How to Fix: Call technical support (800-519-8794).

Error Code E438
What it Means: Abnormality in circulation pump.
How to Fix: Confirm all water supply and return lines are open. Check direction of the internal 2-way valve.

Error Code E439
What it Means: Abnormality in flow sensor.
How to Fix: Call technical support (800-519-8794).

What it Means: Thermistor open or short circuited (hot water inlet 2).
How to Fix: Call technical support (800-519-8794).

Error Code E445
What it Means: Abnormality in bypass mixing valve.
How to Fix: Call technical support (800-519-8794).

Error Code E515
What it Means: Abnormality in PCB.
How to Fix: Confirm proper grounding of electrical cord.

Error Code E517
What it Means: Abnormality in DIP switch setting.
How to Fix: Call technical support (800-519-8794).

Error Code E593
What it Means: Abnormality in front panel key.
How to Fix: Call technical support (800-519-8794).

Error Code E615
What it Means: Abnormality in input and memory.
How to Fix: Call technical support (800-519-8794).

Error Code E736
What it Means: Abnormality in cascade communication.
How to Fix: Call technical support (800-519-8794).

Error Code E740
What it Means: Abnormality in outdoor temperature sensor.
How to Fix: Call technical support (800-519-8794).

Error Code E760
What it Means: Flushing/service alarm.
How to Fix: Call technical support (800-519-8794).

Error Code E782
What it Means: Abnormality in main panel communication.
How to Fix: Call technical support (800-519-8794).

Error Code E785
What it Means: Abnormality in flow switch/sensor.
How to Fix: Call technical support (800-519-8794).

If you have any problems with your tankless water heater in Charlotte, even if it’s not a Navien brand, we are just a click away. Also if you would like to upgrade to a Navien tankless water heater – give us a call! South End Plumbing is one of the only companies that will give you a free estimate. We will also move an existing water heater if needed. Call us today!

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