The chimney for a gas boiler serves as a discharge of combustion products. In order to install such a structure, it is necessary to strictly comply with all requirements for chimneys of gas boilers, approved by SNiP.

The chimney for a gas boiler is a very important heating element. After all, the safety of living depends on the quality of his work. And therefore, before making a choice, it is necessary to study what types of chimneys there are and their distinctive characteristics.

Types of chimneys for gas equipment

The correct choice of a chimney for gas equipment is very important, because the operation of the entire heating system depends on its reliability and service life. Today there are the following types of chimneys:

  • Brick;
  • Stainless steel;
  • Coaxial;
  • Ceramic.

Previously, brick chimneys were built everywhere, but now they are inferior to more modern types in terms of design complexity, performance characteristics and high costs. Stainless steel construction is considered one of the best options when installing heating. This design has a sandwich system - when a layer of thermal insulation is laid between the outer and inner pipes. This ensures a high degree of fire safety and exposure to aggressive environments.

Today, the most high-tech chimney device for a gas boiler is a coaxial chimney. It has a very neat appearance and high technical characteristics. Such a chimney is designed according to the “pipe-in-pipe” principle, which allows air to enter through the outer pipe to support the combustion process, and combustion products to exit through the inner pipe.

Ceramic chimneys have high heat resistance and fire safety. But they are not installed so often, as they are difficult to install and repair, and the structure is heavy.

Also, before choosing a chimney, you need to consider the following points:

  • Type of equipment;
  • Boiler power;
  • Pipe diameter;
  • Installation.

Gas equipment comes with an open or closed combustion chamber. Chimneys for gas boilers with an open combustion chamber are installed in the form of a round, rectangular or square pipe with a diameter of 100 mm or more. And for a boiler with a closed combustion chamber, a coaxial chimney is required, the cross-section of which can be 60/100 or 80/125.

Basic requirements for the combustion product removal system

The chimney for gas equipment performs the complex function of removing smoke and gas. Not only the efficiency and service life of the boiler, but also the safety of people depends on how the device functions. The basic requirements for the system for removing combustion products and connecting to gas equipment are established in the SNiP regulatory documents:

  • The chimney should only be installed in a vertical position;
  • The pipe diameter is calculated according to the boiler operating instructions, based on its power;
  • It is allowed to connect two heating devices to one chimney;
  • It is prohibited to connect two different types to one chimney (gas boiler and wood-burning fireplace);
  • Brick structures should be built from frost-resistant bricks or clay bricks;
  • It is better to install the structure in the internal main wall of the house;
  • When installing the structure in an external wall, the thickness of the brick must be at least 65 cm;
  • The horizontal section of the structure can be made no more than one meter;
  • The cross-section of the chimney must be no less than the cross-section of the pipe;
  • Mandatory presence of thermal insulation made of heat-resistant fiber;
  • It is prohibited to install fungi and weather vanes on the chimney;
  • The height of the pipe above the roof must be at least half a meter from the ridge.

When using modern gas boilers, brick chimneys must be lined to protect them from exposure to acidic environments.

Correct calculation of design parameters

Before you begin installing the structure, you need to design a heating system. To do this, it is necessary to carry out a competent calculation of the chimney. Today there are two methods for calculating parameters:

  • Structural;
  • Check.

The structural calculation is determined based on the technical data sheet of the heating device and sets parameters such as:

  • Height;
  • Diameter;
  • Material;
  • Flue gas movement speed.

A verification calculation is used when a chimney already exists and it is necessary to check its compatibility with the heating device. To calculate such parameters there is a special formula:
F= (KxQ) / (4.19 ∙ √N),

  • where K is the coefficient, equal to the number 0.02-0.03;
  • Q is the power of the heating device (this indicator is indicated in the technical data sheet of the device);
  • H is the height of the chimney.

Next, the resulting calculation is compared with regulatory documents. But it is also worth considering that the dimensions of the structure (height, diameter and cross-section) depend on the location and technical characteristics of the equipment. In the case when two heating devices will be connected to one chimney, it is necessary to make a calculation taking into account the parameters of both boilers. An incorrect calculation can affect not only the efficiency of the heating device, but also create irreversible processes in the entire system.

Installation and installation of the structure

Installation of a combustion product exhaust system is carried out depending on the method of placement of the structure. According to the type of placement, chimneys are:

  • Indoors;
  • Outside the premises.

When installing indoors, it is very important to follow all fire safety rules. To do this, in those places where the pipe passes through the ceilings, pipes are installed and a layer of thermal insulation is laid. The diameter of the pipe must be no less than the chimney pipe. Installation begins from the bottom up, increasing the height of the pipe to the required value.

For structural strength, the pipe is attached to the wall with brackets.

The installation of the brick structure is carried out simultaneously with the construction of the house. Brick chimneys are excellent for using solid fuel boilers, and their advantage is that they retain heat for a long time.

Installing a smoke exhaust system outside the room is not difficult. To do this, a pipe is inserted into the wall opening at a distance of 25 cm. Next, the structure is assembled using clamps and brackets, and the joints are treated with a special sealant. If two heating devices are connected to one chimney, they must operate alternately.

The dimensions of all holes must be selected taking into account the diameter of the pipe and the thickness of the thermal insulation layer.

How to install a chimney for a gas boiler in a private house? Is it possible to retrofit an old chimney? What is the difference between a chimney for a gas boiler?

What technical requirements are there? You can find answers to these and other questions in this article.

What types of chimneys are there?

Before installing a gas boiler, you need to take care of the chimney installation. To do this, you can hire workers, or you can make a chimney with your own hands.

It's not difficult, although there are still certain requirements. First, you should familiarize yourself with the different types of chimneys.

Chimneys can be made of:

  • bricks;
  • ceramic pipes;
  • of stainless steel;
  • coaxial chimney.


Brick chimney

A brick chimney is undoubtedly the cheapest option, but perhaps the most difficult to make with your own hands.

The fact is that a brick pipe has quite a decent weight. Therefore, its construction requires laying a foundation. But ventilation ducts can be installed in the brick pipe itself.

The pipe laying must be done from solid ceramic bricks. To make the upper part of the pipe protruding above the roof surface, it is permissible to use facing bricks.

The requirements for brickwork are such that the thickness of the chimney wall can be half a brick.

But to ensure the strength and reliability of the pipe, it is recommended to lay it in at least one brick.

For a gas boiler, a smoke exhaust duct with a cross-section of half a brick will be sufficient. If desired, you can make it wider.

If you plan to insert a connecting tin box inside the channel, then it is best to make a channel with a cross-section of 20 by 20 cm.

To extend its service life, a brick chimney is installed along the internal wall of the house. The fact is that the durability of such a pipe is directly related to the high temperature of the smoke.

When temperature changes, the brick will begin to collapse. Additionally, maintaining proper temperature ensures better traction.

Ceramic pipes

Making a chimney from ceramic pipes is easier and faster to install yourself. This type of chimney is considered the most durable.

The smooth inner surface of the pipe reduces the chance of soot settling on it and makes cleaning the chimney easier.

Some pipes are equipped with condensate drains, which prevents condensation from forming on the inner surface of the pipe.

The chimney itself is assembled from parts 0.5 - 1 m long. The upper edge of each part has a coupling - an extension into which the next part is inserted.

Ceramic pipes can be of different types:

  • round ceramic pipes for installation in special concrete blocks;
  • rectangular pipes for installation in brick;
  • ceramic pipes in a steel casing;
  • ready-made blocks with ceramic sleeve.

To make a pipe from round ceramic links, you need to purchase special reinforced concrete blocks.

They provide a cavity for installing ceramic pipes and seals. In addition, they have holes into which reinforcement is inserted during installation.

Concrete modules with an additional ventilation duct are available. Asbestos is used as a sealant when installing pipes. It helps protect nearby surfaces from fire.

Rectangular ceramic sleeves have a square cross-section of 20 by 20 cm and are designed for installation in a brick pipe.

The length of each individual section varies between 0.5 - 1 m. They are mounted in the same way as round ones, only you do not have to buy special blocks to install them.

Ceramic sleeves in a stainless steel housing are even easier to install.

Such a chimney is much lighter than a ceramic or brick one, so a foundation is not necessary. Pipes in a steel shell are connected to each other using clamps.

Ready-made concrete blocks are also available for sale, already equipped with a ceramic liner, a ventilation duct and holes for reinforcement.

Coaxial chimney

Unlike all the types described above, the coaxial chimney for a gas boiler has a horizontal outlet.

The convenience of such a chimney is that it is exhausted through the wall, and not through the roof, like a vertical chimney. To install it, simply drill a hole in the wall.

Such chimneys are designed according to the “pipe-in-pipe” principle. Here the possibility of supplying air to the boiler burner and removing smoke is immediately provided.

However, in our climate, a coaxial chimney for a gas boiler has one significant drawback. During the cold season, the air entering the burner significantly cools the exiting smoke.

As a result of temperature changes, condensation occurs. Freezing occurs on the outside of the pipe, which gradually clogs the passage and reduces draft.

Modern gas boilers are equipped with automatic shut-off, so carbon monoxide poisoning due to reduced draft does not threaten anyone.

But in order to resume operation of the boiler, the pipe will have to be cleaned of the ice that has formed in it.

Fewer problems arise with chimneys that use two separate pipes for air supply and exhaust. But such pipes are rarely found on sale.

Stainless steel pipe

The chimney is made of thick stainless steel and can be either vertical or horizontal. Installing such a pipe with your own hands is quite simple.

Disadvantages of a steel chimney:

  • the service life of such a pipe is shorter than that of a brick or ceramic chimney;
  • the cost is higher.

The advantages are simple, quick installation and lightweight design. A stainless steel pipe does not require installation of a foundation.

Since it is light in weight, it is suitable for wall mounting. Their inner surface is absolutely smooth, thanks to which soot almost does not appear.

If such a chimney becomes clogged, it can be easily cleaned and, if necessary, can be disassembled. Replacing used parts is also not difficult.

Stainless steel pipes can be either single-walled or double-walled, with insulation between the walls. It is better to use just such sandwich pipes.

Stainless steel chimneys can be used in rooms where a smoke exhaust pipe is not even provided for in the design. In this case, it is enough to lead the pipe to the street through the wall.

Single-wall steel pipes are used when converting an existing chimney for a gas boiler.

The connection of the gas boiler to the chimney occurs through a steel pipe, which is led into a brick pipe and fixed there.

How to choose the type of smoke exhaust structure?

To make the right choice, first of all you need to familiarize yourself with what requirements the manufacturer sets for the chimney.

When choosing the type of chimney for a specific boiler model, you must be guided by the following parameters:

  • temperature of the exiting smoke;
  • pressure and type of traction;
  • the presence of channels for condensate drainage;
  • recommended requirements for the distance to kitchen furniture and other household items.

Based on the combination of all these characteristics, you can choose which type of chimney is suitable. In addition to these parameters, each manufacturer has its own requirements for the required channel cross-section.

The diameter of the chimney for a gas boiler can only be determined by deciding on a specific model. Therefore, it is not advisable to arrange a smoke exhaust duct in advance.

In addition to the characteristics of the gas boiler, it is also necessary to take into account the characteristics of the building. It is not advisable to install a brick chimney in a panel country house or in a frame building.

For light buildings, a stainless steel or coaxial chimney is best suited. In addition to the fact that these types are relatively light in weight, they are easier to install with your own hands.

The following requirements apply to the chimney itself, regardless of what material was used in its construction:

  • absolute tightness;
  • presence of traction;
  • vertical location of the outlet channel;
  • if a vertical position is not possible, then the slope angle should not exceed 30°;
  • smoothness of the inner surface of the pipe;
  • presence of a hatch for cleaning;
  • ability to reduce cravings;
  • insulation of external areas.

The smoke duct must be completely sealed. Even a small amount of gases can cause poisoning.

To avoid this, it is necessary to check the channel for leaks and the presence of traction. The slope of the pipe from the vertical can be a factor that reduces traction.

The inner surface of the channel should not contribute to the accumulation of soot on its walls, for which it is necessary to check its smoothness.

This is especially true for brick chimneys, since in other types this problem occurs less frequently. The seams between the bricks must be perfectly even. You can also use a pipe insert.

Many people think that the smoke exhaust shaft starts from the boiler. This is wrong. The channel should fall below the boiler outlet by 30 - 50 cm.

This is necessary for installing a wall hatch, which will be used to clean the channel. Using it you can check the traction.

In some cases, it may be necessary to limit cravings. To do this, it is recommended to install a damper in the channel above the boiler.

A damper device is only necessary if the boiler is not equipped with a built-in damper. The damper can be replaced with an automatic limiter.

The greater the power of the gas boiler used, the larger the cross-section of the chimney duct and the height of the pipe should be. This will ensure good draft and proper operation of the boiler.

Security

During gusty winds, air from outside can enter the chimney, blocking the draft. In this case, if the boiler is not equipped with an automatic switch, the room will become smoky.

The same thing can happen during heavy rain or snowfall. To avoid the influence of atmospheric phenomena, the chimney outlet is covered with a special umbrella.

You can make an umbrella for a steel pipe from any piece of metal. You can also make a head for a brick channel.

The head structure provides smoke outlets from the side of the pipe, and the top itself is covered with a brick or plate.

Since most often the chimney is the highest point of the roof, it is worth thinking about making proper grounding - a lightning rod. Any metal structures have an increased degree of lightning hazard.

If the chimney is made of brick, then the lightning rod is manufactured as follows:

  • metal fittings are mounted to the wall of the smoke duct;
  • the fittings are connected by wire to the grounding system of the roof of the house;
  • The grounding cable goes to a metal plate that is buried in the ground.

This grounding scheme can also be used when the smoke duct is made of metal. In this case, the role of the lightning rod is played by the metal head of the channel.

However, such grounding is only possible if the boiler is not equipped with an electronic processor.

To prevent the electronics from malfunctioning, the lightning rod should be made separately, at a distance of at least 50 cm from the chimney.

This grounding scheme provides that:

  • when connecting the smoke exhaust duct and the grounding pole, no conductive materials are used;
  • The lightning rod is located above the chimney.

To properly make a grounding system, you should use reinforcement with a cross-section of at least 10 mm.

When installing a smoke duct, you also need to worry about fire protection. The fire protection scheme provides for a 5 cm indentation when passing through the ceiling, which is filled with asbestos.

Fire safety rules require a minimum distance of 26 cm from walls, furniture and other objects that may catch fire.

Happy construction!

The chimney pipe, rising above the roof, is only a small visible structural element of a complex mechanism responsible for removing smoke and gas. Regardless of what fuel the heating equipment operates on (solid, liquid or gaseous), it must be supplemented with a system for removing combustion products. Every homeowner should have an understanding of the chimney structure in his home, which will allow him to properly operate the heating system in principle. For those who are yet to solve similar problems in arranging their home, before going to a specialized store or inviting professionals, we suggest that you first familiarize yourself with the theory. Let's take gas heating as an example. To begin with, at a minimum, you need to know what chimneys for gas boilers are, what their strengths and weaknesses are.

Types of chimneys: what will a specialist suggest?

Is it possible to install a chimney yourself? Of course! Although, if you have to do this work for the first time, then consulting a specialist will in no case be superfluous. But, one way or another, you still have to figure out what kind of chimneys for boilers exist at the moment.

So, you may be asked to choose one of the following options:

Option #1 - classic brick

Although they will offer you its construction, it is unlikely, since this is not even yesterday, but the day before yesterday. A brick chimney is characterized by a complex design, high cost and its construction takes a lot of time. In addition, in many operational characteristics such a chimney is inferior to more modern designs.

Option #2 - stainless pipe

Here the manufacturer offers a wide range of models. Among the advantages, one cannot fail to note the high resistance to mechanical damage and exposure to aggressive environments. A chimney for a gas boiler, made of stainless steel, is usually made in the form of a sandwich system - two pipes of different diameters, one inside the other. The empty space between them is filled with heat-resistant basalt wool.

The stainless steel chimney pipe is reliable and has a presentable appearance

Without exaggeration, today the installation of a chimney for a gas boiler using a stainless “sandwich” is one of the most successful solutions today.

Option #3 - coaxial chimney

It cannot be confused with another design; its distinctive feature is its presentable appearance. Although the operating parameters are at a high level. Moreover, the coaxial chimney for a gas boiler has a specific shape, on the inner walls of which condensation does not form. This point is very important especially for gas fuel heating systems.

Option #4 - ceramic design

It cannot be said that it enjoys great attention from the consumer audience in the luxury construction segment. And, where preference is given to simplicity and reliability, ease of installation and fire safety, and at all this an affordable price, a ceramic chimney has no alternative.

Whatever technology is preferred, in the end, installing a chimney for a gas boiler involves working with the following elements:

  • An adapter connecting the heating boiler pipe and the chimney pipe.
  • Feedthrough pipe.
  • Telescopic pipes.
  • The bracket and clamp are the main wall fastenings.
  • Tee with revision - in the lower part there is a special fitting for removing condensate.
  • Conical tip.
  • Bends.

We invite you to watch an overview video with advice from a specialist:

What affects the efficiency of a chimney?

Perhaps the question is posed somewhat incorrectly from a professional’s point of view. Since the health and sometimes even the lives of people depend on the effective operation of the combustion product removal system, it is more advisable to consider the requirements for the chimney of a gas boiler.

A chimney of any design must be made in accordance with the requirements of SNiP 2.04.05-91, as well as DBN V.2.5-20-2001. Otherwise, the chimney will be installed incorrectly and the heating equipment will be connected to it. And this, in turn, calls into question the safety of operation of the entire heating system. These documents clearly regulate the design of boiler chimneys. These documents are subject to careful study, since violation of the standards set out in them will certainly lead to problems with the gas industry.

If we briefly outline the requirements for chimneys of gas boilers, then first of all you need to pay attention to the following points:

  • Good traction is the key to efficient use of thermal energy from gas combustion.
  • Correct design of the condensate collector - excess moisture should not accumulate on the walls of the chimney duct.
  • It is prohibited to install deflectors, fungi, etc. on the chimney head. These elements reduce the efficiency of removing combustion products, and there is a risk of carbon monoxide entering the room.
  • Requirements for chimneys of gas boilers require maximum attention to installation work. Particular emphasis should be placed on the tight fit of structural parts at the joints, that is, maximum tightness must be achieved. This will prevent hot gases from penetrating beyond the chimney.
  • It is allowed to use common connecting flue pipes for several units.

From the outside it appears that the chimney is made of brick. In fact, it's just a decoration, and it's located inside the pipe

Algorithm for installing a chimney inside a building

Installation of a chimney for a gas boiler can be done both inside the building and independently (outside). You can understand what the difference is, while making certain conclusions regarding your specific case, from our small table.

As they say, draw your own conclusions.

We bring to your attention the internal structure of the chimney system. Briefly, this process consists of the following stages:

  1. Applying markings in ceilings and roofing pie for holes for the chimney. We check the correctness several times.
  2. Cut an opening for the pipe.
  3. The pipe coming from the boiler is connected to the adapter.
  4. The tee and revision are connected, the steel sheet is attached, and the main bracket is installed.
  5. The pipe is extended, if necessary, “knees” are used.
  6. For installation through ceilings, a special pipe is used.
  7. A sheet of galvanized steel is placed on the pipe, in which a hole of a larger diameter than the chimney pipe is previously made. Galvanization is fixed to the ceiling.
  8. To strengthen the joints, clamps are used, which are tightened with bolts or high-quality wire.
  9. The chimney itself is attached with wall clamps, step - 2 m, as well as brackets, step - 4 m.
  10. To complete the design, a special cone-shaped tip is provided.
  11. The chimney is insulated.

The chimney for a gas boiler in a private house is made in accordance with the rules of SNiP 2.04.05–91. You should first select a heating boiler, then select a chimney system for it.

If a private house is not connected to city communications, then the choice of a heating system and all responsibility for its safe operation falls on the property owner. Only when heating with electricity, a chimney is not needed, but for other types of fuel, its installation is required.

By following the rules set out in this document, the owner of the house remains confident that the health and life of the family is safe, and the controlling organization will give permission to operate gas equipment.

The documentation explains the main terms:

  • The flue is a channel that goes to the chimney pipe and is connected to the boiler through an adapter.
  • Chimney pipes are used to remove combustion products into the atmosphere.
  • The inspection is intended to clean the channel and drain condensate. It is located at the bottom of the chimney shaft.

The inspection is also located in the places where the pipe turns.

When installing a chimney for a boiler and attaching the pipe to the wall, fastening elements are used - brackets, clamps.

Chimney requirements

If the system is designed correctly, the following requirements must be met:

  • Sufficient draft is provided to remove exhaust gases.
  • The chimney material for the boiler is resistant to high temperatures and does not have a porous structure.
  • All joints throughout the system must be sealed.
  • It is prohibited to install fungi and deflectors on the head of the chimney pipe of a gas boiler; such a part impairs the removal of exhaust gases.
  • The section of the chimney for a gas boiler passing through the ceilings should not have joints.
  • It is prohibited to route the pipe through rooms without ventilation.
  • It is not allowed to combine a chimney with ventilation ducts, but exhaust gases from two boilers can be discharged into one pipe.
  • The condensate collection device performs the task of collecting and draining liquid.
  • Inspections are installed at the places where the pipe turns, and the number of turns should not exceed three.
  • To ensure sufficient draft and to prevent reverse draft, the chimney should be located 0.5 meters above the high point of the roof.
  • The distance of the smoke exhaust from the combustible surface of the wall must be at least 0.25 m, and from the wall made of non-combustible materials at least 0.05 m.

Types of smoke exhaust systems

Regardless of whether the owner hires specialists or decides to independently control the installation process of the heating system, it is necessary to know how the chimney for the boiler is designed, the consumer must understand the principle of its operation.

All chimneys must be divided into two categories: internal installation with an exit on the roof, and external, wall installation.

The disadvantages and advantages are reflected in the table.

The choice of chimney is made based on the design of the house and the materials used for construction. To install the internal system, it is necessary to make markings for holes in the roof and ceilings, arrange an opening for the pipe, ensure the connection of the flue with the gas boiler pipe and install an inspection.

Brick chimney

This element is included in the project and constructed during the construction of the house, with the obligatory construction of the foundation. Sometimes a brick chimney is attached to a wall from the outside if the heating boiler is placed near this wall.

The internal surface of a brick chimney must be smooth and free of contractions and expansions. These conditions are designed to reduce the deposition of soot inside the chimney and make it easier to clean.

Resistance of the chimney to aggressive environments is another mandatory requirement. A brick chimney is best combined with traditional options, especially with solid fuel heating systems that have a high temperature of exhaust gases.

To remove combustion products from a gas boiler, steel or ceramic liners are installed in a brick pipe. Installing a brick chimney is a labor-intensive and costly process, and its technical indicators lag behind modern systems.

Chimney made of stainless steel pipe

It exists in the version of a single non-insulated pipe, made of stainless steel, which is used in heated rooms and is suitable for making a sleeve inside a brick pipe.

The second type is a sandwich chimney, consisting of two pipes. The sandwich can be placed both indoors and outdoors. The inner pipe is wrapped with insulation, non-flammable basalt wool.

A stainless steel pipe of larger diameter is placed on the outside. The advantages include fire safety and impeccable smoothness of the inner surface. A large assortment of adapters, plugs, tees, and factory-made fasteners guarantees ease of installation and tightness of the finished chimney.

Coaxial chimney

It is a “pipe-in-pipe” design, but, unlike a stainless steel sandwich, a coaxial chimney does not have an insulating layer; the pipes are separated from each other by jumpers.

The inner pipe serves as the chimney itself, and the outer one is designed to supply air to the boiler to improve its operating efficiency. Heated air enters the boiler, the system increases its performance. The exhaust gases are cooled, reducing wall overheating.

Such a system has fire and environmental safety. During the operation of a gas boiler, air from the street is used, and not from the room. The coaxial chimney is only compatible with boilers equipped with a closed combustion chamber.

The compactness of the system does not spoil the appearance of the building and allows you to install a chimney for individual heating of apartments. The possibility of horizontal installation prevents condensate from entering the boiler, and if during installation you make a slight downward slope, the liquid will drain to the ground.

Ceramic chimney

The structure consists of thermally insulated ceramic pipes installed in a concrete frame. With high-quality joining of modules, this system has high strength, fire safety, water resistance, and resistance to temperature fluctuations.

Chimney made of asbestos cement pipe

The design element combines a low price and a number of advantages. The self-supporting structure does not need to be attached to the wall; its long service life is due to its resistance to aggressive environments. Condensation does not form inside the pipe.

Installation is extremely simple - the first pipe is attached with racks to the foundation.

The chimney is increased to the required height using a coupling connection; all that remains is to install an inspection door and equip the top of the pipe with a deflector.

The connection to the boiler is made using a steel elbow, which can be easily changed if necessary.

Rules for installing an external chimney

If the owner plans to install an external chimney, the following rules should be followed:

  • Installation of the chimney is carried out from the bottom up; first, you should secure the lower section, then extend the pipe upward.
  • The structure is fixed vertically; a straight pipe is fastened every 150 cm.

Individual areas are recorded additionally. It is prohibited to use a pipe higher than 5 meters.

Methods for checking draft in a chimney

After installing a new chimney system or reconstructing a previously existing one, you need to check its performance. The main indicator is draft, precisely the function for which the chimney is built.

It is important at the design stage to calculate the ratio of the height and diameter of the chimney. The draft depends on the cross-section of the pipe; the smaller it is, the faster the combustion products are removed. But if the diameter of the pipe is too small, it will become clogged with soot, and smoke and carbon monoxide will enter the room. Too large a pipe diameter leads to backdraft.

Causes of poor traction

There are a number of factors that cause chimney draft to decrease:

  • Accumulated soot reduces the useful cross-section of the pipe, leading to a decrease in the rate of product removal.
  • Turning the system reduces traction - when cornering, the speed of gas movement decreases.
  • Poor tightness of the system, the presence of even small gaps and microcracks leads to cold air being sucked into the pipe.
  • Violation of tightness disrupts the upward movement of hot gases and leads to a decrease in draft.
  • Weather conditions also affect the rate at which exhaust gases are removed; low atmospheric pressure and humidity reduce traction.

How to check traction at home

If the owners have invited specialists to certify the system, they will check the functionality of the chimney with a special anemometer.

It’s easy to check your traction yourself using home methods.

Organoleptic methods: need to look and smell. If you smell smoke and see it in the room, it means that instead of an exhaust hood, the owners received a reverse draft effect.

Place a sheet of thin paper near the viewing window: The more the paper sticks to it, the better.

With the help of a candle. You need to light a candle, bring it to the opening of the chimney and blow out the candle. If the smoke of an extinguished candle confidently stretches in the direction of the chimney, then the draft is good.

Important Note: The draft check should be carried out with the heating equipment turned off. It is difficult to select a chimney for a gas boiler, but the operation of the equipment requires scrupulousness and thoroughness from the home owner. Safety must come first.

If the causes of poor traction are identified, then work needs to be done to eliminate them. It is easy to clean the pipe from soot on your own using a special brush attached to a cable with a weight. More serious problems require calling specialists. Operating heating equipment with a faulty chimney is prohibited.



Gas equipment remains the most economical and unpretentious type of heating equipment. The only difficulty, judging by the reviews, is the high installation requirements of both the heating unit itself and the smoke removal system.

The chimney installation of a gas boiler in a private house is carried out in accordance with SNiP and PPB. Any violations lead to refusal to commission the equipment by gas service employees.

Despite the high standards, making a chimney for a gas boiler with an open combustion chamber with your own hands is much easier than it might seem at first. To complete the work you will need:

  1. Select the type and design of the chimney.
  2. During installation, take into account existing rules and requirements.
  3. Prevent and avoid common mistakes made during installation.
Provided that all of the above is observed, you can install a smoke exhaust system for an atmospheric boiler yourself.

What is the best way to make a chimney for a gas boiler?

The high requirements for a chimney for a gas boiler in a private house are a good reason why choosing a suitable flue system must be especially careful. Not all types of chimney pipe are suitable for this purpose.

Let's look at the most common options for smoke exhaust systems:

  • Galvanized smoke exhaust pipes are the cheapest way to make a chimney. The low temperature of the exhaust gases makes it possible to use galvanization for connection to a gas boiler. The pipe has several disadvantages: it burns out quickly, needs careful insulation, etc.
    Additional information regarding the possibility of operating a galvanized chimney can be found in.

  • Ceramic smoke removal systems - ceramics have one of the best ratios in terms of reliability, service life and thermal characteristics. For a gas boiler with an open combustion chamber, you need a chimney that can provide stable draft and no condensation. The disadvantages of ceramics are their heavy weight and high cost of construction.
    After installation, a ceramic chimney will last at least 50 years. Read more about the technical characteristics and installation rules.

  • Stainless steel sandwich pipes are one of the most successful smoke removal systems for connecting to a gas boiler. The pipe consists of two circuits, between which a non-flammable layer is laid. Design features ensure almost complete absence of condensation and soot accumulation.
    What adds to its popularity is the simple installation of a sandwich pipe and the ability to make the connection yourself. How to select and install a stainless sandwich pipe is described.

  • Enameled pipes - this type of pipe is coated with a protective layer that prevents corrosion of the walls and improves the appearance of the structure. The enamel can withstand heating up to 550°C, therefore, standards allow its use as a chimney for an atmospheric gas boiler.

  • A brick flue is used exclusively after lining the internal channel. The service life of brickwork, without loss of tightness, is only 7-8 years. Afterwards, the pipe loses its tightness. Installing a metal stainless pipe inside a brick channel largely solves the problem of insufficient draft and loss of sealing.
    Brick chimney ducts for gas boilers have hardly been used lately. Find out detailed guidance on choosing masonry materials and carrying out installation work.

A chimney for a gas atmospheric boiler in a private house is best made of ceramic or stainless steel sandwich pipes. During installation, the design and material features of the smoke exhaust system are taken into account.

For the chimney, it is better to use a stainless steel pipe, marked AISI 416 and with a thickness of at least 0.8 mm. This steel resists acid well and is resistant to burning.

Rules for installing chimneys for atmospheric gas boilers

The gas chimney pipe is subject to building codes and regulations (SNiP), which separately indicate:
  • Ventilation and heating of residential premises using gas equipment -.
  • Recommendations and requirements for gas distribution systems and removal of combustion products from the premises -,.
Using legal standards, it is enough to simply ensure that the smoke removal system complies with the safety regulations, calculate the height and diameter of the chimney, and also determine the frequency of its maintenance.

Fire safety requirements for the chimney

As already noted, there are detailed rules for the safe use of gas appliances with organized removal of combustion products into chimneys. Some points are separately specified in the PPB. Individual standards change from time to time, but in general, the basic guidelines remain unchanged.



Fire safety requirements for chimneys from domestic gas heating appliances may vary depending on the region and emerging situations. Before connecting a smoke removal system, it is better to ask representatives of the Gas Service about existing standards.

How to calculate the height of a boiler chimney

To correctly make a chimney for a boiler with an open combustion chamber with your own hands, not only fire safety rules are taken into account, but also calculations are made in accordance with existing SNiP.

The main task of a smoke removal system is the safe removal of combustion products from a residential building. This will require a stable and consistent traction. In this regard, building codes were developed that stipulate what the height of the chimney should be.

You can make calculations yourself using the following recommendations:

  • The height of the chimney for a gas boiler in a private house is calculated depending on the distance of the pipe from the ridge of the building. If the distance between the center of the roof and the head of the pipe is no more than 1.5 m, it is necessary to raise it by at least 0.5 m. At a distance of 1.5-3 m, it is allowed for the pipe to be flush with the ridge. If the chimney is more than 3 m away from the ridge, the head can be lowered below the ridge by 10°.
  • The length of the chimney, in order to provide the necessary draft, must be at least 5-7 m.

Modern gas boilers have a built-in sensor that records the presence and force of draft in the pipe. If the automation constantly gives a signal to turn off, it means that the calculations were performed incorrectly - you will need to increase the length of the chimney.

How to choose the chimney diameter

There are strict gas service requirements for the diameter of the chimney and supply ventilation, which include several important aspects:
  • The diameter of the chimney must be as specified in the technical documentation of the boiler.
  • Reducing the channel diameter is not allowed. The minimum cross-section of the chimney pipe is the same as at the boiler outlet pipe. It turns out that if the outlet channel on the boiler is 150 mm, then the channel must be at least 150 mm.
  • If necessary, you can increase the diameter of the pipe.
  • The room used as a boiler room must have at least natural ventilation.
The main requirement for the chimney diameter remains strict adherence to the recommendations of the boiler unit manufacturer.

Is it necessary and how to insulate a chimney pipe?

The reason for the formation of condensation in the chimney shaft is poor insulation of the pipe. There is such a concept as “dew temperature”. The purpose of insulation is to ensure that when the smoke removal system is operating, heating above this parameter is carried out as quickly as possible.

Methods for properly insulating a chimney depend on the chosen chimney pipe. Thermal insulation can be done in the following ways:

  • Basalt wool - the material is simply wound onto the pipe, securing it with clamps or binding wire.
  • Thermal insulating shells are optimal for insulating a chimney. Basalt shells have the necessary parameters for use in flue systems with low flue gas temperatures.
  • Basalt mats and cardboard are used to insulate a brick chimney. Mats are used for subsequent plastering.

How to check and increase draft in a chimney

The draft characteristics of a chimney are affected by several parameters:
  1. Pipe diameter.
  2. Chimney height.
  3. Section.
If, after installing the chimney, signs of poor draft appear: an increase in the volume of condensate falling, stopping operating equipment, you will have to increase the circulation of combustion products in the pipe. You can do this in the following ways:
  • Install a deflector on the chimney. Practice has shown that installing a draft limiter improves the speed and intensity of combustion products removal by 1.5 - 2 times.
  • Perform pipe maintenance. A decrease in draft often occurs after 2-3 years of operation of the chimney without maintenance. After cleaning the pipe, the characteristics are restored in full.
  • Increase the length of the chimney. If the pipe height parameters are not observed, the traction force will be insufficient. The problem can be solved by lengthening the head.
  • Another option is to initially install a forced draft chimney. Not every pipe is absolutely suitable for forced draft gas equipment, therefore, before purchasing, you should carefully study the technical documentation of the boiler.

Is it necessary to ventilate a room with an atmospheric boiler?

Boiler rooms with installed household floor and wall-mounted gas boilers with an open combustion chamber are equipped with natural ventilation. This is due to the fact that during operation the boiler burns air taken from the room.

Representatives of the gas service are sensitive to the total area of ​​the boiler room, ceiling height and other parameters that affect the flow of fresh air. Thus, the lower part of the door should not be adjacent to the door frame, forming a gap for the free flow of air into the room. The boiler room itself must have a ventilation duct, as well as windows for ventilation.

How often should you clean your chimney?

The legislation specifies the period of time during which periodic inspection of pipes should be carried out. As a rule, maintenance of smoke exhaust systems is carried out at least once per heating season.

To facilitate subsequent maintenance, a condensate collector and an inspection hatch are installed in the pipe to drain condensate and clean soot. Correct arrangement of the chimney when installing a domestic gas boiler includes the installation of components necessary for servicing the system, with free access to them.

Main mistakes when choosing a flue for a gas boiler

The most common mistakes when installing a chimney are:
  1. Incorrect pipe height and diameter.
  2. Lack of thermal insulation when installing an attached external chimney or when passing through an unheated attic space.
  3. Failure to comply with PPB rules.
Self-installation of a chimney for a gas atmospheric heating boiler in a private house can save approximately 20-30% of the total cost of the smoke exhaust system, but has certain disadvantages.

It is almost impossible to avoid violations of SNiP and technical requirements when installing a gas duct without special knowledge and training. Any violations will lead to refusal to commission the boiler, water heater and other heating equipment. Additional improvements and alterations will be required, which will inevitably affect the budget.

Installing individual gas heating for a wooden country house should be entrusted to professionals. Only in this case can the safety and long service life of the gas duct be guaranteed.