Let's be clear: What is the flue liner?
If you're going to buy anything in this world, you need to be sure that you know what part you are buying and for exactly what purpose. Connecting a flue pipe to a stove or internal appliance is no exception, so let's make sure you first completely understand what a flue liner is and how it fits into your home heating solution.
As with any liner, a flue liner creates an outflow that takes gas, combustibles (the stuff that gets burnt) along with smoke, out of your home. If you own a car, then you have an exhaust pipe. If you have a wood-burning stove at home, then you always need a flue. But, if the flue is broken or not functioning properly, then you need to put a liner in.
Do I need a flue liner?
You use a flue liner to allow the fumes from your internal appliance (yes, the bad stuff -gas, smoke, and dangerous combustible materials) to be released straight into your chimney. However, this is not recommended as there may be an issue with your chimney. Better to get this checked out first
If there is anything about your chimney that isn't totally sound (if it isn't fully sealed or if draughts can come back down it) then sooner or later you'll be in a situation where some of this waste gas is more than likely going to leak into your home, either through the chimney itself or back down into your home. This could also affect your neighbour if you share a chimney with them - this is not good under any circumstance. We don't want unhappy neighbours!
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The Problem With Unlined Chimneys
Chimneys often have rough surfaces that aren't even, because they are generally old and were designed before we fully understood how to get waste gas out of a house with real efficiency. This means that smoke doesn't always naturally just flow up in the way you would hope. One issue is that smoke can cool while it is on the way up. If that happens then it can result in it coming back down and back into the home. At this point, you definitely need to investigate buying a flue liner with a smaller diameter than the chimney.
Clearly, this is not what you want as it means that the smoke will come back down the chimney. You run the risk of getting waste deposits on the internal part of your chimney in the form of creosote or tar. If these increase over time, then you can run the risk of them leaking into your home. This damages the internal parts of your home and furnishings. It will eventually affect the inner lining, plasterboard, or plaster that sits under your wallpaper or the paintwork in your home.
No flue liner simply means that the smoke will draw up much slower, and as mentioned, potentially return back down the chimney. As well as the previously mentioned potential damage to the home, you will also lose performance in the efficiency of the burning of your chosen fuel. You get less draw and heat out of your heating appliance.
Flue liners extremely rarely suffer from fires. Any burning that happens as the smoke rises is completely contained and continues up and out of the house inside there is much less chance of tar deposits getting stuck when you have a liner. If you care about safety, you definitely need a flue liner.
If you aren't sure about the existence of any type of liner at your property, then you can get an inspection to check for you. This way you will know if you have a liner. You'll also find out if it has blockages or leaks or any damage that may cause the risk of a fire.
What type of flue liner do I need?
If you don't already have a flue liner, then you will need one for your chimney if your chimney has a problem or is too broad. This isn't 100% certain in every single case, but based on what we've already made you aware of, it is definitely advisable. Get it checked out either way.
You need to choose the size and type of flue liner based on the stove you buy. Flue liner sizes are as the stove manufacturer states. We cannot stress enough that you cannot adjust the size of the flue liner. You can only use the one specified at purchase.
A Simple Rule for a 20kw Stove
In general, if you have a 20kw stove, then you need to connect it to a flue liner with a diameter of at least 6". There is an exception to this, however. You can use a flue liner that is 5" in diameter with a DEFRA approved stove, but you still need to check compatibility with the manufacturer.
Flue Liner Quality Is Also Something To Consider
In addition to considering the diameter of your flue liner, it is important to contemplate the quality of the liner that you intend to fit.
The main point here is that there are two primary varieties of flue liners. The first one is the 316 grade, which is relatively cheap. However, it's only suitable for those who burn wood & low-sulphur coal. On the other hand, the second type is the 904 grade, which is a bit expensive but much more durable. If you plan on burning COAL frequently, then this grade is the way to go. It's important to keep this in mind while making your choices.
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If you have a chimney that needs upgrading, you can use a flexi flue liner for optimal use. Flue liner kits are available depending on your needs. Whether you are burning more wood, low-sulphur coal or regular coal, there's a kit that fits your needs.
The Multi-flue Liner 316 is ideal for most households' wood stove needs. However, if you plan on burning smokeless fuels, a tonne of coal, or leaving the stove overnight, then the 904 grade flue liner is considered most suitable.
Connecting flue pipe to Stove: The Important Facts
After you have your flue liner fitted, you then need to fit it to your stove pipe. Below are some important facts that can help you plan.
Positioning The Stove
It's important to consider the positioning of your stove in relation to the chimney cavity while connecting it to your chimney liner. This is because the proper installation of the flue liner is critical for the safe and effective operation of your wood-burning stove. The connection between your stove and flue liner should be done accurately, taking into account the location of your stove in relation to the chimney cavity. This guide helps you in your installation process and how to troubleshoot potential issues like the flue getting stuck.
As you may know, the most common wood stove position involves placing the rear half of the stove within the chimney cavity, while the front half protrudes out into the living space. In this case, it's necessary to connect your stove to the flue liner using two 'elbows' from the top of the stove - so in simple terms, if you can’t put the stove pipe directly up and out of the chimney, then you need to create some 45 degree corners in order for the liner to go backwards (into the chimney cavity) and then up out of the chimney.
This approach ensures that the back of the stove is not too close to the rear wall of the chimney cavity, and it also provides easy access when you need to sweep the soot. So, it's crucial to take into account this specific stove position and use the appropriate installation method to ensure optimal performance and safety.
If you prefer to have your stove positioned more towards the living space, an alternative connection method involves using a 90-degree Tee Piece to connect the flue liner to the rear of the stove. However, in this case, it's essential to ensure that you have enough access to the back of the chimney cavity to facilitate soot collection. Therefore, you need to take this into consideration when you choose the stove placement and the corresponding flue liner connection method.
The 90-Degree Bend Could Help You
You could also consider using a 90-degree bend stove flue pipe fitted to the back of the stove. This approach is particularly useful when you want to bring a smaller stove into your living space, and the chimney cavity allows for less air gap left and right than the ideal setup. So, if you have space constraints or prefer a compact stove design, this connection method could be the best choice for you.
If you have a large enough chimney cavity, positioning your stove in the middle and connecting it vertically to the flue liner with a straight connector to your single wall pipe could be the easiest option. In this case, soot sweeping is typically done through the stove (if its design allows it) or via a soot door in the vertical stove pipe.
On the other hand, if you prefer to have your entire stove within your living space, the final option involves passing your stove pipe through a hole in your chimney breast using 90 degree connectors and connecting it to the flue liner. If you are concerned about the heat from the stove pipe damaging your mortar, you can use fireproof rope or webbing to protect it. Therefore, you have various options to consider while connecting your stove to the flue liner, and it's important to choose the one that best suits your specific needs and preferences.
Connecting stove pipes to the flue liners
You know what a flue liner is. But, what about stove pipes?
As you may know, the stove pipe is the visible pipe that extends out of the top or rear of your appliance and runs up the chimney. In case you have a twin wall flue pipe system, it extends up to your wall or ceiling. Given that stove pipes are visible in your living space, it's crucial to ensure that you're content with the appearance of the one you choose. Therefore, it's recommended to choose a stove pipe that complements your decor and adds to the aesthetic appeal of your room. You may also want to consider the material and colour of the stove pipe sealant, to ensure that it matches your interior design.
After selecting your stove pipe, the next step is to securely fit it to your stove collar. It's crucial to ensure a tight fit as any loose fit or gaps could lead to smoke and combustibles escaping into your living space, which could pose a safety hazard. In case you discover a gap between the stove pipe and the stove pipe collar, the course of action would depend on the size of the gap. If the gap is more significant than 5mm, you can use fire rope to seal it up. However, if the gap is 4mm or smaller, you'll need to use fire cement to fill it in. Therefore, it's essential to address any gaps promptly to prevent potential safety hazards and ensure the proper functioning of your stove.
Now you have fitted your stove pipe to your stove securely, you need to connect the flue liner and the stove pipe.
The most efficient, straightforward, and secure approach to connecting your chimney liner to your stove pipe is by using a stove flue pipe adapter, which is also referred to as a flex adapter or connector. These adapters generally resemble inverse cones or collars that fit between the stove pipe and flue liner. They provide a convenient and straightforward means of attaching pipes to the flue, ensuring optimal performance and safety. Therefore, it's highly recommended to use a stove flue pipe adapter while connecting your flue liner to your stove pipe for a hassle-free and secure installation process.
It's crucial to note that a single wall stove pipe is only appropriate for internal use. If you need to pass through a wall or ceiling, or run your flue pipe externally, it's essential to use an insulated twin wall flue pipe in all cases. This is because a single-wall stove pipe can reach temperatures of over 500 degrees, which poses a significant fire risk when passing through walls, ceilings or other materials. Moreover, when hot gases meet cold air, it leads to condensation inside your flue system, causing faster corrosion. Additionally, hot air naturally rises, but rapidly cooling air does not rise as fast, leading to potential updraught problems. Using an insulated flue pipe is an excellent solution to mitigate these issues and improve the safety and durability of your system.
As you install your stove pipe, it's essential to make sure that the spigot end (the tapered or reduced-diameter male end) always points downwards. Condensates in flue pipes are unavoidable, and installing the spigot end facing upwards creates ridges that allow water to collect and sit in, greatly reducing your stove pipe's lifespan. Therefore, installing your stove pipe correctly is critical to ensure optimal performance, durability, and safety. If you'd like a comprehensive guide to installing a stove pipe, click here.
A flange is a flat metal fitting that is attached to the top of a flue liner and extends outward to create a flat surface that can be fastened to the chimney. The purpose of a flange is to provide a secure and airtight connection between the flue liner and the chimney.
To ensure that your flue system is safe and functional, it's vital to seal every joint from the back of the wood stove all the way up with fire cement. Additionally, you must check that all seals are not leaking by testing with smoke pellets. Any leaks in the flue system can pose a significant safety hazard.
Is it big enough? How to choose flue sizes
When it comes to flue system diameter, it's possible to increase the diameter by up to 1 inch from the diameter of the flue outlet on your wood-burning stove, but no more. It's not permissible to reduce the diameter at any point in your flue system. This ensures that the updraught is sufficient for your log burner, and the system functions correctly. Therefore, it's crucial to adhere to these guidelines while setting up your flue system to ensure optimal performance and safety.
As you prepare to connect the flue liner and stove pipe, it's crucial to take your time and apply fire cement or fireproof webbing carefully to the 'snout' of the adapter, which is the end that connects to the stove pipe. This step is essential to prevent any leakages of smoke or combustibles, and ensure optimal safety.
Afterwards, you need to apply fire cement to the inner rim of the adapter, which connects to the flue liner. This additional layer of protection will prevent any unwanted leakages, ensuring optimal performance and safety.
Once you've completed these steps, you can use the wing nuts on the outside of the adapter to lock everything securely in place. This step is especially important when carrying out activities such as soot sweeping or any other invasive activities within the flue liner and stove pipe. Therefore, it's essential to follow these guidelines to ensure a secure and safe installation of your stove pipe and flue liner.
Additional Fittings
Additional fittings can include adapters, elbows, tees, and caps.
When using additional fittings, it is important to ensure that they are compatible with the specific type of twin wall flue system being used. It is also important to follow the manufacturer's installation instructions and to comply with local building codes and regulations. Any modifications to a flue system should be made by a qualified professional.
What are Vitreous Enamel Stove Flue Pipes?
These are an excellent choice for wood-burning stoves and multi-fuel stoves. These pipes are made of high-quality steel, coated with enamel, which makes them extremely durable and resistant to high temperatures. They have a sleek and shiny finish that adds to the aesthetic appeal of your stove installation, making them a popular choice among homeowners. Additionally, they are relatively easy to install, and their interlocking design ensures a tight fit that prevents any leakages of smoke or combustibles. However, it's essential to note that vitreous enamel stove flue pipes are only appropriate for internal use. When passing through a wall or ceiling, it's crucial to use an insulated twin wall flue pipe. By following these guidelines, you can ensure optimal performance, durability, and safety of your stove installation.
Single wall vitreous enamel stove flue pipe is needed for every installation of a wood-burning stove. You need at least one length of stove pipe to connect directly to your log burner's flue outlet. From this pipe, you can connect to either a flexible flue liner if going directly through an existing chimney, or to a twin wall flue pipe if you need to pass through walls or ceilings or route your flue pipe externally.
The Importance Of Fire Cement
You should seal every joint from the back of the wood-burning stove all the way up with fire cement to ensure that all seals are not leaking by testing with smoke pellets. Any leaks in the flue system can be very dangerous.
Fire cement is an essential material used in the installation and maintenance of all the home heating systems we sell. It is specially formulated to withstand high temperatures and provide an airtight seal between joints and surfaces. It's crucial to select the appropriate type for respective stoves. Different stoves have varying properties and are suitable for different applications. It's also crucial to apply fire cement correctly. Always follow the guidelines.
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Did We Miss Anything?
Hopefully, you just got all the answers you need, but maybe you still have a question. If you want to know about this or any other topic relating to domestic burners and flue pipes, then please check out our FAQ page.
Here is our guide to UK regulations or our installation guide.
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