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Napoleon · Gas fireplace troubleshooting

Pilot drops out during operation - direct vent

What is going on

Pilot fails while the unit is running on a direct-vent fireplace.

Likely causes

  • Wrong pilot flame size/position
  • Pressure drop when burner comes on
  • Low thermocouple output
  • Weak magnet coil
  • Venting problem
  • Logs out of place

Check in this order

  1. Check pilot flame pattern, size and position - it must properly heat the thermocouple.
  2. If the pilot shrinks when the burner comes on, check for pressure drop on activation (supply problem).
  3. Test thermocouple millivolts (20-30 mV open, 10-15 mV closed).
  4. Test the magnet coil.
  5. Inspect the vent system (see Complete Unit Shutdown guide).
  6. Check log positions - misplaced logs disturb airflow and make the pilot erratic.

Applies to: Napoleon direct-vent gas fireplaces (general service manual flowchart; applies to GD70NT-S/GD70PT-S)

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Source: Napoleon (Wolf Steel) Service Manual W415-0118, Part 1-3 Troubleshooting, Pilot Failure Flowchart, p.3. Written in our own words; check the manual for your exact model.

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.