The exhaust flue is the channel where exhaust gases are carried away from the heat exchanger. Upon leaving the heat exchanger the exhaust travels up the flue, which is usually a metal pipe.
What type of pipe is used for furnace exhaust?
Suitable materials for the vent and condensate pipes include PVC (polyvinyl chloride), CPVC (chlorinated polyvinyl chloride), and ABS (acrylonitrile-butadiene-styrene) plastic pipe, depending on the furnace's specified exhaust gas temperature. How hot should a furnace exhaust pipe get?
Why do furnaces need an exhaust stack?
If you have an old furnace that doesn’t work very well, then you may need to consider replacing the exhaust stack. Also known as the gas flue, the exhaust stack is the pipework on the furnace that removes toxic gases from the furnace into the outside air. Replacing this kind of flue is rather complicated.
Why is water leaking from my flue vent?
- Chimney cover – a new chimney cover may keep water from entering the top of the chimney
- Flexible roof sealant- apply flexible roof sealant from a can or tube to holes, gaps, flashing and loose shingles around chimney
- Flashing & shingles – replace flashing and shingles around the chimney, creating a good new water barrier
How to install a furnace exhaust pipe?
Process of Installing a Furnace Exhaust Flue (Steps 1 – 4)
- Taking Measurements. Measure the distance from your furnace to your chimney. ...
- Purchasing Supplies. Purchase some single-wall galvanized pipe and elbows—as well as a 1-inch, galvanized hangar strap—from your local home improvement store.
- Making Your Furnace Exhaust Flue. ...
- Secure the Furnace Exhaust Flue. ...
What is the purpose of a flue pipe?
HVAC systems that utilize a gas- or oil-fired furnace or boiler are equipped with flue pipes to vent harmful fuel combustion gases out of the property safely as they exit the heating equipment.
What is a flue on a heater?
This is the job of the flue, a large metal pipe that extends from the furnace to a chimney liner or an independent flue pipe. The flue brings combustion gases safely through your home and up through the roof, expelling them above the roofline.
What is a exhaust furnace?
These furnaces vent gas away from your house through a flue pipe. The flue pipe is attached to the heat exchanger, where the gas combusts and produces heat energy. Gas exits the house through the exhaust pipe, which usually leads up to a house's roof.
Where is my furnace exhaust vent?
They should be near where your furnace is on the inside. Normally, they are a set of curved pipes (PVC, CPVC, or ABS) near the foundation, although sometimes they are on or near the roof.
Is flue same as vent?
The term flue refers to the passage by which smoke, gas, or products of combustion are moved to the outdoors. Ducts, pipes, vents, and even chimneys can all be considered types of flues.
What are the 3 main types of flue?
There are six main flue types, and each can be determined by simply looking at your roof.Brick Chimney. The Classic brick built chimney is suitable for all gas fires and stoves in this website. ... Pre-Fabricated. Pre-fabricated flues are suitable for most gas fires and gas stoves. ... Pre-Cast. ... Balanced Flue. ... Flueless.
Why do furnaces need exhaust?
Your furnace generates a great deal of heat when it runs; it also generates fumes and carbon monoxide, which need to be transferred out of your house safely in order to avoid some serious problems. The way these items are transferred outside your home is via the exhaust flue.
Do all furnaces have an exhaust pipe?
Some older furnaces use a natural draft system to expel flue gases from the home. In a natural draft furnace, there is no inducer fan. Instead, the hot flue gases naturally flow upwards out of the home through a flue pipe or chimney. If you have an older natural draft furnace, you probably don't need an exhaust fan.
What comes out of a furnace exhaust?
The exhaust is mainly water vapor and carbon dioxide, but the absolute majority of furnaces also form a wide range of byproducts (particulate matter, nitrogen dioxide, sulfur dioxide, hydrocarbons, carbon monoxide, etc.); carbon monoxide is especially dangerous as this invisible, odorless gas can lead to poisoning.
How do I know if my furnace exhaust is blocked?
How to tell if your exhaust vent is blockedFurnace doesn't heat the air. By far, the most common symptom of a blocked exhaust vent is a furnace that doesn't heat up. ... Furnace heats up for a little while, then shuts off. ... Furnace cover panel gets hot. ... Bad smells when your furnace is heating.
What happens if your furnace exhaust is blocked?
A blocked exhaust flue might only cause a furnace to short cycle and nothing more. However, a blocked or broken flue also has the potential to circulate exhaust and carbon monoxide into your home.
Should furnace exhaust pipe be covered?
If the vent pipes are not protected by screens, you take a big risk for furnace problems due to pipe obstruction or infestations from pests. A simple screen can prevent pest problems, but the wrong type of screen can create other problems.
How do I know if my fireplace flue is open?
Feel for a Draft An open damper will let air circulate freely in the chimney flue. You should be able to feel cold air by moving your hand or face into the fireplace.
How do I know if my boiler flue is clogged?
How to tell if your boiler flue is blockedA noisy boiler. ... Staining or sooting around the pipe and its seals. ... Water leaks around the boiler or mouth of the flue pipe. ... Strange smell. ... Carbon monoxide alarm is triggered.
How much does it cost to replace a boiler flue?
A simple horizontal flue installation would cost around £200 including parts and labour. Basic flue kits for most boilers are around £100. The rest of the cost includes labour to drill through brickwork and make it right. This should be included when an installer quotes for the cost of boiler replacement.
Where is the flue on a fireplace?
A chimney flue is a vertical passage or duct that runs from the firebox (where the fire burns) to the top of the chimney. Technically, a flue is any open vertical space in a chimney that allows smoke to escape the home from the firebox.
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 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.
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 work without a flue?
A furnace simply can’t operate correctly without a well-designed flue. For more information about the flue in your HVAC system, please contact the home heating experts at C.B. Lucas.
Can a new furnace be compatible with existing flue pipe?
Many people experience flue problems when installing new furnaces. Simply put, your new furnace may not be compatible with your existing flue pipe.
What is a flue pipe?
A flue pipe is an integral component of home heating installations. It is usually located at the fireplace, furnace or water heater installations. Exhaust gases and other byproducts of combustion are expelled into the outside atmosphere through the flue. In this way, pollution of indoor air is prevented. The pipe enables healthy ventilation even as household heating operations take place. It also acts as a safeguard against accidental fires. Flues are made of metal because it is fire resistant. Usually, the pipe is surrounded by some material to assist insulation. Flues may be categorized into 3 types - fireplace, furnace or water heater flues. Below is a brief description of each and functions.
Why is the flue used in a fireplace?
Carbon monoxide poisoning can easily occur if exhaust gases are reversed back into the house. In transmitting the exhaust products of combustion outside, the flue allows the warmth from the fireplace to be retained indoors and benefit household occupants.
Why is the exhaust pipe pitched?
It is usually pitched upwards towards the chimney. This allows the exhaust gases to move easily into the chimney and the outside atmosphere. Toxic gases produced during combustion are expelled from the house through the exhaust vent. This prevents pollution by the furnace from taking place indoors. The exhaust pipe is also a vital safeguard against accidental fires. When exhaust gases are not properly expelled from the building, they can interact with other combustibles to cause a fire.
How does a chimney contribute to the fire resistance of a fireplace?
The chimney contributes to the fire resistant qualities of the flue. Smoke , exhaust gases and other byproducts of combustion are transmitted from the fireplace to the outside atmosphere through the chimney flue. It acts as a vent so that the byproducts of combustion do not find their way back into the room during combustion.
Why are flues made of metal?
Flues are made of metal because it is fire resistant. Usually, the pipe is surrounded by some material to assist insulation. Flues may be categorized into 3 types - fireplace, furnace or water heater flues. Below is a brief description of each and functions. Continue reading below Our Video of the Day.
What materials are used to insulate chimneys?
Heat resistant materials such as brick, tile and ceramic are used to insulate chimney flues. This is because flue gases transmitted can be very hot. Insulation also makes the fireplace more energy efficient. The chimney contributes to the fire resistant qualities of the flue.
Where is the combustion gas located in a water heater?
It is usually located centrally in the heater. Combustion gases are transmitted from the heater and expelled to the outside atmosphere. The safe release of toxic gases is a vital function of the water heater flue. It prevents pollution of air indoors.
What is a flue?
Historically the term flue meant the chimney itself. In the United States, they are also known as vents for boilers and as breeching for water heaters and modern furnaces. They usually operate by buoyancy, also known as the stack effect, or the combustion products may be 'induced' via a blower.
What is a flue in a chimney?
Unsourced material may be challenged and removed. A flue is a duct, pipe, or opening in a chimney for conveying exhaust gases from a fireplace, furnace, water heater, boiler, or generator to the outdoors. Historically the term flue meant the chimney itself.
What is an open flue?
Flue types include: Open flue – An open flued appliance draws combustion air from its surroundings; exhaust gases rise in a vortex up the open flue. The 19th century Rumford fireplace is an appliance that elegantly refined this principle.
How does a wood fire flue work?
In some countries, wood fire flues are often built into a heat preserving construction within which the flue gases circulate over heat retaining bricks before release to the atmosphere . The heat retaining bricks are covered in a decorative material such as brick, tiles or stone. This flue gas circulation avoids the considerable heat loss to the chimney and outside air in conventional systems. The heat from the flue gases is absorbed quickly by the bricks and then released slowly to the house rather than the chimney. In a well insulated home, a single load fire burning for one and a half hours twice a day is enough to keep an entire home warm for a 24-hour period. In this way, less fuel is used, and noxious emissions are reduced. Sometimes, the flue incorporates a second combustion chamber where combustibles in the flue gas are burnt a second time, reducing soot, noxious emissions and increasing overall efficiency.
Why are flues important?
Flues are adjustable and are designed to release noxious gases to the atmosphere. They often have the disadvantageous effect of releasing useful household heat to the atmosphere when not properly set—the very opposite of why the fire was lit in the first place. Fireplaces are one of the biggest energy wasters when the flue is not used properly.
What is a balanced flue?
Balanced flue – Use the natural draught created by the hot exhaust, so the flue is as short as possible, usually sufficiently long to pass through an external wall against or near which the appliance is installed.
Why do you adjust the flue after a fire?
After the flue heats up from the fire, they are easier to move, but also hotter. Hands should be protected when operating the flue lever; and if a new log is added to the fire, the flue must be adjusted again to ensure that smoke does not billow out into the house.
What is a flue made of?
The flue is made from different materials, though the majority are constructed from ceramic, clay, or metal conduit.
What is a Chimney Flue?
The chimney flue is a duct, pipe, or opening in the chimney designed to remove exhaust gases from the fireplace, furnace, water heater, generator, or boiler to the outdoors.
How Does a Chimney Flue Work?
The fire down below in the fireplace needs three things to burn continuously – oxygen, fuel, and ignition. Fuel may come from gas, wood, pellets, etc.
How long do flue liners last?
However, it’s important to understand that certain factors can shorten or improve the life of your flue liner. Stainless steel liners, for instance, tend to last up to 20 years with goof maintenance, with cast-in-place liners lasting even longer – up to 50 years – with good maintenance. Clay tile liners are the least durable, typically lasting 5-15 years.
How much does it cost to fix a fireplace flue?
The cost of fixing a fireplace flue ranges from about $150 to $800. The majority of homeowners pay between $163 and $820 for general flue repairs, regardless of the type of flue. However, expect to pay anywhere between $90 and $2,000 for high-end chimneys.
Where is the flue liner in a chimney?
The chimney liners and flue liners are essentially the same things. It’s the lining found inside the opening in the middle of the chimney, which basically refers to the flue.
Where does air for combustion come from in a fireplace?
In traditional, open-flue systems, air for combustion is supplied from the room where the gas or stove is installed . However, balanced flue systems require that the fireplace is sealed from the room in which it is installed and twin-wall pipe vents directly indoors.
What is a flue?
A flue is simply a passage for conveying exhaust gases from an appliance to the outdoors. A flue may be a duct, pipe, vent, or chimney. An unlined chimney is technically a flue, even though an unlined chimney is a fire hazard.
What is a factory chimney?
Factory built chimneys are generally stainless steel, and may be covered by a chase (for protection or decoration), or left as is. While chimneys vent fuel, they are not considered “vents”.
Why are chimneys lined?
Rather, chimneys are lined, so the smoke passes over a smooth surface that helps prevent excessive accumulation of combustion byproducts and minimizes the chance of fire. Chimney liners are also called “chimney flue liners”. The terms are largely used interchangeably.
What is chimney tile?
Traditionally, chimneys were lined by fireclay flue tile. This special tile is carefully laid inside chimneys to provide no ridges or spots for accumulation; the tile is finished to a smooth, nonporous surface. This classic chimney liner can be difficult to fix if tiles get damaged deep inside the chimney.
Why do vents need to be exposed?
The top of a vent must be exposed to the outside to allow the byproducts to be released, but such exposure will not cause problems given the rest of the vent is properly set up and protected. Sometimes a vent fan is installed to help push (or pull) low temperature byproducts from the vent. Vents are always factory built.
Why do we need vents?
Vents may pass through the house, or run outside of the house, so long as they are protected from the elements. Vents need a degree of temperature protection, otherwise their low temperature combustion products may be too cool to properly vent. This could cause a dangerous amount of flammable byproducts to collect in your vent.
Can a chimney vent run through a chimney?
Vents are always factory built. They are not chimneys, as they cannot handle the high temperature of wood combustion. Some vents, however, may run through a chimney, given that anything else venting through the chimney is contained in a separate flue.
How does a flue work?
With a horizontal flue, the pipe travels straight through the wall behind the boiler. In cases where the boiler is not fitted to an external wall, a vertical flue may be installed. In this case, the flue goes upwards and then out through the roof.
What is a horizontal flue?
With a horizontal flue, the pipe travels straight through the wall behind the boiler.
What is a boiler flue?
Definition: A boiler flue is a component which enables gas to escape safely from boiler. In most cases, this is a pipe or a duct, which is fitted to the boiler to carry exhaust gases away from your home safely.
Where will I find my boiler flue?
In most cases, finding a boiler flue doesn’t involve a full-scale, Anneka Rice style treasure hunt.
How do the shape and location of the flue affect costs?
Most of us don’t have an endless budget, so it’s important to be aware of the potential cost implications of different types of the flue.
Why is a boiler flue important?
A boiler flue is a simple mechanism, but one that is very important for your safety, but also that of those around you. As well as promoting health and safety, boiler flues are also required to ensure your heating system meets the required regulations.
What is the regulation for the location of a boiler flue?
1. Location. The location of the flue is key to protect you, as well as the people who live near you.
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Engineering ToolBox, (2003). Fuels - Exhaust Temperatures. [online] Available at: https://www.engineeringtoolbox.com/fuels-exhaust-temperatures-d_168.html [Accessed Day Mo. Year].
