Complete instructions for selecting a heating boiler (for a private home, industrial buildings, greenhouses, drying chambers)

Properly choosing boilers for heating a private home is necessary for installing an autonomous system. It is heating equipment that will provide housing with heat and hot water. It will create the microclimate necessary for human habitation. In addition, it will work flawlessly. It is so?

We will tell you how to buy a boiler that will meet your requirements and wishes. We have analyzed all the criteria that you should pay attention to when looking through catalogs of online stores or an assortment of specialized retail outlets. Problems that you may encounter before and after purchase are listed.

CONTENT

Introduction1. Why a solid fuel boiler?2. How to choose the boiler power3. Is the boiler for heating only or for heating and hot water (DHW)?4. Dependence of power on fuel type5. Steel or cast iron6. Hot water or hot air
7. Features of choosing a boiler for industrial and non-residential premises
8. Features of choosing a boiler for greenhouses9. Selection of boiler power for drying chambers10. What parameters to pay attention to:10.1. Power 10.2. Efficiency 10.3. IN EU, dimensions10.4. Fuel (including size of firewood) 10.5. Warranty period and service life 10.6. Price 10.7. Equipment

Combination boilers

There is also such a modification of heating boilers as combined heating devices. The most popular option is a solid fuel boiler with several electric heating elements. Such units operate as TT equipment while the wood or coal is burning; when the fire goes out, the boiler cools down slightly, the electrical part turns on. In this case, heating elements are not able to fully heat the house, but they manage to support the system. That is, in the morning the house will not be cold. And in the event of a long absence, the heating elements will not allow the system to freeze.

Several combi boilers

Another popular option is TT combination boilers with liquid fuel burners. Such units have two separate combustion chambers. One for solid fuel, the second for a burner with liquid fuel.

The advantages of such boilers are obvious: you can use several types of fuel. The disadvantage is the high price and average efficiency - the efficiency of each part is not very high. So a combination boiler for heating a private house is a controversial decision.

Introduction

This instruction is written to help those people who are faced with the question of choosing a boiler for heating a room. has been producing and supplying heating boilers for 9 years, and during this time has accumulated considerable experience on this issue. Our boilers are installed in more than 10,000 premises throughout Russia and in the near abroad. In this manual, we will try to describe the process of selecting a boiler as clearly and completely as possible, while making it easy enough to understand. In addition to the issues of selecting a boiler for different premises - private houses, industrial buildings, greenhouses, drying chambers - we will consider additional issues that you should pay attention to when choosing a boiler. IMPORTANT! This instruction allows you to satisfy most requests for boiler selection. At the same time, there are situations when the production process (for example, for growing a certain type of plant, obtaining wood of a certain degree of moisture) requires a stable set temperature throughout the entire operation. In this case, the materials in this manual may not be enough. We strongly recommend that you contact specialized organizations for a full thermal calculation of your premises.

Liquid fuel

Heating boilers for private homes using liquid fuel are the least common. There are too many disadvantages to this type of heating:

• Fuel is expensive.
• It needs to be stored somewhere, and this is a large container that needs to be installed somewhere not very far from the house so that fuel can be supplied to the boiler.
• For normal heating operation, it is necessary to heat the storage tank, since at low temperatures heating oil thickens and clogs the burner.
• During operation, the burner makes noise and smells, so such equipment requires either a separate boiler room or an extension, but with good sound insulation and ventilation.

  
  Storage of liquid fuel requires a large tank

In general, it makes sense to install an oil-fuel boiler for heating a private home if you have a free (or almost) source of fuel. In all other options, it is better to use other heating equipment.

WHY SOLID FUEL BOILER?

All recommendations for selecting a boiler in this manual will primarily concern solid fuel boilers, i.e. boilers operating on wood, coal, peat, fuel briquettes, pellets. Why is that? Firstly, the selection technique itself is suitable for boilers using other types of fuel. Secondly, as practice shows, solid fuel boilers confidently occupy second place in terms of heating costs after mains gas (and in some cases even first). Thirdly, this is a classic type of heating for our country. Fourthly, it specializes in the production of solid fuel heating pyrolysis* (please read about this word in the link below) boilers and has extensive experience in their correct selection. Fifthly, and this is IMPORTANT! In conditions of periodic accidents on electrical networks, decreases in pressure in the gas line and gas quality, and constant growth in tariffs, solid fuel boilers are increasingly being installed as a backup source of heating in many rooms where there is already another source of heat. Therefore, we are sure that this instruction will be useful to a large circle of readers.

HOW TO SELECT BOILER POWER

By and large, power is the main parameter for choosing a boiler. It shows how much heat the boiler will produce, measured in kilowatts (kW). The fact is that any house, building, room has heat loss. Heat escapes through windows, doors, walls, roof, basement, ventilation. And the boiler’s task is to produce enough heat to compensate for these losses and maintain a comfortable temperature inside. *Pyrolysis boilers are solid fuel heating boilers, the design of which includes special elements that make it possible to obtain heat not only from the combustion of solid fuel (firewood, briquettes, peat, coal), but also due to the additional combustion of gases that are released . These gases are called “pyrolysis” gases. Hence the name of the boilers. In other words, such boilers can operate as conventional solid fuel boilers (also called “direct combustion boilers”), or in a more economical and efficient mode of burning pyrolysis gases.
There are a large number of options for calculating power. And, of course, the most correct thing would be to contact specialists to carry out thermal engineering calculations. But such a calculation costs money, and usually not little. Therefore, we will try to calculate the boiler power ourselves. The simplest and most common formula:

For every 10 m2 of room, 1 kW of heating power is required

Moreover, this calculation is correct for ceiling heights of up to 3 meters. Those. for a house, say, 150 sq.m. A boiler with a power of 15 kW is required. However, this formula is valid for new, residential, well-insulated premises. But what if the building has a different purpose? How to take into account the fact that in some regions the temperature can drop much lower than in others? In this case, you can use different formulas, sometimes so specific that only specialists with specialized education can figure it out. The experience of our company (to calculate the required power of solid fuel boilers) shows that in 95% of cases you can rely on the following formula:

W=(S*h*Δt*q)/0.86*1000, where W – boiler power, kW; S—room area, sq.m.; h – ceiling height, m; Δt—temperature difference inside and outside, degrees; q - correction factor is taken from the reference book depending on the type of building; 0.86 is the coefficient for converting calories to watts; 1000 is the conversion factor from watts to kilowatts. Let's assume that we need to heat a store in Vologda with an area of ​​250 sq.m. with a ceiling height of 3 meters. The store always requires a temperature of +20°C. 1) We calculate the volume of the room: V = 250*3=750 cubic meters. 2) We look in the directory (you can easily find it on the Internet by searching for “Climatic parameters of the cold period of the year”) for the lowest temperature in winter (there are several columns in the directory with similar names. You need the temperature of the coldest five-day period). For Vologda it is minus 42 degrees. If you want to have 20 degrees in the building, Δt=20+42=62 degrees. 3) Correction factor for stores with a volume of up to 5000 cubic meters = 0.38 kcal/m3*h*°C. Finding a good reference book is not easy. If you need it, send us a request by email [email protected] and we will send you the one we use ourselves.

4) Substitute the obtained values ​​into the formula:

W=750m3*62°C*0.38 kcal/m3*h*°C/0.86*1000=20.5 kW.

We get the required power of 20.5 kW. Below we will separately consider the nuances of selecting boilers for industrial premises, greenhouses and drying chambers.

How to choose the right type of gas boiler

When deciding which gas boiler is best to choose for heating a private home, you should not focus solely on price. There are other selection criteria, and no less important. And before you go to a company engaged in the supply and installation of heating equipment, you need to get at least a general idea of ​​what gas boilers are. This will help you avoid making mistakes that can cost you quite a lot.

Wall-mounted or floor-standing gas boiler

According to the installation method, all gas boilers are divided into wall-mounted and floor-mounted. The main difference between these two types is the dimensions. All other differences - power, a number of other technical parameters, cost - can be considered as a consequence of the first.

Wall-mounted models are compact and lightweight. As a rule, such devices are not even allocated a separate room, placing them in the kitchen or bathroom. Wall-mounted boilers have relatively low power, which is quite predictable given their modest dimensions. As a result, they do not allow heating a large area of ​​the house. The main advantage of wall-mounted gas boilers is their lower cost.

Wall-mounted gas boiler.

The weight of the average floor-standing boiler significantly exceeds 100 kg. Typically, such units are placed in a boiler room. Most floor-standing models have an open combustion chamber, which means that high-quality forced ventilation must be installed in the room, ensuring a constant flow of air.

On average, floor-standing gas boilers are much more powerful than wall-mounted ones: with their help you can heat a fairly large country house. Another advantage of floor heating systems is durability. This is primarily due to the use of more reliable materials for the manufacture of individual structural elements.

For example, in floor-standing units, as a rule, a cast iron heat exchanger is installed, and not a steel heat exchanger, as in wall-mounted models. Cast iron is known to be less susceptible to corrosion, which means it will last you longer. Of course, cast iron is much heavier than stainless steel, but for floor-standing boilers, unlike wall-mounted ones, heavy weight is not a problem.

Floor standing gas boiler.

Of course, a powerful and reliable floor-mounted unit will cost you more than a wall-mounted one. In addition, the set of floor-standing models often does not include an expansion tank and circulation pumps - these elements of the system will have to be purchased separately.

Single-circuit or double-circuit gas boiler

For comfortable living in a country house, it is necessary not only to heat the premises, but also to provide heating of water for domestic needs. Of course, in addition to a gas heating boiler, you can purchase a gas or electric boiler. However, there is a simpler solution - a double-circuit boiler. It has two heat exchangers connected to two mains: one circuit is responsible for heating, the other for hot water supply.

Note that the second heat exchanger is located far from the burner and is heated not by a flame, but by a coolant heated on the primary heat exchanger. The flow of coolant through the heating circuit is suspended during DHW operation. It follows from this that despite the presence of two circuits, work simultaneously in two directions, i.e. Such a boiler cannot provide hot water and heat the room.

This in turn means that while you take a shower or wash the dishes, your batteries slowly cool down. True, practice shows that in a small house where hot water is consumed in reasonable quantities, this is practically unnoticeable.

Providing the residents of a house with hot water through a double-circuit gas boiler can be done in two ways: using an instantaneous water heater or a built-in tank. The first option is suitable only for those who do not consume more than 10-15 liters of hot water at a time.

In the second option, you can count on large volumes. The capacity of the built-in tank is usually 30-60 liters: this is enough to take a quick shower without experiencing any discomfort.

Sectional view of a boiler with a built-in boiler.

If you have a large family and, accordingly, increased consumption of hot water, it is better to install a single-circuit boiler and connect to it a 100- or even 200-liter indirect heating boiler. The latter is a large thermally insulated metal tank, along the coil of which the coolant of the heating system moves.

During the summer, the circulation of coolant through the heating system is shut off so that only water for hot water is heated.

Boiler with indirect heating boiler.

Which gas boiler to choose—single-circuit or double-circuit—depends on the amount of hot water consumed by residents and on the area of ​​the premises that need to be heated. A double-circuit boiler is a good option for a modest-sized home: there is no need to install a separate heating device and a separate water heater for DHW, and this gives you the opportunity to significantly save space. If the house is large, there are several water points, and the family size is large enough, then preference should be given to a single-circuit boiler with a separate indirect heating storage boiler. You can also think about installing a double-circuit gas boiler and a storage boiler with parallel electric heating: such a system will allow you to have hot water even if any of the appliances fails.

Convection or condensation gas boiler

All gas boilers are divided into convection and condensation. How do they differ, and which one should you prefer?

The efficiency of a traditional convection boiler is ~90%. In principle, this is a good indicator, but a reasonable question arises: where does the remaining 10% go? The answer, alas, is simple: they fly down the drain. The gas combustion products leaving the system through the chimney are heated to 150-200°C (in some modern low-temperature models - up to 100°C), which means that the lost 10% of the energy is spent on heating the air outside the house.

A condensing boiler is capable of cooling the combustion gases to 50-60°C and thereby significantly increasing the amount of heat transferred to the coolant. But that's not all. At a temperature of 56-57°C, condensation of water vapor contained in the smoke occurs. This releases additional energy. The condensing gas boiler “takes” and transfers this heat to the coolant.

Construction of a condensing gas boiler

1. Chimney. 2. Expansion tank.

3. Heat transfer surfaces. 4. Modulating burner.

5. Burner fan. 6. Pump. 7. Control panel.

So, a condensing gas boiler is capable of “taking away” much more energy from the combustion gas than a convection model. In other words, its efficiency is significantly higher. Does this mean that you should forget about less economical convection boilers and initially decide to purchase a condensing boiler? Before making a final decision, it makes sense to talk about the disadvantages of such an ideal unit at first glance.

Water vapor, condensing into liquid, “takes” with it gases also contained in combustion products. First of all, we are talking about carbon dioxide, although this also applies to the oxides of sulfur, phosphorus, nitrogen and a number of other elements present in small quantities.

When interacting with water, these gases produce the corresponding acids - carbonic, sulfuric, phosphoric, nitric, etc. From this it follows that the condensate formed during the operation of the boiler and accumulating inside it is not pure water, but a rather aggressive liquid.

And here we are faced with two problems at once:

• Firstly , so that chemically active condensate does not corrode the boiler elements with which it comes into contact, they must be made of acid-resistant materials (for example, aluminum-silicon alloy or acid-resistant stainless steel). This also applies to the chimney, because some of the water vapor will still fly away with the smoke and condense there. The heat exchanger must be cast, since welds are one of the most vulnerable points. All this further increases the cost of the unit.
• Secondly , the question of disposal of accumulated condensate invariably arises. It is strongly not recommended to pour chemically active liquid down the drain, which means you will need to purchase a separate system for neutralizing acids and consumables for it.

There is another, more significant limitation on the use of condensing boilers. The operating efficiency of such heat generators is determined by the range of coolant temperatures at the inlet and outlet. The fact is that there is only one way to cool flue gases - to take heat from them and transfer it to water, which acts as a coolant.

1. If your home uses a high temperature heating system, i.e. heating of the premises is carried out using traditional radiators, then the ratio of the temperature of the water supplied to the system and the water in the return circuit should be 75-80°C to 50-60°C. It is highly doubtful that at such temperature ranges the boiler will be able to effectively cool the gases to the condensation temperature of water.

2. If the premises are heated using heated floors, i.e. If your house has a low-temperature heating system installed, then the ratio of coolant supply and return temperatures will be in the region of 50-55°C to 30-35°C. Under these conditions, the flue gases will cool enough for condensation to occur in the boiler.

From all of the above, we can draw a simple conclusion: a condensing boiler is effective only in combination with a low-temperature heating system. Otherwise, its efficiency will differ little from that of a traditional convection boiler, which means that the money spent on purchasing expensive equipment will be wasted.

Gas boilers with open or closed combustion chamber

We have already mentioned that the combustion chamber of a gas boiler can be open or closed. In the first case, the air necessary to maintain the gas combustion process enters the burner directly from the room where the boiler is located; in the second, it is forced by a fan through the air intake pipe or through the coaxial chimney pipe.

Condensing boilers, which we talked about just above, always have a closed combustion chamber.

Boilers with closed chambers are more efficient and their efficiency is higher. In addition, they are less sensitive to changes in gas pressure in the pipeline and continue to work effectively even at reduced pressure in the gas pipeline.

But such boilers are more expensive than models with an atmospheric burner, and they require electricity to operate the fan. However, the main disadvantage of gas boilers with a closed combustion chamber is, perhaps, the noise of their operation.

It is worth mentioning one more type of gas boilers - parapet. They have a closed combustion chamber, air is supplied through a coaxial pipe, but without the use of a blower fan. The power of such units is less, but at the same time they are energy independent and silent.

Those who are planning to install a heating gas boiler in their home should understand that to ensure its normal operation, it is necessary to ensure not only the removal of fuel combustion products, but also the flow of air, regardless of the type of combustion chamber used in it. The main product of gas combustion in a boiler that lacks air will not be relatively harmless carbon dioxide, but deadly carbon monoxide.

If we are talking about a model with an open chamber, installing one chimney will be enough, but the room must have high-quality forced ventilation. The latter, by the way, is the cause of significant heat loss in winter, and this should be taken into account when calculating the required boiler power.

For boilers with a closed combustion chamber, the air supply from outside is carried out through a pipe separate from the chimney. In principle, this can be one pipe, but a coaxial one, which is a “pipe-in-pipe” type structure: exhaust flue gases move through the internal cavity of the pipe, and incoming air moves through the outer cavity.

Coaxial chimney.

Since we're talking about pipes, it wouldn't hurt to say a few words about the rules for installing a chimney:

• Don't try to save money on pipes. For metal pipes used for chimney installation, resistance to condensation and burnout is important; plastic pipes must have sufficient heat resistance and reliable seals at the joints. Cheap pipes not intended for gas boilers are unlikely to meet these requirements, which means that in a couple of years you will have large-scale work to replace the chimney.
• The angle of inclination of the horizontal sections of the chimney depends on the type of gas boiler. For convection boilers, the slope should be made towards the street, for condensing boilers - towards the boiler itself.
• The maximum permissible length of a chimney made from a coaxial pipe is 5 meters, and each bend reduces this value. That is why the coaxial pipe, as a rule, is simply routed through the wall. There are no such restrictions for “single” pipes.
• The chimney pipe in a natural draft system must be at least 4 meters in height.

IS THE BOILER FOR HEATING ONLY OR FOR HEATING AND HOT WATER?

Practice shows that in approximately 30% of cases, users use the boiler not only for heating, but also for heating hot water in the water supply system. If you also heat water “at the tap” with a boiler, then you need to take into account the following points. Firstly, it does not matter how your boiler will transfer heat to the water - through the DHW circuit built into the boiler or through an indirect heating boiler. What kind of devices these are, you can always consult our managers using the contacts listed at the end of the instructions. Secondly, you need to understand that at the moment when water is heated for the water supply system, this heat is taken from the heating system. Therefore, a boiler must be selected with a power reserve specifically for heating water. In general, the formula is not that complicated. From experience, you just need to add about 25-30% of the power to the boiler power that you obtained using the formula from point 2. In most cases, this completely covers the need for additional power to heat hot water.

Why you shouldn’t choose a boiler with too much power reserve

With a lack of heating performance, everything is very clear: the heating system simply will not provide the desired temperature level even with continuous operation. However, as we have already mentioned, excess power can also become a serious problem, the consequences of which are:

• lower efficiency and increased fuel consumption, especially on one- and two-stage burners that are not able to smoothly modulate productivity;
• frequent clocking (on/off) of the boiler, which disrupts normal operation and reduces the burner life;
• simply a higher cost of the boiler unit, given that the performance for which the increased payment was made will not be used;
• often greater weight and larger dimensions.

When excessive heat output is still appropriate

The only reason to choose a version of the boiler that is much larger than needed, as we have already mentioned, is to use it in conjunction with a buffer tank. A buffer tank (also a heat accumulator) is a storage tank of a certain volume filled with coolant, the purpose of which is to accumulate excess thermal power and subsequently distribute it more rationally for the purpose of heating a house or providing hot water supply (DHW).

For example, a heat accumulator is an excellent solution if the performance of the DHW circuit is insufficient or when a solid fuel boiler cycles, when the fuel, when burned, releases maximum heat, and after burning out the system quickly cools down. Also, a heat accumulator is often used in conjunction with an electric boiler, which heats the tank during the period of a reduced night electricity tariff, and during the day the accumulated heat is distributed throughout the system, maintaining the desired temperature for a long time without the participation of the boiler.

InstructionsBoilers

DEPENDENCE OF POWER ON FUEL TYPE

Another important parameter that can affect the calculation of boiler power for your premises is the fuel with which you will heat the boiler. And this is a nuance in selecting power specifically for solid fuel boilers. Everyone has encountered a situation where some firewood cannot be lit, and some burn out like matches. The correct moisture content of the wood is necessary. Damp firewood and firewood with natural moisture do not burn well; during combustion, heat transfer is also lost due to internal moisture. Part of the boiler's power is simply used to evaporate moisture. According to various estimates, fresh firewood contains from 80 to 35-45% water. The optimal humidity for the firebox is about 20-25%. This drying out usually occurs during the summer. Today, the bulk of firewood sold is firewood with natural moisture. Chamber-dried firewood exists and is sold, but it is much more expensive. If you were unable to prepare, or you consciously make a choice in favor of “heating with anything,” then when selecting a boiler, you should put at least 20-30% of the power on top.

What happens if you buy a boiler of lower power?

When the owner made a mistake with the power on the smaller side, this is just as bad as an oversupply. The system is working at its limit. Service life is reduced. The house is not heated sufficiently; the system may freeze during abnormal frosts.

STEEL OR CAST IRON

Well, we figured out the boiler power. Now you can move on to the next selection points. Often future users choose for comparison such a parameter as the boiler firebox material. And here there are two options - steel or cast iron. At first glance, cast iron boilers seem more reliable and durable. This is partly true. And if these parameters come first in your values, then you should first take a closer look at cast iron boilers. Additional advantages include smaller dimensions with the same power as steel boilers. But it is necessary to take into account several nuances: 1) cast iron is a fairly fragile material, so it can be relatively easily damaged during transportation, impacts, temperature changes (when, for example, in emergency mode the boiler was extinguished not with sand, but with water); 2) cast iron is poorly repairable, and the proposal to replace individual elements of the firebox (they are also called “sections”) in practice turns out to be very labor-intensive, because During operation, these elements become overgrown with combustion products, “sinter” and become almost a single whole. Steel boilers do not have these disadvantages. 1) They, on the contrary, are easier to repair, and in case of emergency conditions (pah-pah, of course) “any person with a welding machine” can restore them. 2) Due to the plastic characteristics of steel, these boilers are impact-resistant. 3) The ratio of the volume of the loading chamber to the power of the boiler is greater for steel stakes, which means that you will have to approach the boiler less often to add fuel. 4) These boilers are more resistant to pressure increases in the boiler, because less sensitive to temperature changes. 5) Plus, steel boilers are often much cheaper than cast iron ones. And they weigh less, which will reduce both delivery and installation costs. You will be able to save about 15-20%. Well, durability is ensured by proper heat removal. Now manufacturers of steel boilers claim a service life of 10-15 years, which is quite enough. For cast iron boilers, this parameter is usually 25 years. The only thing worth paying attention to is the thickness and grade of steel from which steel boilers are made. , for example, manufactures its Bourgeois-K boilers from special corrosion-resistant heat-resistant steel grade 09g2s with a thickness of 5 mm. By the way, you can judge the thickness of the steel by the weight of the boiler. If two boilers of the same power have a weight difference of about 50 kg, guess where thicker metal is used and which boiler will last longer?

Types of heat exchangers

When choosing heating equipment, the material used plays an important role. The energy efficiency and reliability of the system depend on it.

The efficiency of a device with a copper heat exchanger is higher and the size is smaller, so this metal is used in wall-mounted models.

Cast iron is used for stationary floor-mounted installations of high power. The density of the material makes it unsuitable for use in compact boilers. Cast iron is durable.

The disadvantage of the material is the likelihood of condensation forming on the surface of the heat exchanger when the temperature drops to 60 °C. This can cause erosion of the metal and then lead to microcracks. Copper has no such drawback, so the operation of equipment made from this material does not depend on temperature changes.

Many models of gas boilers are equipped with steel heat exchangers. The material occupies an intermediate position between cast iron and copper. Metal is used in both floor-standing and wall-mounted devices. It is stronger than cast iron, but has lower thermal conductivity than copper. Steel appliances are susceptible to temperature changes, and the material is sensitive to corrosion due to condensation of water vapor.

If your budget allows, it is wise to opt for a model with a copper heat exchanger. However, the material is used mainly in wall-mounted appliances.

WATER HEATING OR AIR HEATING

Most heating boilers are hot water boilers that heat the coolant (water or special antifreeze for heating systems). And it, in turn, enters the premises through pipes to radiators (batteries), where it gives off heat. These are the most popular and familiar boiler models, so we will not dwell on them in detail. At the same time, there are also so-called air-heating boilers. Air passes through their surfaces around the outer walls of the firebox (either independently or pumped by fans). The air is heated and supplied directly to the room. Air-heating boilers are more convenient because there is no need to spend money on a heating system (pipes, radiators, boiler “piping” elements). There is no coolant in them, which means there is nothing to freeze if, for example, firewood was not added to the boiler in time. Such a boiler can easily be stopped when there are no people in the room (nights, weekends, holidays), without fear of defrosting the system and spending a lot of money on its restoration. True, there are several nuances. Firstly, such boilers are not suitable for residential premises. Perhaps these will be some kind of stoves for country houses where you are not constantly present. The fact is that they: a) dry the air; b) dust from your premises burns on them, and the substances obtained from this are not the most useful; c) in the case of boilers with fans (more efficient models), they also make noise. Secondly, by their design, these boilers heat the air in only one room. In order to heat the neighboring ones, this air must be transferred there, and this is already an air duct system. And even though it turns out to be cheaper than hot water heating, it is clearly inferior in appearance. Therefore, air-heating boilers are mainly used in large industrial premises, greenhouses, garages, workshops, car washes, drying chambers, etc. If this is your option, then take a closer look at air-heating boilers, they may turn out to be very suitable.

Selection based on combustion chamber

Boilers can be open or closed. The first uses air directly from the room. In this case, it is necessary to install a chimney. Boilers with an open or atmospheric combustion chamber are mainly installed in separate rooms. Similar types of gas boilers are used in floor-standing installations with a power of more than 35 kW.

In a closed combustion chamber, a coaxial chimney is used to supply air and remove flue gases. This device consists of two pipes of different diameters, the first is inserted into the second. Air is supplied to the burner through one channel, and the combustion product is discharged through the other. The closed type is used mainly in wall-mounted units.

FEATURES OF CHOOSING A BOILER FOR INDUSTRIAL AND NON-RESIDENTIAL PREMISES

In general, the formula specified in paragraph 2 is suitable for selecting boiler power for industrial premises. Here it is: W=(S*h*Δt*q)/0.86*1000, where W is the boiler power, kW;
S—room area, sq.m.; h – ceiling height, m; Δt—temperature difference inside and outside, degrees; q - correction factor is taken from the reference book depending on the type of building; 0.86 is the coefficient for converting calories to watts; 1000 is the conversion factor from watts to kilowatts. A detailed description of how to use it is given in paragraph 2. THE TABLE WITH THE Q COEFFICIENT (SPECIFIC THERMAL CHARACTERISTIC) WILL BE TO HELP YOU:

It should be borne in mind that this formula is designed for new buildings in which a standard number of windows (new), doors, the building was originally intended for a certain type of activity and the corresponding production processes. Practice shows that often buildings are already “aged”, have poor insulation in some places, cracks in window frames and doors, and the roof. It happens that buildings have stood for an impressive period of time without heating, when the heat-saving properties of materials deteriorate significantly, etc. If this is your case, then the result that you obtained from the formula should be multiplied by a number of coefficients. 1) Building age factor. If your building is up to 10 years old, then the coefficient is 1. If it is from 10 to 30 years old – 1.3. If the building is older than 30 years, feel free to multiply the calculated capacity by 1.5. 2) Building insulation coefficient. If the building is well insulated, there are no gaps in the windows, doors, gates, coefficient = 1. If at least one of the surfaces (walls, ceiling, floor) or elements (windows, doors, gates) are poorly insulated, take coefficient = 1.3. If two or more elements leave much to be desired, your coefficient = 1.5. Thus, for an old building with poor insulation, the required boiler power may be 1.5 * 1.5 = 2.25 times greater.

Specifications

Depending on the type of equipment, a different set of parameters is taken into account when selecting a model.

Wall-mounted devices are a ready-made heating system that is easy to install. They are economical, but sensitive to voltage changes in the electrical network. When installing a boiler in a private house, it is wise to install a good voltage stabilizer and an uninterruptible power supply.

When selecting a model for a wall-mounted unit, the most important technical characteristics are:

• installation power – selected based on the area of ​​the room;
• efficiency - fuel consumption depends on the parameter; for most wall-mounted models this indicator changes slightly;
• noise - important when installing equipment in a residential area;
• heat exchanger material - most models are equipped with a copper or steel coil, some use aluminum, which is cheaper, but has lower thermal conductivity and corrosion resistance;
• the presence of additional functions - different devices are equipped with their own list of capabilities;
• the material from which the internal parts of the boiler are made - plastic is used in cheap models, brass is used in expensive boilers.

Floor heating devices are difficult to install. Incorrect installation may cause service problems. However, this technique is insensitive to voltage surges, durable, and reliable.

For floor structure equipment, it is worth considering the following characteristics:

• power - it is recommended to take a boiler with a reserve, since in the cold season the indicator decreases;
• heat exchanger material - in stationary models steel or cast iron is used;
• Dimensions – floor units may differ in height and width;
• energy dependence - complex expensive devices are equipped with automation powered by electricity; simple devices do not require a network connection;
• Efficiency - the spread of this parameter for floor-standing installations varies over a wide range.

FEATURES OF CHOOSING A BOILER FOR GREENHOUSES

To calculate the boiler power for heating a greenhouse, you need to know the heat loss of your greenhouse.
The heat loss itself can be calculated using the following formula: Heat loss = Surface area * K * Temperature difference (°C)

, where:
Surface area (sq.m) - the entire external surface of the greenhouse (roof, walls).
IMPORTANT! For greenhouses, unlike other objects, they take not the area of ​​land that is located under the greenhouse, but the area of ​​all EXTERNAL SURFACES. Temperature difference (degrees) – the maximum temperature difference between the temperature outside and inside the greenhouse. You know the temperature needed to grow certain plants, and the minimum outside temperature can be easily found on the Internet (you need the temperature of the coldest five-day period for your region) K (Watt/sq.m*deg) - the thermal conductivity coefficient of the material. For materials used in the construction of greenhouses, the thermal conductivity coefficient has the following values: Single-chamber cellular polycarbonate 4mm - 3.9 / 6mm - 3.6 / 8mm - 3.3 / 10mm - 3.0 Double-chamber cellular polycarbonate 16mm - 2.3 Glass 3mm - 6.0 Single-chamber double-glazed window 4mm - 1.9 Polyethylene film 1 80 -200 mkm — 7.5 Two-layer inflated polyethylene film 180-200 mkm — 3.5

Separately, I would like to write a little about such a material as polycarbonate. The structure of polycarbonate sheets provides significant advantages where thermal insulation is important. The hollow form provides higher thermal insulation properties with lower heat losses than solid glazing materials. Heat loss is characterized by the thermal conductivity coefficient - this is the amount of heat passing through 1 m2 of glazed area material in 1 hour when the temperature changes by 1°C. The insulating properties of polycarbonate sheets will also help reduce the penetration of cold into the building. The lower the thermal conductivity coefficient, the higher the temperature is maintained on the inner surface of the sheet in winter. Below is an example of the temperature process through a 6 mm thick polycarbonate sheet, at an outside temperature of -10°C and an indoor air temperature of +20°C. If compared with single glass, the inner surface of the glass under the same conditions will have a temperature much below zero, which will affect the overall temperature in the room and will create discomfort near the windows.

Reviews of household mounted models: advantages and disadvantages

Let's look at the specific advantages of wall-mounted boilers. They also have disadvantages, but I don’t consider them that significant. Why? You will learn about this a little later, but for now look at this table:

I compiled all these pros and cons from owner reviews. Separately, I would like to say that the wall mounts are volatile, this is not so bad. Firstly, now electricity is practically never turned off even in villages. Secondly, even if they turn it off for a couple of hours, the house will not cool down completely. And it depends more on the insulation of the room, and not on the boiler. Thirdly, if you are very afraid of a power outage, you can buy uninterruptible power supplies or generators. By the way, in terms of electricity consumption, this is a maximum of 80-100 kW/month.

Current requirements for installing a gas boiler in a private home

SELECTION OF BOILER POWER FOR DRYING CHAMBERS

When selecting boiler power for drying chambers, they are based either on the volume of the drying chamber, or on the volume of raw materials that are to be dried. To select power, you can focus on the following ratios: 1) “Raw materials usually occupy about 20% of the total volume of the drying chamber” 2) “For drying 1 cubic meter. raw materials, about 5 kW of thermal energy is required.” Thus, for a drying chamber, for example, with a volume of 50 cubic meters. meters we need a boiler with a capacity of W=50 cubic meters*20%*5 kW/cub.m = 50 kW. This formula is simplified, although it allows you to quite accurately select the required boiler power. At the same time, if there are strict requirements for the production process, it is necessary to confirm the calculations with the help of a specialized organization.

How to calculate power taking into account heat loss?

What is heat loss? Let’s say it’s -20 degrees outside, but the average temperature at home is +20 degrees. These quantities are balanced through the exchange of energy. Heat losses occur. The amount of heat loss under severe weather conditions helps to calculate the boiler power with high accuracy.

Step 1

Heat loss is determined by the formula: Q = Q roof + Q walls + Q floor + Q doors + Q windows .

Where the extreme value of Q is the heat loss of each surface of the house.

Each Q value is calculated using the formula: Q = S * T / R

Where Q is heat loss in W, S is the area of ​​a specific surface in m², T is the difference between street and room temperatures in degrees, R is reference data on thermal resistance by type of material.

Step 2

This formula additionally includes involuntary heat loss through cracks, ventilation, exhaust hoods, opening doors and ventilation through windows. For independent calculations without a program, an additional 5% of the total leakage figure is added.

Step 3

Next we move on to determining the boiler power. There are only two formulas to choose from:

Rkot. = ( S room * P beat ) / 10 , where Rkot. — boiler power, Sroom. - the total area of ​​rooms in the house where heating is planned, Pud. — specific power according to climate conditions.

Rkot. = ( Q losses * S from area ) / 100, where Rkot. - boiler power, Qloss - heat loss, Sot. area – total area of ​​heated rooms.

Step 4

For an electric and gas boiler, you can use the table to check:

WHAT OTHER PARAMETERS TO PAY ATTENTION TO?

In general, above we have described quite fully how to choose a heating boiler for you. In this section we will tell you what else you should pay attention to when choosing a boiler.

10.1. Power

Manufacturers often label their boiler models using numbers in the names to indicate the boiler's power. For example, our boiler has a power of 24 kW. But there are also manufacturers who put increased numbers in their models. For example, the model name contains the number 30, and the technical specifications indicate the boiler power of 25 kW. Be carefull.

10.2. Efficiency (coefficient of efficiency)

This indicator lets us understand what percentage of benefit we can get from fuel. The higher this coefficient, the less you will “drown the street” in the future. What you should pay attention to is that manufacturers often indicate maximum efficiency in the technical specifications. In practice, the following results: by reducing the boiler power (when raw wood is used or there is simply no need to heat the boiler to full capacity), in some boiler models (usually these are ordinary direct combustion boilers), the efficiency decreases sharply. In other boiler models (for example, pyrolysis), the efficiency is constantly high.

10.3. Weight, dimensions

These characteristics are worth paying attention to in two cases. First, they directly affect the cost and convenience of delivery and transportation. In particular, be sure to pay attention to the dimensions if your building has already been built and you are limited in the area for installing the boiler. In addition, the dimensions of the boiler are important in order to provide for its transportation through doorways in advance. It would seem that in this case, you need to choose a lighter and smaller boiler. But it is not always the case. A “golden mean” is needed, because The weight of the boiler is often proportional to the thickness of the steel from which it is made, which means reliability and durability. Plus, the dimensions affect the amount of fuel you will put in. But more on that later.

10.4. Fuel

We wrote in paragraph 4 how the quality of fuel affects the required power. Here I would like to note that for users who will heat the boiler with wood, an important parameter is the size of the firewood that can be placed in the firebox. Standard firewood has a size of 48-52 cm. So, a good indicator for the boiler would be the ability to lay firewood from 50 cm or more. In this case, you will save a lot of time and effort.

10.5. Warranty period and service life

Two more indicators that are worth paying attention to. Boilers with a 1-year warranty should alert you. Well, the service life for such a serious purchase as a boiler should be at least 10 years.

10.6. Price

Everything seems to be simple here. Whatever budget we have allocated, we will buy such a boiler. The only thing you should always take into account is that in addition to the boiler, you will need to purchase a chimney, piping elements, and materials for the heating system. Plus, investments will be required to install the boiler and heating system. Typically, these costs are several times higher than the cost of the boiler. And one more thing... a good practice when choosing a boiler is the following: look not at the price of the boiler, but at the difference in price of the selected boilers, and what benefits the manufacturer offers you for this difference. Sometimes it happens that the difference in price is 5,000 rubles, but for this money you won’t have to go to the boiler every night to add firewood. And this is over 10 years of boiler service. Are you ready to pay 5,000 rubles for 10 years of good nights?

10.7. Equipment

The boiler is fully equipped if it is supplied with: grates, measuring instruments, automation devices, chimney adapter, gaskets, fasteners, technical data sheet, warranty card. In other words, the boiler should be sold in such a way that you don’t have to buy anything for it except the chimney and elements of the heating system. Some suppliers sin by reducing the cost of the boiler to attract a buyer, but will charge money for additional equipment, as a result of which the total cost may be more expensive. Pay attention to this.

Leaders of sells

Wall-mounted gas boiler Baxi LUNA 3 310 Fi

The wall-mounted double-circuit turbocharged unit can easily be classified as a new generation of gas boilers.
He is able to create truly comfortable conditions in the house, becoming the main participant in heating and hot water systems. The classic type of fuel in this model is combined with innovative “gadgets”: ionization flame control, self-diagnosis and “memorizing” error functions, protection against freezing and pump blocking, LCD display. The Baksi gas boiler is capable of operating in two temperature control ranges (30-85, 30-45 degrees), can use not only natural but also liquefied gas as fuel, and is perfectly adapted to the harsh Russian climate. Characteristics:
Installation method – wall;

Availability of DHW – dual-circuit; Fuel type – natural gas; Width – 450 mm; Height – 763 mm; Weight – 41 kg; Power – 31 kW; Combustion chamber type – closed; Chimney diameter – 80; The maximum service area is 310 m2.

Floor-standing gas boiler Navien GA 23KN

This model of floor-standing boiler from Navien becomes a competent solution for heating a private house, cottage or cottage. The main condition for this is that the area of ​​the house should not exceed 230 m2. By default, the device uses main gas as fuel, but it can also operate on liquefied gas (in this case, a set of jets is required). The device perfectly combines such qualities as simple and convenient functionality, a multi-stage protection system and the ability to withstand voltage surges in the electrical network. Also among the advantages of the Navien gas boiler, buyers include the compactness and lightness of the unit, simple and quick installation, and the model being equipped with a remote control panel with a liquid crystal screen. The double-circuit design allows the boiler to be used effectively for heating water. But one of its main advantages is its low price.

Characteristics:

Installation method – floor; Availability of DHW – dual-circuit; Fuel type – main gas; Width – 382 mm; Height – 856 mm; Weight – 74 kg; Power – 23 kW; Combustion chamber type – open; Chimney diameter – 75 mm; The maximum service area is 230 m2.

Wall-mounted gas boiler ARISTON MATIS 24 FF

Compactness, laconic design and a very affordable price - perhaps it is precisely this combination of characteristics that has brought this Ariston gas boiler model to the top of sales.
The Italian manufacturer has successfully equipped the heating device with all the basic functions, framing the “filling” in high-quality materials - as a result, the boiler is able to be the main source of heat in a house (up to 240 m2) for many years. The copper heat exchanger of the device can withstand regular temperature changes typical of the southern regions of our country and conducts heat well. Therefore, it is not surprising that the efficiency of the Ariston gas boiler is record high - 94.5%. In sharp contrast to this indicator is the price of the device, which only slightly exceeds 30 thousand rubles. Characteristics:
Installation method – wall; Availability of DHW – dual-circuit; Fuel type – natural gas; Width – 400 mm; Height – 770 mm; Weight – 30 kg; Power – 24 kW; Combustion chamber type – closed; Chimney diameter – 60/100; The maximum service area is 240 m2.

If, when choosing a home heating device, you decide to buy a gas boiler, Valles.ru is ready to make you a really advantageous offer! Our online store offers a wide range of instruments of the highest quality at the most affordable prices. Products from the best global and domestic brands meet the most stringent quality criteria. And the prices for gas boilers in the Valles online store correspond to the wishes of even the most economical buyers. Browse through our online catalog, choose the optimal model and make sure it’s profitable with us!

You can place your order online or by calling +7. Delivery is available in the Krasnodar Territory and other regions of Russia.

Why contact a specialist?

We found out that buying a boiler from the square is wrong. It is important to consider the heat loss of the building. For example, a house of 300 m² can be heated by a 15 kW boiler if all surfaces are thoroughly insulated. And a house of 150 m² may require 30 kW equipment with thin walls and uninsulated roof and ventilation.

There are hundreds of standards and regulations on this topic, there are dozens of formulas. Sometimes one thing contradicts the other, or standards change and it is difficult for a non-professional to understand whether these requirements are relevant. You can calculate all this armed with a stack of reference books. Or contact specialists who will make accurate calculations in the program and explain all the details. They will help you save money, time, and model an efficient home heating system.

Comparative table of boilers for a house 200-240 m2