Dometic 1 flash fault code — Furnace
Applies to: DF series furnace
What 1 flash means
The DF furnace manual identifies one flash with a pause as a limit switch or airflow problem.
Owner-safe checks
- Turn the furnace off.
- Check that interior registers and exterior intake/exhaust openings are unobstructed.
- Do not restart if vents were covered, soot is present, or the furnace smells unusual.
Service-only work
- Limit-switch, airflow switch, burner, board, or combustion diagnosis is service technician work.
Safety boundary
Do not operate with blocked vents. Shut off the furnace and LP gas if flame, soot, heat, or exhaust conditions look wrong.