Capacitive water heaters of indirect heating. What is an indirect heating boiler. Proper connection of an indirect heating boiler

Increasingly, in heating systems, indirect heating boilers or the so-called "Tank in a tank" are used as an alternative to double-circuit boilers. When it is necessary to supply a large amount of water, at several points of draw-off "Tank in tank" become indispensable helpers. The stainless steel boiler is suitable for country houses, office and industrial buildings.
"Tank in a tank" are becoming more and more popular in the heating market. Working with heat generated by any other energy sources is the main advantage, since water is not heated directly from electrical energy, solid fuel or gas. Boilers with indirect heating do not overload the power grid, do not need a chimney.
Working principle "Tank in a tank"
The indirectly heated stainless steel boiler is manufactured according to the tank-in-tank principle. It works on the basis of two tanks. The first container is internal, filled with heated sanitary water, the second container - the outer one contains a coolant - it is he who heats the sanitary water. Thus, "Tank in tank" eliminates a large number of disadvantages inherent in conventional water heaters with a coil.

The main advantages of the indirect heating boiler:
1. More hot water taps are provided due to the increased heat transfer area. Also, a short heating time for newly supplied cold water.
2. Water heaters made according to the tank-in-tank scheme have a smaller volume than was required when using a conventional water heater to ensure a given performance.
3.Sanitary requirements are met by the numerous advantages of stainless steel.
4.The use of reliable thermal insulation and self-cleaning effect of descaling results in saving energy consumption
5. Possibility of regulation of heating of sanitary water, due to the built-in thermostat.
6. Long service life

In rooms without a center of a lysed hot water supply system, tank-in-tank boilers are an indispensable assistant.
Boilers can be divided into indirect and direct heating boiler.

The advantages of indirect boilers (for example, boiler, WESTER or) use the heat converted by heating boilers and are intended for economical hot water supply of apartments, office and industrial buildings, cottages.

Gas water heaters use a direct heating circuit. The advantage of this type of boiler is stability and sometimes independence from electricity and other factors.
The advantages of indirect boilers (for example, the acv smart boiler) are the speed of heating and the possibility of using it for several points of water consumption. During a water shutdown, the indirect agent ensures its continuous supply. The volume of the tank can reach 1000 liters. Enormous energy savings!

You can buy indirect heating boilers in the section.

The life of a modern person who is accustomed to comfortable conditions is hard to imagine without hot water. Unfortunately, the work of the central water supply leaves much to be desired. Hot water is supplied intermittently, and some houses are not connected to central heating at all. In such cases, a good solution is to connect an indirect heating boiler.

What is an indirect heating boiler?

Separately, we note indirect heating boilers from the European brand STOUT. These boilers are universal, sold with capacities from 75 to 200 liters - suitable for an apartment or house of almost any size. Each stage of the production process of the STOUT boiler meets the European ISO standards, at all stages the product is checked for tightness.

The brand closely monitors the product, audits every 50th boiler. Absolutely everything is checked, from the quality of packaging to testing of operating modes. Thanks to this, the STOUT indirect heating boiler is reliable, easy to operate and will serve for many years.

For details, go to stout.ru.

How does an indirect heating boiler work?

The inside of the boiler is usually steel or plastic, and the water heating tank itself is made of heat-insulating material. Inside the tank there is a heat exchanger made of brass or steel, through which the coolant from the heating boiler passes. It is usually made in the form of a coil to ensure the fastest and most efficient heating of the tank. To protect against corrosion, a magnesium anode is used to protect the tank from pressure increase, a thermostat and a safety valve are installed inside the boiler. The outer body of the tank is usually made in the manufacturer's design style. Today, other models of indirectly heated boilers can be found on the market - tank-in-tank water heaters or boilers with several heat exchangers. But they are extremely rare to find on sale.

An indirect heating boiler is connected to the water supply system through an inlet for cold and an outlet for hot water.

Cold water fills the heating tank, and at the outlet hot water goes to the consumer. Each indirect heating boiler is connected to a pipeline through which the coolant enters the boiler for the next heating. On such a pipeline, a pumping and mixing system is required, which is responsible for the circulation of water.

Pros and cons of the scheme of work

The main advantages of the indirect heating boiler:

• the operation of such a water heater does not overload the electrical wiring during the heating season, since the boiler depends on central heating and does not consume electricity;
• when properly designed, the boiler has a very high performance and an optimal cost ratio;
• inner surface of the heater and coolant does not interact with running water, which ensures a safe and long service life of the unit;
• hot water is recirculated immediately after opening the faucet;
• an indirect heating boiler can always be switched to an alternative heat source or several can be used.

Unfortunately, each scheme of work, in addition to positive, has negative aspects:

• to re-equip the system, you will need additional expenses;
• the cost of a boiler with indirect heating is much higher than gas or electric heaters;
• initial heating of water (volume more than 100 liters) lasts 1 to 2 hours, this can adversely affect the quality of the heating system of the room;
• for a boiler with a volume of 100 liters or more need a separate room due to the impressive size of the device.

What to look for when choosing an indirect heating boiler?

The most important characteristic of a boiler is its volume.. You need to roughly estimate how much water is needed for a comfortable existence for your family. Based on averages, a person spends 5-15 liters per day on personal hygiene, 15-25 liters per day on washing dishes, 50-100 liters per day on showering, and 150-200 liters per day on bathing.

It is believed that for one resident it is necessary 80-100 liters of hot water Of course, this calculation is conditional, it all depends on the preferences and habits of the residents. For example, someone likes to take a shower twice a day, another manages to take a bath once a week. The larger the volume of the boiler, the higher its cost.

The next thing you need to pay attention to when buying is interior material water heater.

Preference should be given to boilers with a brass coil. It will heat water more efficiently than steel, and besides, it is much easier to clean the brass coil.
The water heating tank must be protected against corrosion. In cheaper models, the tanks are covered with a layer of enamel or glass-ceramic. Expensive instruments are protected from corrosion by stainless steel.
In addition, do not forget about the thermal insulation of the unit, high-quality boilers are insulated with mineral wool or polyurethane foam. Models with foam insulation are best avoided.

The boiler can be connected to the hydraulic and electrical system. The connection scheme on two pumps or hydraulic is considered the most effective.

One pump is used for residential heating, the second is for indirect heating the boiler itself. The electrical connection diagram assumes a mode switching system - a relay.

In a two-pump boiler connection scheme, the coolant flows move in different directions due to the operation of the circulation pumps. The hot water line (boiler and heating boiler) is connected in parallel to the pumps, the operating mode of the pumps is controlled by the heater's temperature sensor. A non-return valve is installed in the circuit after each pump so that the pumps work autonomously, independently of each other. In the presented scheme, the heating circuit is turned off, but this practically does not affect the rate of water heating in the batteries.

Typical connection errors

The first mistake that is most often encountered is the wrong place to install an indirect heating boiler. Need to install it as close as possible to the boiler or to the outlet of the central water supply.

The next error is an incorrect connection of the cold water supply. Serial connection of the inlet and outlet of the coolant ensures efficient operation of the water heater. For optimum heating and heating results the coolant must enter the boiler from above and exit from below.

Incorrect connection of the circulation pump entails many negative consequences:

• motor axis should be placed horizontally this will help to avoid early bearing wear;
• the pump must be protected from debris, you need to constantly monitor the condition of the mesh filters.

The modern market of heating systems offers a wide selection of boilers and other water heaters, so everyone can find a model with the best price-quality ratio. For advice, you can always contact the service center, where you will definitely be assisted in the design, installation and maintenance of heating appliances.

Article plan

If you live in a private house, then installing an indirect heating boiler together with a boiler will kill two birds with one stone - heat the house and provide constant access to hot water. We have selected for you the best models of water heaters that can be found on sale today - choose!

Briefly about the main characteristics

In conventional storage water heaters, the liquid temperature rises due to the operation of heating elements, while in boilers, heating is carried out due to the circulation of a heated coolant in the system. It looks something like this: water is heated in a single- or double-circuit boiler and fed through pipes to a coil or other heat exchanger installed in the tank; at the same time, cold water enters the tank from the main, which is subsequently heated due to heat exchange through the walls of the coil. Instead of a coil, a tank-in-tank design can be provided. In this case, the coolant is supplied to the external tank, and the heated liquid is supplied to the internal one. The presence of temperature and liquid volume sensors inside the tank, as well as automatic relays, ensure the smooth operation of the equipment. Some models are also equipped with additional electric heaters - even with force majeure with a boiler, you can use hot water. Everything seems to be simple, but before buying it is necessary to understand the main technical characteristics of such equipment.

We omitted such a parameter as the thread diameter for connecting to pipes, because. this issue, if necessary, is solved by installing adapters.

Calculation of the volume of water

Only you can determine exactly the required volume, because. calculations are tied to the conditions of water consumption. Our task is to provide information that will somehow help in the choice or suggest thoughts when making the calculation. For example, we open SNiP 2.04.01-85 and see that the norms set 7.9-10.9 liters of hot water (HW) per hour per person. Following some simple calculations, we get the following table.

These calculations can be taken into account only if the water heated by the boiler is used consistently and one draw-off point is operating at the same time (only one tap is open). In practice, the given values ​​\u200b\u200bmust be multiplied by 3-5. Why is this happening? Because the norms do not take into account the desire to bask in the shower (+20 l. HW) and take a bath (+80 l. HW), wash a mountain of dishes (+20 l. HW), etc. etc. Take into account the peak loads on the boiler - choose the volume that is most suitable for your needs.

• 50-60 liters is enough for 1 person;
• for 2-3 people you need to choose from models of 80-120 liters;
• for a family of 3-5 people, the capacity of a boiler of 120-200 liters is enough

To make it easier for you to choose the right model of equipment, we have identified four product groups depending on the volume of the storage tank: up to 100, 200, 300 and 400 liters. All technical specifications are taken from open sources, and prices are provided for comparison purposes only.

Important! Please note that some water heaters are only suitable for certain models of boilers. In the description, we will focus on this, but we recommend that you clarify all the nuances before buying.

Up to 100 liters

1. Baxi Combi 80 (80 liters) - from 52,500 rubles.

A notorious Italian player specializing in heating and water heating equipment, Baxi has been holding the quality mark for decades. The Baxi Combi 80 small volume boiler model is designed to work in conjunction with the LUNA-3 Comfort series boilers of the same manufacturer. Placement is floor, the water heater can be installed directly under the boiler, saving space. One of the advantages of this system is its compact dimensions. Corrosion protection is provided by the use of stainless steel and a magnesium anode. Polyurethane foam is used as thermal insulation. TENA connection is not provided.

2. Gorenje GBK80ORRNB6 (72.6 liters) - from 24,000 rubles.

When looking for a small model that can provide hot water for one or two people, pay attention to Slovenian equipment. This is a classic compact boiler with two tubular heat exchangers, the performance of which is enough for two points of water intake at once. The device is equipped with an electronic control unit and allows you to change the DHW temperature in the range of 15-75 °C. It has outlets for connecting to the boiler on the right side, two dry heating elements are installed as an additional heater. The model is equipped with several types of protection: against corrosion (magnesium anode), against freezing (effective thermal insulation), against overheating and heating without water. The manufacturer also provides a function to control legionellosis (a lung disease whose pathogens actively multiply in hot water). One of the best combined solutions in terms of price / quality ratio.

* operating parameters in flow mode are not specified by the manufacturer. The power of the heat exchanger itself is not indicated - only for the heating element.

3. Protherm FS B100S (95 liters) - from 36200 rubles.

The Czech boiler is structurally tied to the boilers of the same manufacturer - the Bear. Compact, with a concise but informative control panel, it easily fits into the kitchen interior as built-in appliances. Enamelled stainless steel, magnesium anode and antibacterial coating - all aimed at protection against corrosion and microorganisms. The tubular heat exchanger provides a high rate of heating of the entire volume of liquid: water is heated by 50 degrees in 13 minutes. To keep warm, the product is protected by a polyurethane foam coat.

4. ACV COMFORT 100 (100 liters) - from 48,000 rubles.

A Belgian manufacturer with almost a century of history offers an interesting solution based on a tank-in-tank heat exchanger - model. The boiler consists of two stainless steel containers of different volumes, one of which is inserted into the other. Particular attention should be paid to the internal container: its surface is corrugated, therefore, due to thermal expansion, a change in size takes place, followed by the removal of the formed plaque of hardness salts (scale). The equipment is installed on the floor by default, but with the help of additional fixings it is possible to mount it on the wall. The heat-insulating layer is made of polyurethane foam 30 mm thick. The set of standard functions is small, but an optional control panel can be installed. It is also worth considering the lack of the possibility of recycling and connecting the heating element.

Up to 200 liters

5. Baxi Premier plus 150 (150 liters) - from 50,600 rubles.

It is possible to ensure the full operation of two DHW draw-off points using. In a series of these heaters, a tubular coil-in-coil heat exchanger is used. Due to its low weight, the device can be hung on a wall or placed on the floor. The parts of the structure that come into contact with water are made of DUPLEX stainless steel, the minimization of heat losses is achieved by the use of polyurethane foam. The model is equipped with a thermostat and can be used in conjunction with any type of boilers. Optionally, it is possible to connect a tubular electric heater. The manufacturer has provided for the connection of the recirculation circuit. According to reviews, this is one of the best solutions in terms of price and quality for a family of four.

6. BOSCH WSTB 160 (160 liters) - from 28,000 rubles.

If a gas boiler is installed in your house, then you should think about buying a water heater. Although there is no possibility of connecting a heating element here, there is a recirculation system. The model is adapted to the harsh conditions of use in the CIS, i.e. suitable for hard water. To protect steel from corrosion, the material is coated with a special composition of glass-ceramic. There is a recirculation line so you can always count on getting water at a constant temperature. To minimize heat losses, a fur coat of 50 mm polyurethane foam is provided, the lining is made of PVC, soft. Frontal connection, it is possible to connect a temperature sensor. The entire volume is heated to ΔT=45°C in 37 minutes.

7. Protherm FE 200 BM (184 liters) - from 41650 rubles.

Many manufacturers offer storage heaters that are only suitable for their boiler models. If you installed a Proterm boiler, then to meet the needs of a large family in hot water supply, you should think about installing it. This is an indirect floor standing boiler made of stainless steel, enameled for corrosion protection. The installed titanium anode serves the same purpose. To prevent bacteria from multiplying on the walls of the container, they are covered with a layer of antibacterial substance. Productivity is high - with a delta of 25 degrees, you can get more than 30 liters of water per minute. Without the possibility of connecting the recirculation line and heating element.

8. Gorenje GV 200 (188.9 liters) - from 25,800 rubles.

Floor water heater of indirect type Combustion GV 200 - simplicity of the device, reliability of a design and laconic design. The product is an enameled steel tank with a tubular heat exchanger inside. Installed on the floor under the boiler. An overpressure relief valve is used as protection against overheating. The device is protected from corrosion by enamel and magnesium anode. It takes up to 24 minutes to heat the entire volume of water in the tank from 15 to 75 degrees. A 40 mm thick thermal insulation layer is responsible for maintaining the temperature of the hot water supply.

* the possibility of working in flow mode is not announced by the manufacturer

Up to 300 liters

9. ACV COMFORT 240 (240 l.) - from 65,000 rubles.

Another representative of indirect water heaters that use a tank-in-tank heat exchanger. The model is able to provide hot water to three points of water intake. The product is protected from corrosion due to the use of stainless steel and a special approach to the formation of the walls of the inner tank. Here it is corrugated, which has a positive effect on its work even with very hard water. At the same time, the equipment is characterized by the same features as for products of the same series: a minimum of functions, a thermal insulation layer of 30 mm, the inability to connect a tubular electric heater and a recirculation circuit.

10. Protherm FS B300S (295 liters) - from 63,000 rubles.

This accumulator is intended for use with Proterm Grizzly or Bizon boilers. - a capacious tank with a tubular heat exchanger. There are two flanges in the tank: for installing a heating element and servicing the boiler. Enamelled surfaces that come into contact with water, as well as the presence of a titanium anode, protect equipment from corrosion. Not to mention the presence of an antibacterial coating. A layer of polyurethane insulation is responsible for reducing heat loss. The device is characterized by high performance in flow mode, it is possible to connect a recirculation line. The possibilities of this heater will be appreciated by the owners of large private houses with more than three bathrooms.

11. Baxi Premier plus 300 (300 liters) - from 70,000 rubles.

Often the main criterion for choosing a boiler is not only its volume, but also the heating rate. In this case, it is relevant to consider models with a coil-in-coil heat exchanger. - exactly what is needed! Firstly, it is compatible with any boilers. Secondly, high-quality stainless steel, perfectly protected from corrosion, is used for its production. Thirdly, with a fairly compact size and low weight, the equipment has a universal placement and is equipped with an accurate thermostat. The model allows you to supplement the system with a recirculation circuit. Connecting a heating element for 2.7 kW is optional.

Up to 400 liters

12. Drazice OKC 400 NTRR / 1 MPa (380 liters) - from 68,000 rubles.

The Czech boiler is equipped with two tubular heat exchangers, one of which is designed to be connected to a solar collector, and the second to the boiler. This allows you to save a lot on heating water on sunny days, especially in summer. If necessary, for example, a malfunction of the boiler equipment, two auxiliary electric heating elements can be mounted. The enameled tank, as well as the presence of a magnesium anode, provide long-term protection of the tank from corrosion. 50 mm rigid polyurethane foam is used as a heat-insulating layer. There is a recirculation pipe.

Information on the rate of water heating in flow mode is not provided by the manufacturer. This is due to the presence of two independent heat exchangers with different temperature conditions.

13. Bosch SK 400-3 ZB (388 l.) - from 59,500 rubles.

There are not many indirect water heaters of the capacity we are interested in in the Bosch assortment, but among them there is a special model - Bosch SK 400-3 ZB. This is an enameled tank with a stainless steel coil. Corrosion protection is represented by a magnesium anode, which has already become a natural phenomenon in such equipment. The device is quite simple: a built-in thermometer and a flange for easy maintenance. At the same time, it is possible to connect a hot water recirculation line, as well as synchronize with the boiler if the latter has an NTC sensor connector (thermal sensor). Those. you can fine-tune the operation of water heating equipment. Separately, it must be said about thermal insulation. Here it is not polyurethane foam, but made of rigid foam, which, with equal thickness, gives a lower heat-shielding effect.

14. BAXI UBVT 400 SC (395 l.) - from 58100 rubles.

If the prevailing part of the boilers is designed to work in tandem with the boiler, then the model is an exception to the rule. It is adapted for connection to a solar collector, so its purchase will be appropriate in two cases: in places with year-round sunny weather or for seasonal use. Additionally, for heating, it is possible to install electric heaters. The container itself is made of steel coated with titanium enamel - it turned out to be a corrosion-resistant and durable coating. The latter is also facilitated by the presence of a magnesium anode. The kit includes a thermometer for temperature control, there are sockets for connecting sensors. The design provides a flange for monitoring the condition of the coil, as well as a built-in pipe for recirculation.

15. Hajdu STA 400 C (400 liters) - from 64,100 rubles.

The model from the notorious Hungarian manufacturer is interesting in that with one heat exchanger, fine-tuning of the equipment is possible. So, in the cold season, such an indirect heating boiler can be configured to work in tandem with the boiler, while in the summer it can be connected to a solar collector. In the latter case, if necessary, the heating element is additionally connected. The tank and heat exchanger are protected from corrosion by a layer of hot enamel and a magnesium anode. To minimize heat loss, the container is covered on the outside with a layer of polyurethane foam protected by a plastic casing. A branch pipe is provided for connecting a DHW recirculation system.

In the next video, this boiler is presented in section.

Editor's Choice

For ease of comparison, we will enter the main characteristics in the table and decide on the most successful models. To make it clearer, we choose a boiler for 1-2 people, 2-4 people, 4-6 people. (marked in the table below in bold from top to bottom, respectively). Because far from all manufacturers adhere to uniform standards when preparing technical documentation, for example, not all indicate the value of performance in the flow mode, then we introduce the characteristic N. It shows the ratio of a unit of power per 1 liter. water. Those. we simply took and divided the capacities indicated by the manufacturer by the useful volume of drives. The larger this value, the faster the heating takes place.

This question is often asked by owners of private houses. Many rightly believe that if they already have an installed heating system that allows them to supply the house not only with heating, but also with hot water for household needs, then why spend money and install an indirect heating boiler? At first glance, the boiler device really looks like a waste of money. But it's not.

The indirect heating boiler has a very low heat loss coefficient.

What is an indirect heating boiler and why is it needed?

An indirect heating boiler is a water heater that allows you to provide uninterrupted supply of hot water to all households at the same time.

In addition, its design does not imply the presence of its own heat source. External heat sources are used as a heat carrier for an indirect heating boiler. They can be a heating boiler, central heating, etc.

So, why do we need an indirect water heating boiler? Let's take as an example a situation where the hostess decided to wash the dishes, and the host in the meantime decided to take a shower. In this case, both will face either a shortage of hot water, or a sharp drop in water temperature, which is also unpleasant. The device of this water heater will avoid such situations, since it will be able to compensate for the shortage of hot water.

How does an indirect heating boiler work

Externally, an indirect heating boiler looks like a large tank that has a cylindrical shape. And the design of the boiler itself consists of the following parts:

• boiler body;
• insulation;
• tank made of stainless steel;
• thermometer;
• heat exchanger;
• magnesium anode.

Due to the presence of a layer of insulation between the tank and the body of the boiler itself, the heat loss coefficient is 3-4ºС per day. The thermometer allows you to control the set temperature of the water in the tank. The heat exchanger is a spiral steel or brass tube, which is located inside the boiler itself. Very often this tube has a complex shape and is located closer to the bottom of the boiler. Manufacturers claim that it is thanks to this fact that uniform heating of water in the entire tank can be achieved. The magnesium anode is designed to protect the tank from galvanic corrosion. Almost all electrochemical reactions will affect the magnesium anode without affecting other parts of the water heater. Over time, this part of the water heater will have to be replaced, as it is subject to constant wear and tear.

Almost all new models of modern boilers have an alternative heat source. Such devices are also called combined. In the summer, when the heating season is over, boilers use either electricity or gas to heat water. There are also models on the market that are able to heat water due to sunlight.

The principle of operation of the device

The indirect heating boiler is not complicated, and the principle of its operation will be clear to anyone. A spiral-shaped tube, hollow inside, passes inside a large tank, most often it is called a coil. The coolant circulates continuously in the tube. Constant circulation is provided by a pump specially installed for this purpose, which, in turn, is equipped with an automatic control system. As soon as the water temperature reaches the set parameter, the pump turns off. Since the source of the coolant is a working heating system, at the time of heating the water in the boiler, a slight decrease in the temperature of the heating elements is possible. However, the water in the tank heats up quite quickly, so you can only notice a decrease in temperature for a short time with the help of a thermometer.

After the water in the tank reaches the desired temperature, it will remain so for a long time. Modern insulating materials help to significantly reduce heat loss in the tank. As thermal insulation for boilers, polystyrene foam or polyurethane foam is perfect.

Each boiler has two inlet and outlet pipes, and they perform different tasks. The inlet pipe is connected to the heating boiler, where the coolant enters the coil through it, thereby heating the water in the tank. And the outlet pipe delivers already heated water directly to the place of its supply.

Before you decide to buy a boiler, be sure to check the power of your heating system. After all, if you purchase a boiler with a large volume, there is a possibility that the heating system in your home simply will not cope with the task. Or heating will occur very slowly, and during this period the temperature of the heating devices will drop sharply, which will have an extremely negative effect on the comfort of people living in the house. You will also need to choose in advance which type of boiler you want to purchase: floor or wall. If you have a wall-mounted water heating system, then it is best to purchase a wall-mounted boiler. And vice versa. Experts advise purchasing a heating system and an indirect heating boiler from the same manufacturer. In this case, installation and installation will be easy and fast. And the results of their work will be effective and productive.

Advantages and disadvantages of the system

The main and main advantages of indirect heating boilers, in contrast to flow-type heaters, are:

1. The ability to heat water in large quantities.
2. Compensation for the emerging shortage of hot water during the peak load period. For example, when the hostess decided to wash the dishes and the host decided to take a shower. Thanks to the boiler, several people in the house can use hot water at once without causing discomfort to other users.
3. The cost of water heated by an indirect heating boiler is extremely low. After all, no additional energy was spent for its production. An indirect heat source fully satisfied the need for heating water. In winter, the use of a boiler becomes extremely important due to the high savings in energy spent on heating and heating.
4. Compared to a flow type water heater, the use of an indirect heating boiler makes it possible to supply hot water in several directions at once.
5. Possibility to use alternative heat sources (gas, electricity, sunlight, etc.).

The disadvantages of indirect heating boilers include the following:

1. High cost of equipment. Given the fact that in order to install an indirect heating boiler, it is necessary to first install a heating boiler, the installation of the first one places a heavy financial burden on the owners of a private house.
2. In order to heat water in a container weighing 100 liters, it will take several hours. For this period of time, the heating temperature in all residential premises will be reduced.
3. The whole structure takes up quite a lot of space. Usually, a heating boiler and an indirect heating boiler are installed in close proximity to each other. And since the dimensions of the equipment are rather big, sometimes a whole small room in the economic zone is allocated for them.

How to choose the right boiler?

The main criterion that you should be guided by when choosing a boiler is its capacity. In order to understand what should be the optimal mass of your water heater, you can use the average figures, and then multiply them by the number of people living in the house and round the resulting figure up.

So, statistics say that a person spends hot water per day on:

• washing - 6-16 l;
• washing dishes - 20-25 l;
• shower - 60-85 l;
• taking a bath - 160-180 liters.

For example, it will take about 40 minutes to heat water to the desired temperature in a 20-liter indirect heating boiler, and about 6 hours for a 200-liter boiler.

After you have decided on the required volume of the boiler, be sure to specify what material the coil is made of. In inexpensive boilers, the coil is made of steel and welded to the tank. And in models of a higher price category, the coil is removable and made of brass. Of course, a removable coil is more practical, since over time you can easily remove it and clean it from the scale that has accumulated in it.

Also, inexpensive models have a layer of glass-ceramic or enamel as a protective coating. However, such a coating is not entirely reliable, because constant temperature changes will occur inside the tank, which will eventually lead to microcracks and will no longer save the metal from corrosion. Therefore, when buying a boiler, choose a tank that is made of stainless steel, such a boiler will cost you more, but it will also last much longer.

The next thing you will need to pay attention to is the insulation material. In some models, foam rubber is used as a heater; this material is extremely unreliable and impractical. Polyurethane is best suited for these purposes. It is with such a heater that heat loss from the tank is practically excluded, which means that excess energy is not wasted to heat the water again.

Boilers of indirect heating differ from all other sources of warm water in that this design does not have its own heating element. Water heating in such a system is carried out due to the influence of external heating devices. It can be a boiler, central heating or solar panels.

The principle of operation of an indirect heating boiler

A distinctive feature of the principle of operation of an indirect heating boiler is that this device only works together with external sources of heating. From this source, a coolant is supplied through a coil located inside the boiler. Thanks to the operation of the pump, the coolant circulates and thereby heats the existing water. The entire system is covered with thermal insulation materials (polystyrene foam or polyurethane) to reduce heat loss.

Cold water enters the boiler tank through the water supply pipes. Special pipes are used to connect to the heat carrier supply source. After going through the entire cycle through the coil, the heat source returns to the heating system through the outlet pipe. When choosing a boiler, you should be guided by the power of the heating source, if this value is insufficient, the water will not have time to heat up to the desired temperature.

Water connection

For an uninterrupted supply of warm water, the rules for connecting an indirect heating boiler should be strictly observed. The main nuance of the connection is that cold water must be supplied from below, i.e. the inlet pipe is connected at the bottom of the boiler. However, there are boilers where the entrance to the cold water supply is at the top - this means that the water goes through the entire system to the lowest point.

As for the hot water outlet, it is located, as a rule, at the top. The branch pipe takes the upper layers of water, which are always the hottest in the tank. Thanks to such a system, hot water will be supplied until not a single gram of warm water remains in the tank, only after that cold water will go.

Tying an indirect heating boiler can be done with your own hands, but for this you need to know some connection features. The coil, through which the coolant moves from the source, is a spiral pipe that runs along the entire length of the boiler. Under the influence of the buoyancy force of the pump, the coolant passes through the circuit and is cooled in cold water to a certain temperature. After several cycles, the temperature of the coil equalizes with the temperature of the water inside the boiler, at which point the relay is activated, opening the electrical circuit in the electric pump.

As soon as the water temperature drops to a certain level, the circuit closes again and the supply of hot coolant to the coil resumes. For greater heating efficiency and reduced energy costs, the coil must be connected from above to the coolant source. Otherwise, the coolant would not be cooled to the maximum value, passing warm layers of water at the end of its path, due to which the efficiency would decrease. Below is a typical diagram of connecting an indirect heating boiler to a heat source and its connection to hot water consumers.

Benefits of an indirect heating boiler

Among the large number of advantages of indirect heating boilers, many note the absence of energy costs. However, this statement is not entirely true, energy costs are present due to the cooling of the coolant, but they are several times less than when using boilers powered by electricity or other energy sources. In addition, indirect heating boilers have more power than many analogues, which means that water can heat up much faster. This advantage allows you to connect the boiler to several hot water consumers, for example, a faucet in the bathroom and in the kitchen at the same time.

The main advantages of an indirect heating boiler:

• Reducing energy costs;
• Large production capacity;
• Heating speed;
• Ease of connection;

The disadvantages of boilers of this type include the fact that they depend on the connected heat sources. For example, if the heating system acts as this, then it will not work in the summer.

In this case, you have to use electricity, for this, almost all models of boilers are equipped with electric heating elements.

Boilers of indirect heating are slightly more expensive than electric analogues of the same volume. Another disadvantage is the energy consumption for space heating for water heating. In private homes, this problem is solved by increasing the fuel supply. In any case, as a result, energy losses will be lower than when using alternative methods of obtaining hot water.

Analyzing the numerous reviews of the owners of indirect heating boilers, we can conclude that this system is widely in demand. Despite the fact that many are faced with the problem of warm water supply in the summer, this problem is still solvable.

Even if the design of the boiler does not provide heating from electricity, do not despair. In order not to waste a large amount of fuel for the operation of the heating system, it can be switched to an economical mode. To do this, it is only necessary to block all heating circuits, with the exception of what is supplied to the boiler.

Video: connecting an indirect heating boiler