Why the cross-section is important

The chimney must be able to remove the required amount of flue gases without excessive losses or backflow.

What affects the choice

  • Boiler or burner power.
  • Chimney height.
  • Flue gas temperature.
  • Fuel type.
  • Number of bends.

Common mistake

A cross-section that is too large or too small can cause problems with draft and condensation.