What Size Vent Pipe Do I Need for My Furnace?
Gas furnace vent sizing is a critical matter determined by the National Fire Protection Agency (NFPA) and National Fuel Gas Code (NFGC). So, we recommend checking out the two resources. Alternatively, check out this valuable guide from Ameri-Vent. It has all the relevant tables to help you determine the ideal vent sizes for all types of gas furnaces.
What Type of PVC is Used for Furnace Venting?
Beware, however, that not all plastic is good for furnace venting. Why? Because high-efficiency furnaces produce significant amounts of water and carbon dioxide, which typically mix to form carbonic acid within the vent pipes. Carbonic acid is highly corrosive, thus can quickly eat up certain plastics.
What is the Pitch Required on a PVC Venting Pipe?
Gas furnace vent pipes must have a minimum of ¼ inch per foot of slope towards the furnace. This is very important, and something many DIYers overlook. More importantly, PVC intake and exhaust vent pipes must be supported all the way from the furnace to the discharge points outside the house to prevent sagging. Sagging can lead to condensate accumulation, airflow restriction, water pooling, and ultimately furnace shutdown.
Why is my furnace exhaust rusting?
Your furnace exhaust pipe should never have white residue or rust on the exterior. If your furnace exhaust pipe has white or rust deposits around the seams of the piping or if it looks like the metal piping has freckles, your furnace isn’t operating correctly. Both of these conditions are created by poor combustion of natural gas or propane.
Why does my furnace have carbon monoxide?
Furnace exhaust pipe carbon monoxide issues can be caused by the age of the furnace, poor furnace maintenance, or poor installation design issues. If the damaged furnace exhaust piping problem isn’t fixed, carbon monoxide could enter the home or building. Carbon monoxide is caused by incomplete combustion of gas or other combustibles. This happens when your furnace can’t burn correctly. This can be caused by poor air supply, wrong gas supply pressure, or just a dirty, poorly maintained gas appliance. The proper way to prevent your furnace from premature damage is regular heating maintenance.
Why won't my furnace burn?
This can be caused by poor air supply, wrong gas supply pressure, or just a dirty, poorly maintained gas appliance. The proper way to prevent your furnace from premature damage is regular heating maintenance.
What happens if you don't fix your furnace?
The leftover deposits from natural gas or propane are very corrosive and if not fixed in a timely manner will result in the furnace and piping being prematurely damaged. Damaged furnace piping will let carbon monoxide and products of combustion into your home.
What is a gas furnace?
For many homes, a gas furnace is the preferred heating device. It has proven to be an efficient and reliable way of meeting household heating needs over the years. The vent pipe, or flue, is a vital component of the furnace that transmits emissions from the combustion process out of the building. This ensures that those in the building are not harmed by toxic gases and other byproducts of combustion. The flue is also a safeguard against fire. If the waste gases come into contact with other combustibles, a fire can easily break out. Below are three types of venting for gas furnaces.
Why are direct vent furnaces safer than natural vents?
They also do not spoil the quality of indoor air unlike the B-vent type, so safety ratings are higher for direct vent furnaces than natural vents.
What is an induced draft fan?
This is also referred to as an induced draft fan. A fan is placed at the end of an exhaust pipe that runs through a sidewall which draws out combustion gases and expels them outside. The fan works in conjunction with the furnace, usually turning on before the furnace starts. Sidewall vent systems are especially great for replacing old chimneys, and it is one of the more affordable options to consider when installing a venting system for your gas furnace. Sidewall power vents also rate highly in efficiency and safety.
How does a B vent work?
Type B vents are a standard design that most modern gas furnaces use. It draws air from within the house for combustion. Gases produced during combustion are very hot and as such, easily rise through the flue. The air is then vented outside through a B-vent pipe which is set vertically to expel combustion air through the roof. Natural vent pipes can be installed fairly easily, and costs are fairly modest, making them a popular choice. However, back-drafting is more common with natural vent pipes than other varieties. The indoor air can easily pull combustion gases back indoors. This detracts from the efficiency of the B-vent piping. The tendency to back-draft also raises questions over furnace safety where such pipes are used. Back-drafting can affect the health of household occupants through inhalation of toxic emissions if it remains a consistent problem.
What is direct venting?
The outer pipe draws air for combustion from outside, and the smaller pipe occupies the inner position and is used to vent the exhaust fumes. Piping can be set horizontally to allow venting through a sidewall, or vertical installation can also be undertaken to allow venting through the roof. Direct vent systems have versatility to their installation that natural vents do not. Also, no chimney is needed regardless of whether horizontal or vertical installation is used. Installation of direct venting is fairly easy, but more costly than the B-vent type.
What is flue in a furnace?
The flue provides a direct conduit to the outdoors, allowing exhaust gases to move up out of your home and safely disperse. 2. Most Furnaces Use Natural Draft. Unless you own a high-efficiency condensing furnace, chances are your flue system works on the principal of natural draft. The term natural draft refers to the ability ...
What is the most important part of a gas furnace?
One of the most important parts of a gas-powered furnace is the exhaust flue. Although this component plays a largely passive role in furnace operation, your system simply couldn’t work without it. If you would like to improve your knowledge of residential HVAC systems, keep reading. This article outlines three important things to know about ...
What is draft inducer?
A draft inducer consists of a high-powered fan located near the heat exchanger inside the furnace. The draft inducer helps to clear out any lingering exhaust gases inside of your furnace’s combustion chamber, making more room for fresh air. In addition, by speeding up the flow of exhaust gases, a draft inducer augments the negative pressure ...
What are the two things that would happen if a furnace was perfect?
1. Flues Vent Exhaust Gases. In a perfect furnace, the combustion of natural gas would generate only two side effects: water vapor and carbon dioxide. Neither of these substances pose any serious threat to human health. Unfortunately, virtually no furnaces can achieve 100 percent efficiency.
Why do furnaces cost more to run?
Such furnaces cost more to run since they fail to capitalize on a significant amount of energy. When the time comes for a new furnace, more and more homeowners choose a high-efficiency model. Many such furnaces contain a component known as a draft inducer.
Does exhaust gas have a higher temperature than incoming air?
The exhaust gases produced by your furnace have a much higher temperature than the incoming air. As a result, the exhaust gas exists at a lower pressure relative to the fresh air flowing into your furnace.
Can a furnace be 100 percent efficient?
Unfortunately, virtually no furnaces can achieve 100 percent efficiency. Instead, some portion of gas fails to combust entirely. This process of partial combustion leads to the formation of a wide range of byproducts. Many of these substances — carbon monoxide, most notably — have a highly toxic nature.
