Adhere to them even if you are building the vent on your own.
Venting a gas furnace through the roof.
The diameter of the vent pipe should always be larger than that of the gas furnace flue ensuring that no gas escapes from the pipe.
If your furnace has an afue rating below 90 percent it will most likely have a flue pipe that goes up through your roof.
The best exhaust fan venting is through smooth rigid ducts with taped joints and screwed to a special vent hood.
Push the male end of a new vent pipe up through the bottom of the roof flashing and set its female end on the male end of the vent pipe that connects to the gas furnace.
That depends on whether you have a standard efficiency or a high efficiency furnace.
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.
Place the vent cap on the top end of the duct and tighten the set screws with a screwdriver.
Also known as the type b this vent is operating on the natural air convection.
Vent your bath and kitchen exhaust fans through the roof through a special roof hood.
Are you venting through a wall to the exterior for a horizontal termination or through the roof with a vertical termination.
You ll need to measure the distance between the rafters where the duct will go through the roof.
With the exterior complete you can finish the rest of the job inside your garage.
You ll want to know the thickness of your walls so you can properly prepare for your wall penetration if venting through an exterior wall to a horizontal termination.
When the vent is withdrawing air from the house it expels the gas outside through the vent.
The vent pipe must overlap at each joint to prevent gas from leaking.
Put a cover on the vent.
Gas furnaces usually come with their own specifications.
Should my furnace flue pipe go through the roof or the side of the house.
How to vent a furnace in a roof 1.
The exhaust system typically uses metal venting often routed into a chimney stack to exhaust the combustion gases created in the furnace fire chamber.
If your furnace has an afue rating of 90 or lower it probably exhausts the gases though the flue pipe on your roof.
Another problem is that flue pipes that go through the roof tend to be less efficient.
Run the vent pipe up through the roof and install a metal or pvc flashing collar over it.
Venting through a roof vent or exhausting them in the attic could cause moisture problems and rot.
A conventional natural gas furnace will vent the dangerous combustion gases through a simple vertical exhaust system that is attached to the furnace.
Locate the spot to install the vent pipe using a tape measure to determine distance from a wall or other.
Then add about 16 to this measurement.
So which type of venting system should your furnace have.
High efficiency furnaces take advantage of the heat in the combustion gases that are wasted in natural ventilation systems.
You will now insert the long portion of your duct through the hole in the roof from below until it s about 24 above the roof shingles.
