What is the typical vent stack temperature range for a natural draft furnace?

The typical vent stack temperature range for a natural draft furnace usually falls between 450°F and 550°F. This temperature range is critical because it ensures that the flue gases, which can include harmful substances, are sufficiently elevated to promote efficient draft and prevent condensation within the vent system.

When the flue gases are at the correct temperature, they rise quickly through the vent stack, drawing in fresh air for combustion and expelling exhaust gases safely outside. If the temperature were to drop significantly below this range, it could lead to condensation in the vent pipes, resulting in moisture buildup that may cause corrosion or blockages. Maintaining the vent stack temperature within this specified range ensures optimal performance and safety of the natural draft furnace.