Vent caps 12 and smaller may terminate a distance above the roof if 8 feet or more away from a vertical surface as follows.
Furnace vent high above roof.
This structure generally uses the furnace vent pipe through roofbecause the b venting pipe is designed in vertical manner.
While one foot above the roof surface may meet the recommendations for fire clearances in one storey buildings or in buildings with heating equipment on the uppermost floor the total chimney height may be inadquate to establish sufficient and safe draft unless you extend the chimney.
When the vent is withdrawing air from the house it expels the gas outside through the vent.
Notes to the table above 1 measure on the up roof or shorter height side of the chimney 2 watch out.
It s made of zinc coated galvanized steel for durability and reliability.
Roof pitch is easily calculated and if you don t know how read my article understanding and calculating roof pitch.
A high efficiency condensing furnace can achieve efficiency ratings of 90 or above.
How to vent a furnace in a roof.
Above the roof surface with a listed cap or listed roof assembly.
High efficiency furnaces produce different combustion gases than standard efficiency furnaces.
The 1992 vent sizing tables require that all type b gas vents terminate above the roof with a listed cap or listed roof assembly in accordance with the manufacturer s instructions.
Also you ll need the horizontal distance between the peak and the edge of the high side of the pipe see figure 1 where you plan your roof penetration.
Table of type b vent rooftop clearance requirements.
Goose neck vent the master flow 4 in.
Goose neck vent in black can be used to cover exhaust pipes extending through your roof or for attic ventilation.
What is vented is a residual corrosive condensate of water and carbon dioxide.
First you ll need to know the pitch of your roof.
It uses a venting system to extract that heat before venting.
Also known as the type b this vent is operating on the natural air convection.
It provides a vent pipe for exhaust gases but uses unconditioned not cooled or heated air from the space around the furnace for combustion air.
So the gases can float up through the flue pipe and out of your roof.
This vent is designed to be used on 4 in.
The master flow 4 in.
Gas vents 12 inches 305 mm in size or smaller with listed caps shall be permitted to be terminated in accordance with figure g2427 6 5 provided that such vents are at least 8 feet 2438 mm from a vertical wall or similar obstruction.
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.
All gas furnaces must be vented to allow exhaust gases from the combustion process to escape.
