The pipes can be set in two ways.
Direct vent furnace exhaust.
The vent cap installs on the outside wall of the home.
24 inches to 6 feet note 6 distance to air intake and exahust vent openings of another direct vented gas fired appliance.
Direct venting or side wall vent chimney and flue systems are a method of venting the exhaust gases from a heating appliance directly out through the side wall of a building while eliminating the need for a vertical chimney of any sort.
Gas or oil fired side wall power vents are provided by several manufacturers listed at the end of this article.
The single pipe non direct vent system is used where there is no real need for a separate combustion air intake vent.
This construction uses two different sizes of pipes within one unit.
Distance to an air conditioner or heat pump compressor condenser unit to the nearest point of a direct vent gas heater exhaust.
In a direct vent system you can readily see the two pipes emerge through the side of your house.
A direct vent gas furnace has an air intake and exhaust system that is enclosed in a sealed pipe system.
The outer and bigger pipe draws the air for combustion from outside while the smaller one is constructed on the inner position to expel the exhaust gas.
Vents can also be terminated above the roof.
The required air is drawn in from outside through horizontal piping in a direct wall vent and the burnt exhaust gases are expelled the same way.
Direct vent systems mount on an outside wall and have a vent within a vent system to draw in outdoor air to support combustion and exhaust flue products to the outdoors.
Horizontally through the sidewall or vertically through the roof.