Venting. A condensing furnace doesn’t require a chimney. Instead, these furnaces are vented in one of two ways: Direct vent (two-pipe) vent system – This system uses one pipe to bring in outside air for combustion and another to remove exhaust gases.
What type of vent is required for a high efficiency condensing furnace?
Traditional gas-fired, forced-air furnaces produce hot combustion exhaust gasses and therefore need metal vent pipes, or chimneys. 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.
Why is PVC pipe used for venting on condensing furnaces?
These PVC pipes are connected to the furnace and expelled outside. This high efficiency venting system must be installed when you install the new furnace. The PVC pipes are used for air intake, exhaust gas, and to remove the corrosive condensation resulting from the combustion process .
Where do you vent a furnace?
The larger outer pipe pulls in air for combustion from outdoors. Exhaust fumes are vented through the smaller, inner pipe. These furnace vents can be installed horizontally through an exterior wall , or vertically so exhaust fumes go out through the roof.
Where do you vent a high efficiency furnace?
Because high-efficiency furnaces use sidewall vents , they’re more susceptible to airflow blockages. The area around the sidewall vents should be clear of all airflow blockages for a minimum two feet in all directions. When air intake is blocked or hindered, fuel combustion suffers, and the furnace locks out.
Can you use PVC pipe to vent a furnace?
Ironically, even though the presence of plastic vent pipes has become synonymous with high-efficiency condensing furnaces, PVC pipe manufacturers do not recommend PVC for this application . Nor are there any official ASTM standards for plastic pipe used as combustion gas venting.
Can you use PVC to vent a water heater?
A standard will be needed for plastic flue pipes that should include a temperature gauge and a high limit probe. Then PVC, CPVC and polypropylene flue gas piping can be safely used on high efficiency boilers and water heaters.
How do you tell if your furnace is venting properly?
How Do I Know If My Furnace Isn’t Venting Properly? Gas furnace fumes are moist , so if you notice “sweat” on your windows, this is a sign that your furnace isn’t venting correctly. When your furnace comes on in the morning, if it is venting into your house rather than outdoors, moisture will condense on the cold glass.
Can I vent my furnace out the side of my house?
You CANNOT just take the vent off an 80% efficient furnace and run it out a side wall. You need to use an auxiliary power inducer . ... The combustion air flow through the furnace must be controlled or its efficiency will decline. The barometric damper will prevent pulling additional excess air through the furnace.
Can you vent high efficiency furnace through roof?
Depending on the installation, a high efficiency furnace will have at least one, and sometimes two, PVC pipes exiting the home. In newly built homes these vents will usually exit thru the roof . ... If there are two pipes, one is for the combustion air intake.
What type of venting is used on a high efficiency furnace?
The condensate that is left over from a high efficiency condensing furnace contains acidic water that would damage normal vents. As a result, instead of using a conventional vertical venting system, a high efficiency system uses PVC pipes that are connected to your furnace and lead out of the side of your home.
Where does a furnace get its air from?
Conventional furnaces draw air from the area immediately surrounding the furnace . Just imagine a box mounted in the middle of a room in your house with an exhaust fan pumping air into it and a vent carrying it up out of your house.
What is the difference between a direct vent and non direct vent furnace?
Direct vent (two-pipe) vent system – This system uses one pipe to bring in outside air for combustion and another to remove exhaust gases. Non-direct (single-pipe) vent system – This system uses only one pipe to remove exhaust gases.
Do PVC pipes off gas?
PVC is extremely low- maintenance, easily recyclable, and it doesn’t off-gas or leach harmful chemicals if it comes in contact with water. ... PVC measurably reduces cooling loads in buildings when it is used as a roofing material.
What is code for furnace exhaust?
The exhaust vent terminal shall be located at least 3-feet above any forced air inlet located within 10-feet. The vent terminal shall be at least 12-inches below, 12-inches horizontally from, or 12-inches above, any door, window, or gravity air inlet into a building.
