Proper Venting For Furnace Into The Roof

The different types of venting.

Proper venting for furnace into the roof.

Illustrations of proper gas fired water heater venting using type b double wall vent pipe through a roof above or through a chimney below include details for the flue vent connector such as the requirement of a minimum. Most old gas furnaces use such a mechanism while modern furnaces use the b pipes. Well making sure that you choose the right venting style will protect them. When we are talking about gas furnace vent pipe code we need to talk about the different types of the vents first after all you want to keep your family safe from harm.

Consequences of improperly assembled vent pipes problematic chimney flue deteriorating chimney walls can be sometimes fatal fire and carbon. 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 chimney that s too short can result in poor appliance performance. The two systems use different venting systems.

A direct vent will directly throw all the air into the atmosphere. In contrast modern high efficiency condensing furnaces exhaust much cooler gasses and need only plastic pipe materials such as pvc cpvc or abs for their exhaust vents some high efficiency furnaces also include a plastic pipe for intake area and all types. The conditions explained in this post also apply to the wood burning appliances. Drip edge vents are a two in one installation that promote water shedding at the eaves and rakes of a roof while also allowing for ventilation into the attic.

With offsets tallied and the roof penetration point determined you can calculate how much chimney pipe you need. Otherwise such vents may be unsafe venting combustion products including dangerous carbon monoxide into the building. This combination of carbon dioxide and water would damage the type of vents. To guarantee you have enough pipe you must follow the 3 2 10 rule.

Match the vent pipe to the furnace maker s recommendations either sheet metal or vinyl. Traditional gas fired forced air furnaces produce hot combustion exhaust gasses and therefore need metal vent pipes or chimneys. If you don t have soffits or your roof style doesn t allow for soffit vents some homeowners will consider a drip edge vent. Run the vent pipe up through the roof and install a metal or pvc flashing collar over it.

Example of high efficiency furnace venting on a roof.