HVACopediaNapoleon · Gas fireplace troubleshooting
Oil-canning (popping/banging metal noise)
What is going on
Metal pops or bangs as it heats/cools. The sooner after ignition it happens, the closer it is to the heat source.
Likely causes
- Loose screws/panels/baffle in firebox
- Vent not supported
- Vent collar stressed
- Burrs at screws behind upper louvres
- Unsealed 7" vent (cold days)
- Compressed venting (top vent)
Check in this order
- Early after ignition check the firebox heat shield, log support and baffle for loose or stripped screws; tighten or replace.
- Late after ignition support the vent pipe every three feet.
- Relieve stress on the vent collar by adjusting the venting.
- Check screws behind the upper louvres on the zero-clearance shell for burrs/tears; file smooth.
- Worse on cold days seal the 7" vent pipe and area around it.
- Top vent units make sure the venting did not compress when the unit was slid into place.
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 4 Other Issues, Oil-Canning Flowchart, p.28. 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.