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Flue Condensation Problems Flue Condensation Problems - This picture shows a furnace flue with condensation problems. Flue condensation problems are caused by hot gases cooling too quickly in the flue. As the hot gasses, cool moisture in the gases condense and start dripping back down the flue.

Flue Condensation Problems

Flue condensation problems can be solved by making sure the gases are hot enough to be vented into the atmosphere. Vented up the flue before the moisture condenses in the gases. It could be a problem that requires a slight adjustment at the burner. It is a good idea, when you observe a furnace flue condensation problem where the condensation is dripping back down the pipe, to call a professional. They can analyze the combustion process and make the precise adjustments necessary to prevent this problem. Condensation dripping back down the flue causes flue to prematurely corrode and rust. Flue condensation problems, if left alone, can cause the flue to rot and vent hot gases in an area where it could be very dangerous to the occupants of the building. Furthermore, there is carbon monoxide present in these gases and carbon monoxide is very dangerous.

See the related furnace flue videos below

Safety First

Flue condensation problems have been observed on all kinds of furnaces including gas and oil furnaces. If you have this problem or see it on your furnace heating system please consult a professional. If not repaired, eventually the corrosive condensation dripping down the flue will cause a flue or ventilation failure. That is a serious hazard to your health. Additionally, for everyone who occupies the building where this is occurring. Many HVAC companies have policies to always recommend carbon monoxide detectors be installed. Installed in buildings that have any type of fossil fuel burners. This includes furnaces, cooking appliances, and other things including gas logs or hot water heaters. Furthermore, Safety First!

For information on various flue venting materials and the ratings for those materials see the flue venting materials table. All furnace venting should comply with the Fuel-Gas Code and the Mechanical Code.

High Performance HVAC

Flue Condensation Problems

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