Chimney draft calculation: guaranteed functioning of the heating system. How to check the draft in the chimney. Why does reverse thrust appear?

If you have a stove or fireplace, then you know what a chimney is, and if you are just going to purchase or build such a useful thing, then knowledge of the chimney and draft in it will not be superfluous for you. During the operation of the chimney, the most common problem is how to check the draft in the chimney. To begin with, let's figure out what traction is and why it is needed.

The expansion of the chimney requires professional equipment, experience and knowledge. In addition, independent actions in this regard are incompatible with the provisions of the Decree of the Minister of the Interior and Administration on the technical conditions for the use of residential buildings. According to Art. 3 A user of premises using pipes and chimneys, flue gases and ventilation ducts, may repair and service these facilities only to persons with qualification certificates specified in separate rules. Self-excitation of chimneys is contrary to the provisions of construction legislation and may include fines.

The principle of operation of the chimney

In order for not even a gram of exhaust gases to enter the living room, the chimney must have very good draft, due to which all exhaust harmful substances enter the pipe.

To measure traction there is a special anemometer device. Its cost is quite high. Usually it is used by gas service specialists when they start checking chimneys in apartments or private houses. For individual use, buying such a device, frankly, a little expensive. In addition, you can use other methods to determine the presence of draft in the chimney.

Therefore, it is worth entrusting this activity to a trusted team with experience and the necessary certificates. Professional milling companies can be found in the contractor search service. You fill out one form, and companies come to you with specific offers.

How much does a chimney repair cost?

The grinding process may take 1 to 3 days. We need not be afraid that dust will pollute all rooms. The entire ventilation grill will be sealed and secured. The cost of repairing or deploying chimneys can be very diverse. Many repairs are evaluated separately. However, we can highlight some fixed costs, which are as follows.

Usually they use the most ordinary paper, which is set on fire and brought to the chimney grill. If there is draft, then the flame will deviate towards the chimney. Instead of paper, you can use matches. (See also: )

Traction problems

In order to determine the presence of good traction in the pipe, it is not necessary to have a special device. Sometimes the problems that arise acquire such a large scale that it is not difficult to determine the complete absence of gas exit from the premises.

Based on the above data, we can determine the estimated cost of repairing the chimney. However, remember that each assessment must be done individually. The chimney is one of the most important elements of any building. It is worth taking care of this and taking care of the full efficiency of the chimneys. All repairs and repairs must be carried out immediately after the error has been noted. Deferring repairs later may increase damage and jeopardize our health.

The basis of regular visits to the chimney. If the chimney draws attention to the poor condition of the elements that are projected above the roof, this will be a clear signal of the need for repair. In many cases, it is recommended to demolish the upper part of the chimney and rebuild it. Clinker brick with increased resistance will be the best. Let's also remember to apply a protective layer.

As a rule, the following indicates the failure of the outlet pipe:

If you look at the color of the flame during a stove or fireplace, you can talk about the following. Insufficient traction is indicated by the flame in the firebox, which has a dark red color.

The bright, almost white color of the burning fuel, on the contrary, indicates a thrust of great strength.

If there is a smell of smoke in the room, then this may indicate a malfunction of the chimney and the complete absence of draft, this effect is called reverse draft. In this case, all the smoke and waste combustion products do not fall outside, but rather into the room.

Causes of malfunctioning chimney

Sometimes a chimney repair must be carried out in the event of a furnace change. As a rule, it is necessary to expand the chimney and insert a special chimney sleeve into it. These actions should be assigned to a qualified team. Make sure that professionals use high quality materials to ensure the long life of the entire chimney design.

There are various types of chimneys and ventilation ducts. Selection should be made at the design stage before the construction of the house. It happens that a chimney is being constructed, although the stove has not yet been selected. You should not save too much on the quality of the materials from which we build a stove or fireplace, as well as the quality of combustible fuel. The more we invest in quality, the more we will save money and nerves.

During the ideal operation of the chimney, the flame in the furnace or fireplace is usually golden in color, there is no extraneous noise in the chimney, there is no smell of smoke in the room. The reasons for the malfunction of the flue system are mainly the following:

Errors in the initial stages of design. Possibly, the chimney is not large enough and simply can not cope with the incoming stream of waste substances.

Perhaps the wrong pipe height was selected, which can also significantly affect the operation of the chimney.

The first two cases are relevant when, at the first start of a gas column or furnace, it shows that there is no draft in the chimney. And if before that you drowned a stove or a fireplace and there were no problems with exhaust gas removal, then the reasons that affected the draft could be as follows.

Cable Types It's good to know what we're dealing with. Thus, chimneys are divided into different types because of their function, structure, location and nature of work. Because of the function, we have chimneys: fumes that serve to remove flue gases from flue gases with solid fuels - they are used to discharge flue gases from gases and are fueled by liquid fuel. ventilation chimneys: - supply air, providing the air necessary for the combustion process. - exhaust - is used to replace the exhaust air in the room.

Due to the design of the casing we have chimneys: a single layer, the wall of which is, for example, brick or thick-walled steel or multi-layer chimneys made of cement-fireclay tiles, the wall of which consists of several layers. On the contrary, depending on the location, the chimneys are easily divided into :. internal - chimneys are transported inside the building, since a separate structure that is not connected to the building or connected to the supporting wall and works as an external chimney - a chimney outside the building - can be connected to the building or free standing.

Too big temperature difference.

Blockages in the chimney.

The presence of a large amount of soot in the chimney.

Weather conditions: strong, heavy wind or high humidity due to prolonged precipitation.

How to fix the situation

If checking the draft in the chimney shows its complete absence or poor quality, you will have to make a certain decision so as not to be left without heat in bad weather.

We selected and used a well-built chimney to serve us for many years. Of course, provided that the entire installation will work correctly. To avoid this, it is recommended to clean the chimney at least once a quarter - advises. The fireplace is not a garbage collector. Do not burn furniture, rags, plastic bottles, or colored newspapers in it. Although the “fuel” is quite high in calorific value, as a result of its combustion, toxic compounds and tar are formed, which are ready to settle on the inner surface of the chimney, slowly and systematically clogging it. “It's also very bad to get wet with wet wood, such as birch,” Mr. Leszek explains. - Smoking with this wood causes precipitation into glass soot.

In general, ideally, a special device is installed in the chimney flue - a chimney draft regulator. It helps maintain the pressure required by building codes in the flue gas system. This in turn eliminates the malfunctioning of the system as a whole. If necessary, the regulator can both reduce and increase the exhaust force of the exhaust gases in the pipe.

Even then, purging the chimney cannot do much, because the tools that it uses will simply slide like glass. Glass soot has the ability to bite a brick and damage it. This is too much for a chimney that just burns or - if the outlet is blocked - will burst. Light chimney How easy is it to check our chimney? Just grab a mirror and use it to look into the chimney. If we see the sky - the chimney is open. The chimney master has the knowledge and the right equipment.

It is also useful to clearly state the condition of the chimney - whether it is suitable for use or whether repairs are needed. We can only do this with a special camera. How about this coffee? Jackpots nest high. Therefore, when building a house, it is worth protecting the inlet of the chimney in the network. Otherwise, we can forget about evening coffee by the fireplace, because jackets cannot be destroyed.

So, such a device is useful for prevention, and what to do when the chimney pipe can no longer cope with the load, or in general, as it turned out, was designed incorrectly. Then it remains only to correct the errors and do it as soon as possible.

Therefore, it is simply forbidden to use a fireplace or stove if the chimney is not working properly. Carbon monoxide may not be noticed at all. Sometimes the head just starts to hurt and drowsiness appears, a person can lie down for a while and breathe in poisonous substances.

Each new chimney must be raised by a chimney master. The chimney also controls and cleans the chimneys. Ventilation ducts should be checked and cleaned at least once a year. Flue gas pipes - twice a year. Chimneys - four times a year.

We also take care of the gas installation, which we check and tighten at least once a year. Control is carried out by a person authorized to do this, and responsibility for its implementation rests with the owner or manager of the building. Temperature and density are two important physical properties of sea water that affect the calculation of the amount of cargo in use.

If we talk about the height of the pipe, then in accordance with the established standards, its value directly depends on the slope of the roof. If the pipe height does not correspond to the given parameters, it will have to be increased. According to the established norms, it is allowed to arrange the height of the pipe slightly more, but not less than the established norms.

Just be sure to consider the fact that sooner or later the pipe will have to be cleaned. Maybe you will do it yourself, or maybe you will use the services of a specialist, it doesn’t matter. Just remember that too high a pipe will not be able to clean properly and well.

The temperature of sea water varies depending on a number of factors operating in the surface layer, the geographical location of the basin, wind, and currents. For most practical situations, these two corrections cancel each other out and their effect can be neglected. The water meter will rise in the water, indicating a higher density, but the ship will rise to the water, indicating a smaller displacement, and the product of the two indications will not significantly change the initial data. Therefore, we can conclude that the water temperature method is usually not taken into account for calculating the amount of cargo under a project, since this can lead to errors of up to 0.35%.

Traction reinforcement

If checking the draft of the chimney showed its complete absence or small value. You can also use a device such as a chimney draft stabilizer or a turbine. True, their use is limited only by gas boilers. Too high temperature of the exhaust gases at the outlet of the pipe will contribute to the malfunction of the device or its failure.

The density of sea water varies with temperature, hydrostatic pressure and salinity. High density variations are recorded in intertidal zones and in areas where ice melts. To accurately determine the density of sea water, measurements are made at three levels between the draft of the vessel in the bow, in the center and at the stern. Actual density or density is determined by the average reading.

The density of sea water is determined using a hydrometer. To correctly determine the density of sea water, the following recommendations should be considered. The sample vessel should be washed with water from the test sample. The hydrometer slightly falls into the liquid and is released only after it is discovered that it is floating.

If we talk about stoves or fireplaces, in order for the chimney to work correctly on time not very good weather conditions. Special tips are installed on the pipe - wings. This device rotates freely so that its back is always located against the wind. This position prevents wind or rain from entering the chimney directly.

Remove air bubbles that form around the hydrometer by twisting or lifting it. You read, applying meniscus correction, finding the real level. For processing, the read data is corrected with corrections of the instruments indicated in the certification of each measuring device. After reading, the devices are cleaned and stored in their boxes to protect them from tremors.

Reading drafts is a simple operation that is performed directly or using deleted drafts. Drafts can only be read to the third grade sea, above which the limit cannot be guaranteed with the accuracy necessary for calculation. Errors of one centimeter when reading drafts can lead to errors in estimating the quantity of goods over 100 tons.

You can use special fans. Such devices have a built-in electric motor. Their principle of action is as follows. They mainly work from the wind, with strong gusts, the fan rotates, increasing the exhaust gas output from the pipe, if the wind flows are not strong enough, the electric motor turns on, which forces the fan to work forcibly and all harmful substances are also on the street.

Reading is done on the promenade, in the carriage or on the cat's ladder, left on the desired board. If the sea is not quiet, read the fish several times, looking for the average value of the fluctuations. If the drawing of the main pair is not readable on the board, it is calculated by the formula.

Liquid weights on board are determined by probing or reading bottles with a graduated level where they exist. By sensing, the liquid level in the tanks is determined, according to which the volume of liquid in the tanks is determined using calibration plates.

When conducting probes, the following compartments should be considered. Front and rear tanks. Light, heavy fuel tanks and lubricants. To determine the weight of the liquid in these spaces, it is necessary to know their density, which will be measured in case of doubt about its value.

A small reservation, you should not immediately after reading the article run to the store and buy a new device. Before you know how to install it, you should make calculations. And already, based on the results obtained, it will be clear whether this device can be installed in your chimney.

If draft is lost in the chimney, it will be useful to check operation and dampers. For stoves and fireplaces, this is a kind of regulator of the exhaust gas exhaust force.

The study is carried out using a manual probe on a specially made sample of the probe. The fluid status of the tanks is shown in the tables below, as well as the navigation of the vessel after the vessel has been loaded. Correctable drafts for drafts - draft measurements made on drafts are prone to errors when the ship has a longitudinal inclination.

Correction of the final draft for deformation of the ship’s hull - when loading the cargo, it stops due to the uneven distribution of containers on the hulls. The ship's body may exhibit deformations materialized in the arches or contractions of the ship's corridor, depending on the distribution to the limbs or the center of the weight of the cargo.

To summarize

If you have a question: why there is no draft in the chimney, then first of all you should check the following. If problems with the removal of waste substances occurred during the first use of the stove or fireplace, then pay all your attention to the design documentation. Check the correct design and dimensions of the chimney.

If until now you used the stove and everything was in order, then you should first check for clogging in the pipe. It is possible that after prolonged stagnation, the chimney was clogged with different dirt. Sometimes a bird's nest can be made in a pipe.

Perhaps over time, the destruction of the chimney pipe. In this regard, normal sealing has disappeared, the exhaust gas flow has become not so strong. First of all, it is worth checking the chimney, part of which is located above the roof. A pipe that is constantly exposed to precipitation can easily collapse. This can happen if a solution with a low cement content was used for masonry.

Another reason that very often leads to the problem of poor traction is the large amount of traction accumulated in the chimney. In this case, the chimney must be cleaned. After removing soot, it is imperative to check the return draft in the chimney. If for many years your chimney has not been cleaned of soot, then after cleaning it, be sure to use means that prevent excessive soot settling on the walls of the chimney.

Useful advice. If you have not used a stove or a fireplace for a long time, and the weather has turned out with a large amount of precipitation, then it is recommended to check the efficiency of the chimney before burning. Otherwise, it may happen that all the smoke goes directly into the room, and not into the chimney.

If you find that there is a return draft of the chimney, what to do in order to eliminate it? Try to remove excessive moisture accumulated in the pipe. To do this, before burning the stove or fireplace with wood or peat, be sure to burn a couple of newspapers. Such actions will slightly dry the pipe walls and eliminate the increased humidity, so the stove will melt easier and faster, and the smoke from the burning fuel will begin to escape into the pipe.

Use of materials is allowed only if there is an indexed link to a page with the material.

Combustion products generated during the operation of the boiler with air flow are carried through the chimney to the street. The process of moving a stream through an exhaust duct is called draft. It occurs due to the difference in pressure and density of cold air and heated in a furnace or boiler. Improper design of the chimney or its clogging leads to a decrease in the intensity of the air flow, and sometimes change its direction to the opposite. Weak draft reduces the efficiency of the heating system, and the reverse is a health hazard. To improve the combustion of fuel in the boiler, you need to know how to increase draft in the chimney.

Checking traction with tools

The productive work of heating depends not only on the availability of traction, the quality of the fuel also affects the combustion temperature. To exclude other factors, you need to check whether the air moves through the chimney. How to check the draft without a special device? To do this, you need items at hand and simple steps:

A burning match is brought to the furnace compartment, with normal traction, the flame is drawn into the furnace.
A lit candle is placed near the chimney and extinguished, the direction of air movement is determined by smoke.
A sheet of tissue paper is inserted from the channel opening and watch for fluctuations.
The thrust is not only insufficient, but also excessive, while the heat is quickly carried away into the atmosphere. A strong stream of air makes the flame in the firebox buzz.

Lack of traction

It is important to determine why there is no traction. Reduced traction provoke various reasons:

incorrect design of the chimney duct;
low location of the pipe edge relative to the roof ridge;
the deposition of a large amount of soot on the walls of the chimney or other types of blockage;
climatic conditions - low pressure, high humidity, strong wind;
insufficient air flow due to poor ventilation;
violation of the tightness of the channel.

Having found out the reason for the decrease in traction, they immediately begin to correct the situation. Most of these defects can be fixed by yourself.

What to do

Now let's figure out how to improve traction. Design errors, such as a narrow pipe diameter or numerous channel bends, will have to be fixed by shifting, but other cases have simpler solutions. The insufficient height of the pipe is corrected by building, if a brick was used, then additional masonry is carried out. An additional part is fixed on the metal pipe, bringing the design to the recommended height - 5 m from the furnace.

The narrowing of the channel caused by the accumulation of soot reduces the volume of gas passed through. To clean the chimney, a simple device is made from a brush and cargo tied to a rope. The device is lowered into the pipe and progressively clean the passage.

Violation of the tightness of the brick chimney is eliminated by coating the slots with a solution, if necessary, part of the pipe is shifted. With a sufficient size and direct construction of the channel, they are cased with a ceramic or metal pipe. The chimney becomes airtight, and the circular cross-section of the channel is more effective for the removal of gases than a rectangular one.

Note! The diluted air in the room does not provide enough oxygen and has a low pressure, this provokes a back draft. To increase the pressure, good ventilation is needed, just open the windows for a few minutes and the composition of the air will be restored.

In adverse weather, there are several ways to improve traction.

If the outside temperature is low, cold air creates a pressure that prevents the outgoing flow. To warm the pipe, you can burn some paper with it, it is also important to take care of the insulation of the structure.
Use a strong wind to enhance traction allows the installation of a deflector. This device is placed on the pipe, at the time of exposure to air masses, a low pressure arises in it, contributing to an increase in traction. The diameter of the deflector depends on the size of the chimney. In the absence of wind, the device does not have a reinforcing effect. Devices are made of stainless steel, they are resistant to high temperature and humidity.
A similar effect is exerted by a rotational turbine mounted on a head. It spins under the influence of wind and creates the movement of air in the smoke channel. The ball-shaped design with blades protects the smoke channel from precipitation and foreign objects. The turbine is installed for a gas boiler with a low temperature of the exhaust gases.
Installation of a weather vane allows protecting the pipe mouth from wind blowing. The device rotates so that smoke exits from the leeward side, and the flowing air enhances the draft. reduces the likelihood of tipping over draft in the chimney. So that the moving part does not suffer from corrosion, it must be lubricated; periodically, the weather vane is also cleaned of soot.

Note! One of the reasons for the lack of draft can be a closed gate (damper) of the chimney, if the reason is this, then after opening the air flow is normalized.

Traction stabilizer device

The draft stabilizer is a pipe having an extension in the form of an umbrella. At this point there is an opening for air intake. The operation of the stabilizing device is controlled by a sensor. If gases accumulate from back draft or poor passage through the channel, it heats up and turns off the boiler. After eliminating the causes of traction deterioration, the heater is switched on again. The stabilizer by supplying additional air optimizes the gas velocity in the chimney. It automatically changes the intensity of the combustion products, depending on the situation increases or decreases traction.

Forced traction installation

Even the minimum draft is normalized with a heat-resistant fan mounted on the chimney duct. The device is powered by an electric motor and requires laying a wire for power from the network. This is the most effective solution that allows you to activate the movement of air mass in the chimney, despite the weather or other factors. Due to the rotation of the exhaust fan blades, a forced draft is created. An electrical device will improve gas removal even in channels where a small pipe diameter is mistakenly selected. Insufficient chimney height is also compensated by the installation of a fan. Unlike mechanical devices that operate solely on wind power, an electric fan is ready for use under all conditions.

Good traction is an important component of the effective functioning of the heating system, work on its control and strengthening will ensure the stable operation of the boiler or furnace.