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Napoleon · Gas fireplace troubleshooting

Test: thermocouple and thermopile millivolts

What is going on

Generator output specs.

Likely causes

  • Weak thermocouple or thermopile
  • Poor pilot flame

Check in this order

  1. Thermocouple (Robertshaw with adapter, or SIT 820 Nova at solder button): open circuit 20-30 mV, closed circuit 10-15 mV.
  2. Thermopile open circuit disconnect leads from terminals 1 & 2, meter on mV across thermopile leads - should read 500 mV.
  3. Thermopile closed circuit meter on terminals 1 & 2 with the main burner on - minimum 150 mV.
  4. Low readings check pilot flame first, then replace the generator.

Applies to: Napoleon gas fireplaces - direct vent, natural vent and vent-free (general service manual)

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Source: Napoleon (Wolf Steel) Service Manual W415-0118, Part 5 Testing & Adjustments, Testing: Millivolts, p.33-35. 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.