How to increase draft in a chimney. How to improve draft in a chimney: where does reverse draft come from and how to deal with it? Increasing the chimney height

Sometimes there is not enough draft through the chimney, the fuel does not want to burn intensely, the wind blows in, smoke is released into the room when the damper doors are opened - why does this happen, and what needs to be done to improve the draft - maybe install a smoke exhauster?

Why is there no traction?

Natural draft depends on the pressure difference in the chimney. And the pressure depends to a large extent on the difference in temperature of the air and gases, or more precisely on the difference in their densities... In winter, when it is frosty outside and warm inside, the air flows well into any raised chimney, the boiler melts without problems. When the firebox is hot and the frost is still good, the draft is usually tolerable even in the most poorly designed systems. In the off-season, traction is also usually satisfactory.

But in the heat of summer, it can be problematic to light a stove or a regular boiler using natural draft. The initial thrust may be completely reversed. The room fills with smoke stable combustion is not achieved - what to do?

Also, natural cravings can be significantly affected for the following reasons.

• The chimney is covered in soot and coked.
• Other chimney ceilings - collapsed plaster, compression by structures, bulging and lifting of rusted, burnt shells...
• A hole has formed in the chimney - a leak in addition to the boiler firebox.
• A low chimney was installed - below that required by SNiP.
• A chimney with a small cross-section is installed - smaller than that specified according to the instructions for the boiler, for a given combustion power - the aerodynamic resistance is too high.
• Boiler installed, stove with too much aerodynamic drag inside, with complex system chimneys around the heat exchanger.
• Air supply dampers, blower covers, etc. are closed.
• The draft regulator is closed, the damper at the gas outlet, at the point where the chimney is connected to the equipment, is blocked.
• There is no free flow of air into the room, it is hermetically sealed, during combustion a vacuum is created in the firebox, and the draft stops.

As you can see, if the traction is broken, then you first need to check the serviceability of the equipment, correct adjustments air supply, the position of the dampers, and be sure to clean the soot from the chimney.

• But for many people it is important: - how to light a boiler in the summer, for example, to heat water...
• Also, many people are aware of the “diseases” of their boiler-chimney system, but there is a desire to increase draft on existing equipment - how to do it?

Installing a deflector - helps increase traction

A deflector is a device at the top of the chimney that creates additional vacuum in it due to the force of the wind. Disadvantages of this method of increasing traction:

• If there is no wind, then there is no increase in traction - too obvious a drawback.
• Another hard-to-reach unit appears that needs to be cleaned from soot, giving reverse effect when dirty, inhibits traction.
• The method also has a slight increase in draft - only 20 - 25%, provided there is wind on high chimneys.

Is it worth doing this or is it enough to install a regular rain umbrella? In addition, the instability of the traction force is not the best situation, then we will look at why...

However, you can make a deflector yourself from stainless steel, according to the drawings provided.

How to make a TsAGI deflector - manufacturing diagram.

Making a deflector on video.

Drawings for the manufacture of a Volpert-Grigorovich deflector.

Install a smoke exhauster to increase draft

There are electric ventilation units to increase draft in chimneys. Large boiler houses are equipped with them according to the designs initially. For boilers, such equipment can be installed additionally on standard diameters pipes

• There are draft enhancers installed at the end of the chimney in the form of a propeller fan. But the option is unpopular due to the complexity of installation at height and subsequent cleaning there, especially if resinous firewood is used.
• Another version of the smoke exhauster is a centrifugal type, installed at the outlet of the boiler in the hot gas zone. Usually a separate chimney bypass is made for it, blocked by a damper, so that during natural draft the gases do not flow through the fan.

During operation, this device creates a powerful fixed draft that will blow through virtually any system, provided there is free air access to the firebox (into the room), and will not pay attention to wind blowing, for example... But this system has very significant disadvantages.

Disadvantages of installing a smoke exhauster.

• During operation, a stable draft is generated and a large amount of fuel is burned. In the event of an emergency power outage, the draft disappears, then a large amount of carbon monoxide can be released into the room. This is extremely dangerous. Such a smoke exhauster must work in conjunction with automation with other boiler room devices, or for a short time under constant human control.
• The impeller gets dirty too quickly and needs regular cleaning, so its use is not practical.
• Obstacles are being created to implement slow long burning.

Ways to increase traction

If the chimney produces insufficient draft, it is necessary to replace it and install sandwich pipes matched in diameter to the given power heating equipment(according to instructions, according to tables), and height according to SNiP requirements (half a meter above the ridge when placing a pipe near it... etc.).

If necessary, summer fireboxes can be equipped with a boiler centrifugal exhaust fan for confident, infrequent launches under the supervision of a responsible person in hot weather. But there is a simpler solution...

How to light a boiler in summer or a stove after a long break? - a popular method is to stick a vacuum cleaner blowing into the blower, or put any other fan on blower for a couple of minutes until it flares up... - watch the video

Designing a chimney is complex and responsible, the efficiency and safety of use depends on its correct execution. heating device. Not a single heat generator is able to function normally without a pipe that removes smoke from the room. Smoke is a mixture of gases containing residual products of fuel combustion. The appearance of smoke inside a heated room is a sure sign of incorrect calculation of the chimney system, which entails the risk of fire and poisoning carbon monoxide. This article will tell you what it is reverse thrust in the chimney, how to prevent its occurrence.

If you doubt that the draft of the chimney duct of a stove, fireplace or heating boiler sufficient, it needs to be checked. The easiest way to dispel doubts is to check it yourself using an anemometer. If the device shows a draft of 10-20 Pa, then it is considered normal. The problem with this method is the low measurement accuracy of inexpensive anemometers; if the draft is less than 1 Pa, then they will show that there is no draft. More accurate professional instruments are expensive; they are used by stove makers.

If you don't have an anemometer, use one of the traditional methods determination of chimney draft force:

Note! The draft inside the chimney duct is created due to the difference in pressure outside and inside the room. In a heated room, the temperature is higher than outside, so there is more pressure there. Heated air, supported from below by colder air, is squeezed into a zone with lower pressure, that is, into the atmosphere. If you take measurements in the summer, when the temperature difference between inside and outside is minimal, you will get a lower result than in winter.

Causes of malfunctions

After making sure that there is not a sufficient draft level inside the chimney system, you need to determine and eliminate possible reason this defect. Experienced craftsmen claim that the most common reasons malfunctions of smoke exhaust ducts are:

The first step when detecting problems in the chimney system is to dismiss the most obvious causes of insufficient draft. When inspecting, make sure that the connections of all pipe segments are tight and that there are no soot blockages. Check what's in smoke ducts no moisture got in, but Atmosphere pressure corresponds to the norm.

Ways to increase traction

If the draft force is in the chimney duct of the heating device, eliminating this defect is not always easy. Experienced stove makers use the following methods and methods to increase it:

If you were unable to find a solution to the problem of lack of draft inside the smoke exhaust duct on your own, seek advice from an experienced stove maker who will tell you what to do and correct the defect in the most rational way.

Video instruction

When there is no normal draft in the oven, it is not surprising to lose peace of mind. Due to the lack of circulation of air masses, the firewood does not ignite, and the room is filled with smoke. What prevents the chimney draft from fully performing its function is not always clear. But the annoying problem can be eliminated if you properly understand the issue.

What processes support cravings?

The draft force depends on any factors that determine the air density in the room and outside it.

The efficiency of smoke emission from a chimney depends on many conditions

Conditions inside the house that affect the rarefaction of air masses in the chimney include:

• construction raw materials used in the construction of a dwelling (natural ones allow air to pass through, but artificial ones do not);
• average room temperature;
• the dimensions of the room in which the heating equipment is located;
• the number of people in the house;
• number of additional air consumers, for example, kitchen hood, exhaust fans etc.;
• method and frequency of ventilation of rooms.

Internal factors can be influenced to improve traction. The only thing that cannot be done is to change the influence already finished design building.

Factors external environment, correcting the traction force, consider:

• temperature, atmospheric pressure, wind and humidity outside;
• activity of convective flows - the nature of air movement from the ground upward;
• the effect of isothermia - static air as a result of the equality of its temperature, regardless of altitude (this does not happen for long in the morning, evening and when it is cloudy);
• the appearance of inversion - the movement of cold air downwards, which happens only in the evening and night hours and under the influence of wind.

You need to be able to adapt to environmental conditions.

The wind helps pull smoke out of the chimney

The functioning of the draft is also affected by circumstances related to the design of the chimney, that is:

Terms related to design features chimney are the most important. By coordinating these factors, it is possible to limit the influence of unfavorable aerodynamic processes and make them work not as a minus, but as a plus.

Control and measurement of air vacuum in the chimney

A common way to check whether a chimney is functioning is to place a lit match or lighter near the chimney channel. Sometimes a piece is used instead toilet paper and a smoking cigarette.

You should only study the draft force in the chimney during the day. At night, the result will be inaccurate due to the effects of such natural processes, like inversion and isothermy.

If the light or smoke is directed into the chimney, there is a vacuum in the air. If the flame is completely motionless, then this means that there is no draft.

Too strong a draft can even extinguish a burning match.

If the light or smoke is directed away from the channel, that is, into the house, it is recognized that there is a rarefaction of air, but it is broken. This phenomenon is called overturned draft, which negatively affects the operation of the heating system.

Incorrect air pressure has to be constantly changed, and this leads to unplanned fuel waste. An overturned draft is a consequence of violations in the design of the chimney. These defects could be the wrong diameter, poor insulation or incorrect height.

The normal flow of gases when the thrust is turned over is disrupted

Thrust calculation

Since thrust is created due to pressure difference, it is calculated using the formula ∆P = C∙a∙h (1/T 0 - 1/T i), where ∆P is the pressure difference in Pa, a is atmospheric pressure in Pa, h - the height of the pipe in meters, T 0 is the absolute external temperature in K, and T i is the absolute internal temperature in K. C is a coefficient that is taken equal to 0.0342 in calculations.

In any case, calculations will provide only approximate data regarding the degree of rarefaction of air masses in chimney. An accurate result can only be obtained in laboratory conditions.

Depending on the obtained ΔP value, the following air rarefaction levels are distinguished:

• less than 2 Pa - 1st, 2nd or 3rd;
• exactly 2 Pa - 4th;
• more than 2 Pa - 5th or 6th.

There is no point in trying to find out on your own what the traction force is. It is better to use heating equipment in such a way that there is no need to check using formulas and instruments.

How to increase draft in a chimney with your own hands

If it is determined that the draft is weak due to a violation of the chimney structure, then the following must be done:

It must be borne in mind that each heating equipment needs its own chimney. Combustion products from two heat generators cannot be discharged simultaneously through one channel.

The use of smoke exhausters and deflectors in conditions of violation of the chimney structure is out of the question. The temporary help of these devices (after all, one day they will break) will lead to an unexpected disaster.

Being confident that there are no problems with the design of the chimney, other measures are taken:

1. Clean the smoke channel from soot deposits. To do this, an iron ball tied to a metal cable is passed through the chimney. You can use it instead plastic bottle 2 liter capacity filled with water, or a brush with a long handle. The device must be lowered until it hits an obstacle, and then raised one and a half meters and lowered again. This is how it should be done along the entire length. smoke channel, each time directing the ball, ruff or bottle below the previous level.

   Deterioration in traction may occur due to soot deposits on the pipe walls. They must be removed using a special brush or other similar object tied to a long rope

2. The areas of the furnace from which smoke should not escape are sealed. The joints of the chimney with other parts of the heating equipment are also clogged with clay and sand.
3. Check whether the weather vane covering the chimney on the roof is in working order. If necessary, it is cleaned of dirt or ice.
4. Windows are opened in the house to ventilate the rooms. Thanks to this, additional air supply from the outside is created. Alternative way increase traction - open all doors, providing access warm air to heating equipment.
5. Achieve additional rarefaction of air masses in chimney, that is, they eliminate “blockages” in the channel by burning several sheets of newspaper.

   Burning paper will clear the way for smoke

Manufacturing of air vacuum stabilizer

A draft stabilizer is a mechanism that supplies secondary air in portions, which is why the necessary vacuum is maintained in the chimney. It works autonomously; a person does not need to monitor the work. A safety valve is installed in the stabilizer, which protects against excessive pressure.

The stabilizer helps remove smoke from the pipe because it regulates the pressure inside it

Before designing a traction stabilizer, you need to stock up on:

• a cylinder filled with gas - compressed argon;
• semi-automatic for welding metal in argon;
• grinding discs made of stainless steel with a special shape of petals;
• sheet stainless steel 1 mm thick (for example, metal grade Aisi 321, 304);
• steel rod for an axle with a diameter of 1 cm;
• screws, washers and nuts.

The raw material for the manufacture of a traction stabilizer can only be stainless steel. Galvanized metal must not be used.

The traction stabilizer can only be made of stainless steel

A stabilizer, which is capable of both regulating and limiting traction force, is created as follows:

1. A pipe 30 cm long is formed from a metal sheet.
2. Do weld, overlapping one edge of the sheet with 1 cm of the other. This should result in a product with a diameter of 11.5 cm.
3. Welding areas are cleaned with a grinding disc.
4. A plug with a cutout, the size of which is equal to 15% of the cross-sectional area of ​​the pipe, is installed inside the created valve.
5. Two holes are made in the pipe opposite each other. They should be in the middle of the metal product. A steel rod is threaded through them, fixing and turning the valve.
6. The valve is welded to a rod inside the pipe. The outside of the axle is equipped with a handle.

Video: features of creating a draft regulator

Causes of reverse thrust

The fact that there is reverse draft in the chimney will indicate the exit from combustion chamber a lot of smoke.

If the wood does not burn, but only smokes, then the draft in the chimney is bad. The release of smoke into the room indicates the occurrence of reverse draft

Smoke in a room is caused by:

Owners of stoves with a metal chimney usually face the problem of backdraft. Such heating equipment instantly heats up and cools just as quickly. As a result, cold air masses in the smoke channel tend to go down each time. In chimneys made of bricks, this phenomenon occurs very rarely.

Reverse draft, unlike normal draft, leads smoke into the room and not outside

In some cases, the appearance of reverse draft must be blamed on insufficient or, conversely, excessive ventilation. Because of it, the smoke seems to be “knocked out of its usual rut.”

Volumetric air flows often form in a house or bathhouse, where there is a staircase to the second floor. To fix this problem, you just need to keep the windows on landing closed.

Backdraft in the chimney is a consequence high humidity outside and heavy winds. The problem arises even when it is cooler inside the house than outside, because this creates a “reverse” pressure difference.

Less commonly, the appearance of backdraft in a chimney is associated with strong wind blowing around the pipe coming out of the roof. Typically, whirlwinds are caused by trees big amount branches.

Because of the branchy tree there may be people walking around the pipe strong wind

The culprit of the draft overturning is sometimes the location of the pipe. If the smoke channel is located inside the bathhouse, then there are practically no problems with air rarefaction. But when installing a chimney outside, the situation looks different: the pipe takes longer to warm up, which often causes condensation to form.

Solving the problem of lack of rarefaction in the smoke channel

Actions to eliminate backdraft depend on the causes of the problem. The most popular methods for eliminating this phenomenon are:

Video: how to act when the draft overturns

The draft in the chimney of heating equipment often becomes poor due to the fault of the owners of the house or bathhouse. To prevent smoke from entering the room, you should constantly monitor the performance of the heat generator.

A draft amplifier is a simple device that allows you to make your heating system more efficient. It is necessary to understand its structure in more detail. In addition, you should understand how to measure traction and how to increase it. by different means. A chimney draft amplifier is necessary for normal heating of residential premises. In device different designs everyone should figure it out home handyman. This will increase the efficiency of heating equipment.

Measurement methods

If there is any doubt that the chimney draft is at a sufficient level, a check must be carried out. The most in a simple way is to conduct research using an anemometer. When the device readings are around 10-2 Pa, the draft is considered normal. However, this method has one drawback. It has low measurement accuracy. It refers to inexpensive devices. For example, if there is a thrust of less than 1 Pa, they can show that there is none at all. This indicates the need to use better measuring devices.

Professional devices are different at a high price and at the same time quite expensive. Such devices are usually used by experienced stove makers. If you do not have an anemometer, you can use one of the following methods:

Attention! The draft in the chimney appears due to the difference in pressure indicators outside and in the room. The pressure in the room that needs to be heated is higher than outside. This is explained by the fact that the temperature in it is higher.

When operating a fireplace or stove, many owners of private houses note a decrease in the exhaust force during certain periods. To correct the situation, you will need to create a chimney exhaust force amplifier.

Reasons for the decline

First you need to understand why the traction force has decreased. That is why the condition of the chimney is first checked. Be sure to review other elements of the system. This can be done quite simply. First you need to completely turn off the heating system. Then the amount of soot in the chimney is changed using a long probe. This figure should not be more than 2 mm.

There are quite a few reasons why there may be no draft in the chimney. They should be divided into two groups - design features and factors influencing from outside.

The first include:

External factors may be:

• Installation of the chimney outlet below the roof ridge. This factor often leads to the traction overturning.
• The presence of fairly large objects near the chimney. Because of this, a large area of ​​​​low or increased pressure is formed.
• The predominance of calm or strong winds in a certain area.

This may affect traction force. Increased resistance is created. To prevent this, certain measures should be taken. Thanks to such actions, heating equipment will be operated more efficiently.

Devices and methods

In order for the chimney to function normally, all conditions must be met under which the upward flow will have a pressure of 10-20 Pa. After determining the traction force using an anemometer and, based on the amount of fuel burned, they decide whether to increase or decrease the traction force.

There are several common and effective options solutions to this problem. Traction can be normalized by the following means:

Such methods have their advantages.

Chimney extension

A simple method to increase the draft force is to create a longer chimney pipe. For a channel that removes smoke, it is better to choose a length of 5-6 m. This indicator is selected when minimum distance from the furnace to the vertical section of pipe. It is worth considering the number of narrowings and elbows.

If the roof is low and there are large objects, which significantly reduce the traction force, thanks to this method it can be significantly increased. However, if the traction force becomes too strong, a lot of heat will escape into the external environment. In this case, the heating system will not work efficiently.

Deflectors

The deflector is a mechanism through which air flows are distributed optimally. Due to this, the exhaust force in the chimney increases significantly.

The simplicity of the chimney design ensures its functionality. Flows that are reflected from the chimney and side winds can significantly increase the draft force, sucking in smoke. Even in the event of heavy winds, the deflector will prevent the thrust from tipping over. However, such a device does not work in calm conditions. The amplifier model must be selected in accordance with the size of the chimney, as well as the expected wind load.

To build a deflector yourself, you will need to have a sheet of galvanized iron and standard set tools. The work is not difficult. To make such a device, you need to prepare:

• roulette;
• square;
• grinder and metal scissors;
• riveter;
• wooden hammer;
• sheets of galvanized sheet metal;
• available material from which the fastenings will be made;
• set of drills;
• hand drill.

After performing the necessary calculations and marking the metal parts, you must perform the following steps:

Before installing the deflector in the lower ridge, it is necessary to install studs to connect them to common building. When mounting on legs, they are fixed with rivets from the outside. However, it must be remembered that each connection of the device must be made as strong as possible. This is due to future exposure strong winds.

Such traction enhancers are capable of excellent tolerance flue gases and high temperature. In addition, they are very resistant to rust and can last for quite a long time.

Vane

This device is another traction amplifier. The weather vane has a simple design and when installing it there is no need to extend the chimney. However, the weather vane is dependent on the strength of the wind. In addition, such a device does not interfere with traction in complete calm. It is necessary to install a small wing on the head, which will cover the edge of the chimney from gusts of wind.

The device has an auxiliary blade. Due to the fact that it is placed opposite the installation site of the weather vane, the device is able to perfectly cover the chimney openings from air flow. They will flow around it, creating a vacuum at the outlet. As a result, traction increases significantly.

Typically, weather vanes are chosen when installing fireplace chimneys or when vortices often form above the chimney. This makes the heating system more efficient. In addition, such devices are low in cost.

Rotary turbines

Such devices are mechanical devices that are used to increase draft in the chimney. They are able to harness wind energy. The turbine nozzle, regardless of the wind, will rotate in a certain direction. In this case, a vacuum is created above the chimney. This allows you to increase traction.

The creation of such devices ensures the safety of the chimney from debris, snow and rain. Main distinctive feature such a turbine is incapable of operating in calm conditions. At the same time, in the case of strong winds, an increased vacuum is created, which also does not have a very good effect on operating efficiency heating system.

It is better not to install rotary turbines on the smoke exhaust ducts of coal furnaces and wood fireplaces. Maximum permissible temperature gases that are removed from heating systems with such draft amplifiers is 250 degrees. It is better to install such devices in natural ventilation systems.

Electric smoke exhausters

Sometimes, for example, when using wood stoves, installation of smoke exhausters can be carried out. Such devices are used to remove gases high temperatures. They are not afraid of ash and condensation. However, such devices should not be installed on the chimneys of solid fuel boilers. In them, the temperature of the exhaust gases can reach 800 degrees.

Thanks to the installation of electric smoke exhausters, the combustion product removal system is fully automated. This is ensured by installing temperature sensors. As a result of the operation of such a system, the intensity of work is regulated electric drive. At the same time, optimal traction in the system is constantly maintained.

When choosing a method for increasing thrust, it is necessary to pay attention to the design features of the pipe. The use of all devices to create increased traction is relevant only when windless weather prevails.

conclusions

Traction booster is required for normal operation heating systems if smoke removal is difficult. When choosing a suitable device, you need to take into account the reasons for the deterioration of traction and the features of the heating equipment. This will allow you to design a smoke exhaust system that will work as efficiently as possible.

To normalize cravings use various devices. They have their own advantages and installation features. Some of these devices are easy to assemble with your own hands. Most often, simple amplifiers like a weather vane and deflector are used.

Stove heating in a private house requires additional costs and special equipment to prevent ventilation problems and ensure safe living. Particular concern should be given to the condition of chimneys, which can cause fires and accidents due to the reverse draft effect.

What is backdraft

This concept means a malfunction of the heating system and combustion product removal system. There are several reasons for the occurrence of reverse draft, and any consumer of heat from their own heating units should know everything about this phenomenon. Because this is not only a household inconvenience, but also a life-threatening factor.

Draft is a targeted flow of air from a heating unit to the exit from the chimney. Reverse draft is a change in the direction of flow from the external environment to the furnace. In this case, the furnace starts to smoke heavily. solid fuel or penetration of combustion products from gas appliance into the room. The option of attenuation is also possible, then gas can enter the room, which in itself is very dangerous.

The draft largely depends on the design of the chimney

What does draft in a chimney depend on?

Air movement is determined by the presence of pressure differences at different points in the atmosphere. For natural reasons, it tends to equalize the pressure, heading towards an area of ​​low pressure.

If there is a targeted channel in the form of a chimney, the movement accelerates and allows air to be sucked into the firebox, ensuring fuel combustion. At the same time, combustion products are removed from the firebox and discharged outside.

Air exchange in the chimney occurs due to the fact that the air heated in the firebox, being lighter, rises through the channel, displacing the cold air in it. Along with it, combustion products are removed, in particular carbon monoxide.

Several factors can be considered that directly influence this process:

1. Smoke channel configuration. When purchasing a heating device, you need to carefully study the included technical documentation. Recommendations for the diameter of the chimney must be strictly followed. If it is not possible to use pipes the right size, you can slightly increase the draft by increasing the length of the chimney. It should be taken into account that it should not be longer than 5 meters. You should avoid turning the smoke channel at right angles; it is better to use an angle of 45 degrees. If it is necessary to use a horizontal part, its length should not be more than 1 meter, and it is advisable to increase the height of the pipe within the permitted limits. On long-burning heating units, only round chimneys should be used. In general, such ovens are characterized by low temperatures flue gases. Slow burning, and, in fact, smoldering of fuel, does not allow them to sufficiently warm up the chimney, as a result of which condensation is released on the walls, collecting soot. The size of the smoke channel quickly decreases, the draft worsens until it stops completely. For such furnaces, it is better to use two-layer chimneys with insulation and a condensate collector. Using chimneys with round channel due to the nature of the movement of gases - the flow twists in a spiral. IN rectangular chimneys Stagnant zones form in the corners, worsening flow conditions.

   A round chimney will be most effective, but a square or rectangular one can create problems

2. Chimney height. It is indicated in the passport heating device, and if the stove is made by hand, then the main requirement is to raise the pipe above the ridge of the roof by 0.5 meters. You can also look at hardware store passport of a stove similar in size to the home-made firebox to clarify the diameter of the smoke channel. A pipe located at a distance of up to three meters from the ridge can be on the same level with it.

   The height of the chimney on the roof depends on its location and is determined by regulatory documents

3. Chimney insulation. External chimneys or areas located in the attic space must be insulated. A flue gas temperature of 70 degrees promotes condensation of moisture, which is always present in furnace gases, on the walls of the chimney. Solid components of smoke easily settle on it and soot forms. This can be avoided by using sandwich pipes. They consist of two pipes one inside the other; insulation is placed between the walls, allowing to maintain optimal temperature furnace gases. You can insulate a single pipe by covering it with mineral wool and wrapping it with foil.

   Insulation from mineral wool will help maintain the desired gas temperature

4. Fuel quality. The use of wet firewood is strictly prohibited. They contain a lot of moisture, and we already know what happens to it in the chimney. Besides, it's just not practical a large number of The heat is used to evaporate moisture.
5. It is not advisable to use coniferous wood for heating. Due to the high resin content, a lot of soot is formed.
6. And it is not at all recommended to use waste containing resins - plywood, chipboard and the like - for burning waste. In this case, chimney blockage is guaranteed.
7. Insufficient ventilation. During the combustion process, the stove consumes oxygen from the air in the room. If there is no influx fresh air, the oxygen content in it decreases rapidly. In the end, combustion products may be released into the room with the formation of reverse draft.
8. State of the atmosphere. In bad weather, such as strong winds, high humidity or fog, a pressure difference occurs between indoors and outdoors. This can also cause backdraft. The room should be ventilated to equalize the existing difference.
9. Cold air in the chimney. In severe frosts, a lot of heavy cooled air can accumulate in the pipe, creating a blockage. When igniting a large load of fuel, a large amount of smoke quickly forms, which cannot penetrate it and enters the room. In such a situation, before laying firewood, you need to burn several sheets of paper in the firebox in order to gradually warm up the stagnant air in the pipe, and only after that load and ignite the stove.

In cold weather, it is necessary to warm up the stagnant air in the pipe before lighting.

If a lack of proper draft is observed in newly installed stoves and fireplaces or in the chimney gas boiler- this is most likely a mistake by the builders, that is, the installation of a smoke removal and ventilation system in a private house was carried out with errors.

Checking and measuring draft in the furnace

The presence and direction of traction can be checked in simple and reliable ways:

1. By deflection of the flame of a candle or match. To do this, you need to open the firebox door slightly and bring a burning candle to the opening. The flame will deviate in the direction of air movement. If there is none, you need to check the position of the gate and open it completely. The field of what to check again.
2. You can use a strip of newsprint in the same way.
3. Measuring the amount of thrust in domestic conditions does not seem necessary. They are used by professional stove makers to monitor the correctness of the work performed. An anemometer is used for this purpose. It is placed inside the firebox, and the device reacts to the movement of air in it.

Reliable verification of the presence of draft in the chimney by flame deflection

How to increase draft in a chimney with your own hands

To obtain good air movement in the chimney, you must follow all the rules for installing this device, including the cross-section and height of the channel. But in parallel with this, you can take some steps to ensure good traction in all weather conditions:

1. Installation of the deflector. This device is especially effective in windy weather. By changing the direction of the wind over the pipe, the deflector helps to increase the speed of movement of flue gases. The optimal fuel combustion mode with a pipe with a deflector provides increased efficiency heating unit. In addition, such a device protects the pipe from debris getting into it.

   The deflector effectively increases draft in the chimney

2. To improve traction, use this decorative element like a weather vane. To do this, one side of it is made convex. Turning in the direction of the wind, the weather vane deflector with its convex part directs the air so that it passes over the pipe. This creates a rarefied zone, which helps to increase the speed of movement of furnace gases through the chimney.
3. The gate is important for adjusting traction. This is a damper that regulates the clearance in the cross section of the chimney. When ignited, it is installed in the open position, at which the draft in the still cold oven is maximum. As the stove warms up, it is covered, adjusting the intensity of fuel combustion. The second point of adjustment is the damper in the combustion chamber, which regulates the air flow into the combustion zone. By adjusting at these two points it is possible to achieve optimal mode combustion of fuel with maximum heat transfer.

   A reliable damper with a rotary damper for the chimney is necessary in order to regulate the draft force

Making a deflector with your own hands

To make sketches of the device parts, you need to measure the internal diameter of the chimney and calculate their dimensions.

You can make a deflector for any pipe size yourself

To do this, we present several defining relationships:

• the width of the diffuser is determined depending on the internal diameter of the pipe by multiplying by 1.5;
• the width of the umbrella should be 1.7 in relation to the same parameter;
• the same coefficient is used to determine the height of the device.

After calculating the dimensions, you can begin making part developments. They can be done on whatman paper or any other thick paper.

Paper parts need to be collected in ready product, using paper clips or a stapler, and try it on the chimney pipe. If necessary, make adjustments to fit the product to the pipe.

To make the deflector, galvanized or stainless steel sheets with a thickness of at least 0.5 millimeters are used.

Based on the development of parts, you need to transfer their contours to sheet metal and cut with plumber's scissors.

Assembly is carried out in accordance with the preliminary design.

Video: how to make a deflector with your own hands

Tools and materials for making a deflector

To make such a device, you will need the following:

• steel sheet;
• metalworking scissors for cutting metal;
• drill with drills of the required sizes;
• hammer;
• pliers;
• fasteners;
• marker for marking parts on metal.

The procedure for making a deflector

The production technology consists of sequentially performing a number of operations:

1. Converting the contours of parts to a metal sheet using a marker. You need to get the following parts - cap, stand, diffuser and outer cylinder.
2. The blanks for the cap, diffuser and cylinder are rolled to size. Connections are made with rivets or screws, and sometimes semi-automatic welding is used.
3. To install the cap you will need strips of metal. They are made from waste from cutting the main parts. You need to drill several holes on the cap and secure the parts with rivets.
4. The opposite ends of the strips are secured to the diffuser in the same way.
5. The resulting product is fixed to the shell.

Video: homemade turbo deflector for a chimney

Causes of backdraft in the chimney

Reversing the direction of air flow in a chimney is called “draft reversal.”

It is quite easy to notice the first signs of backdraft in the chimney - wood burns in the stove with a lot of smoke, the glass on the door quickly smokes, and if it is opened, the smoke immediately spreads throughout the room.

This can happen by various reasons: a sharp gust of wind or the presence tall trees in close proximity to the heating facility. However, the main prerequisites for such an incident are design errors:

Particular attention should be paid to room ventilation when using gas boilers and water heaters. When the draft is turned over, they may go out and gas will flow into the room. On modern devices Automatic gas supply shutoff is installed, but do you need to depend on it?

In some cases, backdraft may only occur for 1-2 days, such as when the oven has not been used for a long time, or due to wet weather.

Photo gallery: means for cleaning the smoke duct from soot

Backdraft in the chimney: what to do

If there is insufficient draft, first of all you need to check the entire chimney structure and eliminate any detected faults. Most often, it is possible to determine the presence of contamination or blockage of the channel. This could be debris blown into the pipe by the wind or even bird's nests, arranged during the unheated period. But most often the cause of insufficient draft is the deposition of soot on the walls of the chimney. To eliminate it you need:

1. Cut a bucket of potatoes into small pieces and burn the root vegetables in small portions in the firebox. The released starch softens the soot coating, and it falls in pieces into the firebox. At the end of the fire, they must be removed. The same effect can be achieved by burning potato peelings.
2. Firebox with aspen wood. When such fuel burns, a large amount of heat is released, but the stack should contain no more than 2-3 logs. When using this method, special care must be taken as the soot may ignite, which will lead to a fire.
3. Rock salt, periodically added to the firebox. Its vapors clean the walls of the chimney. Used as a prophylactic.
4. Pipe brush in the form of a brush for mechanical cleaning of pipes.
5. Installing a deflector always creates additional draft in the chimney direction.

Mandatory chimney maintenance must be performed annually before the start of the heating season.

Individual heating country house any type of fuel can be safe if during the construction and installation of chimneys all devices are provided to ensure normal draft and preventive maintenance is carried out regularly.