HVACopediaNapoleon · Gas fireplace troubleshooting
Main burner will not light - natural vent
What is going on
Pilot is on but main burner will not fire on a natural-vent unit.
Likely causes
- Pilot too small to reach burner ports
- Low thermopile output
- Low supply pressure
- Spill or vent safety switch open
- Blocked burner/orifice
- No switch on terminals 1 & 3
- Faulty switch/wiring
- Bad operator coil
Check in this order
- Check pilot size and position - it must reach the ignition ports.
- Test thermopile millivolts and confirm it is connected.
- Test inline supply pressure.
- Test spill and vent safety switches for function and connection.
- Check and clean burner and orifice.
- Confirm a switch or remote is on terminals 1 & 3; jumper 1 & 3 to test - if the burner lights, the switch/wiring is at fault.
- If not, test the operator coil and replace the valve if out of spec.
Applies to: Napoleon natural-vent (B-vent) gas fireplaces with spill switch (general service manual flowchart)
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Source: Napoleon (Wolf Steel) Service Manual W415-0118, Part 1-3 Troubleshooting, Main Burner Not Lighting Flowchart, p.13. 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.