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Navien · Combi boiler

E003 Ignition failure

High severity Navien NCB-HNavien NFC-H

What the control is telling you

The burner did not light (no flame proven) during the ignition attempts. NFC-H manual lists the reset type as: Manual reset.

Applies to: Navien fire-tube combi boilers, NFC-H series (NFC-250/200H, NFC-250/175H) and NCB-H combi boilers (NCB-250/150H, NCB-240/130H, NCB-240/110H, NCB-190/080H, NCB-190/060H)

Likely causes

  • Main gas supply valve closed or gas supply interrupted
  • Inlet gas pressure out of range
  • Wrong gas type / orifice for the gas supplied
  • Dirty or badly positioned ignition/flame detector electrode, poor ignition ground

Test and repair steps

  1. Make sure the main gas supply valve is open (the manual's listed remedy).
  2. Measure inlet gas pressure at full fire NG 3.5-10.5 in WC; LP 8.0-13.5 in WC (NCB-H) or 8.0-13.0 in WC (NFC-H).
  3. Confirm DIP SW2 #1 matches the gas supplied (OFF = natural gas, ON = propane) and the correct orifice is installed.
  4. Remove and clean the ignition/flame detector electrode; replace it if it cannot be cleaned, and check its gasket.
  5. Check the ignition ground wire is secure and has continuity to the casing.
  6. Check Service Status Info for repeated 2nd-10th ignition attempts to judge how often lighting is marginal.
  7. Reset from the front panel by pressing the Back button, then confirm the code clears.
  8. Code keeps returning? Phone Navien Technical Support, 1-800-519-8794.

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Source: Navien NCB-H Installation & Operation Manual, 11.7 Understanding Error Codes, p.129-130; Navien NFC-H Installation Manual, 11.7 Understanding Error Codes, p.127-128. Summarized in our own words; check the original manual for your model.

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For licensed technicians. Gas, electrical and refrigerant work must be done by a qualified, licensed person. Shut off power and gas before servicing, never bypass a safety control, and follow the manufacturer’s manual for the exact model; it and local codes always take priority. HVACopedia is not affiliated with any manufacturer; brand and model names only identify the equipment.