High Efficiency Furnace Venting Freezing At Roof Vent

That depends on whether you have a standard efficiency or a high efficiency furnace.

High efficiency furnace venting freezing at roof vent.

That s because the combustion byproducts are in a gaseous form so the gases can float up through the flue pipe and out of your roof. If your furnace has an afue rating below 90 percent it will most likely have a flue pipe that goes up through your roof. This vent pipe is connected to the shared vent stack with the furnace. There is a disconnection at the elbow.

This residual liquid is highly acidic. Once a high efficiency condensing furnace removes this excess heat that conventional furnaces vent to the outside of a home the leftover mixture is acidic water. A high efficiency condensing furnace can achieve efficiency ratings of 90 or above. It uses a venting system to extract that heat before venting.

When exhaust gases discharged from a high efficiency furnace exhaust vent meets the cold air the air condenses faster than conventional furnaces because it is cooler. Many municipalities do not allow metal foil tape either. Due to the condensing nature of a high efficiency furnace its venting must be made of a material that is resistant to corrosion. This condensing process along with the one that occurs within the high efficiency furnace itself creates moisture that can collect and freeze around and inside exhaust pipes since it can t travel far enough away from the home before condensing.

Cloth duct tape is not permitted to be installed on fuel burning appliance vent pipes. The gas vent pipe from the water heater tank is improperly sloped. What is vented is a residual corrosive condensate of water and carbon dioxide. In a great majority of cases plastic piping is used to vent high efficiency equipment.

This combination of carbon dioxide and water would damage the type of vents used in conventional systems which run vertically out of a home. If your furnace has an afue rating of 90 percent or above it will have a flue pipe that goes out of the side of your house.