Rating of double-circuit gas boilers

Due to the fact that a large number of new, modified models of domestic and foreign production, having different characteristics and price levels, have appeared in the assortment of heating appliances offered to consumers, nowadays it is possible to replace the old boiler with a more economical, compact and aesthetic one without any problems. Many owners decide to “kill two birds with one stone” with such an acquisition, that is, at the same time solve the issue of autonomous supply of hot water. And now it is not difficult - they are offered a wide selection of double-circuit boilers.

However, such a high saturation of the market often contributes to the “reverse effect”, that is, it makes choosing the optimal model a very difficult task. We will try to help in this - we will give a list of devices that are steadily included in the constantly changing rating of double-circuit, wall-mounted and floor-mounted gas boilers. True, a reservation can be made: the authors deliberately did not begin to award certain places to the listed boilers - simply so as not to interfere with the subjective factor in this issue. The determining criterion was the positive feedback from consumers who have already tried this technique in practice. In a word, the models of boilers indicated in the publication can be purchased with close to 100% confidence in obtaining a device of high build quality and with the expectation of long-term operation.

Of course, when choosing any heating boiler, it is necessary to pay attention to other criteria that affect quality and durability.

The main criteria for choosing a heater

Unit type by location.

Double-circuit boilers are divided into floor and wall.

floor standing double-circuit gas boilers, as a rule, are designed for a higher thermal output than wall-mounted models, so they are most often installed in houses with a large area. However, for such heaters with a power of 30 kW or more, a room separate from the residential area is required. Therefore, before choosing such a model, it is necessary to study not only the technical characteristics and operating rules, but also the standards for boiler room equipment.

On sale you can find models of floor-standing gas boilers that do not require power supply - it is only important that natural or liquefied gas is supplied. Such unit options are especially suitable for heating in homes located in rural areas, where power outages are not uncommon. The design of non-volatile boilers is quite simple, but very reliable, such units are more durable than boilers with complex automation.

The efficiency of modern floor models is 90 percent or more.

wall d double-circuit gas heaters, as a rule, are compact in size, so it is convenient to install them in small houses or even in a city apartment.

Since such a unit does not take up much space, it is usually placed on the wall of the kitchen, where all the communications necessary to connect it are located. For the operation of almost all models of wall-mounted heating devices, an uninterrupted power supply is necessary. Both the circulation pump and the automation unit require power, and, in models with a closed-type combustion chamber, fans for supplying air and removing combustion products.

Naturally, the installation of a gas boiler in the residential area of the house increases the requirements for organizing a more efficient ventilation system.

Unlike floor-standing boilers, which are often equipped with steel or cast-iron heat exchangers, wall-mounted appliances, in order to reduce their weight, are often equipped with copper heat exchange elements.

The power of wall-mounted units usually varies from 9 to 30 kW.

Power of double-circuit boilers

In order for the heating and water heating device to be really effective in operation, it is necessary to correctly calculate its power for a particular house or apartment.

Very often on the Internet you can meet this sign:

To be honest, such information, instead of a clear presentation, can cause the consumer, on the contrary, a lot of questions. Agree that the difference in price between 9 kW and 20 kW models will be very significant, and the scatter of options for such a “coordinate system” is impressive.

In addition, this approach does not take into account the peculiarities of the regional climate, the building itself and its individual premises, the degree of glazing (that is, the number and size of windows) and many other important circumstances. Therefore, it seems more reasonable to carry out more thorough calculations, in which the calculation calculator below can help.

The basic principle is that the calculations are carried out for each heated room separately, and then the results are summed up. This, by the way, gives the owners one more "preference" - having such calculation results on hand (and it is best to issue them with a sign - for each room separately) it will be much easier and correctly to arrange heat exchange devices in the premises - radiators or convectors.

Calculator for calculating the required heat output for space heating

The calculation is carried out for each room separately.
Sequentially enter the requested values or mark the required options in the proposed lists.
Click "Make a calculation of thermal power"

ROOM PARAMETERS

Room area, m²

100 watts per sq. m

Number of external walls:

External walls look at:

The position of the outer wall relative to the winter "wind rose"

The level of negative air temperatures in the region in the coldest week of the year

What is the degree of insulation of the outer walls?

Average degree of insulation External walls are fully insulated

Ceiling height in the room

Up to 2.7 m 2.8 ÷ 3.0 m 3.1 ÷ 3.5 m 3.6 ÷ 4.0 m over 4.1 m

What's on the bottom?

Cold floor on the ground or above an unheated room Insulated floor on the ground or above an unheated room Heated room is located below

What is on top?

Cold attic or unheated and uninsulated room Insulated attic or other room Heated room

Type of installed windows

Ordinary wooden frames with double glazing Windows with single (2 panes) double glazing Windows with double (3 panes) double glazing or argon filling

Number of windows in the room

Window height, m

Window width, m

Doors facing the street or balcony:

It should be noted that the value obtained already includes the required operating power margin, there is no need to exceed it.

Experts in this regard even advise purchasing a boiler with indicators slightly lower than the calculated power. The fact is that the boiler will show its maximum “ability” for a very limited time, literally one or two weeks, at the peak of winter cold. The rest of the time, the equipment operates only with partial use of its potential, which, by the way, negatively affects both the efficiency and the durability of operation. This is especially true for devices assembled according to the old scheme - with a single-stage burner. Each stop of the boiler when the required temperature in the heating circuit is reached is accompanied by cooling of the combustion products removal system - and this is the appearance of condensate on the walls of the chimneys, and the need for absolutely unnecessary energy costs for heating these channels after the next start of the boiler.

To some extent, this problem is less pronounced in boilers with stepped power control - either all burners, or only a certain part of them, are involved in the work. Well, the most economical in this regard will be the operation of a modern unit equipped with a burner flame modulation system. With a high-quality setting, it works almost continuously, but very economically consuming gas and creating the necessary comfortable temperature in the premises. True, the primary costs for such equipment, especially if you overestimate the power, are always significantly higher.

Boiler power indicators for operation in DHW mode

All of the above would be completely true if the calculation was carried out for a conventional boiler. But in our case we are talking about a two-circuit, and this makes its own significant adjustments.

The fact is that all double-circuit boilers are designed for the priority of hot water supply. This suggests that when using hot water, the operation of the device switches exclusively to its heating. But here the power indicators are already completely different, since very significant energy costs are required to ensure a rapid increase in the required temperature in the flow circuit.

Each of the plumbing fixtures installed in residential buildings (apartments) is characterized by its own consumption of hot water. Approximate values are shown in the table below.

Draw-off point type	Average consumption of hot water
	- liters per second	- liters per minute
Kitchen sink	0.14	8.4
Wash basin	0.07	4.2
Shower	0.12	7.2
Bath	0.2	12
Bidet	0.07	4.2
Dishwasher	0.15	9

In the passport data of flow heaters, this indicator is usually indicated - the nominal flow rate of water heated by the device.

However, there is still a dependence on the inlet water temperature (and in winter it can be only 5÷8 ºС), and what is required at the inlet. For the adoption of water hygienic procedures, 40÷45 ºС is usually sufficient, for a kitchen sink - up to 50÷55 ºС.

Knowing the “hardware content” of your home plumbing system, it is easy to estimate how much hot water consumption may be required. And using the calculator below, you can bring this to the indicators of the thermal power of the heater.

Calculator for calculating thermal power for instantaneous water heating

Specify the requested values and click "CALCULATE THE POWER FOR INSTANT HEATING OF WATER"

Type of appliances connected to the DHW (indicate only those that are likely to be used simultaneously)

WATER TEMPERATURES

Required outlet water temperature, degrees

Supply water temperature, degrees

Pay attention to the following nuance. There is probably no point in carrying out a summary calculation for all points of water consumption - the likelihood of their simultaneous operation is low, especially if the appropriate “discipline” among family members is established with this issue. Otherwise, generally “cosmic” power values are obtained, which will significantly exceed the need for this parameter for heating needs. So it would be more correct to assess the situation taking into account only the most "energy-intensive" device for consuming hot water.

When choosing a specific double-circuit boiler, the priority in terms of power will again be for DHW. We will have to look for a "golden mean" in order not to overestimate the total capacity, but at the same time - to ensure the need for hot water, in an economical mode of spending it. And in this regard, again, models with the ability to modulate the flame of burners will have an advantage.

Another acceptable way out is to use not a flowing, but a storage principle of hot water supply: installing an indirect heating boiler. The excess power of the boiler (and, as we have seen, it is almost always present) should be more than enough to maintain a certain volume of constantly heated water. By the way, some modern models of boilers already have a built-in boiler of one capacity or another.

Features of the water heating circuit

Another criterion to consider when choosing a double-circuit boiler is the method of heating and supplying water. It has already been mentioned that hot water has priority over heating, but water can be heated in one, the so-called bithermal heat exchanger, or two are used in the circuit - the main one for heating, and the secondary one for heating domestic water.

The bithermal heat exchanger has separate channels for the circulation of the coolant and heated water, according to the principle (pipe in pipe). Its main advantage is that devices of this type are more compact. Their cost is also somewhat lower, since in any case the price of one, even a complex heat exchanger, is less than two separate ones.

There are many disadvantages of such a scheme, and the main one is that such heat exchangers are most susceptible to scale overgrowth and rapid failure. Moreover, in such a situation, both the heating system and the hot water supply become inoperative.

More advanced is the scheme with two heat exchangers.

In such devices, when the hot water tap is turned on, the automation is triggered by the ceiling sensor and switches the circulation of the coolant from the heating circuit to the "small circle" - through the secondary heat exchanger, in which it gives up its thermal potential to the flow of cold water.

It is clear that the boiler itself turns out to be more overall, but the absence of disadvantages inherent in bitermal models compensates for this, and such models are considered more modern and reliable.

Boilers equipped with a primary condensing heat exchanger are considered the most advanced. The fact is that in conventional devices, heated air vapors, which are always present in the air, simply fly out into the chimney, carrying away a certain energy potential. In condensing boilers, a special scheme for their cooling (condensation) is provided with the selection of additional thermal energy. The efficiency of such devices, and hence the overall efficiency in terms of gas consumption, is much higher.

Open (atmospheric) and closed combustion chambers

According to the principle of supplying the air necessary for combustion of gas and the removal of combustion products, boilers are divided into two groups.

Appliances with an open combustion chamber receive a tedious volume of air directly from the room, and gases are removed into a vertical chimney of the required height, due to natural draft.

The advantages of such a scheme include the absence of additional devices (fans, special pneumatic sensors, etc.), noiselessness, a simplified general scheme, and therefore its lesser vulnerability, lower price of boilers.

The disadvantages are the need to install a properly designed chimney (sometimes it is simply impossible), special requirements for air supply ventilation equipment. The construction of the chimney itself is a costly task, and the relatively low price of the boiler is still not justified.

In devices with a closed combustion chamber, both the supply of the required volume of air and the removal of gaseous products of combustion are carried out forcibly, using a built-in fan. This allows you to avoid the installation of a bulky "classic" chimney - you can get by with installing a small coaxial chimney, through separate channels of which counter flows are organized.

The advantages are obvious - such a boiler can be installed almost anywhere by bringing a coaxial chimney through an external wall. This fully justifies the higher cost of such devices. There is no need to provide additional ventilation of the room.

However, there are also many disadvantages. The temperature difference in the channels of a coaxial chimney is always the formation of a considerable amount of condensate, which in extreme cold can even freeze, reducing or even completely blocking the normal exhaust gas. The saturation of such devices with additional automation is, whatever one may say, a decrease in overall reliability. Another disadvantage is the complete dependence on the stability of the supply of electricity. In addition, some users may be annoyed by the noise of the fans running.

Heating boiler output adjustment

The type of heating power regulation is also one of the factors that you need to pay attention to when choosing a heating device. This has already been briefly mentioned above.

Boilers differ in this parameter in the following way:

Single-stage burners have one mode of operation, that is, they cannot be adjusted. In short, they either work or they don't. Starting and stopping the burner is carried out automatically when the minimum and maximum heating temperatures of the coolant are reached.
Two-stage models have two modes of operation, that is, they can operate at full power or at half it, i.e. by 50÷60%. Moreover, the automation itself regulates the desired power level as needed. This type of device is quite economical, as gas consumption is reduced, and the temperature regime, maintained automatically, is more accurate.

The modular version of the burners is the most modern, economical, but at the same time the most expensive type of device. Adjustment of gas flow, intensity of combustion, height of flames is carried out using automation, that is, the power that is needed at a particular point in time is selected, and it can vary from 10 to 100%. The advantages of this design of the device is that it provides significant fuel savings and reduces the number of on and off cycles, which extends the life of the unit. Ideally, the boiler should not fade at all - combustion of optimal intensity is always maintained.

Burner ignition type

A double-circuit boiler can have a different type of ignition - this criterion is also worth paying attention to when purchasing a device:

Electronic ignition does not require constant monitoring, as it works automatically - this option is convenient if the boiler is installed in a separate room. However, this option is volatile, as it runs on electricity and if it turns off, then the device does not function. True, a system is provided for automatic restart when power is restored.
In boilers with piezo ignition, the situation is different. The user manually, by pressing a button, ignites the igniter, which then burns constantly. When water is turned on in the hot water supply or when the automation of the heating system is triggered, gas begins to flow from the burner, which lights up from the igniter. The ignition torch, by the way, is a kind of indicator of the normal state of the entire boiler. So, for example, with a lack of traction, it fades, and thereby shuts off the general gas supply. And this suggests that, perhaps, the unit needs to be cleaned.

However, there are still devices that are similar in principle to models with piezo ignition, but where the torch of the igniter is ignited and “in the old fashioned way” - from a match.

Heat exchanger material

The efficiency and duration of operation of the boiler directly depend on what material the heat exchanger is made of. Therefore, when choosing a double-circuit heater, this factor is also worth paying attention to.

The cast-iron heat exchanger has a high resource of thermal strength and corrosion resistance, therefore it can last 30÷50 years. However, due to the large weight, material heat exchangers are installed only in floor models of boilers. Such a heat exchanger is afraid of sudden temperature changes and mechanical shocks.
A steel heat exchanger weighs much less than a cast iron one, and appliances with it are cheaper. But steel, unlike cast iron, is already susceptible to corrosion, the life of an element made of this material is much shorter. True, many modern grades of stainless steel make heat exchangers practically invulnerable to the negative effects of the coolant listed above.
The copper heat exchanger is lighter than all the others, therefore it is ideal for installation in wall-mounted boilers. The heat exchanger made of this material does not corrode, has excellent thermal conductivity, and a sufficiently long service life.

Fuel consumption

Another important criterion for choosing a double-circuit boiler can be fuel consumption. This parameter depends on several factors that have already been mentioned above - this is the power of the unit, its efficiency, type of adjustment, equipment with automation and others.

Knowing the passport gas flow rate of the boiler allows you to predict in advance the approximate costs of operating the heating system. Usually this parameter is also indicated in the accompanying technical documentation of the product.

Trustworthy models of double-circuit gas boilers

A large number of domestic and foreign companies represent their products on the heating market, so the range allows you to choose the option that is ideal for heating a particular house. To navigate the models of these products and their manufacturers, it is worth considering the most popular of them.

Russian manufacturers

The products of domestic manufacturers are no less, and sometimes even more popular than foreign ones, since such boilers are always developed taking into account Russian climatic conditions, the quality of network gas and possible voltage drops in the power supply system.

It can be noted that Russian products sometimes differ from those of foreign companies in a less aesthetic appearance, but on the other hand, in terms of reliability, they not only are not inferior, but sometimes even surpass foreign counterparts.

Boiler AKGV Zhukovsky

This heater has been produced for more than 30 years by the machine-building plant in the city of Zhukovsky, Moscow Region. The plant produces single-circuit and double-circuit units. To date, the company's product range includes more than 15 models of boilers of different capacities, which are designed for installation in non-volatile autonomous heating and water supply systems with natural and forced circulation.

Heat-resistant steel heat exchangers with turbulators, slotted atmospheric burners of the German companies HONEYWELL or SIT are used in the devices of this manufacturer, which significantly increased the environmental parameters of the boilers and increased their efficiency up to 88%. The DHW circuit of the boiler is made of copper. All products of this manufacturer are certified by the State Standard of Russia, and also passed the sanitary and epidemiological examination.

The main technical characteristics of the boilers "Zhukovsky" AKGV of the "Comfort" line are shown in the table:

Name of parameters	Double-circuit models and their technical characteristics
	AKGV-11.6	AKGV-17.4	AKGV-23.2	AKGV-29
Burner power, kW	11,6	17,4	23,2	29
Heated area, m²	up to 100	up to 140	up to 200	up to 250
Gas pressure, nom / min / max, Pa	1274 / 635 / 1764
Natural gas consumption, m³/h	1,3	1,87	2,55	3,18
Efficiency for heating / hot water supply, %, not less	86/75	86/75	88/75	88/75
Water consumption in hot water supply at t=35 °C, l/min	3,34	5,4	7,1	8,9
External diameter of the gas outlet, mm	117	135	140	140
Overall dimensions, HxWxD, mm	850×310×412	1050×420×480	1050×420×480	1050×420×480
Machine net/gross weight, kg	30 / 35	49 / 57	52 / 60	55 / 63

Double-circuit boilers "Conord"

Zavod CONORD LLC is Russia's largest manufacturer of building heating equipment. The enterprise already in 1979 became a recognized leader in the production of these products and still does not give up its positions, remaining at the peak of popularity among Russian consumers.

The range of this manufacturer includes products such as instantaneous water heaters, pellet boilers and burners, AOGV and, of course, gas, solid fuel and universal heating boilers.

Over the years of the company's work, the boilers "CONORD" and "DON" have been improved many times, and today this equipment has European quality, and at the same time is ideally adapted to Russian operating conditions. The plant manufactures single-circuit and double-circuit heating devices, with a unique design of heat exchangers, which perfectly copes with any operating conditions, which is guaranteed to provide heat to the residential building.

The plant's products have gone through ISO 9001-2011 international certification. They have repeatedly been awarded the title of Laureate of the All-Russian competition "100 Best Goods of Russia", and deserved other prestigious awards.

Double-circuit gas boilers "CONORD", equipped with automatic "SIT", have the following characteristics:

Boiler name	power, kWt	For a house up to, m²	Efficiency, % not less		Average gas consumption, m³/hour	Weight, kg	Dimensions, mm
KSts-GV-8S	8	80	90	3.3	1.15	34	428×304×925
KSts-GV-10S	10	100	90	3.3	1.2	37.8	428×304×925
KSts-GV-12S	12	120	90	3.3	1.35	39.5	414×304×925
KSts-GV-16S	16	160	90	5	0.95	53.7	494×368×925
KSts-GV-20S	20	200	90	6	1.2	54.7	494×368×925
KSts-GV-25S	25	250	90	6.7	1.4	67.7	581×454×925
KSts-GV-30S	30	300	90	8.3	1.8	67.7	581×454/×925

A similar model of CONORD gas boilers, but having thermo-hydraulic automation in its design:

Boiler name	power, kWt	For a house up to, m²	Efficiency, % not less	Water consumption in hot water supply (Δt=35ºС), l/min	Average gas consumption, m³/hour	Weight, kg	Dimensions, mm
KSts-GV-8S	8	80	90	3.3	1.15	34	428×304×925
KSts-GV-10S	10	100	90	3.3	1.2	37.8	428×304×925
KSts-GV-12S	12	120	90	3.3	1.35	39.5	414×304×925
KSts-GV-16S	16	160	90	5	0.95	53.7	494×368×925
KSts-GV-20S	20	200	90	6	1.2	54.7	494×368×925
KSts-GV-25S	25	250	90	6.7	1.4	67.7	581×454×925
KSts-GV-30S	30	300	90	8.3	1.8	67.7	581×454/×925

In the tables, the letter marking means: "K" - boiler; "C" - heat-resistant steel heat exchanger; "Ch" - cast iron heat exchanger; "G" - gas boiler; "B" - the presence of a hot water circuit; "c" - the body of the heat exchanger and the furnace have a cyclonic shape.

OJSC "Borinskoe"

OJSC Borinskoe has been producing gas boilers since 1992. At first, the company produced devices with low power. Subsequently, ISHMA devices were developed, which became popular throughout Russia, as they are excellent for various regional conditions. The products of this manufacturer have been awarded with many diplomas, including the nomination for “100 Best Goods of Russia”.

Today, this manufacturer manufactures 30 models of heating devices with a capacity of 7 ÷ 100 kW - these are single-circuit and double-circuit, as well as floor and wall-mounted boilers, which are convenient for installation in autonomous systems of private houses and apartments. Users who have already experienced the operation of these devices note such qualities as ease of use and economy. All heating units of this manufacturer are equipped with automatic shutdown systems in emergency situations, for example, too high coolant temperature, gas shutdown or insufficient draft.

In addition, heating units are non-volatile, which is very important for their use in areas with an unreliable power system.

The main line of heating devices of this manufacturer can be safely called boilers of the ISMA series, in a wide range of capacities

In all boilers of OJSC Borinskoye, a piezoelectric element is used for ignition, steel heat exchangers for heating systems and copper - in some models for hot water supply. The efficiency of the boilers reaches 87%. These are general characteristics for all dual-circuit devices, and individual ones are presented in the table.

Boiler name	power, kWt	For a house up to, m²	Water consumption in hot water supply (Δt=45ºС), l/min	type of instalation	Weight, kg	Dimensions, mm
"ISHMA 12.5 BSK"	12.5	120	3.5	wall	47	700×530×225
"AKGV 11.6 (M) Eurosit"	11.6	110	2.5	floor	55	978×403×463
"AKGV 17.4 (M) Eurosit"	17.4	140	4	floor	60	1050×403×463
"AKGV 17.4 Eurosit", copper DHW circuit	17.4	140	4	floor	60	994×403×463
"AKGV 23.2 (M) Eurosit"	23.2	190	4	floor	65	1050×403×463
"AKGV 23.2 Eurosit" copper DHW circuit	23.2	200	4	floor	65	995×403×463
"AKGV 29 Minisit (M)" copper DHW circuit	29	Up to 250	6	floor	70	1050×403×463

JSCNEVA LUX

One of the most famous Russian manufacturers of wall-mounted gas boilers is Neva Lux OJSC. The Neva company, founded in 1996, was already engaged in the manufacture of gas heating boilers and economy class columns. In 2004, the company was renamed "Neva Lux". Today, Neva Lux gas water heaters and heating boilers are manufactured at one of the largest Russian enterprises - the Armavir Gas Equipment Plant.

Double-circuit wall-mounted boilers of this manufacturer have the following characteristics:

Name of parameters	Double-circuit models and their technical characteristics of NEVA LUX boilers
	8230	8624	7224	7218
power, kWt	30	24	24	18
Number of heat exchangers	2	2	1 (bithermic)	1 (bithermic)
Nominal gas flow, m³/h	3.43	2,65	2.62	2.62
Efficiency at 100% / 30% power, %, not less	92,5 / 90,7	92 / 90	92,5 / 90,7	92,5 / 90,7
Heated area, m2	up to 300	up to 240	up to 240	Up to 180
	14	14	14	14
Overall dimensions, mm	720×410×326	720×410×326	720×410×326	720×410×326
Net weight, kg,	35	28	34	34

The following factors can be attributed to the general characteristics of these wall-mounted double-circuit boilers:

- operating temperature range 30÷85 degrees;

- in models with two heat exchangers, an economical copper heat exchanger is installed for the heating circuit, which is adapted to chemical flushing;

– devices can operate on natural and liquefied gas;

— the combustion chamber is equipped with water cooling;

- The warranty period for the products is two years.

Foreign manufacturers

Now consider the products of several well-known foreign companies. Basically, these are European firms, but you can also find products from Asian countries. So, the most popular are the products of Italian manufacturers Ferroli, Ariston and Beretta, German companies - Bosch, Vaillant and Viessmann.

These manufacturers have an impeccable reputation, but still it is better to choose models made specifically for Russian operating conditions. Therefore, when purchasing foreign products, it is best to ask the seller if the unit is adapted for installation in Russian heating systems.

Vaillant Company (Germany)

The Vaillant company was founded in 1874, and during this long period of work it has managed to gain popularity and trust of consumers and experts. It should be noted that 27% of heating devices manufactured in Europe fall on this company.

The company produces several model lines of wall-mounted and floor-standing boilers of various capacities. The devices are compact in size and always have an aesthetic appearance.

Double-circuit boilers "Vaillant", designed for heating and hot water supply, have two heat exchangers, one of which, primary, is made of copper, secondary - of stainless steel.

The boilers are designed to run on natural gas, but if necessary, they can be converted to liquefied gas, for their reconstruction a set of jets is required. The devices are volatile, as they require the control board to be connected to the power supply. At the same time, it is recommended to install a voltage stabilizer as well, it will help protect the device from power surges.

Voltage stabilizer - a guarantee of uninterrupted efficient operation of boiler equipment

Many modern boilers are equipped with innovative control and management systems that require a stable power supply. how to decide on its basic parameters - all this is in a separate publication of our portal.

These boilers can be equipped with an open combustion chamber and are called atmospheric, since combustion products are removed by creating natural draft through a vertical chimney (atmoTEC range). Other models with similar parameters have a closed combustion chamber and a forced air supply system for combustion (turboTECK).

Table of parameters of wall-mounted models of gas heating double-circuit boilers "Vaillant":

Boiler name	Power (max.), kW	For a house up to, m²	Efficiency, % not less	Water consumption in hot water supply (Δt=25ºС), l/min	Average gas consumption, m³/hour	Weight, kg	Dimensions, mm
"turboTEC pro VUW 242-5-3"	24	up to 240	91	11	2.9	46	800×440×346
"turboTEC plus VUW 202/5-5"	20	200	91	9.6	2.4	35	800×440×346
"turboTEC plus VUW 242/5-5"	24	240	91	11	2.9	36	800×440×346
"turboTEC plus VUW 282/5-5"	28	280	91	11	3.5	37	800×440×338
"turboTEC plus VUW 322/5-5"	32	320	91	14	3.7	38	800×440×338
"turboTEC plus VUW 362/5-5"	36	360	91	17.2	4.4	38	800×440×338
atmoTEC Pro VUW 240/5-3 H	24	240	93	11	2.9	34	800×440×338
atmoTEC Plus VUW 200/5-5	20	200	91	9.6	2.4	39	800×440×346
atmoTEC Plus VUW 240/5-5	24	280	91	11	2.9	41	800×440×346

Bosch Company (Germany)

Bosch was founded in 1913. For more than a century of work, its products, and of completely different directions, have earned the widest popularity and are practically the quality standard for many newly formed companies around the world.

Heating devices are considered one of the main directions of this manufacturer. Several lines of models have been developed and are being produced, differing in design parameters, which allows you to choose the appropriate option for a particular region and operating conditions. All products presented on the Russian market are adapted to the technical parameters of supply and fuel quality.

The table shows the characteristics of wall-mounted models of heating double-circuit boilers "Bosch":

Boiler name	Power (max.), kW	For a house up to, m²	Efficiency, % not less	Average gas consumption, m³/hour	Weight, kg	Dimensions, mm
WBN 6000-35 C RN S5700	35	350	92	3.9	39	700×400×299
WBN 6000-12 C RN S5700	12	120	93.2	2.1	32	700×400×299
WBN 6000-18 C RN S5700	18	180	93.2	2.1	32	700×400×299
WBN 6000-18 N RN S5700	18	180	93.2	2.1	32	700×400×299
WBN 6000-24 C RN S5700,	24	240	93.2	2.8	34	700×400×299
WBN 6000-35 H RN S5700	35	350	93	3.9	39	700×400×300
ZWC 24-3MFK	24	240	93	2.8	42.9	825×400×370
ZSC 24-3MFK	24	240	93	2.8	43	825×400×370
ZSC 24-3 MFA	24	240	93	2.8	42.9	825×400×370
ZWC 24-3 MFA	24	240	93	2.8	43	825×400×370
ZWC 28-3MFK	28.1	275	90	3.2	45	825×400×370
ZWC 28-3 MFA	31.1	280	93	3.2	43	825×440×370
ZSC 35-3 MFA	36.5	330	93	2.9	47	825×480×370
ZWC 35-3 MFA	33.4	330	93	4	47	825×480×370
ZWA 24-2 A	24	240	92	2.72	39.9	750×400×355
ZWA 24-2K	22	220	92	2.52	36	750×400×355

Gas wall-mounted double-circuit boilers of the Bosch GAZ 6000 WBN and Bosch GAZ 7000 ZWC line are characterized by the following features:

- All devices are adapted to work at low gas supply pressure;

- Equipped with separate heat exchangers, which is a clear advantage for installation in regions with hard water. The primary is made of copper, the secondary is made of stainless steel;

— Boilers have a convenient, intuitive control panel with an LCD display.

- equipping with a fan for forced air intake and removal of combustion products;

— All WBN 6000 models are equipped with a closed combustion chamber. Boilers of the ZSC line are available in two versions - MFK means open chamber, MFA - closed.

- Bosch ZWA models - with an open or closed combustion chamber (K or A, respectively), have one bithermal heat exchanger of a unique configuration that eliminates the active formation of scale in the hot water supply channels. They have a built-in three-stage circulation pump with blocking protection; built-in expansion tank with automatic air vent; well thought out system of self-diagnosis.

All Bosch heaters are volatile and, if necessary, can be converted to use liquefied gas as a fuel, using a set of jets.

Kiturami Company (South Korea)

The South Korean company "My Kiturami" does not have a "rich history" behind it, but even in this short period of its work it has become a well-deserved leader in the production and sales of equipment for heating systems. The popularity of this manufacturer is explained by the fact that its products are highly reliable and have minimal operating costs.

Such successes have been achieved thanks to a well-thought-out personnel policy, involvement of leading specialists, and carrying out our own scientific and experimental research in the field of heat engineering and electronics. In Russia, the products of this manufacturer are in high demand.

There are several model ranges of Kiturami double-circuit heating boilers, perfectly adapted for use in Russian conditions:

Table of wall models of heating double-circuit units "Kiturami":

Boiler name	Power (max.), kW	For a house up to, m²	Water consumption in hot water supply (Δt=35ºС), l/min	Efficiency, % not less	Weight, kg	Dimensions, mm
"World Plus-13R"	15	150	6.6	92.5	33	721×430×250
"World Plus-16R"	16	160	10	91.6	34	721×465×278
World Plus-20R	20	200	11	92.5	34	721×465×278
World Plus-25R	29.1	180	16	93.2	39	788×507×310
World Plus-30R	34.9	350	20	92	37	788×507×310
"Twin Alpha-13"	15.1	130	5.4	91.2	26	730×430×210
"Twin Alpha-16"	18.6	160	10.7	91.4	26	730×430×210
"Twin Alpha-20"	23.3	240	13	91.8	26	730×430×210
"Twin Alpha-25"	29	280	10.4	91.6	29	730×486×210
"Twin Alpha-30"	34.8	320	20	92.3	29	730×486×210
"Twin Alpha-13 Coaxial NEW (15.1 kW)"	15.1	121	5	91.4	26	730×430×210
"Twin Alpha-16 Coaxial NEW (18.6 kW)"	18.6	146	6	93.1	26	730×430×210
"Twin Alpha-20 Coaxial NEW (23.3 kW)"	23.3	186	8	92.3	28	730×430×210
«Twin Alpha-25 Coaxial NEW (29 kW)»	29	233	10	91.8	29	730×486×210
"Twin Alpha-30 Coaxial NEW (34.8 kW)"	34.8	279	12	92.3	29	730×486×210

Each of the model ranges of heating units differs in design features or materials for the manufacture of some elements:

- "Kiturami World PLUS" - this boiler is equipped with two separate heat exchangers made of copper. The device is equipped with a fan for forced removal of combustion products and air intake, as well as separate chimneys.

- "Kiturami Twin Alpha" and "Kiturami Twin Alpha Coaxial NEW" - two separate heat exchangers made of stainless steel are installed in these heating devices.

All Kiturami models are volatile, they are also recommended to be connected through a voltage stabilizer in order to protect the boiler automation from voltage surges.

ARISTON Company (Italy)

The ARISTON company was founded in the 30s of the last century, and its founders immediately chose a name that fully justified itself. The fact is that "ARISTON" in Greek means "the best", and indeed, this trade brand is one of the most popular in the Russian and, of course, the European market.

The gas appliances of this company are designed to operate on natural gas, but when changing the burner, they can also be used for liquefied gas. It is the double-circuit wall-mounted boiler that is very popular, because of its compact size and the efficiency of the unit.

Table of characteristics of wall-mounted models of heating double-circuit units "ARISTON":

Boiler name	Power (max.), kW	For a house up to, m²	Efficiency, % not less	Water consumption in hot water supply (Δt=35ºС), l/min	Average gas consumption, m³/hour	Weight, kg	Dimensions, mm
Ariston Genus Premium Evo 24	24.4	240	108.1	14.2	2.33	35	770×400×315
Ariston Genus Premium Evo 30	31.1	300	108.1	15.8	2.96	35	770×400×385
Ariston Genus Premium Evo 35	34.5	350	108	18.6	2.41	36	770×400×385
Ariston Genus Premium Evo System 24	24.4	240	108	14.2	2.33	35	770×400×315
Ariston Genus Premium Evo System 30	33.3	300	108	15.8	2.8	35	770×400×385
Ariston Genus Premium Evo System 35	34.5	350	108	18.6	3.28	36	770×400×385
Ariston Clas Premium Evo 24	24.4	240	107.7	14.5	2.33	32	770×400×315
Ariston Clas Premium Evo 30	31.1	300	107.7	16.8	2.96	35	770×400×385

All models listed in the table have a closed combustion chamber, that is, these boilers are called turbocharged. The boilers are equipped with fans that remove combustion products while simultaneously supplying air to the combustion chamber. For appliances with this design, coaxial chimneys are usually used.

The heating unit has two separate heat exchangers - primary made of copper, secondary made of stainless steel. The EVO series appliances use additional heat extraction due to the condensation of water vapor. Please note that the manufacturer claims efficiency - above 100%!

All models of these series are volatile and require additional connection through a stabilizer. This is necessary for the correct operation of the precise weather-dependent automation installed on all models.

It should be noted that this table shows a small part of the two-circuit models produced by ARISTON. In addition to them, in Russian specialized stores or on the Internet you can find many other options with different characteristics. Therefore, it is not difficult to choose the right model for all parameters.

Another well-known foreign brand that is in high demand among Russian consumers is the products of the South Korean company NAVIEN. We bring to the attention of readers a short video about one of the models.

Video: a brief presentation of the double-circuit boiler "Navien Deluxe Coaxial"

So, if you are going to purchase high-quality heating equipment, you should first of all study the technical characteristics of models that can be classified as rating ones. Products of an unknown manufacturer, information about which is not freely available, or it is very scarce and contradictory, should be “swept aside” immediately. If you plan to buy a foreign-made model, then you need to opt for a boiler, the control and management system of which is maximally adapted to local conditions. Only in this case, you can count on the durability of the installed equipment. will be true.

At the end of the publication, it is appropriate to place a video in which a specialist will share advice on choosing a heating boiler.

Video: useful recommendations for choosing a gas heating boiler

Author Nikolai Strelkovskiy, editor-in-chief