Correct operation of heating gas equipment depends largely on the system that removes the combustion products. Before constructing a chimney for a gas boiler in a private house, it is necessary to have an idea of the types of equipment, the principles of its operation and the regulatory documents according to which it is installed. Regardless of who will carry out the work, the choice of device and installation should be taken with full responsibility.
Types of chimney systems: which chimney to choose
Installing a system of utilization of combustion products on a gas boiler contributes to the effective functioning of the equipment and the entire heating system, safe and comfortable heating, as well as trouble-free operation of the boiler. Before you buy a chimney for a gas boiler, it will be useful to consult a specialist about the existing options for chimneys and the feasibility of their use.
Types of smoke channels to gas boilers:
- brick chimney – its construction is planned at the stage of building a house and a foundation is laid for it. A prerequisite is the smooth surface of the internal walls of the chimney. It should be noted that the structure must be resistant to the action of acid, which is formed as a result of steam condensation. Otherwise, there will be a rapid destruction of the brick chimney pipe. Applied in combination with ceramic or steel liners. Brick chimneys for gas boilers are notable for their complex construction, construction duration and costly cost. In terms of technical indicators, they are in many respects inferior to the modern chimney systems that have appeared;
- stainless steel construction – this version of the chimney is highly resistant to chemical environment and mechanical damage. The system is implemented as a sandwich structure: when a pipe with a smaller diameter is inserted into the outer pipe. Fire-resistant material – basalt wool is placed in the free space between them. Manufacturers offer a wide range of chimney models;
- coaxial chimney – the structure is assembled according to the “pipe in pipe” principle: combustion air is taken along one pipe, combustion products are drawn out on the other. Such a system has high technical characteristics that contribute to improving the safety of all gas equipment and increasing its efficiency. And due to the fact that the combustion cycle occurs outside the room, the boiler with a coaxial chimney is environmentally friendly equipment;
- Ceramic chimney flue – is a ceramic block with thermal insulation installed in a concrete frame. Such a chimney system is resistant to temperature fluctuations, waterproof, fireproof and has high mechanical strength. The main requirement for installation is a quality joining of ceramic modules.
Which chimney pipe is better to use – everyone decides on the basis of their particular situation. The main thing is to highlight the strengths and weaknesses of any option. Regardless of which type of chimney you prefer, its design and installation must comply with SNiP 2.04.05-91 “Heating, ventilation and air conditioning.” After studying these standards, you can learn how to properly install the chimney on the gas boiler.
Chimney for a gas boiler in a private house: the basic requirements of SNiP 2.04.05-91
The chimney arrangements for the gas boiler, starting from the design stage and ending directly with the installation of the system, must comply with the requirements of the current regulatory framework, as improper installation and operation of gas equipment calls into question the safety of people using gas installations.
The main elements of the design of the chimney:
- the flue duct – the channel coming out of the boiler into the chimney pipe is connected with an adapter;
- chimney pipes;
- revision – attached to the bottom of the smoke outlet and serves to clean the channel from the products of combustion and remove excess moisture;
- fasteners (brackets, clamps) – used for mounting to the wall;
- other components for the device system.
As a rule, the location of the gas boiler in a private house is planned on the lower floor in a separate room (boiler room). All elements of the heating system must be interconnected strictly tightly. The basic rules for the installation of chimneys for gas boilers regulating the technological procedure are presented in the regulations of SNiP 2.04.05-91 and contain the following requirements:
- proper traction – ensures complete removal of exhaust gases;
- resistance to high temperatures;
- tightness of the joining points – all components throughout the entire length of the chimney system should fit snugly together;
- the pipe at the point of its passage through the ceiling must be integral, without joints;
- condensate trap – the design of this element should ensure the collection and removal of liquids;
- if there are turns in the construction, in these places they arrange inspection hatches for diagnostics of the state of the chimney, its cleaning and condensate drainage;
- the length of the branch pipe to the side should not exceed 1 m;
- possible permissible number of turns on chimneys – no more than 3;
- the height of the chimney pipe must exceed the height of the roof (at the highest point) in order to ensure good traction and the reverse does not occur;
- the distance between the flue pipes and the surface, which is made of non-combustible materials, may be at least 5 cm, and if the material of the surface of the fuel is at least 25 cm.
Helpful advice! Complete tightness of the chimney sections will not allow the hot combustion products to go beyond the system.
Depending on at what stage it is planned to install the chimney for a gas boiler, the exhaust system can be internal or external (remote). In the cottages under construction, where the use of gas boilers is foreseen, internal chimneys are used, the placement of which is taken into account by the project. In the houses of the old building during the transition to heating through a gas boiler, the chimney is taken outside.
To compare the strengths and weaknesses of the external and external chimneys, please refer to the table:
|Requires complete thermal insulation chimney||Thermal insulation is only necessary on the site that goes outside|
|At observance of norms safe operation is guaranteed.||The possibility of the penetration of combustion products into the room is not excluded, high fire hazard|
|The chimney device is made of the same type of elements and is characterized by ease of execution.||Differs in difficult installation as there is a need for a large number of accessories and components of a chimney|
|Availability in carrying out any kind of repair work and maintenance||Difficulty in maintenance and repair of the chimney|
The installation of the chimney gas boiler of internal type is associated with the construction of the foundation and the protective channel of bricks. Then the safety of operation will be ensured. Such systems are more efficient and the formation of condensate in them is minimal. In some cases, chimneys can be attached to the wall of the house, behind which the boiler is installed.
The device of the external chimney requires high-quality mounting and the mandatory maximum warming, as condensate in such structures is formed in larger quantities.
The main stages of the installation of the chimney for gas boiler domestic performance:
- marking places for the device holes in the ceiling and roof of the house;
- device opening under the chimney;
- connection of the boiler pipe with the flue;
- installation revision tee;
- chimney pipe buildup;
- reinforcement of joints with hose clamps;
- fastening of the structure with brackets;
- thermal insulation of the outer part.
Helpful advice! The location of the chimney system must be strictly vertical, without narrowing or widening the channel.
Steel flue ducts can be single-walled and double-walled. Single-layer chimney pipes can be installed in heated rooms and used for gilding brick chimneys. In the three-layer systems between the two pipes there is a heat-insulating layer, which makes it possible to apply them both for indoor and outdoor installation.
Due to the fact that gas fuel contains sulfur impurities, during the withdrawal of waste products its vapors have an aggressive effect, corroding the walls of the flue channels. Therefore, in the production of stainless steel chimneys for gas boilers use heat-resistant and acid-resistant material brand AISI 316L. Its use greatly increases the life of the chimney systems.
From the weak sides of the stainless steel chimney pipe for a gas boiler, it is possible to note not quite an aesthetic appearance. The benefits include:
- resistance to corrosion and aggressive chemical composition;
- light weight, no need for a base device;
- incombustibility of the material – the stainless steel does not melt even at a temperature of 500? С;
- the modularity of the design – the factory production of a large number of tees, adapters and knees allows you to embed a chimney into any home;
- the factory production of all elements of the steel chimney allows you to assemble and withdraw it at any convenient angle;
- absolutely smooth round internal surface – provides a minimum of obstacles in the way of a conclusion of products of combustion;
- possibility of installation in an already built house;
- quite affordable chimney price for a gas boiler.
When constructing an external chimney made of steel, the probability of a dew point formation is high: if the outside temperature is low, the exhaust vapors form condensate and a water plug is created. It clogs the channel, preventing the products from leaving, and thereby blocks the burning process. This can be avoided by placing the pipe in a lined channel of the chimney made of brick. This technique will decide the aesthetic side of the structure.
Another option to avoid the formation of a water plug is to use a sandwich construction of two pipes, one of which is protected by a layer of basalt wool. Such a remote chimney system no longer needs additional warming. The diameter of the chimney for the gas boiler is selected in such a way that it coincides with the cross section of the outlet of the equipment.
Helpful advice! Stainless steel flues are easily maintained, but once in 3 years it is necessary for the system to be examined by a specialist.
The key to safe operation of a gas water heater is the correct exhaust system. For the column, chimneys are used that discharge the products of combustion into the flue duct or directly into the atmosphere. To remove the exhaust gases using these types of pipes:
- corrugated pipe – easy to install, the flexibility of the material allows
pull it up to 2-3 m in length, as well as lengthen by connecting several segments of the corrugations;
- aluminum pipe – easy to install, resistant to condensate, needs additional thermal insulation;
- coaxial chimneys – the price of such systems can be reduced due to the possibility of removing the pipe through the wall. This reduces material consumption and installation costs. The main advantage of such a chimney is that the air from the room does not participate in the operation of all the equipment.
Basic requirements for the installation of chimney pipes for gas columns:
- operation of devices is prohibited without a chimney securely fixed in it;
- thrust inside the chimney system must be constant;
- pipe material must be non-flammable, resistant to corrosion, condensate and high temperatures;
- the outer section of the chimney must be vertical;
- the design should be sealed to avoid carbon monoxide entering the room;
- the exhaust pipe must be mounted in an open area for quick troubleshooting if necessary;
- The flue pipe must be at least 0.5 m above the roof level;
- It is strictly forbidden to use for removal of combustion products ventilation systems, the space between floors, attics.
Traction – one of the main indicators of the correct functioning of the chimney. Its effectiveness depends on the following parameters:
- the cross section of the flue pipe – heated gases are discharged more quickly with a smaller section, but if it is too small, there is a threat of combustion products entering the room. If the cross section of the chimney is unreasonably large, a reverse thrust effect may be created;
- the accumulation of a large amount of soot on the walls of the trunk – due to this, the working section is reduced, which leads to a decrease in the rate of output of carbon monoxide;
- a large number of turns in the system – any of the turns of the pipe inhibits the movement of exhaust gases;
- insufficient tightness of the chimney – the presence of small cracks, gaps contributes to the penetration into the system of cold air, which prevents the rapid removal of smoke;
- weather – high humidity and lower atmospheric pressure can cause reduced thrust.
You can check the condition of the rod by several methods. If the diagnostics are carried out by professionals, they use an anemometer – a device for measuring the velocity of movement of gases. In everyday life they use the so-called folk methods:
- visual inspection – if there is smoke in the room, then there is a reverse thrust;
- using a thin sheet of paper – it is brought to the viewing window: the stronger the paper is attracted, the better the draft;
- Candle flame – a lit candle is brought to the channel and the flame is blown out. The direction of smoke from the extinguished candle in the direction of the chimney testifies to a good burden.
Important! Traction in gas boilers should be checked with equipment disconnected.
Depending on the reason why there is weak traction, they are taking measures to improve it. The canal is cleaned from soot using a special device consisting of a ruff, a sinker and a rope. The device is lowered into the channel and the translational movements clean it along the entire length. In order to achieve complete sealing of the brick chimney, it is necessary to eliminate all cracks resulting from the destruction of the masonry.
The main advantage of installing a coaxial chimney for a gas boiler is that such a chimney not only brings exhaust gases to the outside, but also provides a combustion chamber with air from the street. Due to this, the room does not need additional ventilation, and the air in the house remains able to maintain the health and efficiency of the people there. Equipment with this combustion product discharge is called a gas boiler without a chimney.
The basis of the design of the coaxial chimney consists of two pipes of different diameters, one of which is inside the other. The inner tube is designed to discharge waste substances to the outside. Through the outer pipe, or rather, through the space between the inner and outer pipe from the outside, air is taken in, which is used for burning gas. Thus, the chimney copes with several functions at once:
- increasing the safety of the chimney – the incoming air from the street is heated, and the outgoing combustion products cool down;
- increase in boiler productivity – the efficiency of equipment increases due to the fact that the air enters the combustion chamber already heated;
- maximum combustion of gas – due to the fact that the efficiency of the boiler increases, complete combustion of the fuel is achieved;
- environmental friendliness of the heating system – the entire working cycle of gas equipment passes outside, which ensures comfort and safety of heating.
For the manufacture of the chimney, round pipes are used: the outer pipe with a diameter of 100 mm is made of steel with a thickness of 1-2 mm, the inner one is made of aluminum alloy. The diameter of the latter is 60 mm. Pipes with such a ratio of the values of diameters are used in coaxial chimneys for wall-mounted gas boilers and floor devices with a closed-type combustion chamber. To avoid contact of the pipes with each other, jumpers are installed along their entire length.
By the method of installation, coaxial-type flues can be horizontal and vertical. The horizontal version is more popular due to the simple installation. In the case when installing the system in a horizontal way is technically impossible or the distance from the boiler to the outer wall is more than 4 m, they resort to installing a vertical coaxial chimney. It is worth noting that its installation is more complicated.
Coaxial chimneys are used for various gas equipment in which the combustion chamber has a closed structure. These are gas boilers of floor and wall layout, gas flow heaters (columns), convectors and other devices.
It is worth noting the main advantages of using coaxial chimneys over other types of flue gas systems:
- natural heat exchange – heating of the incoming air and cooling of the outgoing gases occurs due to the construction of the pipe, which, in turn, prevents the wall from heating up strongly;
- increase in productivity of the gas equipment itself;
- compactness – the chimney is neatly mounted and does not take up much space, which allows it to be used not only in private cottages, but also in high-rise apartment buildings;
- safety of operation – in the air of the room where the boiler is installed, there is no shortage of oxygen, as the contact of air from the room with the discharged substances is completely excluded;
- ease of installation – reduces the cost of installing a coaxial chimney.
Helpful advice! If you purchased a wall gas boiler for autonomous heating of an apartment, using a coaxial chimney for it is the safest, since the combustion products are not removed into the ventilation channel, but directly into the atmosphere.
As with any gas equipment, the installation of coaxial chimneys has specific requirements SNiP 2.04.05–91, section 3 “Heating”; 2.04.08–87, as well as the requirements regulated by the “Safety Rules in the Gas Economy”. They can be different depending on the method of installing a coaxial chimney: horizontal or vertical.
For any type of installation there is a general requirement for the maximum length of a coaxial chimney for a gas boiler: it cannot exceed 4 m. When it is required to carry out the flue system at a considerable distance, special coaxial models with overall standards are used.
When a vertical coaxial chimney for a gas boiler passes through the ceiling and roof, an adapter is used, the design of which is provided by the manufacturer for this system. This also applies to coaxial chimney extenders when you need to install a system of the required length. Tightness in places where pipes pass through the ceiling is provided by a special tip – a terminal. It also prevents precipitation from entering the system.
The horizontal method of installing a coaxial chimney is used, as a rule, for wall-mounted gas equipment. To avoid condensation, it is necessary to maintain a chimney slope down from the boiler, ranging from 3 to 5%. There are standards for the location in the outer wall of the smoke channels for the chimney. So, if the hole is supposed to be in the wall next to the window, the distance to the window should not be less than 0.5 m, if above the window – not less than 0.25 m.
Many manufacturers of gas equipment include the supply and pipe for removal of combustion products. If you bought a coaxial chimney for a gas boiler with the equipment, you need to check the presence in the complete set of the horizontal part of the pipe (usually about 1 m long), outlet, terminal (tip), a set of gaskets, membrane. If at installation of a pipe through a wall it is required to bypass any ledges or reinforcement, use bends and bends.
Helpful advice! It is necessary to provide for the protection of all the leads and entrances on the coaxial chimney from the ingress of foreign objects.
Before installing a coaxial chimney with your own hands, it is necessary to familiarize yourself with the manual on the device and operation of the purchased gas equipment. Due to the specificity of the design of the coaxial pipe, the installation of the chimney for the wall-mounted gas boiler must be done extremely carefully. The formation of dents on the pipes or other damage leading to a depressurization of the system should be avoided.
To perform the installation work will need the following elements of the system:
- pipe with flange;
- crimping clamps;
- coaxial knee;
- adapter to connect to the boiler;
- extension cord with sealing cuffs (if required);
- decorative overlays.
According to the requirements for the installation of the chimney, an opening of the required diameter is arranged in the outer wall. If there is a window opening in the wall, it is necessary to locate the hole at a distance not closer than 0.5 m from the window. When connecting the chimney to the gas boiler, first connect the adapter, and then all the links assembled into a single structure.
Pipe through a hole in the wall output, respecting the slope of the boiler. If it is necessary to move the chimney to the wall, the structure is fixed with clamps. The gaps between the wall hole and the inserted pipe are blown with foam or sealed with mineral wool. After that, these places are closed with decorative rings.
The construction of a brick chimney is an exclusively vertical channel with a square or rectangular cross section. For masonry brick chimney use solid ceramic brick, which is laid on the solution. The outer section of the canal is laid out with ordinary brick, which corresponds to the house-building style, which can be seen in numerous photos of brick chimneys. If the house is lined with stone or plastered, you can also arrange the chimney in the same way.
Before laying the chimney for the boiler out of a brick, it is necessary to build a foundation whose height must be at least 0.3 m. The dimensions of the base around the perimeter should protrude beyond the contour of the channel itself not less than 0.15 m. parts of the outer wall, its foundation must be flush with its base. The bricklaying of the chimney with their own hands (video instructions confirm this) begin at the stage of building the walls of the house.
Requirements for brick chimneys:
- the smoke channel should be vertical, without ledges, narrowed and widened areas;
- brick masonry thickness for a chimney is taken with regard to freezing exclusion;
- the minimum permissible cross section of the exhaust ducts is 14 x 14 cm, which corresponds to the size of half a brick with regard to the seam;
- the size of a brick chimney whose height is less than 5 m should be increased to a section of the channel of 14 x 20 cm;
- the construction of the chimney is made in the walls between the heated rooms, which will prevent its cooling and reduction of thrust;
- tightness – laying of a brick chimney is carried out with a dressing so that the vertical seam of the previous row is covered with a brick of the next;
- the inner surface of the channel should be smooth;
Helpful advice! To achieve a smooth and smooth inner surface of the channel, use a special template when building a brick chimney with your own hands.
- the distance between adjacent chimney channels should not be less than 5 average external pipe diameters;
- if there are ventilation ducts near the chimney, their height should be equal to the height of the chimneys.
In order to reduce construction costs, as many channels as possible should be located in the common chimney. In this case, located near the chimney and ventilation ducts will heat each other, which in general will improve the functioning of the chimney.
The composition of the mortar for masonry brick chimney is selected taking into account which section of pipe is laid out: external or internal. For the construction of the external channel the same solution is used as for the laying of the supporting walls of the house-building. It is made from cement, sand, water and can be hardened in air and in water. The mixture is prepared in such a volume that within an hour it will be developed, as it quickly sets.
In order for the mixture under the action of an aggressive environment not to break down, it is recommended to add special additives to it, which increase its plasticity, strength and acid resistance. With these additives, you can improve the quality of the masonry itself, increase the speed of construction and the durability of the work performed.
Preparation of the solution for the chimney from a brick that passes inside the house is based on the use of refractory clay and chamotte in its composition in a ratio of 1: 1. Such mixtures do an excellent job at high temperatures, they are strong and do not emit harmful substances. To give the clay mixture strength, you can add in its composition table salt (about 120-150 g per bucket).
Helpful advice! The strength of the mortar for masonry chimney can be enhanced by adding portland cement in the proportion of 1 kg per bucket.
Performing masonry chimney brick with your own hands, you can buy ready-made mixtures, characterized by heat resistance and acid resistance. Preparation of the solution on its own can reduce the cost of building a chimney.
It is quite possible to build a brick chimney with your own hands – the video below will help to get acquainted in detail with the stages of construction of the structure, taking into account all the basic requirements.
Given the advantages and disadvantages of brick chimneys, it is possible to draw conclusions regarding their use in combination with gas boilers. Their benefits include:
- the likelihood of using an existing chimney, which reduces the cost of the chimney;
- possibility of operation in conjunction with gas equipment with an open combustion chamber;
- acceptable cost of materials for the construction and decoration of buildings.
The durability of brick channels is observed only when using them for fireplaces or stoves. If they are used for gas boilers, due to the low temperature of the combustion products, condensate will form on the channel walls, and harsh operating conditions in aggressive media will lead to a gradual destruction of the brickwork and deterioration of performance.
In addition, the requirements for such chimneys more stringent:
- flawless masonry – if the skills are not enough, you will need to invite a qualified bricklayer to work, which will cost you a lot of money. Prices for the work: masonry chimney brick rough from 6000 rubles per 1 m ?, facing masonry – 2500 rubles. for 1 m ?;
- the inability to perform a complex configuration of the channel (if you want to bypass, for example, a beam in the ceiling);
- the use of the old channel should be carried out with the use of a sleeve;
- the need for thermal insulation.
The disadvantages of such a system include reducing the thrust at the time of heating the brick. Thus, the correct chimney for a gas boiler will be a brick channel together with an insert made of steel or ceramics. In the photo of brick chimneys it can be seen that the liners are equipped in the process of laying the channel. At the same time it is necessary to leave a gap between the liner tube and the brick surface. This is necessary so that the pipe can move inside the channel.
When planning your budget when purchasing chimneys, you should consider the length and diameter of the channel, the presence and number of turns, as well as the material from which the pipes are made. There are no fundamental differences in the design and cost of chimneys for floor gas boilers and wall mounted appliances. A stainless steel chimney will cost more than a brick chimney, but a steel pipe is easier to install, which makes installation costs quite affordable.
You can buy a chimney for a gas boiler in specialized sales points and in online stores selling these products. A large assortment of fittings, shaped parts, tees, adapters, plugs and other necessary construction details are also offered for sale. Given the convenient sorting of products into categories and models, you can quickly find and order the right product.
The cost of a 1 m single-contour stainless steel pipe with diameters of 100, 110, 115, 120 mm is 650 rubles, the same pipe with a diameter of 140-150 mm will cost 750 rubles. The price of a knee with an angle of rotation of 90 ° stainless steel for a pipe with a diameter of 110-120 mm is 550 rubles. with a metal thickness of 0.6 mm. Buy 1 m stainless steel sandwich pipe with a diameter of 140-230 mm can be for 1900 rubles.
Helpful advice! You can save on purchasing high-quality and durable chimney pipes if you place an order during the discount period.
The price of a coaxial chimney for a gas boiler with a diameter of 60-100 mm and a length of 1 m, sold in a horizontal kit, is 3,500 rubles. Acquisition of a coaxial chimney Baxi – the global manufacturer of modern heating systems – will cost 4200 rubles. The complete set of chimney for a wall-mounted gas boiler includes a pipe 75 cm long with a diameter of 60-100 mm, a 90 ° outlet and a nozzle. All products are warranted.
Competent installation of any household appliances is a guarantee of its safe and long-term operation. Especially when it comes to gas equipment. The installation of a flue gas exhaust system for gas boilers requires a preliminary engineering calculation and qualified implementation.