The furnace flue

What if my chimney vents a furnace?

The furnace flue is used to vent furnaces for gas and oil. High efficiency furnaces do not waste energy by sending heat up the chimney. As a result, temperatures in the flue drop low enough to produce condensation. The condensation combines with acids in the flue to create a damaging acidic moisture. Understanding and maintaining your High Efficiency Furnace

Clay liners are particularly vulnerable to this acidic moisture assault.

Signs to look for of a deteriorating flue:

  • Flaking plaster and/or peeling wallpaper.
  • Staining on wall surfaces due to moisture.
  • Excessive moisture in gas or oil flues.
  • Excessive soot with oil furnace use.
  • Deterioration of the chimney structure.
  • Eroded or missing clay liner.
  • Carbon monoxide leaking into the home.
  • Joints between the tiles are not sealed.

    I Want to Prevent all of These Problems Home: The DIY Chimney Repair Resource