Why does my furnace vent outside?

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. That’s because the combustion byproducts are in a liquid form, so they need to be drained out of your home in a similar way that the condensation from your air conditioner is drained outside.

Should pipe coming out of furnace be hot?





It’s normal for your exhaust pipe and the exhaust to feel warm. It’s also normal to see icicles or other icy build-up around the pipe during freezing weather. If your pipe is very hot, call Breedlove Dobbs so we can have an experienced and qualified technician check it out.

What are the PVC pipes on a furnace for?

If your furnace is 90% efficient or greater, you probably have PVC pipes coming out of the wall of your home that look something like those pictured here. These pipes allow the furnace to intake fresh air and to safely vent flue gasses out of the home.

Can I use PVC pipe for 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.

How do you vent a furnace with PVC pipe?

Quote from the video:
Quote from Youtube video: So make sure it's level. So for the exhaust. In the screen and a coupler for the intake you have an elbow. And you want the exhaust to stick out six inches past the intake.

Does a furnace vent outside?





At the end of an exhaust pipe, a fan is integrated to help vent the combustion gases from the furnace to the outdoors. Sidewall vent systems are affordable options for gas furnaces, and they also have high-efficiency ratings and safety.

How hot should the outside of my furnace get?

With a conventional gas furnace, you should be at about 140°F-170°F at the supply plenum. A high efficiency furnace will be lower, around 110°F-140°F. However, the temperature at the outlet of the furnace, is dependent on the temperature of the incoming air.

How hot should a furnace vent pipe get?

Hot End Temperatures



The temperature in the flue pipe of your furnace can run as high as 400 degrees Celsius, which is about 750 degrees Fahrenheit. This temperature is an indication that your furnace is not running at maximum efficiency and you are losing heat up the chimney.

How can you tell if your furnace is overheating?

Signs of an Overheated Furnace

  1. You notice a “hot” or burning smell coming from the vents. …
  2. You hear strange noises or loud humming coming from the furnace. …
  3. You notice the furnace cycling off without starting again.



What type of PVC is used for furnace venting?

Quote from the video:
Quote from Youtube video: So the local installers went and they found whatever material they could find readily. Available on the east coast they use standard pvc pipe like this this is drain waste and vent pipe that you'd see

Is PVC pipe heat resistant?

Explanation: PVC is a thermoplastic, and therefore, at some point it will begin to degrade and break down as it’s heated up. It just so happens that Schedule 40 PVC’s maximum operating temperature is 140 degrees Fahrenheit, around the same temperature that hot water gets to in most homes.

Can you use PVC pipe for heat ducts?



PVC is considered a good option for mitigating the risk and is often used to comply with mandated safety regulations. In homes, PVC ductwork can allow a heating and cooling system to run beneath the house without being corroded by moisture or even radon. Over time, metal ductwork can rust and will need to be replaced.

What happens if there is improper venting of the furnace?

Sometimes improper venting can cause heat exchangers to corrode. Corrosion can also be a result of old age. The big problem is that this corrosion can lead to cracks in your heat exchanger.

What happens if furnace exhaust is blocked?

If the exhaust flue is blocked, the inducer fan won’t move any air, and the pressure switch won’t trigger. The furnace won’t proceed to heat until the pressure switch is triggered. This is to ensure that your furnace has enough airflow for complete combustion and to remove gaseous byproducts from your home.

How should a high efficiency furnace be vented?

A two pipe venting system should be installed that provides combustion air to the furnace directly from outside. Acidic condensate should be drained or pumped directly into the plumbing system.

How long can a furnace vent pipe be?



The maximum vertical distance you can run a furnace exhaust vent is about 15 feet. If there is a forced air inlet within 10 feet of the exhaust vent, the exhaust gas ventilation terminal should be positioned at least 3 feet above it.

Does furnace vent need to be sloped?

No , no slope is needed on the inlet. The exhaust is sloped to discharge or drain the moisture created in the combustion process.

Should furnace exhaust be higher than intake?

The exhaust pipe should be pointing up and the intake pointing down. If your intake is above the exhaust terminal, the intake might be sucking up exhaust gases (carbon monoxide, etc.) back into the home!

How far apart should intake and exhaust be on a furnace?

Wall intakes must be located at least 10 feet from any appliance vent or any vent opening from a plumbing drainage system. Wall intakes must also be 10 feet from any exhaust fan discharge outlet unless that outlet is 3 feet or more above the intake location. (IRC 2006, Section M1602.