Navien Error Code E004: False Flame Detection

Severity
Warning
Type
digital display
Where to look
front panel
Estimated repair cost: $75 — $200 (part only)
Warning: Your Navien boiler has detected a potential safety issue and has shut down to prevent any hazards.

How to Fix Navien Code E004

  1. Step 1: Turn off the boiler and allow it to cool down for at least 30 minutes.
  2. Step 2: Inspect the flame sensor for any signs of dirt or soot. If present, clean it gently with a wire brush.
  3. Step 3: If the issue persists, call a professional HVAC technician for further diagnosis and repair.

How to Reset Navien Code E004

  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 E004 Mean?

The E004 error on your Navien boiler indicates a false flame detection. This means the boiler's sensors have detected an issue with the flame, even though there might not be one. This is a safety feature designed to prevent any potential gas leaks. To resolve this issue, you'll need to troubleshoot and potentially replace some components.

Common Causes

  • A dirty flame sensor
  • A faulty ignition or flame sensor
  • Incorrect gas pressure
  • A problem with the boiler's control board

Diagnostic Steps

If... Check Expected
The boiler is not igniting The gas valve and ignition system Both should be functioning correctly
The boiler is igniting but the flame sensor is not detecting the flame The flame sensor's resistance Between 50-200 ohms

Applicable Navien Models

Source Documentation

Referenced in 6 official Navien technical manuals.

ManualPageReasonAction
NFB-H Installation & Operation Manual116False FlameCheck electric ground.
Navien NCB-H Installation & Operation Manual129False FlameEnsure that the electrical cord is properly grounded.
Navien NFB-H Installation & Operation Manual116False FlameCheck electric ground.
Navien NFC-H Installation & Operation Manual127False flame detectionManual RESET Auto RESET
Navien NHB-H Installation & Operation Manual119False FlameCheck electric ground.
Navien NPF Installation & Operation Manual125False-flameThis error occurs when the flame detector does not operate properly. ● If the furnace is operating properly, this error will be cleared automatically. ● If the furnace is continuously inoperable, contact Technical Support at 1-800-519-8794.

Replacement Parts

Part OEM Number Est. Cost Where to Buy
Flame Sensor
Gas Valve
Control Board

Related Codes on Same Models

Other codes that affect the same Navien model families as E004.

Code Description Severity
E001 Ignition Failure Warning
E003 Abnormal Ignition Warning
E012 Flame Loss 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