Navien Error Code E012: Flame Loss

Severity
Warning
Type
digital display
Where to look
front panel
Estimated repair cost: $100 — $250 (parts + labor)
Warning: Your Navien boiler has experienced a flame loss, which could lead to system damage if not addressed promptly. It's safe to troubleshoot, but call a professional if needed.

How to Fix Navien Code E012

  1. Check if the reset button (if present) has tripped. Press it once to reset the boiler.
  2. Ensure the boiler's power switch is ON and the boiler is in heating mode.
  3. Inspect the gas supply valve to ensure it's open and gas is flowing.

How to Reset Navien Code E012

  1. Turn off the unit using the power button on the front panel.
  2. Turn off the gas supply valve.
  3. Turn off the circuit breaker supplying power to the unit. Wait 30 seconds.
  4. Restore power at the breaker, then open the gas valve.
  5. Turn the unit back on. If the error returns, the underlying issue needs repair.

Resetting clears the code from the display but does not fix the underlying fault. If the code returns after reset, proceed to the diagnostic steps above.

What Does Navien Error Code E012 Mean?

The E012 error on your Navien boiler indicates a flame loss issue. This could be due to a problem with the ignition system, a blockage in the combustion chamber, or an issue with the gas valve. The boiler will display this error and shut down to prevent further damage. While it's safe to check a few things, do not attempt to open the boiler or tamper with gas lines.

Common Causes

  • Faulty ignition system (spark electrode or igniter)
  • Obstruction in the combustion chamber
  • Problem with the gas valve or gas supply
  • Incorrect flame sensor readings

Diagnostic Steps

If... Check Expected
Boiler won't restart after reset Gas pressure using a manifold gauge Between 3.5" to 7.5" W.C.
Flame sensor is dirty Clean the flame sensor using a fine emery cloth or sandpaper Clean sensor

Applicable Navien Models

Source Documentation

Referenced in 6 official Navien technical manuals.

ManualPageReasonAction
NFB-H Installation & Operation Manual116Flame LossCheck gas, venting and condensate trap.
Navien NCB-H Installation & Operation Manual129Flame Loss● Clean the intake air filter. ● Ensure that the electrical cord is properly grounded.
Navien NFB-H Installation & Operation Manual116Flame LossCheck gas, venting and condensate trap.
Navien NFC-H Installation & Operation Manual127Flame lossManual RESET
Navien NHB-H Installation & Operation Manual119Flame LossCheck gas, venting and condensate trap.
Navien NPF Installation & Operation Manual125Flame loss during combustionThis error occurs when the flame detector does not operate properly. ● Check if the supply and exhaust pipes connected to the furnace are installed properly. ● If the furnace is continuously inoperable, contact Technical Support at 1-800-519-8794.

Recall Notices

Navien Tankless Water Heaters and Combination Boilers Recalled Due to Carbon Monoxide Hazard 19-027 Active

Issued: December 20, 2018

Affected models: NPE-180A, NPE-180S, NCB-180E manufactured July 9 - October 14, 2018

LP gas conversion kits can cause units to produce excessive carbon monoxide.

View official notice

Replacement Parts

Part OEM Number Est. Cost Where to Buy
Igniter 400-00014-00
Gas Valve 400-00018-00
Flame Sensor 400-00015-00

Related Codes on Same Models

Other codes that affect the same Navien model families as E012.

Code Description Severity
E001 Ignition Failure Warning
E003 Abnormal Ignition Warning
E004 False Flame Detection Warning
E016 Overheating Warning
E030 Exhaust Overheat Sensor Warning
E031 Inlet Thermistor Open/Short Warning
E046 Outlet Thermistor Open/Short Warning
E047 DHW Thermistor Open/Short Warning
E060 Fan Motor Abnormality Warning
E109 Fan Motor Speed Low Warning