Why does the gas boiler blow out?

Today, private houses equipped with autonomous heating systems can be found in any locality. The efficient operation of heating equipment largely determines the level of comfort indoors. However, there are situations in our life when the order and comfort that have been established in the house are under threat. The reason is banal — the gas boiler goes out and refuses to work, the heating system becomes useless. The circumstances of the occurrence of such an emergency situation can be very different, from low gas pressure in the line to the usual wind blowing. The latter option is directly related to the wrong ventilation device. Why the gas boiler blows out, and how to deal with it, let’s try to figure it out in more detail.

Why does the boiler go out in windy weather, the main reason

The owners of private houses are well aware of the situation when, with a strong wind, the gas boiler simply goes out. Residents of city apartments are not familiar with this problem if the gas boiler installed in the apartment has a coaxial air duct — this design does not allow a strong gust of wind to get inside, causing the burner to blow out.

In a private house, the design of the chimney and the ventilation device looks different, and blowing out the gas boiler is not uncommon.

There can be many reasons.

Important! The main reason for the wind blowing a gas boiler is poor ventilation design, non-observance of technological parameters during the installation of the chimney. It is not worth solving the problem on your own. To fix the problem, it is better to contact the services of heating specialists.

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Other reasons, as a result of which the burner flame suddenly goes out, are associated with the design features of the gas heating equipment or the influence of third-party factors.

Main article: do-it-yourself burner

Other factors that can cause the boiler to blow out

The most common situation faced by the inhabitants of a private house is the operation of a check valve as a result of excessive pressure of the air mass coming from outside. With a strong gust of wind, the valve becomes in the closed position — the automation is sensitive to its position and shuts off the gas supply to the furnace. If this situation is repeated frequently, it is necessary to reconstruct the chimney. Pay attention to its height. For normal operation of ventilation, the upper edge of the chimney must be at least 0.5 m higher than the extreme point of the roof of the building, and the diameter of the air duct must correspond to the parameters of the boiler equipment and is determined by calculation.

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To improve draft, it is necessary to regularly clean the ventilation ducts, since the boiler constantly needs an influx of oxygen with air. The lack of oxygen in the combustion chamber causes a low intensity of fuel combustion. With poor draft, the flame can go out altogether.

The flame of the burner is blown out — we solve the problem with the chimney

If you constantly blow out an autonomous gas boiler, first look for problems in the design of the chimney. Pressure drops in the gas pipe are extremely rare, and the pressure drop is negligible. A technical malfunction of a gas boiler, due to the simplicity of the design of heating equipment and the high degree of reliability of modern models, is also unlikely.

The most common situations that you have to deal with are related to the chimney:

• ice crust covering the ventilation channel of the heater — the formation of an ice cap inside the chimney prevents air circulation, putting the gas boiler in a position of oxygen starvation (together with combustion products, water vapor enters the chimney channel, condensing and freezing on the walls of the chimney);

• reverse draft that occurs when the wind strengthens or changes direction (strong air flow, getting inside the chimney, reaches the combustion chamber and extinguishes the flame in the boiler).

In the first case, frozen condensate creates an artificial obstacle to the air flow. The chimney in such a situation must be cleaned and insulated, allowing the condensate to simply drain down.

In the second case, the situation is dangerous. With the reverse movement of warm air, amplified by gusts of wind, there is a high probability of attenuation of the burner flame. Good automation will work when the burner is attenuated, stopping the gas supply to the furnace. However, the combustion products will first enter the heater, polluting the combustion chamber in the gas boiler, and then they will enter the living space. The reason for this effect is obvious — the insufficient height of the chimney.

See also: if the gas boiler does not work.

How to deal with backlash. Basic mistakes and misconceptions

It was previously said that back draft can be combated by increasing the length of the chimney. The solution to the problem is quite simple, but not always such a solution gives positive results.

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The second solution to the problem in such a situation is to install a deflector on the upper edge of the chimney, the task of which is to increase the draft in the chimney.

The third option is to reduce the number of bends and sharp turns of the chimney, which increase the cavitation (swirl) of the flow of hot air with smoke when passing through the chimney.

Both in the first and in the second case, the situation will not change radically. Extending the pipe by 1 meter will not give the expected effect. Installing a deflector on the chimney also does not completely solve the problem. With a significant deterioration in the weather, the wind still blows out the unprotected gas boiler, and the heating will fail again. What to do? What is the optimal solution?

Special design deflector — problem solving

An effective method that is able to solve once and for all the problem of reverse thrust is the installation of an aerodynamic device on the chimney — a deflector of a special design.

In a conventional deflector, air currents act on its outer part. As a result of the interaction of the air mass with the surface of the deflector, a rarefied atmosphere arises, which increases the draft in the chimney. The phenomenon is called the Bernoulli effect, the concept of which came to us from aviation. In other words, when the air, when meeting with an obstacle, goes around it, a rarefaction zone is created around the obstacle, which enhances the lifting effect of the wing.

For reference: a deflector of even a conventional design increases the efficiency of any chimney by 15-20%, not to mention fixtures with a more complex design.

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If a conventional deflector is not able to eliminate the wind blowing of a gas boiler, a device of a more complex design is installed. Today, there are several types of deflectors with a complex configuration. Among the most popular products, the following types should be distinguished:

• deflector type «Smoke tooth»;
• deflector Grigorovich;
• deflector type «Voller»;
• spherical and rotating deflectors.

Two types of devices are considered the most popular in ours: the Grigorovich deflector and the “smoke tooth” type devices.

The Grigorovich deflector is a device in the design of which all contours and elements are directly related to aerodynamics. Unlike the usual deflectors in the form of umbrellas that are familiar to us, standing on pipes in private houses, this device has two cones, direct and reverse. The interaction of the two cones provides the necessary movement of air flows, thereby creating a zone of reduced pressure around the chimney. Due to the temperature difference between cold and hot flows, the draft in the pipe increases several times, preventing any penetration of outside air into the inside.

On a note: deflectors of complex design, on the contrary, use the force of the wind to increase the draft in the chimney, that is, when the wind gusts at an angle, from above or below, the air, penetrating under the lower cone of the deflector, sucks in the air masses entering the chimney.

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With the correct location and design of the chimney equipped with a deflector, reverse draft does not threaten you — any gusts of wind will not be terrible for a working boiler.

Another point should be noted — when the wind blows out the gas boiler, and the heating system does not start. This is an underheated chimney. During long shutdowns of the heating system, which is typical for country houses and cottages, when the boiler is first started, the burner flame often quickly dies out. The explanation for this behavior of gas heating equipment is quite simple — it is difficult for the spent combustion products to climb up the cold chimney, and any gusts of wind only prevent the channel from heating.

To get out of this situation, it is enough to warm up the chimney at low operating modes of the boiler, gradually increasing the power of the device to optimal parameters, and the hot combustion products in the heated chimney will rush up naturally.

Main article: all about the ventilation of a gas boiler in a private house.

Conclusion

In conclusion, I would like to say a little about the fact that competent thermal calculations included in the project will allow you to create an efficient heating system in your home. Do not underestimate ventilation, on the design and quality of installation of which the subsequent operation of the heating boiler depends.

Do not save on exhaust and ventilation. The layout of the house should not interfere with the design equipment of the ventilation system. Otherwise, aesthetics will have to be paid for with discomfort — climbing onto the roof in the cold and re-equipping the chimney.