Do not test the system with a fire

An idle flue may contain nests, debris, damaged components or deposits, and building changes may have altered airflow. Lighting a small fire is not a safe substitute for inspection.

Collect what is known

Identify the appliance, fuel, approximate idle period and any visible changes. Look from safe occupied areas only; do not climb onto the roof or dismantle venting.

  • Manuals and service records
  • Visible debris or water
  • Animal sounds
  • Renovations and new exhaust fans
  • Alarm age and test status

Arrange assessment before use

Ask which inspection scope fits the unknown history, whether the full vent route can be viewed, and what documentation you will receive. Follow property-specific advice before operating the appliance.

Field note: A fresh coat of paint or an open damper does not establish that the vent is clear or suitable for use.