Hot water supply, without which it is impossible comfortable accommodation in modern housing, can be established by connecting a boiler indirect heating... Such units are much more profitable and more efficient in operation than traditional ones. flow heaters thanks to higher power and efficiency. What options for connecting the boiler are used, we will consider later in the article.

How an indirect heating boiler works with a connection to a heating boiler

The installation of modern water heaters guarantees the supply of hot water in the correct amount at several points of analysis - in the bathroom, in the kitchen, etc. Specifications of the selected boiler must meet the requirements for water consumption at a comfortable temperature in the required volume. To ensure rapid heating for short term, it is necessary to correctly calculate the capacity of the water heater. For example, when consuming water in volumes of 500 liters per hour, a tank with a capacity of 100 liters or more is required.

The main elements of the heating system:

• Heating boiler;
• A pump that provides constant water circulation;
• Three-way valve;
• Hose with branch pipes for connection to the pipeline system;
• Indirect heating boiler.

The unit for indirect heating outwardly resembles a simple storage boiler powered by electricity, and performs the same tasks for creating hot water supply. The main difference is the operating principle used with the use of a heating boiler for heating.

The basic set of the indirect heating device includes:

• a storage tank in a casing, surrounded by a layer of thermal insulation;
• coil built for water circulation;
• Sleeve for connecting a temperature sensor;
• Branch pipe for connecting the boiler to the water supply system;
• Recirculation line (on some models).

The principle of operation of the device is based on heating the coolant passed through the coil of the storage tank. When interacting with water, heat is transferred from the coil with a simultaneous increase in temperature and pressure in the tank. During operation, it is necessary to monitor the degree of heating using the function of setting the desired temperature, avoiding limit values. When connecting an indirect heating boiler, the use of temperature sensors will help in this. When the water is heated, the temperature sensor signals the pump or three-way valve that the required temperature has been reached, and the water in the coil stops circulating. A similar principle underlies the operation of the sensor when the coolant is cooling.

When connecting, several different schemes piping with a single principle of supplying cold and releasing a heated coolant: cold water enters the tank from below for indirect heating, and heated water is released to the water supply. When passing through the coil, heated water gives off heat and comes out from below. This connection option allows you to maximize the volume of heated water.

The heating scheme can be described as follows: when the hot flow is directed to the user, the cold water supplied from below acts in the form of a piston, and, passing through the heated heat carrier, the cold flow heats up and moves to the upper part of the reservoir.

The piping of the indirect heating boiler is carried out according to the principle of piping the radiator, differing only in the need to stop the circulation of water in the coil after reaching the desired temperature. To resolve this issue, a three-way valve or an additional pump connected to a built-in thermostat is used. The possibility of using a dead-end DHW circuit or circulation is provided. The first option will require additional opening of the tap to drain the cooled water in the pipes.

Simple principles for connecting to a double-circuit boiler

The use of an indirect heating unit has its own advantages and disadvantages. TO positive aspects applications of this device include:

• the ability to connect various sources of heating;
• ability to connect with different types heat sources;
• uninterrupted supply of hot water supply;
• no additional energy consumption;
• the possibility of using heated water for any purpose due to the absence of communication between the coolant in the heating system and heated water.

The disadvantages of such a connection include high initial installation costs and the need for additional free space for mounting equipment.

When connected according to this scheme to gas device equipped with a pump for circulation and automation, the process of valve control, based on the signal supplied by the thermostat of the water heater, is carried out by the boiler.

When using a three-way valve, the DHW circuit has priority over the heating circuit. It is recommended to use this scheme in the presence of a large-capacity tank, as well as in conditions of using water of increased hardness, which interferes with the normal functioning of the hot water supply circuit.

The connection is based on a double-circuit heating device, which provides for parallel operation of heating and supplying heated water. It should be borne in mind that if there is a large demand for hot water supply, such a diagram for connecting an indirect heating boiler can negatively affect the existing heating system. For this reason, it is recommended to carry out the main flow within the DHW using a boiler, limiting the use of water from the boiler to a minimum.

Connection to a double-circuit boiler is carried out according to a simple scheme:

1. 1. A three-way valve is installed immediately after the pump, which is responsible for water circulation.
2. 2. The temperature sensor is connected directly to the pump.
3. 3. After the water reaches the set temperature on the regulator, the valve closes.
4. 4. The water flow circulates within the heating system.

During installation, the choice of the priority function is taken into account: if the most important is DHW, the installation is carried out in parallel with the heating system, and with the dominant role of heating, they are mounted in series, without using a temperature sensor.

Connection to a single-circuit heating unit

To connect an indirect heating boiler to a boiler with one circuit, a scheme with 2 circulation pumps can be used. This connection is based on the principle of dividing water flows through pipelines using pumps. While doing of this type connections give priority to the DHW circuit, which is achieved only by setting up the switching algorithm. The pumps are used according to a signal supplied by a thermostat built into the tank. To prevent mixing of flows, a check valve is installed in front of the pumps.

Functioning according to this scheme is similar to connecting to a double-circuit device. R The difference is that the temperature sensor must control the operation of 2 pumps alternately: if the DHW pump is turned on, the pump for heating is turned off, leading to the cooling of the coolant in the system. If the volumes of DHW are small, there will be no noticeable deterioration in heating performance.

A feature of working with a connection to a standard single-circuit device is the absence of a function for heating water for hot water supply, and, therefore, only the tank of the boiler will be used to supply heated water.

The connection is made as follows:

1. 1. The boiler is connected to a single-circuit boiler using the provided hoses and pipes.
2. 2. A pump for circulation is installed in the system.
3. 3. A special three-way sensor is installed that controls the heating process to the required temperature.

When installing a boiler connected to a single-circuit heating device, one serious drawback should be taken into account - if the equipment fails, the supply of heated water is impossible due to the lack of backup source for heating.

If a decision is made to install an indirect heating device, a number of specialist recommendations should be taken into account, which will make it possible to correctly and efficiently carry out the installation. When choosing a device, proceed from the standard needs for hot water per user. The optimal choice will be the choice of a container, calculated on the basis of 20 liters of water per consumer.

1. 1. During installation, provide for the possibility of grounding.
2. 2. Compensation of thermal expansion and damping of possible water hammer occurs due to the installation of a hydraulic accumulator on the outlet line.
3. 3. The place for installation must be in the immediate vicinity of the socket, thereby ensuring the possibility of turning on the boiler in the event of a shutdown or breakdown of the boiler.
4. 4. To facilitate the operation and ensure protection, taps are installed on the highways, allowing the device to be disconnected from the heating system at any time.
5. 5. In order for the water to heat up faster, the device should be installed as high as possible above the radiators.
6. 6. Installation of equipment will be easier if the location is chosen near the heating unit, with the obligatory control of the correct orientation of the pipes in relation to the pipeline.
7. 7. The heated heat carrier is supplied from the top of the device, and the cooled water comes out from the bottom.

Diagram for connecting an indirect heating boiler.

If you, for the organization of individual hot water supply to an apartment or house (which happens more often), opted for, then this article will become a guide in the wilds of issues with connecting this water heating device to the heating and water supply system.

It is good because for the production of hot water, it does not need to use any energy resources, except for the system autonomous heating apartments (houses) or other, alternative, energy sources (for example, a solar system that uses solar energy).

This article discusses ways to connection of an indirect heating boiler to the water supply and heating system.

Before the start installation works consult with experts, because various brands boilers and heating boilers have different ways connections. Even visually identical equipment may require an individual approach.

One more tip: if you decide to install an indirect heating storage water heater, then it is recommended to select it of the same brand as the heating boiler. Many manufacturers of such equipment specially produce devices that are adapted to work with each other. They have identical inlet and outlet openings, which makes it easier to select pipes and as well as them. For this equipment, a calculation was made in terms of power (for the boiler) and volume (for the boiler), which ensures their maximum performance in tandem.

Connecting an indirect heating boiler to heating and hot water supply systems.

To connect a water heater with indirect water heating to autonomous system heating three main methods are most often used:

● connection using a three-way valve and servo. A servo is a kind of three-way valve control. This organ, in this case, is the boiler thermostat (thermostat);

● scheme with the use of two circulation pumps;

● use of a hydraulic separator of water flows (hydraulic arrow) in the piping of a water heater with a heating system.

There is another way to install a boiler and a heating system. This is the case when the heating system is served by several boilers and, most often, is used in rooms with a complex configuration and a large volume for heating. For the high-quality operation of such a system, careful adjustment of the valve group that regulates the water flows is required. But this does not threaten our apartments, so you shouldn't stop there. Although, this method is based on three main methods of installation.

Basic piping scheme storage water heater indirect heating.

1 - ball valve. 2 - check valve. 3 - expansion tank of the water heater *. 4 - safety valve... 5 - pump of the hot water recirculation circuit of the DHW system **. 6 - circulation pump heating systems. B 1 - cold water supply. T 1 - supply pipeline from a heat source (heating boiler). T 2 - return pipe to the heat source (return). T 3 - hot water supply pipeline. T 4 - pipeline of the boiler recirculation loop.

* The expansion tank for the water heater has its own design features, due to which it cannot be used as an expansion tank for a heating system. One of these features is the water temperature at which the tank operates. So, an expansion tank for a heating system can work with a coolant with a temperature of up to 120 ° C. While a tank for a hot water system is designed to work with hot water up to 70 ° C. The visual difference between the tanks is indicated in the video clip.

** The pump for recirculation of the flow in the DHW system is designed to take cooled water from the hot water supply system and return it to the boiler for further heating. This is especially true with significant distances between the water heater and the water intake point. Thus, the consumer always has the opportunity to get hot water almost instantly.

Let's start with the first method.

BKN connection using a three-way valve with a servo drive.

This method is most often used to connect a wall-mounted boiler (with a storage tank volume of up to 100 liters inclusive) to a single-circuit heating boiler. Its essence lies in the fact that a three-way valve, controlled by a thermostat (thermostat) of a water heater, upon receiving a signal from it, closes one or another channel, directing the flow of water either to the heating system, or to the water heater circuit and the hot water supply system.

Many modern heating boilers have a built-in circulation pump, a three-way valve with a servo drive and other devices for effective work, both with a heating system and with external indirect storage water heaters. As an example, we can consider a single-circuit gas wall-mounted boiler De Dietrich MS 24 FF (France).

But such equipment is not available in every apartment or house. Many users are content with economy class boilers. In this case, you have to install the controls for the heating system and DHW system in the "external" version.

Servo-assisted 3-way valve.

Such a wiring diagram assumes that priority remains with the boiler circuit, since it is its thermostat that regulates the operation of the entire system. When the temperature of the water in the storage tank of the water heater drops, the thermostat sends a signal to the electric drive of the three-way valve and that, shutting off the heating system circuit, bypasses the coolant (hot water from the boiler) to heat the water in the boiler. Upon reaching set temperature in the boiler, the servo drive sends a signal to the actuator of the three-way valve, which in turn opens the heating circuit.

An important point in the operation of an indirect heating storage water heater, when connected through a three-way valve, is correct adjustment boiler thermostat. The temperature set on the boiler thermostat must be lower than the temperature set on the heating boiler thermostat. V otherwise, the coolant coming from the boiler will not be able to heat the water in the boiler to the temperature required for the servo drive and the electric drive of the three-way valve to operate. This means that the valve will not open the supply of coolant to the heating system circuit, since the water heating in the boiler has not reached the set temperature.

1 - ball valve; 2 - check valve; 3 - expansion tank of the water heater *; 4 - safety valve; 5 - pump of the hot water recirculation circuit of the DHW system **; 6 - circulation pump of the heating system; 7 - boiler of the heating system; 8 - expansion tank of the heating system; 9 - three-way valve;

Connection of an indirect heating boiler using two circulation pumps.

As in the previous method of connecting a hot water device with indirect water heating, this method is based on the priority state of the hot water supply system (boiler circuit) over the heating system. The difference is that two circulation pumps are involved here: one in the DHW circuit, the second in the heating circuit. Moreover, the circulation pump serving the boiler is installed in front of the pump serving the heating system (closer to the heating boiler).

With such a piping, there is no need for a three-way valve.

The principle of operation of such a scheme is that when the water in the storage tank of the boiler cools down, the thermostat automatically turns on the boiler pump, which, as can be seen in the diagram, is mounted closer to the boiler than the pump heating system... And that, in turn, creating a greater vacuum in the coil of the water heating apparatus, "draws" the hot water coming from the boiler for heating needs into the heating circuit of the boiler. As a result, heating performance decreases. But this can only become noticeable during the initial heating of a large volume of water in the storage tank. Subsequent heating occurs quickly enough and there will be no noticeable fluctuations in the temperature of the coolant in the heating circuit.

To prevent mixing of the heating medium flows from the heating system and the water heater circuit, use check valves.

Connection diagram for an indirect heating boiler using two circulation pumps.

1 - ball valve; 2 - check valve; 3 - expansion tank of the water heater *; 4 - safety valve; 5 - pump of the hot water recirculation circuit of the DHW system **; 6 - circulation pump of the heating system; 7 - boiler of the heating system; 8 - expansion tank of the heating system; 9 - DHW circulation pump;

In order to exclude the possibility of temperature drops in the heating agent in the heating circuit when the water heater is turned on, a DHW heating scheme is used with the use of two boilers. Then one boiler works for heating, and the second, maintaining heat in the heating circuit, if necessary, switches to the needs of the boiler.
But, such a problem can be successfully solved by including a hydraulic flow distributor (hydraulic arrow) in the heating system.

How to connect an indirect heating boiler via a hydraulic switch.

First, I will explain what is hydraulic arrow... This, in fact, and the principle of operation, is a distributor of coolant flows in the circuit (or circuits) of the heating system.

What is such a distributor for and where is it used. Hydraulic arrow It is mainly used in large rooms with a highly branched heating system with several independent heating circuits. It allows you to stabilize the pressure and water flows in all circuits of the system, interconnected by means of a hydraulic arrow, thereby making it possible to achieve an even distribution of heat to all consumers (heating radiators, underfloor heating circuits, indirect heating water heaters, etc.). How the hydraulic flow distributor works is shown in the video.

I want to warn you right away that the installation of a multi-circuit heating system is fraught with certain difficulties in the process of designing, installing, setting up and adjusting the equipment that is part of the heating system. Therefore, it is better to entrust its installation and, especially setting with adjustment, to a specialist.

But, if you decide to do everything yourself, I present to your attention the installation diagram and try, in short, to describe the possibility of connecting an indirect heating water heater to the heating system using a hydraulic arrow.

For a multi-circuit heating system (two or more heating circuits * + indirect heating boiler), it is used.

* Two or more heating circuits, for example a radiator heating circuit + underfloor heating circuit, etc.

You can, of course, do without a hydraulic separator for water flows, but, in this case, problems may arise with uneven heating and high blood pressure in the pipelines of the heating system.

How, when and where the hydraulic arrow is used is shown in the video "Low loss header".

Diagram for connecting an indirect heating boiler through a hydraulic arrow.

2016-12-23 Evgeny Fomenko

To understand how best to connect an indirect heating boiler, you first need to know whether it has a built-in control system. If yes, then such a water heater can be safely connected to any type of boilers and central heating without auxiliary equipment.

The built-in temperature sensor will send a signal to the control system when the water reaches a certain temperature and will cut off the coolant flow in the coil. It is important to connect it correctly: the coolant must flow from top to bottom, this allows you to maximize the efficiency of the boiler. Pure water on the contrary, it enters from the bottom and is discharged from the top of the tank.

If the device does not contain automatic control, then it will need to be connected to the boiler. A temperature sensor is placed in a special place in the device body and connected to the boiler. Next, the device is connected using one of the schemes.

Installation with a single-circuit boiler

There are two main schemes for connecting an indirect heating boiler to a single-circuit boiler:

Connection to a double-circuit boiler

The double-circuit boiler itself is designed for heating and DHW at the same time. But usually there is enough water from it only for one point of the watershed. An indirect water heater allows you to increase the amount of hot water produced.

It can be connected in the same way as with a single-circuit one using a three-way valve or two pumps. At the same time, separate the pipes to different points of the watershed, for example, from the boiler to the washbasin, and from the boiler to the shower.

In the second method, the water heater is used as a storage buffer tank... Hot water from the boiler enters the tank, where it is heated if necessary. A more uniform liquid temperature will also be a plus.

Solid fuel boiler and central heating

The connection of the indirect heating device to a solid fuel boiler is carried out according to similar schemes. The solid fuel boiler allows the installation of thermostatic valves on the radiators. This makes it convenient to regulate the temperature in the room, but there is a danger of the boiler overheating.

To prevent this from happening, firms are installing an emergency heat exchanger, which leads to a loss of energy. If an indirect heating water heater appears in the system, it protects against overheating and, at the same time, excess heat is not wasted.

If the batteries in your apartment are stably heating in winter, you can connect to the central heating. In this case, you should take a combined boiler with a removable heating element so that hot water remains in the summer, for example, OKC 125. Here it will not be possible to set the priority of heating the water supply system, since the riser is not yours personally, but the whole house. Here the scheme is suitable with a circulation pump.

Recirculation system

If you are supposed to have a heated towel rail, you should purchase models with recirculation, for example, Drazhice OKC NTR / Z. There is a recirculation point in the center of the tank. This makes the heated towel rail constantly warm and the tap water immediately hot. There is no need to wait for cold water to drain.

The downside of such systems will be the loss of thermal energy. Also, in circuits without recirculation, heated water is located on top of the tank and from there it goes to the draw-off points. This allows the maximum amount of warm water to be used. Recirculation mixes the water layers in the tank, so this effect is partially lost.

Installation of systems

You can install and connect an indirect heating boiler with your own hands. To begin with, a connection scheme is selected depending on the needs and hardware.

After that they buy necessary materials: three-way valve, pumps, metal-plastic pipes, tees, valves and check valves. Next, the location of the installation of all nodes is selected and a plan is drawn with reference to the room.

Installation consists of the following main steps:

We offer you to watch a video about connecting an indirect heating boiler:

The topic of this article is wall gas boilers and indirect heating boilers. Consider how they work together, and possible options their connections.

1. The first option for connecting the boiler

So, the first connection option is when on the wall of a gas single-circuit boiler there are initially already outlets for connecting an indirect heating boiler.

If you look at the boiler from below, it will somewhat resemble an ordinary double-circuit boiler, but according to the passport it is listed as a single-circuit wall-mounted gas boiler.

If you look at the diagram of this boiler, we will see that it has one pipe - supply to the heating system, the second - supply to the boiler, as well as pipes for gas inlet, return from the boiler and return from the heating system. Also in this boiler there is already a built-in three-way valve with an electric drive.

Let's take a look at how it all works. Since the boiler already has ready-made outputs, we immediately connect our boiler directly to the boiler.

The boiler is turned on and heats the coolant along this circuit:

Radiators or underfloor heating are heated - this, in principle, does not matter. The boiler works to heat the house. Let's say that our boiler, which has a power of 24 kW and maintains a temperature of 50 ° C, uses 15 kW of thermal power. At some point, through a temperature sensor installed directly on the boiler itself, the boiler receives a request to heat the boiler.

After that, the boiler automation instructs the three-way valve to switch from the heating circuit to the boiler heating circuit.

The supply of heating medium to the heating system stops and it begins to flow into the boiler heat exchanger to heat the service water. At the same time, the boiler burner starts up at full power, at 24 kW, and the temperature is kept at a maximum level of about 80 ° C.

This is necessary in order to quickly heat the water in the boiler to the desired temperature. When the hot water is fully heated in the boiler, the boiler automation switches to the heating circuit through the same temperature sensor. Let's say that before that, the coolant temperature was set at 50 ° C. This requires only 40% of the burner power. Let's take a look at how this system works in the summer when the heating is off. We put the boiler into summer mode, most of the time it does not work, but it is in standby mode. As soon as a signal is sent to the boiler automation that the boiler needs to be heated, the boiler starts up, brings the burner to full power, by 24 kW, and the temperature of the coolant leaving the boiler is again maintained at around 80 ° C.

After hot water is fully prepared in the boiler, the boiler is completely turned off and goes back to standby mode.

1. The second option for connecting the boiler

Let's consider another connection option, also with a wall-mounted gas boiler. Its only difference is that the boiler has no way to initially connect an indirect heating boiler. Unlike the first option, this boiler does not have a built-in three-way valve, so we will have to install it separately.

It looks something like this and is installed at the outlet of the boiler. After that, we connect the boiler and the heating circuit to the boiler.

To control the three-way valve, we connect the electric actuator to the automation of the wall-mounted boiler. The temperature sensor from the boiler is still connected to the boiler.

Further, the operation of the boiler is, in principle, no different from the operation shown in the first version. When the boiler operates in heating mode, there is no circulation through the boiler heat exchanger. As soon as there is a request from the boiler for water heating, the boiler automation switches the external three-way valve, and all the coolant from the boiler flows only to the boiler heat exchanger.

With the first and second connection methods, we can set the temperature directly on the boiler, which must be maintained in the boiler.

Some boilers have a very useful feature called anti-legionella. Let's say we keep the boiler at around 45 ° C in the summer, but from time to time the boiler in the boiler heats the water up to 65 ° C to kill Legionella.

1. The third option for connecting a boiler, its pros and cons

Let's look at the third connection option. In this case, there is also a single-circuit wall-mounted boiler without the possibility of connecting a boiler. We will consider the connection of an external boiler using the example of pumping groups from the “Meibes” company.

In this case, the boiler will be connected via a hydraulic switch to three independent separate circuits with separate pumps.

Let's say this is a radiator circuit, an underfloor heating circuit and a boiler. Let's take a look at how the system works. Let's say we only need to heat the radiator and the warm floor.

In this case, the boiler drives the coolant into the hydraulic gun, and through the distribution manifold, the coolant is taken by pumps for radiators and underfloor heating.

After a request for heating the boiler is received, the boiler automation turns off the pumps that go to the radiators and to the heated floor. The circulation of the coolant stops there and the pump turns on, which only goes to heating the boiler.

Thus, all the coolant that comes from the boiler circulates only through the boiler circuit. At the same time, the burner in the boiler starts up at full capacity and the outlet temperature is maintained around 80 ° C.

Thus, the boiler heats up quickly, literally in 10 - 15 minutes.

After that, the boiler automation turns off the circulation pump, which goes to the boiler, then turns on the pumps again, which go separately for heating the house, and the boiler burner also goes into normal operation. V summer period when our heating is turned off, the boiler is also in a disabled state and starts up only when it is necessary to heat up the boiler.

If the boiler automation does not allow controlling external pumps, a separate controller can be installed, which itself can control both the boiler and individual circuits.

You may ask: why turn off the pumps that go for heating before heating the boiler? It is enough just to turn on the boiler loading pump and add the burner power. And you don't need to use any complex automation.

But in practice, unfortunately, this does not work out that way. Let's say that our house has an area of ​​approximately 200 m² and a boiler with a capacity of 24 kW. We need all the power of the boiler for heating and for heating the boiler. The heating circuit requires an average of about 12 - 16 kW. Thus, if our boiler works simultaneously for heating and for a boiler, the boiler will get about 8 kW. Let's say the volume of the boiler is 150 liters and the heat exchanger of this boiler has a capacity of about 24 kW.

If we only heated a boiler without heating with a boiler, it would warm up in about 15 - 20 minutes.

But if the boiler works simultaneously for heating and for a boiler, it will turn out differently. Let's say that our power is divided in half by 12 kW. In this case, the boiler will heat up much longer - from 60 to 80 minutes, and maybe even longer.

There is one more nuance. Any boiler must deliver hot water in the channel - when the heated hot water is completely exhausted in the boiler, it must still continue to deliver hot water in the channel of the order of 12-14 liters per minute.

If the heat exchanger of the boiler gets only 12 kW, then the water in the channel will flow about 6 liters per minute, and maybe 4 liters per minute.

You can, of course, get out of this situation differently - take a wall-mounted boiler with a good power reserve, about 50 kW. But where to get such a powerful wall-mounted boiler? Is there anything to put ionization? But it will be three times more expensive. You can also try to put a floor-standing boiler and re-equip it with a separate pump and expansion tank with a security group.

Let it also be with a good power reserve of 50 kW.

We do not need automation in this case either. We will have to set the temperature on the boiler to about 80 ° C, so that it maintains it constantly.

But the most interesting thing is that for underfloor heating, 40 ° C would be enough for us, for radiators, as a rule, 60 ° C is enough.

(figure 41)
It turns out that we only need such a high temperature to warm up the boiler. Considering that the boiler heats up quickly enough, and we do not use hot water around the clock, we can say that such a high temperature will remain unclaimed most of the time.

Summing up, let's say that of the three above connection options, the first one is the most optimal, where the boiler already has a built-in three-way valve, and the boiler automation is already sharpened for connecting the boiler. If you use this connection option, you will not encounter any problems when connecting and when operating the boiler.

All rights to the video belong to: Marat Ishmuratov

In order to always have warm water in the house, an indirect heating boiler (BKN) is installed. Installation of such a device is expedient and cost effective. When installing, it is important to pay Special attention for piping an indirect heating boiler with recirculation to avoid common mistakes. You also need to learn more about how this type of equipment works.

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How the device works

Before purchasing and installing a boiler, you should understand some design features and the principle of operation of the most popular models. There are many types of similar installations capable of operating simultaneously from the heating system and alternative sources energy.

It is advisable to consider as an example traditional installations with a classic coil, which work (receive thermal energy) from hot water. To begin with, you should understand in more detail the term "indirect heating". Classic installations use an electrical connection or natural gas to get warm. Boilers do not have these advantages. They are connected to hot water supply and use the heat of water or other heat carrier.

DHW recirculation (boiler and DHW pump)

Standard installations are in the form of a round barrel (although today there are already more convenient and compact models square shape). If you take a closer look at the product line from renowned manufacturers, then you can notice a certain trend. They all have same design... This applies to both boilers and gas boilers. You can significantly save space when placing them by installing one unit on top of another.

The only heating element is a brass or steel coil. It is located inside the body (tank), which has a protective enamel layer. To reduce heat loss, the case is well insulated, and sometimes it is covered with a protective casing.

If you need to quickly heat water, then you should choose devices with several heat exchangers. For a slow cooling of water, models with good insulation are needed.

- one of the most important elements in modern boilers. The part serves to prevent the appearance of corrosion on all interior surfaces, and the rod itself is inside the structure in the upper part of it. Thanks to this, the unit lasts several times longer. The design must necessarily have a thermostat and built-in valves, since they are protectors against a strong increase in pressure as a result of failure of the entire system.

A common myth is that boilers are not efficient equipment for heating water, since the temperature of the coolant in the coil does not exceed 70 ° C. This is not true. It all depends on the area of ​​contact of the coolant in the coil with water. In the BKN, it is quite large, so the water is heated efficiently even at a seemingly low temperature, not exceeding 70 ° C.

The device works very simply. The boiler is full cold water for heating. Inside there is a coil into which hot water from the boiler is started at this moment. Cold water after a certain time it heats up and becomes suitable for taking a shower, washing dishes and other household needs.

Diagrams for connecting an indirect heating boiler to a wall-mounted single-circuit boiler



Equipment with control unit

Today there are two options for boilers - simple (cheaper) and with a built-in control unit. It should be remembered that such a unit is mandatory if the main heating device, for example, a gas boiler, does not have a control function.




A temperature sensor is often installed inside the built-in control unit. It is also possible to stop or turn on the water supply to the heat exchanger. The device can work in automatic mode. To connect the equipment, you must perform the following steps:

• connect the inlet and outlet lines for starting water from the boiler;
• connect the hose and turn on the cold water supply;
• install a collector to distribute hot water at the outlet.

Many people think that with a control unit, the temperature of the water in the boiler can be adjusted. This opinion is wrong. The maximum attainable temperature is the degree of the heat carrier itself, which is supplied directly from the boiler. Typically, the liquid will heat up 1-2 degrees less. If you need water with more high temperature, then it is better to choose a model with a built-in heating element. Typically, such a scheme is needed in the presence of a low-temperature boiler.

It is better to buy such units together with solid fuel boiler... Even if the wood burns out, there will always be access to hot water for a long time.

Overview of water supply with DHW recirculation



Varieties of aggregates

Tanks with the simplest design occupy only a certain part of the market for such equipment. There are more advanced models, the functions of which are very useful for combining with a DHW system. For example, there is a possibility of heat accumulation in such equipment. It is necessary in the event of frequent power outages or high electricity tariffs. Such units are distinguished by reinforced insulation, which prevents heat loss, as well as an increased volume of the storage tank up to 300 liters.

There is another option for piping a DHW boiler with recirculation, in which water is supplied to the water intake points much faster. The difference between this design is to provide the device with not one pipe for connection to the hot water supply system, but three or more. Hot water flows through two pipes, and cold water flows through the third. Circulates liquid using a pump. With such a scheme, you can realize a lot useful ideas, for example, arrange a place for drying towels. Water in such equipment heats up faster than in conventional structures, but its price is also much higher.



Optimal tank size

Cylindrical tanks have dimensions that differ from square (cubic). The dimensions of the device must be selected taking into account the installation possibilities, the availability of space and the family's needs for hot water. There are very compact models for 80-100 liters. The largest ones can be up to 1600 liters.

When installing the device, these indicators are very important. When placing the boiler on the wall, you only need to choose small models up to 150 liters. Larger devices must be installed on the floor.

All wall-mounted units are supplied with special fasteners and brackets. The outdoor equipment is equipped with legs or a special stand.

Single-circuit boiler and indirect heating boiler, how to connect?

Boiler piping

A simple piping scheme for a boiler and an indirect heating boiler assumes their joint installation along with all pumps and other equipment. It will be much easier that way. If you install the boiler in an already installed DHW network, then this is much more difficult. In order for the devices to work normally, you must adhere to some rules:






If the walls in the house are made of plasterboard or thin wood, then it is better not to buy wall-mounted boilers, since they simply will not stick to such a surface. In this case, it is better to choose floor models. For fastening wall devices concrete or brick surfaces are more suitable.

The brackets of the wall units are fixed with dowels, brackets or anchor bolts. As a rule, they are provided by the manufacturer together with the equipment. If not, you can buy them at any hardware store.

The boiler must be installed at or above the boiler level. If with wall models everything is clear and they can be attached in any suitable place, then for floor-standing appliances it is necessary to make a special pedestal no more than 1 meter high.

All connections should be directed towards the boiler, even if they are hidden behind the device or false wall.

Correct installation

When choosing a piping scheme for an indirect heating boiler, you should also decide on the principle of its operation. It can be with or without priority.

The first option is to prioritize water heating in the boiler. If necessary, all the coolant from the boiler can be passed through the BKN coil, as a result of which the water will heat up much faster. After the liquid is heated to required temperature, the coolant is redirected to the radiators using a mode changeover in the control unit.

If you connect the system without priority, then the entire coolant cannot be redirected. The water will take longer to heat up, since only a fraction of its volume is used.

Heating with a boiler on the principle of priority is much more efficient than usual, since it makes it possible to heat a large number of water very quickly without damage to the heating system.

When the heating is turned off, the air temperature in the room in half an hour, if it drops, is insignificant, but during this time it will be possible to get a large volume warm water... It should be remembered that such a scheme requires a very powerful boiler.

BKN connection diagrams

Boiler connection diagrams depend on its class, manufacturer and heating system in the house. It is important to choose the right installation location. In this case, you need to take into account the location of the boiler, the pump insert and other nuances. There are such basic strapping methods:



Thus, installation of a BKN boiler in the heating system of a private house or apartment plays important role in savings family budget and quick access to hot water.