Pipes for gas boilers. Requirements for installing a gas boiler chimney

In the Russian climate, heating is the most important element ensuring comfortable and safe living in the house. Particular attention is paid to chimneys, since they are the ones that remove hazardous combustion products from the premises.

Why is a chimney so important for a gas boiler?

The most important element of a gas heating system is a device for removing fuel combustion products. This is confirmed by the attitude of gas service workers, who place special demands on such structures. Flue gases in such boilers do not have a specific odor, but immediately poison the human body. Therefore, smoke exhaust ducts should be given increased attention both at the stage of choosing design and materials, and during regular operation of the heating system.

The products of fuel combustion in a gas boiler are very dangerous for the human body, so the chimney must work smoothly and without failures

The arrangement of chimneys must comply with the requirements of SNiP 2.04.05–91 and DBN V 2.5.20–2001. When planning the installation of a boiler and chimney, you must first study the requirements of these documents and strictly comply with them from the design stage to commissioning. The design of the device must be agreed upon with the gas service.

The initial data when choosing a chimney for a gas boiler are as follows:

1. The temperature of the exhaust gases is about 150 o C, so pipes of any material can be used. Structurally, it is better to build a chimney from double-walled sandwich pipes with basalt insulation, which will reduce condensation of furnace gases.
2. When using a gas boiler, it is necessary to install exhaust ventilation equipment with a diameter of at least 100 mm.
3. The development and approval of a heating and ventilation design is required.

The natural solution would be to choose a double-walled austenitic stainless steel pipe that is resistant to chemicals, especially for the inner pipe. You can check this with a magnet - good stainless steel does not attract it. The outer pipe can be made of galvanized sheet.

A sandwich pipe is a double-walled structure made of metal pipes filled with insulation.

The ventilation duct from the boiler room is installed simultaneously with the chimney. You can use plastic pipes for it.

Upon completion of the installation of the chimney and ventilation system, it is necessary to obtain a commissioning certificate from the VDPO (All-Union Voluntary Firefighting Society).

When choosing a boiler for heating, you need to take into account the actual conditions of its installation.

What is the device?

The classic chimney device of a gas boiler consists of the following components:

1. The flue is the connecting link between the boiler and the chimney.
2. Additional elements - tees, adapters, bends, clamps. These are the parts for forming the exhaust duct.
3. Brackets - for fastening the outer part of the chimney.
4. Inspection - hatch for cleaning the chimney from soot.
5. Condensate collector in the form of a tee with a device for draining it.

The chimney also includes special elements:

When designing a chimney, it should be taken into account that it cannot contain more than three turns of the channel. Otherwise, cravings are sharply reduced, which can lead to serious consequences.

Choosing a chimney for a gas boiler

There are many ways to construct chimneys using various materials.

Brick chimneys

Laying a brick chimney is a labor-intensive and complex process that requires certain skills. The result is a square or rectangular channel. Its disadvantage is that it does not correspond to the conditions of gas movement. They move, twisting in a spiral, resulting in stagnant zones in the corners. In these places, increased condensation occurs and soot deposits form. In addition, the outer part of the chimney is subject to destruction under the influence of atmospheric phenomena.

A traditional brick chimney is not suitable for gas boilers because it does not provide optimal gas movement

The situation is corrected by installing a round pipe liner inside the brick chimney. It can be made of special plastic, ceramics, steel or asbestos. In this case, making an audit is mandatory. Installing the liner is called sleeving.

A brick chimney needs to be insulated in the external area above the roof.

The chimney will last longer if it is lined

Video: chimney lining

Metal chimneys

The use of metal for combustion product removal systems is a very common phenomenon. The advantage of this material is ease of installation and durability, especially if it is stainless steel. The inner surface of the metal pipe has a smooth surface, which promotes condensate drainage and reduced soot formation. This is especially effective on gas heating units, since the temperature of the exhaust gases does not exceed 150 o C. For the same reason, rapid burning of the pipe walls does not occur.

Using a metal pipe you can make a chimney with any acceptable configuration

Ceramic pipes for chimneys

Clay is the most ancient building material. Currently, the scope of its application has expanded significantly. One use is ceramic chimneys. They are made in the form of separate sections 50–100 centimeters long, at the ends of which gutters and protrusions are arranged for precise connection of the elements. Installation is carried out using specially shaped expanded clay concrete blocks, which form the frame of a fragile chimney.

Ceramic chimneys must be lined with special expanded clay concrete blocks to protect it from mechanical stress

During installation, the pipe is simultaneously insulated with basalt wool and the structure is reinforced through special openings in the blocks.

A special feature of ceramic chimneys is their mandatory installation in a strictly vertical position. Therefore, they are installed on a separate foundation and in a place that allows the chimney to be routed without intersecting the supporting structures of the house. . Turns and bends of a ceramic chimney are not allowed.

Asbestos-cement chimneys

It should be noted that heat-resistant pipes are not produced from this material. The heat resistance limit of asbestos pipes is 300 o C, so they are quite suitable for gas heating units. The disadvantages of pipes made of such material are that it is impossible to install an inspection window in them, and they must be installed strictly vertically. The connection is made using couplings with thread sealing with asbestos cord. It is believed that fine asbestos fibers are released from the pipe during operation, causing harm to the human body.

The inner surface of the asbestos pipe is rough, which contributes to increased formation of soot on the walls. The installation of an asbestos pipe on a chimney is carried out with support on a separate foundation.

The use of asbestos pipes for installing chimneys in gas boilers is quite acceptable, since the temperature of the gases at the outlet of the boiler is significantly less than 300 degrees

When choosing a chimney for a gas pipe, there are practically no restrictions on the material. The main criterion is the cost of the purchase itself and the complexity of the work.

DIY installation

The procedure for performing work is almost the same for all chimneys. The differences appear during the installation process and depend on the type of material chosen for the chimney.

Brick chimneys

They are installed in the following order:

1. The heavy structure of a brick chimney is built on a separate foundation. An inspection window is installed at the bottom for inspection and cleaning of the chimney.
2. The masonry from the foundation is carried out with ordinary solid bricks using fire-resistant masonry mortar. A clay-sand mixture is also used, which is quite strong and stable for furnace work.

   For laying chimneys, ordinary red fire-resistant bricks are used.

3. At the height of the boiler flue, a hole for it is left in the masonry wall.

   At the required height, a window is left in the chimney to enter the pipe from the boiler

4. Upon reaching the ceiling, the masonry is fluffed - the pipe is laid out with a widening of at least twice. The opening in the ceiling must be sealed with basalt wool or sewn with asbestos sheet. Next, the masonry is carried out in the original order.

   At the point of passage through the ceiling in the masonry, a special element is made - fluff, the diameter of the internal channel remains unchanged

5. The crucial point is the passage of the roofing pie. In this place, another expansion element of the chimney is made, which is called an otter. The gaps between the opening made in the roof and the chimney are filled with basalt wool, and the intersection plane is covered with a sheet of the appropriate profile. To obtain a tight connection, you can use bitumen sealant.

   The intersection of the otter and the roof slabs is laid with insulation, and on the side of the roofing material it is sealed with a special apron made of metal plates

6. At the very top of the pipe, a widening is also made to prevent water from entering the outer wall of the chimney. A cap is attached to it to protect the smoke channel from debris.

The design of the chimney throughout its entire length must comply with the requirements of the technical documentation specified above.

For laying a brick chimney, solid ceramic bricks of grade M50 or M75 are used. The minimum cross-sectional size of the chimney duct must be at least 140x140 mm, and when lining - at least 150 mm along the inner diameter of the sleeve. If the chimney has a height of less than five meters (from the grate to the head), its size must be increased to 140x200 mm or to a diameter of 180 mm.

A prerequisite is the passage of smoke channels inside heated rooms, otherwise their cooling and a drop in draft are inevitable. If there are several heating units in the house, it is advisable to group the chimneys so that they have one multi-channel outlet above the roof. In addition to improving the conditions for fuel combustion, this will reduce construction costs.

Chimneys made of metal pipes

As already noted, this is the most popular material for chimneys. Its distribution is due to the ease of installation and a wide range of various components that allow you to install a chimney of any configuration.

There are three main types of metal chimneys:

• external, arranged along the wall of the building;
• internal, carried out indoors through ceilings and roofing;
• coaxial, designed specifically for closed gas boilers.

External chimney made of metal

To install an external chimney, a hole is cut in the boiler room wall through which the chimney pipe is led out at an angle of 45 or 90 degrees. The length of the horizontal section should not be more than one meter. The internal part of the pipeline is made of a single-wall pipe so that the heat from it remains inside the house. The horizontal section is equipped with a tee, in the lower part of which a tap is installed to drain condensate from the vertical part of the pipe.

The vertical section of the chimney is insulated with fire-resistant material, most often basalt wool is used for this, over which a protective jacket made of foil film or galvanized steel is placed.

If the chimney is planned to be installed outdoors, it is removed through a hole in the wall and directed upward using a tee with a condensate collector

The vertical parts of street chimneys are usually made from sandwich pipes. In them, the inner pipe is surrounded by insulation, and the outer pipe is a protective casing. The ends of the pipes are prepared for connection during the production process using the pipe-to-pipe method.

The vertical sections of the chimneys of gas boilers are collected “by condensate”, i.e., the upper pipe is inserted into the lower

The connection is made “by smoke” or “by condensate”. In the first case, ideal conditions are created for the release of combustion products, in the second - for the drainage of condensate. But in any case, the connection is sealed with special sealants.

The chimney is attached to the walls of the building with brackets; if the height is high, the upper part must be secured with braces made of stainless wire.

Metal pipes are attached with special brackets to the wall, and if the height of the roof part is high, with guy wires to the roof surface

A protective device in the form of a cap or deflector must be installed at the upper end of the chimney.

Video: installing a wall chimney

Internal metal chimney

The chimney can be installed inside the house with the intersection of at least one floor and roof, so its installation has its own characteristics.

The internal chimney crosses at least one floor and roof structure

Flue gases are removed from the boiler through a horizontal or vertical flue from a single-wall pipe. The vertical part of the sandwich pipe begins before crossing the ceiling . The construction of a junction inside the transition is strictly unacceptable. To arrange the crossing point you must:

1. Cut out part of the ceiling at a distance of 12–15 centimeters from the pipe.
2. From below, on the ceiling of the boiler room, install a steel sheet 1.5 mm thick, which is attached to the base with self-tapping screws.

   A metal sheet is fixed to the ceiling, which can be connected to a box for laying loose insulation

3. Seal the opening in the ceiling with basalt wool.

   The free space on top is filled with basalt wool or filled with expanded clay (if a box was installed for it), then a metal sheet is laid

4. Install a steel sheet similar to the bottom one on top of the basalt wool.

The intersection with the roof is carried out according to the same principle. When using metal pipes, standard covers placed on the pipe are used to isolate the passage. They are available with different angles of inclination or universal ones with plastic bases that accept any inclination.

Coaxial chimneys

Coaxial chimneys are a relatively recent invention that is used only with closed gas boilers. Air from the boiler room does not enter such a heating unit, but is sucked in from the outside space. The chimney pipe is a double-walled product in which longitudinal partitions are installed instead of insulation.

In a coaxial design, the smoke removal channel is the internal channel of the smaller pipe, and air enters the combustion chamber through the interpipe space

When fuel burns, furnace gases begin to displace cold air through the internal pipe, and since the heating unit is isolated from the boiler room space, air is sucked in through the outer part of the coaxial chimney.

The coaxial chimney is discharged through the wall. This is done because there is no need to create natural draft in it - in closed systems, draft is generated forcibly due to the rotation of a fan built into the smoke duct.

Coaxial chimneys are not subject to the rules established for systems with natural draft; here draft is created forcibly

Video: heating a private house - coaxial chimney

Asbestos and ceramic chimneys

Asbestos and ceramic chimneys are installed in compliance with the same requirements as metal ones. A feature of their installation is the need for a strictly vertical location of the smoke channel and the installation of a separate foundation.

Insulation of chimneys for a gas boiler

Insulation of chimneys must be done for the following reasons:

1. Heat loss in the chimney occurs when exposed to cold outside air. At the same time, the temperature of the furnace gases decreases, and therefore the speed of their movement decreases, that is, the draft decreases. And if we add to this a decrease in draft due to soot in the pipe or the adverse effects of wind, it is quite possible that reverse draft will occur with carbon monoxide entering the room. This is fraught with serious consequences.
2. A well-heated pipe provides sufficient draft for active combustion of fuel and its high heat transfer. As a result, the efficiency of the thermal unit increases. This is especially important for gas boilers with low temperatures of combustion products.

Chimney insulation is done in various ways:

1. Brick chimneys in the under-roof space can be effectively insulated with a layer of plaster, and if the attic is not insulated, you can use rolled non-combustible materials in the form of stone, slag or basalt wool. To ensure the safety of the insulation, it can be covered on top with foil or thin sheets of metal.
2. In the same way, you can insulate the outer part of a brick chimney, it depends on the climatic conditions in the area.
3. Metal chimneys are also insulated with insulation; the insulated surface can be protected with galvanized or aluminum sheets.
4. Ceramic chimneys are insulated during installation with expanded clay blocks and mineral wool, as mentioned above.
5. Care must be taken when insulating asbestos pipes. When overheated, this material can explode with predictable consequences.

Photo gallery: methods of insulating chimneys

Mineral wool is fireproof and stores heat well The insulation must be protected from destruction by a metal casing. Stone wool and expanded clay block reliably insulate a ceramic pipe Brick chimneys are insulated with basalt or mineral wool, placed in a frame fixed to the pipe

Features of operation

Installation of a gas boiler chimney and its connection is such a responsible undertaking that it is best to entrust it to a gas specialist. But if you decide to do it yourself, you need to strictly fulfill the following requirements:

1. Connecting more than one gas boiler to the chimney by combining pipes is unacceptable. With this design, combustion products will enter the house.
2. It is prohibited to combine galvanized elements with brick, asbestos and aluminum.
3. Work can only begin after careful calculations of the chimney cross-section in accordance with the parameters of the purchased gas boiler.
4. The length of the chimney must be at least 5 meters from the lower level of the firebox to the upper end.

   When installing any type of chimney other than coaxial, it is important to position it at the correct height

5. When installing a chimney on a building with a flat roof, the height of the pipe above the roof must be more than 1.5 meters.
6. The head of the pipe, the axis of which is located at a distance of 1 to 3 meters from the ridge, must be no lower than its level.
7. If the distance from the pipe to the ridge is less than 0.5 meters, the elevation of the pipe above the junction line of the slopes must be at least 0.5 meters.
8. If the length of the part of the pipe above the roof is more than two meters, it must be strengthened with additional guy wires in an amount of at least three pieces.
9. A deflector must be installed on the head of the pipe.

   Installing a deflector increases traction by 20–25%

Checking the draft in the chimney of a gas boiler

The reason for checking is obvious indicators of improper combustion of the boiler, which can be recognized by the following signs:

1. The smell of gas and a feeling of smoke in the room.
2. Changing the color of the burner flame towards red. This is a clear sign of incomplete combustion of fuel.

If these circumstances exist, you must immediately turn off the gas supply and ventilate the premises. After this, check the draft in the pipe and determine the reason for its insufficiency:

The reasons for the drop in traction may be:

1. Insufficient pipe height. Under certain weather conditions, traction may deteriorate or disappear altogether.
2. Contamination of the chimney with soot, resulting in a critical change in the effective cross-section of the channel.
3. Lack of deflector at the upper end of the pipe. With a certain direction and strength of wind, air currents may arise that prevent combustion products from leaving the chimney until reverse draft is formed.

It is necessary to reliably establish the cause of the drop in traction and eliminate it. The house must have an alternative source of heat. Then measures to eliminate the causes of the drop in traction can be carried out in a calm environment and in comfortable conditions.

Video: checking the draft in the chimney of a gas boiler

Traction adjustment

Each boiler and smoke removal device is individual and its characteristics may change over time. Therefore, you will have to spend some time to understand the features of traction settings for different weather conditions. This is especially important during the transition period at temperatures around zero degrees. The principle and methods of regulation are as follows:

1. The draft is adjusted using a damper installed on the chimney. Its position is indicated by a pen.
2. Traction adjustment and automatic settings should be done in the fall, when the temperature is 5–10 degrees below zero, and also in the spring, during thaws with temperatures up to 5 degrees below zero.
3. Autumn adjustment is based on a further decrease in temperature, at which the pressure of cold air on the exhaust gases increases.
4. In clear frosty weather, the valve position should be set to maximum gas flow. By gradually closing the chimney, we ensure that the burner flame turns yellowish, which indicates incomplete combustion of the gas. In this case, the combustion should be smooth, without popping. The flame deviates towards the burner, which indicates the presence of draft and the serviceability of the boiler. After this, the position of the gate must be set to the middle position at an angle of 45 degrees.

Spring adjustment is made in reverse order, taking into account the expected temperature increase. Complete shutoff of the gate is unacceptable.

What to do if the boiler firebox blows out

There may be several reasons for this phenomenon:

1. Insufficient pipe height.
2. Chimney freezing.
3. Excessive number of pipe kinks.
4. Planting the pipe.
5. Wind blowing the pipe.

To get rid of the boiler blowing out, you need to establish and eliminate the cause of this phenomenon.

The burner can blow out for various reasons, some of which are temporary.

A fundamental way to improve draft is to install a deflector at the upper end of the chimney. This device increases the efficiency of the hood by 20–25%. And the use of a rotary deflector turns the wind from the boiler’s enemy into its ally. The deflector rotor rotated by the wind creates forced draft in the chimney.

With all the variety of deflector models, they perform one task - increasing chimney draft

The most dangerous situation occurs when all burners, including the igniter, go out. This may cause gas to accumulate in the room and cause it to explode. The reasons for this situation may be:

1. A drop in pressure in the gas line or a short-term interruption in fuel supply.
2. Lack of draft in the chimney.
3. Power supply interruption.
4. Igniter extinguishment.

The first action when one of the listed situations occurs is to immediately stop the gas supply manually. Modern gas boilers have a built-in security system, consisting of a mandatory set of sensors:

• flame presence sensor;
• traction control device;
• device for blocking gas supply in the event of a short-term drop in pressure in the network;
• a device that turns off the boiler when the voltage in the boiler control network disappears;
• a device for turning off the boiler when fuel consumption is below established standards.

This set of control equipment is required for each boiler. If any of the above circumstances occur, first of all you need to stop the gas supply and ventilate the room. Only after this can you use electrical devices that can create a spark. You need to keep an LED flashlight ready in a certain place to safely move around the house.

A wall-mounted gas boiler is usually equipped with a coaxial chimney, which is “pipe-in-pipe” design.

Internal the pipe serves to remove flue gases, and external to supply air to the burner in the amount necessary to maintain the combustion process. This decision is the simplest, most effective and aesthetically pleasing.

Chimney installation for a wall-mounted gas boiler

The operating principle of a coaxial chimney is as follows.

Through an internal, smaller diameter pipe products are removed from the combustion chamber. During the exhaust process, flue gases are cooled by cold air in the outer pipe, which reduces the fire hazard.

On the outside, larger diameter, the pipe supplies street air to the burner. Due to the temperature of the exhaust gases, the air is supplied to the burner already heated, which increases the efficiency of the heating unit.

Main difference the chimney of a wall-mounted boiler from the smoke exhaust system of a floor-standing boiler consists in the absence of a vertical chimney. This is due to the fact that the burners of wall-mounted boilers with a closed combustion chamber are equipped with fans. To maintain the combustion process, no additional draft is required, which in floor-standing boilers is created due to the length and diameter of the chimney.

An important advantage heating system based on a wall-mounted gas boiler over a similar one with a floor-mounted one - is the absence of the need to construct supply and exhaust ventilation. As a result, a wall-mounted one with a closed combustion chamber can be placed, for example, in a kitchen, the parameters of which satisfy current standards and regulations.

Included as standard smoke removal systems of a wall-mounted gas boiler, as a rule, includes:

• coaxial pipe made of 2 segments: one for vertical area from the boiler, the second is for horizontal, for output through the wall;
• rotary 90 degree elbow, 1 piece;
• sealed gaskets, crimp clamps;
• decorative overlays, as an option.

In some cases it may be necessary additional purchase of extension cords coaxial pipe, second swivel elbow 90 or 45 degrees, tee for connecting two boilers to one chimney.

Coaxial tubes and connecting elements for them made of steel and painted with white heat-resistant enamel. Some manufacturers make the outer element from plastic for better thermal insulation. The most common coaxial size: outer pipe diameter 100 mm, inner pipe diameter 60 mm. Larger diameter pipes are found on condensing boilers, which have the highest efficiency and low exhaust gas temperatures. Increasing the diameter in such boilers is a measure to reduce the amount of condensate formed.

Installation of a coaxial chimney: requirements

Total length coaxial chimney must be no more than 3 meters(for condensing boilers up to 5 meters).

Photo 1. Assembly diagram of a coaxial chimney for gas heating. All main parts of the structure are indicated.

Along the entire length of the smoke channel it is allowed no more than 2 turns (2 turning bends).

Important! The smoke exhaust channel is routed to the street through the wall. It is forbidden to display it out of a window or vent!

It is prohibited to lead the smoke exhaust duct into the entrance, onto a closed balcony or loggia., as well as on a street that has buildings of architectural or historical value, children's and medical institutions.

In addition, must be observed general requirements related to all types of chimneys:

• Diameter must be equal to or greater than the cross-section of the outlet pipe boiler
• He must not have any distortions along its entire length, its cross-section should not decrease.
• Smoke exhaust channel must be gas-tight, watertight, joints must be carefully insulated.

Installation

Installation of a coaxial chimney is not particularly difficult. In the standard case, the output is carried out through the wall, on which the boiler is mounted.

Photo 2. Installation diagram of a coaxial smoke outlet for a wall-mounted boiler. The required indentations and diameter of the pipes are indicated.

In this case, connect to the device pipe a small piece of vertical section, then located swivel elbow 90 degrees. Next comes horizontal part, which is led out through a hole in the wall to the street. Length the street part is at least 30 cm. The design ends with a special head.

When the smoke exhaust channel is removed offset from the boiler or through an adjacent wall the scheme becomes somewhat more complicated and requires purchase additional details.

Attention! To avoid condensate getting into the boiler furnace horizontal section must be located with a slope of 3 degrees towards the street.

The fitting of the coaxial chimney parts by the manufacturer is carried out carefully, Additional sealing of connections is usually not required.

​

Wall hole diameter to remove smoke to the street, they are carried out on several centimeters larger than the diameter of the outer pipe. Upon completion of installation, the space is sealed with polyurethane foam.

Some manufacturers provide supply boilers with separate pipes for smoke removal and air supply.

This design expands installation possibilities up to three options:

• both pipes are displayed through one wall;
• pipes are removed on different walls;
• air supply system is displayed into the wall, and the system removal of smoke into an existing chimney.

Third option especially relevant for multi-apartment residential buildings.

Advice. In non-standard cases of chimney location for drawing up a diagram contact specialists.

Useful video

Watch a video that tells you how to deal with freezing at the tip of a coaxial chimney.

When installing this device, mistakes should not be made, as this will lead to insufficient draft, high fuel consumption and incomplete removal of combustion products to the outside. To avoid having to redo the chimney, you need to take into account all the recommendations of specialists. The arrangement of equipment must be carried out taking into account established standards and requirements.

A proper chimney is necessary in every home with an autonomous heating system

Read in the article

Chimneys for a gas boiler in a private house: features of design choice

Before you buy a chimney for a gas boiler, you should better understand its structure. Regardless of the type of device, each type consists of certain components:

• main smoke exhaust pipe;
• a set of pipes for transitions;
• adapters, fasteners and clamps;
• tees for eliminating condensate and outlets;
• telescopic tubes and tips.

To create such a structure, a variety of materials can be used. If the device is installed correctly, the following parameters will be provided:

• high level of efficiency;
• safety of house occupants;
• efficiency of the structure;
• comfortable indoor microclimate.

Rules and requirements for chimney operation

Chimneys for and their installation in a private house require a special approach and compliance with installation rules. The material for the product must be resistant to temperature fluctuations, anti-corrosion qualities and chemical inertness.

Condensation forms on the surface of the pipes inside, which is why it is so important that the material used does not interact with acids and does not corrode.

During the installation process you must adhere to the following rules:

• installation is done from bottom to top;
• the structure should be located only in the vertical direction;
• the pipe should not exceed a height of 5 m;
• any bends in the pipe are eliminated;
• transitions and joints must be sealed;
• the head is placed above the wind support zone.

Useful information! To reduce the amount of condensate released, the chimney should be insulated.

Nuances of installing a chimney for a gas boiler in a private house

Any types of products must be installed in accordance with SNiP standards. If they are violated, various problems can arise. It is necessary to organize normal traction. It is worth considering a design for collecting condensate so that moisture does not accumulate on the walls. It is necessary to maintain tightness of joints and connections. All parts at the connection points fit tightly to each other.

Chimneys for a gas boiler are built taking into account the following factors:

• condensation is eliminated using a special mechanism that is mounted at the bottom of the structure;
• installation is carried out in a vertical direction and has no ledges;
• the area of ​​the pipe that connects the boiler with the chimney must have a vertical section.

Mineral wool is laid in the ceilings and partitions where the pipe is laid. The pipe head is mounted half a meter above the roof. The device is equipped according to the scheme presented by the manufacturers of certain models.

Types of chimneys

When choosing a chimney for a floor-standing gas boiler, you need to familiarize yourself with its varieties. Brick models are no longer as popular as they used to be. They take up a lot of space and are difficult to install. Many owners are abandoning brick structures in favor of more modern options.

Metal options

One of the popular types are stainless steel models. Their advantage is resistance to corrosive components and strength. Such mechanisms are sandwich systems of lines of different diameters. The voids between them become clogged. Such models look modern and are characterized by high reliability.

Thermal insulation properties and multi-layer sandwich panels ensure the reliability of the structure. Condensation rarely forms in such products. When installing such products, certain rules must be observed:

• the first elbow, which is fixed to the heating apparatus, must be without insulation;
• the diameter inside the structure depends on the type of gas equipment;
• during assembly, the upper part should be installed on top of the lower one, which will allow condensation to be discharged outside;
• Heat-resistant sealant is used to connect the elements.

They are characterized by high fire resistance. At the same time, the surrounding elements do not heat up.

Ceramic varieties

Ceramic products are fireproof, durable and simple options. They are characterized by a simple device. The chimney is made of a ceramic pipe, which is wrapped in mineral wool.

Such a system is considered durable. It is resistant to high temperatures and aggressive chemical components. Ceramic products must be equipped with condenser collectors. A ceramic chimney has certain features:

• the pipe consists of individual elements that are connected with a special mastic;
• the insulation is made of mineral wool;
• the casing is made of concrete blocks with ventilation holes.

A gap is left between the concrete surface and the insulation, which is necessary to remove moisture and. In some cases, gas boilers without a chimney are used. In this case, air supply and smoke removal are carried out through a small diameter.

Coaxial chimney

You can buy one, which has excellent operating properties and excellent design. A similar design is made according to the scheme of one pipe inside another. Can be selected for boilers that are equipped with a closed combustion chamber. In such a device, air is taken from the street. The air supply is carried out through an external pipe that passes through the outer wall. Exhaust smoke is discharged through an internal pipe. When installing such equipment, there is no need for additional equipment. The shape of the coaxial chimney does not allow condensation to accumulate on the walls.

Coaxial type equipment has the following features:

• increased productivity;
• complete security;
• if the pipe size is less than 3 meters, then the boiler productivity increases due to increased draft;
• To install such a structure, you do not need to touch the roof.

If there is a coaxial design, the boiler can be installed in the basement, pantry or kitchen.

Review and prices of some models

Before purchasing a chimney, you should consider individual models, their characteristics and prices.

Image	Model	Cost, rub.
		5 440
		3 160
		2 500
		4 800
		900
		6 100
		60 700

Features of installing a chimney for a gas boiler

It is important to connect the chimney to the gas boiler correctly. Such a device cannot be connected to several devices, since smoke masses can enter the house. If a pipe of more than two meters is installed, it must be additionally secured with special braces. A plug with a tee is installed on the device. In this case, the pipe is extended with links that are fixed to the wall.

It is necessary that the cross-section of the outlet coincides with the diameter of the chimneys for gas boilers. To drain outside, you need to measure all dimensions and mark the area. After all the holes are made, the heating device pipe is attached to the passage piece. The resulting holes must be well insulated.

The design of the chimney is carried out as follows:

• markings are made for the passage of the pipe;
• holes are made according to the marks made;
• an adapter is installed to connect to the pipe on the boiler, and then a tee is installed, which has a compartment for collecting moisture;
• The kit includes pass-through pipes for passing through;
• the joints of the structure are fixed with clamps and tightened with bolts;
• the chimney is attached to the wall surface using special brackets;
• Finally, a cone-shaped tip is mounted, which protects from wind and various precipitation.

If the chimney is not made of sandwich materials, then it must be equipped. A simple installation option is to use a ready-made structure and insulate it.

When performing self-installation, you need to take into account some factors. Before purchasing, you should check the ratio of the cross-section of the pipe and the heating boiler pipe. And to ensure stable draft, the height of the chimney must be greater than the top point of the roof. The outer part of the chimney should be insulated from the outside. You also need to know how to check the draft in the chimney of a gas boiler. For this, a special anemometer device is used. Also, with poor draft, the color of the flame will be dark red. With the reverse draft effect, combustion products enter the room. This happens when the chimney is installed incorrectly, the boiler is clogged, or the structure is poorly sealed. The chimney parameters are indicated in the instructions, but general building codes and recommendations on installation technology must be followed.

To ensure normal, uninterrupted operation of the boiler, timely cleaning of the chimney and gas channels is necessary. Moreover, the frequency of maintenance is regulated by regulatory documents - snips for chimneys for gas boilers.

According to SNIP, the chimney and ventilation ducts must be checked and cleaned:

1. Before the start of the heating season - chimneys in which boilers and heating devices operate seasonally.
2. At least once a quarter - combined and brick chimneys.
3. At least 1 time a year - asbestos-cement chimneys and ducts, pottery, made of heat-resistant concrete.

The initial inspection of gas boiler chimneys should cover the following points::

• correct use of materials is carried out in accordance with the requirements of DBN V.2.5–20;
• presence of clogged channels;
• checking partitions that serve as protection for combustible structures;
• How separated are the ventilation and smoke ducts;
• how serviceable and correctly positioned is the head?
• checking the presence of normal draft, this parameter depends on the correctness of the construction, in particular, the height and cross-section of the pipe has an influence (see).

The check is repeated ventilation and chimneys for blockages, their separation and density, the draft is checked:

• Inspections for the first time and after repairs of ventilation and chimneys are carried out by specialists. organization with the participation of the operating organization. The results obtained are included in the act.
• If the ventilation ducts and chimneys of gas boilers are recognized as unusable and not subject to operation, the inspector is obliged to warn the owner in writing about the dangers of using gas appliances.
• Chimney SNIP in private houses allows owners to clean ventilation ducts and chimneys if they have a document confirming that they have undergone training.
• Before starting repairs of ventilation passages and chimneys of gas boilers, the operating organization, which is the owner of the apartment building, is obliged to warn residents about the start of work. After completion of the repair, all chimneys and ventilation ducts should be checked.

Requirements for premises when placing gas appliances in them

• SNiP 01/31/2003- about multi-apartment residential buildings;

• SNiP 41-01-2003- everything about air conditioning, ventilation and heating is explained;

• SNiP 42-01-2002- instructions on gas distribution systems;

• SP 31-106-2002- will talk about the creation of the project and the construction of single-family houses used for living;

• SP 42-101-2003- on the construction and design of gas distribution systems from pipes of various inlets.

What the letter of the law says:

1. The room in which the gas water heater will be placed and the chimney of the gas boiler will be provided for the removal of combustible products must meet certain requirements; not only the area, but also the height of the ceilings is regulated. So, the ceiling height should be no less 2 meters. The volume of areas is no less 7.5 m³ to install one device, and no less 13.5 m³ for two units.
2. The room must also be equipped with a ventilation duct. A grate or passage between the floor and the door should be provided at the bottom of the door or wall, where the open cross-section should be no less 0.02 m².
3. Attention: It is unacceptable to exhaust smoke into the ventilation duct. It is prohibited to install ventilation grilles on smoke ducts.
4. In rooms with a standard hood, it is necessary to compensate for the removed air by penetrating it from outside the room, as well as by replacing it from the remaining areas of this apartment.
5. Attention: When installing airtight windows in a room, the speaker may turn off due to inconsistent air supply. This is due to the automation of the column itself.
6. In the bathroom and utility rooms, doors should open outward.
7. The installation of sockets and switches in the bathroom is strictly prohibited.

Requirements for chimneys

General rules

Depending on the conditions of use, chimneys may have different designs. Its uninterrupted operation and efficiency depend on the quality of the chimney and its material.

Their installation is carried out in accordance with the requirements set out in DBN V.2.5-20-2001 and SNiP 2.04.05–91.

Improper design and use, improper connection to thermal equipment may lead to improper operation and accident.

This manual describes the principles of operation and installation of chimneys, sets out fire safety requirements, which are reflected in the documentation.

• SNiP 41-01-2003— “Air conditioning, ventilation, heating”;
• NPB 252–98- “Heat generating devices that operate on different types of fuel. Test Methodology";
• GOST 9817–95- “Household appliances that run on various types of fuel. Technical specifications";
• VDPO- “Rules for production work, repair of smoke ducts and furnaces.”

SNIP chimneys must comply in full. After commissioning of the chimney, a chimney inspection report is issued.

Installation rules read:

The rules for installing chimneys say that placing smoke ducts is allowed inside walls made of non-combustible materials. If there are no such walls, it is required to use crown and cap pipes (clause 3.69.SNiP-91).

Sections of the chimney passing through unheated rooms and on the outside of the building must be thermally insulated so that condensation of thermal vapor and flue gas does not occur in the inside of the chimney (4.2.16.VDPO).

According to the requirements of VDPO and SNiP-91, the following chimney options are allowed:

• With modular chimney systems it is prohibited:
  1. Melting with flammable liquids.
  2. Melting with wood larger than the size of the firebox itself.
  3. Drying clothes, shoes and other items on chimney parts.
  4. Removing soot by burning.
  5. It is prohibited to operate the unit using a method not specified in the manual.
  6. Pouring water onto the fire in the firebox.
  7. Use chlorine for its compounds.

Chimneys must be inspected by a qualified specialist at least twice during the heating season. To ensure the operation of the heating unit, chimneys should be inspected, and this should be done by specialists.

• When two boilers are connected to the chimney, the cross-section of the pipe is determined by their joint operation DBN V.2.5-20-2001 (Appendix G, Clause No. 6). The dimensions of chimneys are determined by calculation, which is indicated in the technical documentation.
• Gas appliances for non-domestic purposes (digesters, restaurant equipment) are allowed to be connected to common chimneys.
• It is allowed to install smoke exhaust pipes with an exit through one, but an additional calculation of the pipe cross-section must be made.
• The release of exhaust gases for several devices is allowed. The calculation must be made at different levels, according to DBN V.2.5-20-2001 (Appendix G, Clause No. 3).
• The cross-section and height of the chimney is determined taking into account the operation of all devices simultaneously, DBN V.2.5-20-2001.

Chimneys made in accordance with SNIP work efficiently and do not contradict legal standards.

Pipe connections

Installation requires welding. Quality control of welding work is regulated in SNiP 3.05. 03.85 5.

• Gas water heaters and other gas appliances must be connected to the chimney using pipes that are made using roofing steel.
• The length of the connected pipes should not exceed 3 meters in new buildings and more 6 meters in existing ones.
• The slope of the pipe in relation to the device must be at least 0,01.
• On smoke exhaust pipes, no more than 3 bends are allowed, the radius should not be less than the diameter of the pipe.
• The connection of the pipes must be tight; the entry of one pipe into the other must be at least half the diameter of the pipe.
• If the pipes are made of black iron, they require painting with fire-resistant varnish.

Attention: If the above requirements are violated, water heaters must be disconnected from the gas supply.

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 on 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.