Navien water heater error codes

Navien codes fall into a few groups. Codes near the start of the list, like E003, E012 and E016, relate to combustion and heat. Codes in the 400s point to a sensor, valve or pump. Codes in the 500s and above generally point to the control board.

Many combustion codes share the same basic causes: gas supply, venting and the condensate drain. Those are also the things a homeowner can check without opening the unit.

How to reset a Navien error code

1. Turn off all hot water taps.
2. Press the power button on the front panel to turn the unit off, wait about a minute, then turn it back on.
3. Open a hot water tap and watch whether the unit fires normally.

If the same code returns, the cause is still present. Repeated resets on a combustion or overheating code are not a repair.

The codes homeowners see most

Ignition and flame: E003 and E012

E003 means the burner did not light. E012 means it lit and lost the flame. Check the gas valve, other gas appliances, the propane level and the vents.

Overheating: E016 and E030

E016 means the heat exchanger got too hot, and E030 means the exhaust temperature was abnormal. Scale buildup and a clogged inlet water filter are frequent causes, so maintenance history matters.

Exhaust or condensate blockage: E110

E110 means the exhaust path is blocked, and on condensing units that includes a condensate drain that cannot drain. Check the vent outside and the condensate line.

What you can safely check yourself

• The gas valve to the heater, and whether other gas appliances work.
• Intake and exhaust vent terminals outside, for snow, ice, debris or nests.
• The condensate drain line, for kinks, clogs or ice.
• The cold water inlet filter, which can clog with sediment.
• When the unit was last descaled.

When to call a technician

Sensor, valve, fan and control board codes, and any combustion code that returns after the checks above, need a licensed installer with the right test equipment. Navien's service steps for these codes involve the sealed combustion area and gas pressure testing.