For safe operation of a gas boiler, it is necessary to ensure complete removal of combustion products. If the chimney diameter is incorrectly selected, they can enter the room, which will lead to carbon monoxide poisoning. The danger is aggravated by the fact that combustion products are odorless and colorless, so it is impossible to determine the location of the leak without a special device.
The durability of the channel depends on the material. It must withstand high temperatures, moisture and acid produced during gas combustion. The material should be chosen light enough so that you do not have to strengthen the walls and foundation of the building. For production are used:
- Stainless steel– resistant to most types of corrosion, not heavy, considered the best option. Provides reliable traction for 15 years.
- Aluminum- also durable, but due to low mechanical strength it is used only for interior decoration.
- Enameled pipes– are produced with built-in thermal insulation, which simplifies the installation of the chimney.
- Cink Steel– will last a maximum of 5 years, as it will lose its tightness under the influence of fumes of high acidity.
- Ceramics– the service life of such products reaches 30 years. European manufacturers reinforce them with beautiful steel frames. However, due to the heavy weight, sometimes it is necessary to take measures to strengthen the walls and foundation. Such structures provide maximum traction only in a vertical position, which is not always possible to realize.
- Sandwich chimneys– consist of two pipes inserted into one another, with insulation between them. Due to 2 layers of metal they are highly reliable. Durability depends on the material of the inner tube. No additional insulation is required during installation.
- Coaxial chimneys- also consist of two pipes, but the space between them is used to supply air to closed-type gas boilers from the street. They are produced in modules, convenient for quick assembly.
- Brick chimneys- turn out to be heavy, so they require a foundation. Due to the rough walls, the draft is not at its best, which leads to the accumulation of soot on them. Therefore, the pipe will have to be cleaned twice a year. In addition, brick is hygroscopic, absorbs condensation and quickly collapses. But a preserved chimney can be used as a protective frame if you insert a stainless steel pipe into it with a condensate collector at the bottom.
- Asbestos cement channels- cheap, but rarely used, as they are prone to cracking and releasing carcinogens when overheated.
Depending on the installation method, chimneys can be external or internal. Which one is better to choose depends on the type of building and location of the boiler. External channels lead horizontally to the street and are attached to the external wall. They are easier to install; you just need to follow the fire safety rules when arranging the hole if the house is built from flammable materials. However, careful insulation and installation of a condensate collector will be required.
The internal chimney is discharged through the ceilings and roof, which is not always acceptable in multi-storey buildings. Installation is complicated by the installation of several special passage units that ensure fire safety.
Calculation of the chimney cross-section for a gas boiler
To accurately determine the parameters of the system through which combustion products are removed, complex calculations are made. This takes into account the shape and material of the pipe, the average temperatures outside and inside, the roughness of the walls, and more. However, the cross-section of the chimney (F, m²) can be calculated with sufficient accuracy for practical purposes using the formula:
F = (K ∙ Q) / (4.19 ∙ √ˉ N),
wherein:
- K– coefficient from 0.02 to 0.03;
- Q– boiler power in kW, indicated in the technical passport;
- N– chimney height in meters.
The result obtained must be checked for compliance with SNIP 2.04.05-91 and, if necessary, adjusted. The regulatory document states that, depending on the power, the internal cross-section of the chimney round shape should be:
It is possible to install square-shaped pipes if their parameters meet the requirements, but it should be taken into account that they tend to accumulate soot. Therefore, such products will have to be cleaned more often, otherwise reducing the hole will negatively affect the operation of the system. If two boilers are supposed to be connected to the chimney, the cross-section is calculated based on their total maximum power.
Determining the size of the chimney for an open type gas boiler
Unlike the previously mentioned units, such devices receive combustion air from the premises where they are located. To determine the transverse parameter, use two simple methods:
- On the installed boiler, they are guided by the size of the pipe for removing combustion products. The cross-section of the chimney should be equal to it or slightly larger.
- When there is no boiler yet, but its characteristics are known, or a chimney is installed for two heaters, its cross-section is determined by multiplying the power by 5.5. The result is obtained in cm 2. For calculations, the passport parameter is taken, not the thermal parameter, which can be an order of magnitude larger.
To calculate the diameter of the chimney, use the formula for the area of a circle S = πr². Then r = √S/π. Substituting the previous result, you get the radius in cm. Multiplying by 2 and 10, you determine the diameter in mm. The calculated result is adjusted according to the table above.
Conclusion
Since human health and fire safety depend on the correct calculation of the chimney cross-section, it is better to overestimate the obtained result a little. Gas service workers usually turn a blind eye to this when issuing permission to operate a boiler. But if the cross-section is less than the standard, then a ban will be imposed, which means that all the work will have to be done again with associated costs.
A hood for a gas boiler in a private house performs two main functions:
- It is necessary for the efficient functioning of the equipment;
- The combustion process occurring in it is impossible without a regular supply of oxygen.
Secondly, ventilation ensures the safety of people living in the house. The circulation of air flows prevents the accumulation of moisture, which, in turn, prevents the appearance of mold and fungi that are dangerous to health. In case of unforeseen situations, ventilation protects against carbon monoxide intoxication, fires and explosions. In this article we will look at what components make up the exhaust system for gas equipment and how to install it yourself in your home.
Low power boilers (up to 30 kW) can be placed in the kitchen if it meets a number of requirements:
- the kitchen area is at least 15 m2;
- the ceiling is located at a height of 2.2 m and above;
- sufficient glazing (total window area) - at least 3 cm 2 per m 3 of the kitchen;
- the windows are equipped with transoms and vents;
- between gas device and the wall has a distance of 10 cm;
- the walls are finished with fire-resistant material;
- air flow is ensured through cracks, for example, at the bottom of the door.
In order for powerful devices (from 30 kW) to serve for a long time and at the same time be safe, experts strongly recommend equipping a separate room - a boiler room. Of course, not every room in the house is suitable for such purposes. Its volume should be at least 13.5 m 3 for devices with a power of 30-60 kW and at least 15 m 3 for 60 kW.
How to choose material for the hood?
For these purposes, brick, galvanized and stainless steel and ceramics can be used. Let's take a closer look at each of them, and also study what other options the market and engineering offer.
Brickwork hood
Although brick is used by builders when arranging ventilation, its properties do not allow them to save on other materials. Firstly, brickwork is not durable. The most comfortable conditions for her are constant contact with hot gases. Otherwise, condensation will form, which leads to its rapid destruction. Secondly, a brick chimney is labor-intensive to install and has complex design and unreasonably high cost. Therefore, if you are faced with the task of arranging a chimney for a gas boiler, it is better to pay attention to other options. In this situation, a shaft is made of bricks. This same option can be chosen if for some reason heating the house with gas is currently impossible, but in the future it is planned to use it.
If brickwork is chosen as the material for the shaft, then the chimney itself is assembled from single-circuit galvanized pipes. The thickness of their walls is selected taking into account the temperature of the outlet gases.
Steel hood
Very convenient in this situation steel pipes. They are easy to install when compared, for example, with brickwork. The wall thickness is selected depending on the heating. Gas boilers produce quite hot exhaust gas, about 400-450˚C, so the thickness of the walls should be 0.5-0.6 mm. However, there are pitfalls here too. Of course, steel is resistant to negative impact condensate But on average, its wear resistance is much lower than, for example, the wear resistance of ceramic products. In addition, thin-walled pipes quickly burn out if used with solid fuel devices, so this option is not optimal when used different types heating elements at different times. Steel choose:
- during reconstruction;
- if there is no space for a ceramic hood.
Since steel ventilation ducts They often spoil the exterior of a private house; they are covered with brickwork or other finishing materials.
Steel pipes are marketed in two variations - single-circuit and double-circuit. The second option is called a “sandwich” in slang. It consists of two pipes nested one inside the other, the gap between which is filled with fire-resistant basalt wool. The thickness of the inner pipe is determined by the temperature of the outlet gases (recall that this value is 0.5-0.6 mm for the devices discussed in the article).
“Sandwiches” are considered more economical among all steel hood options. This conclusion suggests itself if we take into account good thermal insulation, which increases the efficiency of the heating device.
Double-circuit steel chimneys are made of stainless and galvanized steel. Both metals are combined in “sandwiches”, since using only stainless steel is not economically feasible. The difference between galvanized and stainless steel is the latter’s higher resistance to condensation, which negatively affects its price. Otherwise, the properties of these two materials are not inferior to each other.
It is critically important that the internal part of the double-circuit structure is made of stainless steel; the material of the external part does not play a special role. This is due to the properties of zinc. Its heating above 419.5°C is dangerous. In this situation, the metal is oxidized, further chemical reaction leads to the release of toxic fumes. Everything becomes even worse with high humidity, which cannot be avoided when commissioning a gas boiler. Therefore, when purchasing a sandwich structure, pay attention to this.
In principle, you can make a double-circuit chimney yourself without any special skills. To do this, wrap the stainless steel pipe in fire-resistant heat-insulating material. When choosing the latter, you can pay attention to basalt fiber, expanded clay or polyurethane. Then place everything together in a galvanized pipe of larger diameter.
Features of installing a steel ventilation column:
- The segments are assembled using the “pipe to pipe” method in order, starting from the bottom;
- For the convenience of subsequent cleaning of the post, provide a sufficient number of inspection wells;
- For stability, wall brackets are attached in approximately 150 cm increments;
- When designing, pay attention to the horizontal segments - they cannot be more than 1 meter long unless forced draft is provided.
Ceramic hood
This type of hood is the most versatile, so it is an ideal option if you plan to switch from or to gas fuel. They are easy to clean, resistant to dirt, due to their high gas density, and to aggressive chemical compounds, so you don’t have to worry about toxic substances getting into your living rooms. And, of course, ceramics are durable.
But there are also disadvantages. Ceramic pipes have high moisture absorption. If you choose them, you will have to provide good external ventilation and equip the structure with condensate drains, otherwise the invested effort and money will not be worth it.
Ceramic alone is not used in chimneys. To make the most of its positive properties, it is combined with mineral wool and stone. Simply put, the ceramic pipe is wrapped in insulating material and then placed in an expanded clay concrete shell.
Coaxial ventilation structure
When designing ventilation for gas boilers, pay attention to the compact “pipe-in-pipe” design, or, in other words, a coaxial chimney.
Coaxial systems, due to their characteristics, are suitable for heat generators with a closed combustion chamber (which is a gas boiler). Oxygen necessary for combustion enters through the outer pipe, and exhaust gases are removed through the inner pipe. This design has its advantages:
- safety (exhaust gases are cooled by cold air circulating in the outer pipe);
- the incoming air heats up and increases the efficiency of the boiler;
- high efficiency means that the coaxial design is more environmentally friendly than others;
- can be used with the appliance in the kitchen (it is located outside the room and does not affect the comfort in it).
Features of installing a coaxial chimney
- You cannot use a horizontal coaxial chimney if you do not plan to install forced draft;
- try to get by with no more than two knees;
- if there are several boilers, create a separate chimney for each; combining them is undesirable.
Video - design and installation of a chimney and hood for a gas boiler
Natural and forced ventilation of the boiler room
According to the method of updating the air space, natural and artificial (or forced) ventilation are distinguished.
Natural ventilation operates without the use of fans; its effectiveness is determined solely by natural draft, and, consequently, weather conditions. The draft force is influenced by two aspects: the height of the exhaust column and the temperature difference between the room and the street. In this case, the air temperature outside must be lower than that indoors. If this condition is not met, reverse draft occurs and ventilation of the boiler room is not ensured.
Forced ventilation involves the installation of additional exhaust fans.
Usually these types are combined into one boiler room exhaust system. When calculating it, it is important to take into account that the volume of air drawn outside must be equal to that pumped into the room. To ensure this condition is met, check valves are installed.
Calculation of the ventilation system
According to building standards, the entire air space of the boiler room must be replaced with new one every 20 minutes. To ensure the appropriate air circulation, you will have to arm yourself with a calculator and formulas.
If the ceilings are located at a height of 6 meters, then without special devices the air in the room is renewed three times per hour. Six-meter ceilings are a luxury for a private home. The reduction in ceilings is compensated for in calculations in the following proportion - for each meter lower, air exchange increases by 25%.
Suppose there is a boiler room with dimensions: length - 3 m, width - 4 m, height - 3.5 m. To solve this problem, you need to perform a number of actions.
Step 1. Find out the volume of air space. We use the formula v = b * l * h, where b is the width, l is the length, h is the height of the ceiling. In our example, the volume will be 3 m * 4 m * 3.5 m = 42 m 3.
Step 2. Let's make an adjustment for the low ceiling using the formula: k = (6 - h) * 0.25 + 3, where h is the height of the room. In our boiler room the correction turned out to be: (6 m – 3.5 m) * 0.25 + 3 ≈ 3.6.
Step 3. Calculate the air exchange provided by natural ventilation. Formula: V = k * v, where v is the volume of air in the room, k is the correction for lowering the ceiling height. We got a volume equal to 151.2 m3 (3.6 * 42 m3 = 151.2 m3).
Step 4. It remains to obtain the cross-sectional area exhaust pipe: S = V / (w * t), where V is the air exchange calculated above, w is the speed of air flows (in these calculations it is taken as 1 m/s) and t is time in seconds. We get: 151.2 m3 / (1 m/s * 3600 s) = 0.042 m2 = 4.2 cm2.
The dimensions of the channel also depend on the area of the internal surface of the boiler. This number is indicated by the manufacturer in the technical documentation of the device. If this number is not indicated, calculate it yourself based on the volume of the device. Then compare the area with the radius of the section according to the inequality:
2πR*L > S, where
R – internal radius of the chimney pipe section,
L – its length,
S is the area of the internal surface of the boiler.
If for some reason such a calculation is difficult, you can use the table.
The last stage of the calculation is the height of the weather vane relative to the roof ridge. The need for this is due to the creation of additional draft by the wind, which increases the efficiency of the entire exhaust structure. At this stage, we are guided by the following principles:
- vane height above flat roof, or at a distance of up to 1.5 meters from its ridge, must be at least 0.5 meters;
- at a distance from 1.5 to 3 meters - not lower than the ridge of the roof;
- at a distance of more than 3 meters - not lower than a conventional line drawn from the roof ridge at an angle of 10˚;
- the weather vane should be 0.5 meters higher than the building, which is attached to the heated room;
- if the roof is made of flammable materials, the chimney must be raised 1-1.5 meters above the roof ridge.
Installation of natural ventilation
Natural ventilation in the boiler room is ensured by installing supply and exhaust ducts.
To install the supply channel you need:
- Select a piece of plastic pipe, a suitable size grille and a check valve. The diameter of the first is selected taking into account the power of the boiler. If the power is less than 30 kW, 15 cm is enough. Higher power means larger diameter.
- To allow air to pass directly into the firebox, a through hole to the street is punched next to the heating device and not higher than its working area. Then a pipe is placed in the hole, the gaps inside are filled with mortar or foam.
- From the outside, the hole is covered with a fine grille to protect it from dirt and animals. It is necessary to install a check valve inside to prevent reverse thrust outside.
The exhaust duct is ducted outside through an opening above the boiler at the top of the room. Usually it is also supplied check valve, preventing air from entering from the street. The chimney can also be equipped with a protective rain canopy or weather vane, condensate drains and inspection windows for cleaning.
Artificial ventilation
Additional draft in the exhaust system is created using fans. Their power and number depend on the air load on the channel and the volume of the room.
- power is taken from the calculation: maximum load plus a reserve of 25-30%:
max * 1.25, where max is the maximum load;
- the number of devices is selected in proportion to the volume of air required for pumping (increase the volume of the room three times):
(h + b + l) * 3, where h is the height of the ceiling, b is the width, l is the length;
- the length of the chimney, its geometry and the number of bends are taken into account.
The fan is protected by an installation box. This box is made of non-flammable and stainless materials. Usually copper or aluminum alloys are used.
The design of artificial ventilation is similar to the installation of natural ventilation. After installing the supply pipe, the duct fan is installed. Next, the builders lay the wiring to power the engine, install sensors, a noise absorber and a filter. Same as during installation natural ventilation, gratings are attached to both ends of the pipe. The device for the exhaust pipe is installed in the same way, only taking into account that the air is drawn out and not pumped.
Artificial ventilation requires constant energy costs. Sometimes during construction they save money by installing a fan only for exhaust or only for air supply. However, more efficient circulation is achieved by using both.
The automatic ventilation system allows you to turn off the fans when the boiler is stopped and turn them on when it starts.
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 heating system and all responsibility for it 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 backdraft, the chimney should be located higher high point roofs by 0.5 meters.
- 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
Exists in the version of a single non-insulated pipe, made from 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.
Outside put on stainless pipe larger diameter. 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 appearance buildings and allows you to arrange a chimney when individual heating apartments Opportunity horizontal installation prevents condensation 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 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 environment. 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 draft.
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.
When installing of this device You cannot make mistakes, as this will lead to insufficient thrust, 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. At correct installation The device will provide the following parameters:
- 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.
Helpful 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 they are used gas boilers without chimney. 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:
- productivity increase ;
- 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. |
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 | 3 160 | |
 | 2 500 | |
 | 4 800 | |
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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.
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D To remove combustion products inside the furnaces of heating devices, chimneys for a gas boiler in a private house of different designs from different materials are used. The standards SP 7.13130 specify the requirements for cross-sections, heights, location of chimneys, safe diagrams of passage units through structures made of flammable materials.
Chimney from a gas boiler on the facade of the house
Requirements for chimneys and installation rules
Combustion products have high temperatures, so chimneys must fully comply with the standards of SP 7.13130. The use of factory products that have not passed the Russian Federation certification is not allowed.
The main provisions of the set of fire safety rules are:
- internal cross-section of the chimney - 14 x 14 cm - 14 x 27 cm depending on the thermal power of the boiler (3.5 - 7 kW, respectively) for concrete, brick, ceramic structures, the area of round or asbestos-cement pipes must correspond to these dimensions;
- height – 5 m minimum from the firebox to the deflector;
- chimney thickness - 6 cm for heat-resistant concrete, 12 cm for ceramic brick, not standardized for asbestos cement, sandwich.
The height of the deflector (an umbrella structure that protects the pipe from rain and wind) relative to the ridge depends on the distance of the chimney from it:
- 0.5 m higher at a distance within 1.5 m;
- level with the ridge at a distance of 1.5 - 3 m;
- at the level of an imaginary line at an angle of 10 degrees relative to the horizontal, drawn from the ridge to the pipe, at a distance of more than 3 m from it.
When moving the chimney outside, elbows are allowed within 1 m from the axis of the main pipe to the side at an angle of less than 30 degrees relative to the vertical. The cuts should exceed the thickness of the floors with decorative ceiling cladding by 7 cm with an even distribution of this size from below/top.
The distances from the outer surfaces of structures to wooden elements of load-bearing structures (sheathing, rafters, beams, crossbars) must be greater than the specified dimensions, depending on the chimney material:
Attention! It is prohibited to combine chimneys with ventilation ducts without a special design. But you can run combustion products from two boilers into one pipe if necessary.
Chimney structures
When choosing chimney or channel, you should focus on the best combination of construction budget, resource, and maintainability. Depending on the materials used, chimneys for a gas boiler in a private house are attached with clamps to the enclosing structures or rest on separate foundations.
Attention! Gas boilers have gases with low temperatures at the exit from the combustion chamber. Therefore, the “condensate” technology is used.
The chimney assembly technology looks like this:
- installing a damper on the boiler outlet pipe to adjust the cross-section of the chimney channel;
- installation of pipes until they are blocked by condensate;
- making a cutting from a steel box attached to the floor from below;
- cutting through the chimney, building up to the roof;
- fastening to the canopy sheathing - a plate with a conical pipe located at the desired angle to it, depending on the slope of the slopes;
- fixing the sandwich chimney pipe to the roof with a okapnik (a conical clamp of a complex profile), which decorates and seals the joint.
After that, it remains to install one of the elements at the mouth of the pipe:
- volper - deflector for increasing traction with a flat cover;
- weather vane - deflector to improve draft of the original design;
- fungus – conical nozzle for protection from precipitation.
These elements are made of stainless steel and fully correspond to the style of sandwich chimneys.
Stone and brickwork
Chimneys for a private house can be built into brickwork (only into a load-bearing internal wall) or made from blocks. Domestic manufacturers produce several types of chimney modules:
- concrete - used only in conjunction with ceramic pipes running inside them, outside surface square, inner round;
- ceramics - pressed into special molds, then fired in kilns, have the design of an internal pipe, an external square thin-walled box, connected by stiffening ribs.
The Ukrainian company Schiedel produces chimney blocks made of volcanic pumice. The modules are called Isokern, are budget option for individual developers. The material is much lighter than concrete and ceramics, the only drawback is the rough inner surface and the lack of Russian certificates. Regional fire safety services accept structures made from this material in 50% of cases.
Brick chimneys are built into walls during the construction of enclosing structures. To lay the blocks, it is necessary to concrete a separate foundation. But the pipes can be placed in any convenient place, there are no problems with the passage nodes, rafter systems, floors.
Asbestos cement pipe
Aggressive advertising by manufacturers of sandwich chimneys cites the main disadvantage of asbestos - the lack of environmental safety. In fact, only safe raw materials and technologies are used in domestic production. According to reviews from craftsmen who install all types of modern chimneys, an asbestos-cement pipe has the following advantages:
- is self-supporting - no need to attach to walls;
- does not condense moisture - there are no leaks into the combustion chamber;
- resistant to combustion products - the resource is higher than that of concrete and brick;
- cheaper than ceramics - the cost is much lower.
Installation of an asbestos cement pipe is extremely simple:
- the first pipe is installed on the foundation, secured with racks or a frame;
- the chimney is increased to the required height, the pipes are connected with couplings;
- The top is covered with a deflector, and a hatch is made at the bottom to install the cleaning door.
The connection from the boiler is made with a steel elbow, which can be replaced if necessary.
Installation of coaxial structure
Unlike other chimney modifications, a coaxial pipe can only be used for closed combustion chambers. (supercharging) is a mandatory operating condition of the system. The design of a coaxial chimney is similar to a sandwich, but instead of insulation, there are jumpers between pipes of different diameters. The inner pipe is used to remove combustion products, street air required for combustion natural gas, is sucked into the interpipe space.
Unlike conventional chimneys, the pipe does not need to be pulled vertically through all floors. Instead, a 90-degree outlet is put on the outlet pipe, a coaxial chimney is attached to it horizontally, and goes out through the nearest wall while maintaining fire safety distances:
- maximum length of horizontal part 3 m;
- minimum 0.2 m to the ceiling, floor, ground;
- more than 30 cm from the axis of the chimney to the wall surface;
- at least 60 cm from the mouth of the pipe to the opposite wall.
The coaxial structure can be installed vertically above the roof, horizontally through the wall, or connected to a smoke duct built into the brickwork of the wall.
conclusions
Thus, for closed combustion chambers, a coaxial chimney is preferable, saving the construction budget and the aesthetics of the roof, in which there will be no holes. The most reliable for open fireboxes are asbestos-cement pipes or sandwiches. The most discreet wiring is ensured by built-in smoke channels in brickwork, structures made of concrete, ceramic blocks or Isokern modules made of volcanic pumice.
