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Navien · Combi boiler

E012 Flame loss

High severity Navien NCB-HNavien NFC-H

What the control is telling you

The flame went out during operation after ignition. 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

  • Clogged air intake filter
  • Poor ground on the power supply
  • Low or fluctuating inlet gas pressure
  • Vent or intake restriction
  • Dirty flame detector electrode

Test and repair steps

  1. Clean the air intake filter (top left inside the cabinet; rinse, let it dry fully, reinstall).
  2. Make sure the electrical cord/outlet is properly grounded.
  3. Check inlet gas pressure at full fire against the rated range on the rating plate.
  4. Inspect the exhaust and intake piping and terminations for blockage.
  5. Clean the flame detector electrode; check Service Status Info > Flame Loss count.
  6. Reset from the front panel by pressing the Back button, then confirm the code clears.
  7. 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.