home Heating

Boilers of indirect heating - what is it? Connection of the indirect heating boiler to the gas boiler. Schemes for connecting BKN to the source

Boiler indirect heating (BKN) - an excellent solution for holiday homes, private houses, hotels, sports complexes and other facilities not connected to centralized water supply. This equipment can easily cope with heating large volumes, easily maintains the desired temperature and ensures uninterrupted supply of hot flow.

In a word, if you are looking for a budget water heater in a kit for a single-circuit boiler - consider the installation option in the house BKN. And that the choice was easier, we will consider in detail the principle of operation of this device, the scheme of its connection and tell you what to look for when buying.

The indirect heating boiler can work only on the resources of an external source, but for maintenance of the system in the warm season, you can connect the heater.

In order to ensure uninterrupted supply, the system provides a recirculation loop - water will constantly move through the pipes, and when the tap is opened, a hot flow will flow in the draw-off points connected to the circuit.

An indirect heating boiler is usually installed next to the boiler, and this "duet" occupies a rather large area, especially if both floor type instruments

Thus, the device allows to save considerably on energy resources, but at the same time to receive no less comfort than using centralized system hot water supply.

How is the indirect heating boiler constructed?

The device that heats the water by indirect principle. Is a warmed storage tank, inside which is installed a heating element, which operates from an external coolant. The tank itself can be made in the form of a rectangle or cylinder, and in its walls there are nozzles - for circulation hot water from the heating system and the inlet / outlet of water supply pipes.

The basis of the design is a metal or plastic container with a capacity of ten to several thousand liters. From the inside, the tank can be treated with a coating of enamel, ceramic or glass porcelain, which helps to maintain the proper water quality and avoid corrosion. The body protects the insulation layer from polyurethane, foam rubber or mineral wool from heat loss.

Spiral with the heat carrier can be evenly distributed throughout the container, or densely to be laid down below, in order to warm up the cold water that enters it

To prevent scaling, a magnesium or titanium anode is installed in the upper part of the container, which softens the water, protects the metal against galvanic corrosion and prolongs the "life" of the device. The device is also equipped with a thermostat that controls the heating to a certain temperature and the safety valves that are part of the protection group.

Types and model types of equipment

The most common type of device is a storage tank, inside which are placed steel or brass pipes (coil) with a circulating coolant. The speed of heating the water depends on the number of turns on its spiral. The principle of operation of such a construction of an indirect heating boiler is extremely simple: cold water enters the tank, and the coolant, moving along the coil, warms it up to the desired temperature.

But there are also devices designed according to the "tank in the tank" scheme, where instead of a spiral pipeline two tanks of different diameters are used.

The system operates as follows: a smaller reservoir receives cold water, which is heated by a hot coolant circulating between the walls of the tanks. In such appliances, the water becomes warm in a matter of minutes - a large heating area allows the equipment to work efficiently in flow mode, ensuring an uninterrupted supply of hot flow.

Boilers operating in the "tank in the tank" system not only quickly heat the water to 90 ° C, but also have a self-cleaning function

Combined BKN for water heating can use energy directly from several sources or be equipped with an integrated heating element.

Varieties of the boiler

By placement:

Wall - Usually, this is a small device with a capacity of up to 200 liters. Mounted with special brackets on any vertical surface, strong enough to withstand the weight of a completely filled reservoir (gypsum plasterboards are definitely not suitable). It can be located high enough and does not occupy the useful area of the room.
Floor - capacious boiler, designed for a large number of consumers. True, for a device with a capacity exceeding 1000 liters, it is recommended to allocate a separate room - a boiler room. But such a system is usually installed to service large cottages, businesses, hotels and other institutions, for family use can be managed and a device for 250-300 liters.

Tank shape:

Horizontal - takes up a lot of space, but it is easier to independently maintain the desired level of water, without resorting to connecting pumps.
Vertical - saves free space, but is very limited in capacity.

Depending on the nuances of use, layout features and availability free space, you can choose optimal model BKN, which will seamlessly fit into the design of the room and will ensure your house with uninterrupted hot water supply.

Pros and cons of the device

The main advantage of an indirect heating boiler is energy saving. For its operation, it is not necessary to connect a gas burner or to use electricity, as required by a direct heating device. The heating system gives all the necessary resources, so hot water is practically a free "bonus" that will help to save considerably family budget in the cold season.

Most boilers of indirect heating are additionally equipped with heaters with a thermostat so that it can be used also in the warm period when the heating is switched off

Other benefits of BKN:

High productivity - a tank with a capacity of 100 liters is able to "give" per hour about 400 liters of hot water (provided a sufficiently powerful boiler).
Long service life (the heat carrier does not come into contact with running water, as in similar direct heating devices).
Does not overload the power grid - it works from an external power source.
Instantaneous hot water supply - no need to wait for a cold flow to flow, as in use gas columns, or the used tank is heated, like an electric boiler.
There is the possibility of connecting to several sources of energy, for example, solar collector, a boiler, a heat pump of a geothermal system.
Affordable cost - if desired, the system can be assembled with your own hands.

Of course, there could be no minuses here either. With all the advantages, the speed of heating the water in the device leaves much to be desired - for processing 100 liters, even modern equipment will spend at least 15-20 minutes, and self-made systems can not cope in an hour.

Also indirect heating boilers are cumbersome enough, therefore occupy an impressive amount of free space (for larger tanks, a separate room may be needed).

The indirect heating boiler can also be made from improvised materials using a curved copper pipe for a coil, a capacious drum with a lid or gas cylinder for the tank

In addition, this device will be really economical only during the heating season, and in the warm season it will be necessary either to turn on the boiler or to provide for alternative sources heat (solar batteries, heating elements). Yes, and the price of a quality "indirect" exceeds analogs with direct heating.

What to look for when choosing BKN

One of the main parameters that should be the decisive argument when buying a boiler is its capacity. To find out the required capacity of the tank, it is advisable to focus on the number of people in your family.

2 consumers - 80-100 liters.
3 people - 100-120 liters.
4 - 120-150 liters.
5 - 150-200 liters.

It is important to divide the concepts of "total tank capacity" and "working capacity", because the spiral pipe, located inside the boiler, occupies a considerable area. Therefore, be sure to specify when buying how much real water is placed in the device (in technical specifications, this nuance should be specified).

Also, in addition to the "total" conversion of potential consumers, it is necessary to take into account both the frequency and volumes of water use. For example, if your family likes to luxuriate in a warm bath and not take a shower quickly, the working capacity of the tank must be at least 120 liters.

BKN is advantageous for use with a solid-fuel or single-loop gas boiler, but if the water flow is less than 1 L / min, a double-circuit boiler will cost less, and it will take much less space than the system with indirect heating

Other important parameters:

Power - the more water consumption, the higher the resource of the device. But it is important that the power of the "indirect" does not exceed the capacity of the heating system (or other external energy source). For example, if the volume of the storage tank varies between 120-150 liters, the boiler output should be at least 23 kW, and for the 160-200 liters, 31-39 kW will already be needed.
Heating time - a parameter that depends on the volume of the tank and the number of turns on the coil (large or combined tanks can be equipped with several spirals).
Tank material - for long-term use, boilers made of stainless steel or medical steel are the best.
Thermal insulation - cheap models use foam rubber, which wears out quickly and allows heat, so it's better to buy a more expensive device, where polyurethane was used.
Control - the device will be able to work in automatic mode, if necessary, disconnecting and starting the water current, control the heating with the help of a temperature sensor.

When choosing the shape and size of the tank, it is also necessary to take into account that although theoretically the boiler can be installed in any room where there is access to the heating main, its optimal location is next to the boiler. So the transfer of heat is most effective.

Nuances and wiring diagrams of the boiler

As already mentioned, BKN uses the energy of an external source to heat water. Therefore, before connecting to the heating medium, it is important to select the appropriate circuit for mounting the device. Consider the most common options.

General principles of the device installation

Mount the boiler on a prepared, level surface in the immediate vicinity of the boiler. Suspended models are mounted on a concrete or brick wall, on one level or slightly above the boiler. For a floor-standing device - level the area reserved for the tank (if the floor is critically uneven, you can make a stand in the form of a podium).

The BKN strapping is designed to connect the device to two systems - water supply and heating. For this, there are special nozzles on the body.

The safety group of the indirect heating boiler includes a return and discharge valve, which protect the system from excessive pressure and hot water leakage

Principles of accession:

Cold water from the drainage system should enter the bottom of the tank, and hot water should come out from the top.
At the entrance cold water should be established check valve, which will prevent the leakage of hot flow from the boiler in the event of a pressure drop in the system.
In the middle of the device, a recirculation point can be located.
When the heating circuit is switched on, the heating medium must move from top to bottom. That is, the pipe with hot water It is put in the upper branch pipe, and the pipe with cooled down - comes from below.
All nozzles must be provided with cranes with union nuts to ensure that the boiler can be switched off, for example, in the event of a replacement of the appliance or repair work.

Thanks to this scheme, the maximum efficiency of the device is achieved, since the coolant circulating in the coil heats the water in the upper part of the tank, gives the rest of the heat to the low-temperature layers and enters for new heating into the boiler.

Schemes for connecting BKN to the source

In order to choose the right scheme for connecting the boiler to the heating system, it is necessary to take into account the possibilities of the wiring already available and the place of installation of the heating device. There are several solutions.

The most common scheme for the constant use of hot water - connection via a three-way valve. It assumes the presence of two heating circuits - the main and separate for BKN. For this, the hot water supply is cut circulation pump, and after it a three-way valve is installed, which is controlled by the boiler thermostat.

The scheme works as follows: when the water temperature in the boiler drops below a preset level, the valve switches the system to heat the storage tank at the thermostat's signal, and after reaching the desired value, it sends the flow through the common house circuit.

For correct operation of the three-way circuit, it is important to adjust the thermostat data so that the temperature programmed for the boiler is not set lower than in the boiler thermostat

If there is no need for constant and large volumes of hot water (for example, a boiler is installed in a country house and is only used on weekends), you can consider option installation of a two-pump system.

In this case, the BKN and the boiler are connected in parallel, and the coolant flows will move along the two lines. For forced movement of water, two pumps are installed: on the heating circuit and the supply pipe for the boiler. Heating is carried out using a thermostat, which temporarily turns off the radiator heating, directing the entire system resource to the boiler.

According to the double-ended scheme, the heating circuit will be switched off for the duration of the boiler operation, but in the 30-60 minutes that are necessary to heat the tank from scratch, the radiators will not have time to cool down critically

For rooms where a multi-circuit heating system is used (for example, in addition to the radiators there is a "warm floor"), apply hydraulic distributor.

Hydraulic guns redistribute the pressure on individual sections of the circuit and ensure uninterrupted flow of the coolant even without the aid of circulation pumps.

Without engineering experience, this complex scheme it is unlikely to do it yourself - to provide a lot of nuances and establish a smooth operation of the system, it is better to turn to professional designers

Without a hydrocollector in a multi-circuit system, pumping equipment may be damaged and even a heat stroke with damage to the radiators may occur.

Recirculation system

If a third input is provided in the boiler, a recirculation system can be connected to it. For this purpose, a loop loop is wound at the recirculation point on the body of the device.

The flow of water is in constant motion due to the operation of the circulation pump, so it instantly delivers warm water to the point of consumption

To implement the scheme, you will need to mount an additional circuit and install the following elements:

Check valve at the heater inlet.
Automatic air vent, protecting the pump from air penetration before starting.
A safety valve that will protect against pressure drops.
Membrane expansion tank, in which excess water will escape when the pressure in the system rises. Please note that the capacity of the reserve capacity should not be less than 1/10 of the volume of the BKN itself.

If the indirect heating boiler device does not have a branch pipe for the recirculation loop, it is possible to inset the return line into the cold water pipe and install the pump. Then the connection is made according to the diagram below.

The choice of the binding scheme with or without recirculation should be based on the design of the BKN and the heating system, as well as the capacity of the equipment

Connection on a return scheme ensures uninterrupted supply of hot water - that is, you will not have to wait until the coolant warms up the water in the tank.

Video about the device and connection БКН

Before deciding to buy and install a new water heater in the house, we suggest studying video materials that clearly demonstrate the advantages of the "indirect" and the nuances of its connection.

In this video, you can find out how indirectly heated boilers operate with a coolant located inside the coil:

All the nuances of the internal device and the principles of operation of various types of indirect heating boilers in a detailed video-educational program from a practitioner:

Overview and connection of the device for 300 liters, which operates on two heat carriers - a boiler and solar panels:

Detailed analysis of the device BKN and its connection schemes. Practical tips and tips from the wizard:

As for the service, the indirect heating boiler is a rather unpretentious equipment. With the correct installation and proper operation of the system, it may only be necessary to replace the magnesium anode once every 6-12 months and preventive washing of the tank (the frequency depends on the quality of the tap water and intensity of use).

But if you have installed a device that operates on the "tank in the tank" technology, which has a self-cleaning function, you do not need to change the consumable. However, about regular maintenance equipment can always be negotiated with masters, specializing in the installation and repair of water supply systems.

Almost all people can not imagine comfortable living conditions without the constant presence of hot water in the house. Even with minor disruptions, there are irregularities in life. Those who live outside the city and are deprived of supplies of hot water and central heating, require the use of any alternative method.

In this case, the best solution is to install a boiler. There are several types of this equipment:

Direct heating boiler, which operates at the expense of electrical network or a special gas column;
Boiler indirect heating, heating water by using heat from.

Devices belonging to the first kind are more popular, however they are not profitable. This is because electrical equipment requires a lot of energy, so a lot of money is needed. In addition, gas boilers are not able to fully ensure the uninterrupted supply of hot water.

In connection with this feature, indirect heating boilers are considered more profitable if they are considered in the long term for exploitation. Some people think that the optimal solution is to provide both hot water and warm air at the same time. However, in such systems, many different shortcomings can be found. So, they can not regularly provide the necessary amount of hot water for several people. In addition, an increase in the number of costs causes a sharp drop in the heating temperature.

Usually the cost per day of heated water per person is from ten to one hundred and eighty liters. In the current situation, you can not use it in the kitchen and at the same time take a shower - the residents of the house should always inform the others about plans for heated water.

Experienced professionals advise to install a single-circuit boiler, which should be supplemented with a boiler, characterized by an indirect method of heating. This option provides around-the-clock hot water supply in a large number, as well as a constant temperature. However, the number of points of its application is limited only by the volume of the boiler. The main advantage is that the boiler warms up evenly. It should be taken into account that the device of small dimensions heats twenty liters of water in half an hour. It takes six hours to heat two hundred liters.

Equipment arrangement

The external shape of the boiler, functioning by indirect heating, resembles a cylindrical vessel. Its capacity is from tens to several hundred liters. Each individual design is distinguished by a certain capacity.

Manufacturers offer devices for both vertical and horizontal installation methods. The first option is an excellent option for rooms with a small area, where they are mounted on the wall, and in the second -.

In the photo: the device indirect boiler.

For the manufacture of cases, only enameled and stainless steel is used, as well as high-strength plastic. These materials are resistant to corrosion. This extends the life of the equipment.

The standard boiler includes the following parts:

External tank;
Internal tank for liquid storage;
Water supply pipe to the boiler;
Hose for hot water outlet;
Thermostat;
Heat exchanger;
The damper of a current of a liquid;
Anode from magnesium;
Teng is an electrical type.

For the heat exchanger, the components are made either of brass or of a steel alloy. It has a complex snake-like shape that makes it possible to significantly expand the contact area with water heated in the device. The turns in this part are arranged in two ways:

At the location of the cold liquid layer;
Evenly on a cylindrical tank.

With uniform fastening of turns, water is heated uniformly. There are options equipped with special tube-type heat exchangers. One such element is used to support the movement of the heating system, and the second device is connected to solar battery or to a heat pump.

In the photo: the scheme of connecting an indirect heating boiler.

Also there are boilers that do not have heat exchangers. Similar models are devices reminiscent of equipment category "tank in the tank." They are supplied by a Belgian manufacturer. It has an internal storage tank made of quality high-quality steel alloy. Water is heated by moving it between the walls of two tanks: internal and external. The problem of the magnesium anode is the protection of metallic material from possible galvanic corrosion.

Electric tan serves as a so-called "spare" option. It is applied in the event that heating system leaves the working mode. The heat insulator is designed to reliably maintain the temperature of the liquid contained in the collection tank. The inner container is usually made of mineral wool or strong polyurethane foam.

The safety equipment includes a positive pressure valve together with a non-return valve.

Principle of operation of indirect heating boilers

The device operates on a simple principle. So, water is supplied to the tank thanks to a special input; in the heat exchanger there is a coolant; The latter heats the liquid, coming into contact with it through a thin plate in the storage tank; The heated liquid is supplied to the points of analysis thanks to a special branch pipe.

A circulating pump is mounted in the device connection circuit to ensure independent operation of the DHW from the heating equipment. Due to this, it is possible to safely turn off the heating system.

How to choose the right boiler?

To the main technical specifications equipment include:

Options;
The value of the storage tank inside;
Method of installation;
Heat exchanger power;
Time required to bring the liquid to the highest possible temperature;
Pressure set in the DHW system circuit;
The highest value of the heating parameters.

This device is sold at a high price, so you need to choose the right one. It is necessary to pay attention to some features:

Availability of equipment passport;
The flow rate of the installed heat carrier, which passes through the coil. The specified value should not exceed 50% of the consumption of the single-circuit boiler used.

In good and reliable models, a brass coil is usually installed. In such a boiler, water heating is much more efficient. In addition, the parts can be easily removed for replacement or cleaning.

It is not necessary to buy units in which the foam layer is the heat-insulating material. It is recommended to give preference to boilers that have the advantage of high performance of the device. To install an indirect heating boiler, it is necessary to invest a large amount allocated for the purchase and installation of the unit. However, the purchase of the device will ensure the living conditions in the house.

Video: how to choose the right boiler

Indirect heating boilers use the heat generated in heating systems to heat water. For these purposes, both stand-alone boilers operating on liquid or solid fuel are suitable, and central systems heating.

Hot water from them enters the coil inside the boiler, thereby heating the cold water in it. The size of the tank itself can be unlimitedly large, however, when calculating the required volume, it is sufficient to take into account the peak consumption of hot water in the house.

Also, a circulation pump is connected to the boiler through a special branch pipe, which ensures constant movement of hot water along all the sanitary devices connected to the hot water supply system. Thus, the water consumption is significantly reduced, since the warm water starts to flow immediately after opening the crane. To ensure that no heat loss occurs during the circulation of water in the pipes, they must be isolated with the help of heat-insulating hoses or the so-called PPU shell.

To save energy, the circulation pump can be connected via a weekly programmable timer, which will turn it on at a specific time. When it is turned off, the hot water system will work as usual. The presence of automation is also necessary in boilers with two heat exchangers, in which it is possible to combine completely different sources of energy, for example, gas and solar.

Indirect heating boilers heat water faster than electric heaters, and the use of hot water at several points simultaneously does not cause sudden fluctuations in its temperature. Weak water pressure in common system The water supply is also not affected in any way by the operation of the indirect heating water heater.

Despite the fact that the use of an indirect heating boiler has obvious advantages, it is necessary to carefully consider the feasibility of using this or that equipment. For example, installing a hot water system consisting of a single-circuit boiler and an indirect heating boiler makes sense with the regular use of large volumes of heated water - when filling a bath, pool, long-term shower. If hot water is not needed in such quantities, it makes sense to simply install a dual-circuit boiler.

If the boiler is not used for a long time (for example, at the time of departure), it is better to pour the water out of it. It is also necessary to periodically warm the water to 60 degrees and maintain this temperature for at least an hour. Such thermal disinfection will prevent the reproduction of harmful bacteria in the boiler.

Every summer, urban residents are clouded by the shutdown of hot water. This brings a lot of inconvenience and hassle, especially if the house has small children. Very uncomfortable living modern people without hot water and in an unsuccessful dacha. In order not to depend on utilities and not to waste your time on warming up cold water, it is best to purchase a water heater. The most important thing is to choose it correctly.

Today, a large number of water heaters are on the market. Which one to choose depends on your needs and preferences.

How to choose a water heater among such a huge variety of types and models presented today in the market?

For this you need to learn about them all the most important, to study the features and characteristics, advantages and disadvantages, because we choose a water heater only 1-2 hours, and we operate it for years. Water heaters are divided into the following types:

Diagram of an electric storage boiler.

According to the principle of operation there are electric and gas.
In size and performance are compact and large, for heating small containers and large tanks with a volume of hundreds of liters, with water consumption from several to tens of liters per minute.
On execution there are with standard (manual inclusion of only one mode of water heating) and with prestigious execution (electronic control, automatic functions and several modes of water heating).
According to the installation rules, there are models that are mounted above and below the sink, on the wall and on the floor, horizontally and vertically.

In order to choose a water heater, you must first determine how many people will use hot water and for what purposes it is needed. Also, you should consider whether hot water is needed only at one point (for example in the kitchen) or in several places in the apartment or a country houseWhether it is necessary to solve a problem with the help of a water heater and with heating of an apartment or the house.

Storage heater and its characteristics

The storage water heater is convenient in that it constantly has hot water and it is economical.

A storage heater (boiler) is a heated thermos consisting of a tank with thermally insulated walls and a heating source.

Its main advantages are economy, constant availability of hot water and simple connection to electricity due to a much smaller one-time capacity.

Advantage of storage water heater before flowing is that when connected to several water points it allows creating jets with different head of water.

Accumulating water heaters with gas heating are the most economical in operation, they have the most minimal electric power consumption, which is necessary only for automation devices.

Their shortcomings are relatively large dimensions, a sufficiently long time for heating the water and the need for periodic maintenance. If the water heater is installed in an unheated room, then in winter time it will be necessary to drain the water from the tank.

Electric storage boilers can be vertical and horizontal.

Boilers with electric heating are vertical and horizontal, wall and floor. Some models can be installed both horizontally and vertically - depending on the desire and layout of the apartment. Installation can be made using existing valves and water pipe mixers.

Boilers with gas heating can only be installed in an upright position.

Boiler capacity

Boilers differ in the size of tanks, constructive features and the power of the heaters. Banks are small, medium and large capacity. Models of small capacity are quite compact for installation in any apartment, large capacity models can be used not only for heating water, but also for heating apartments, offices and shops.

The capacity of the boiler can be 5 - 300 liters.

Choosing a water heater for the volume of the tank, you need to be guided by the necessary need for warm water, taking into account the dilution of hot cold water. To wash dishes or take a bath, 30-40ºC is enough, and the temperature in the tank can be much higher. Therefore, the volume of the tank may be less than necessary to meet the needs of the amount of warm water.

In conventional domestic boilers, the capacity of tanks is from 5 to 300 liters, the capacity of tanks in boilers, which are used to provide domestic hot water, can reach up to 10,000 liters. The larger the capacity of the tank, the more expensive the boiler.

To wash and wash the dishes, enough tank capacity of 20 liters.

Durability of tanks

This characteristic, like the longevity of the tank, will help determine the life of the water heater. Thermally insulated tanks are not subject to repair, and if there is a leak in them, the water heater will need to be replaced, and not repaired.

The longevity of the tank depends on the quality and material of the anti-corrosion protection.

The water in the boiler can be heated from 40 to 80 degrees.

The most durable are tanks made of stainless steel and passed passivation. They have a manufacturer warranty of up to 8 years.

Tanks made of carbon steel and covered with titanium enamel, are valued a little lower. They do not crack even at very high temperature and pressure drops. The guarantee for them is valid for 5-7 years.

Tanks made of ordinary steel with a polymer coating are less reliable and durable than tanks made of stainless steel and ordinary steel with titanium enamel. The guarantee for them is 3 years.

Tanks made of plastic, not subject to corrosion, but significantly inferior in strength and other indicators of metal tanks. But they have technological advantages over steel tanks and are much cheaper in production. They are given a guarantee of up to 5 years.

In the metal tanks magnesium anodes of various sizes are inserted to strengthen the corrosion protection, which need to be changed 1-2 times a year to new ones. To isolate the tanks use rigid polyurethane foam and basalt glass fiber. High heat-insulating properties of polyurethane foam make it possible to reduce the thickness of the walls of the tank and the dimensions of the boiler. Such a tank provides a constant presence of hot water, perfectly preserves heat and has high rates of economy. Having such a tank, you can use hot water even with a short-time power outage. The temperature of the water in a well-insulated tank decreases by 0.5 ° C per hour when the heating is switched off.

Water heating in the tank

The temperature of heating the water in the tank depends little on the temperature of the incoming cold water. The water in the tank can be heated up to 80 ° C. In more expensive models, the temperature of water heating is regulated in a fairly wide range and can be maintained at a given level. To heat 30 liters of water to 70 ° C, it takes about an hour, and 100 liters - about 4 hours.

Heating starts immediately after filling the tank cold water. When the hot water tap is opened, hot water is drained, and at the same time a cold water is supplied. Cold water comes from a water pipe or a large tank into the tank from below, thereby displacing the hot water upwards. If the cold water is supplied autonomously, the difference in the levels at the inlet to the boiler and in the tank must be at least 2 m.

Open and closed output

The scheme of connection of the boiler to the network and the water supply system.

Boilers, in which the water supply comes from a water pipe, are with an open and closed exit.

If the hot water supply is only needed in one water point, a water heater with an open outlet should be chosen, in which the hot water tap can not be shut off during the initial start-up.

If the supply of hot water is necessary at several points of water, it is best to choose a water heater with a closed outlet, in which the pressure of the hot water at the outlet and the pressure in the water pipe are the same.

Operating pressure

Water heaters differ in terms of working pressure. Required water pressure in the water supply for the boiler closed type - 4-6 atmospheres. If this level is higher in the house, then a pressure reducer must be installed. In the tank for protection from high pressure it should be safety valve. When the pressure rises, excess water exits the tank through the drainage tube.

Boiler connection

Scheme of dry TEN.

Boilers with a capacity of up to 2.5 kW can be directly connected to the household 220 V using the existing wiring. Boilers with a capacity of up to 5.5 kW must be connected with a separate special wiring. With a higher power, the boiler should be connected to a 3-phase 380 V network.

For sale there are boilers that can work with a change in power up to 6 kW at different voltages in the network.

The most common models storage water heaters with electric heating volume of 100 liters consume an average of 7 kW.

Heating element - TEN

As heating elements, "wet" and "dry" heaters are used.

"Wet" heating elements are immersed in water, so they must be periodically cleaned of scale. "Dry" heaters do not have direct contact with water, so they are more preferable. In addition, they are durable, they do not need to be descaled and can be replaced without draining the water from the appliance.

The most reliable are water heaters, in which there are 2 heaters. If one of them fails, the water heater can still be used. Using 2 heaters allows you to heat the water faster. Such a water heater can be switched to an economical mode to maintain a low water temperature by turning off one of the heaters.

Electronic control makes the use of the water heater more convenient.

Electronic control creates increased user-friendliness. Includes a digital display with buttons on the front panel of the boiler, where you can monitor the water temperature, fill the tank and adjust the water flow. In addition, you can choose the time to turn on the heating water and automatically maintain the temperature at a given level. In some models, there is a self-diagnosis function, in the event of any malfunction, a fault code is displayed on the display. In the event of an emergency, the machine switches off the water heater.

Flow-through water heaters are designed to heat water in a stream.
The advantage of such a water heater is the receipt of an unlimited amount of warm water immediately after the opening of the crane. With minimal dimensions, the water heater is able to provide the maximum demand for hot water. And in appearance, a flowing water heater is more attractive than a cumulative water heater.

A flow-through water heater with a minimum size can heat up a large amount of water, immediately after opening the crane.

A disadvantage of a flowing water heater is the increased power consumption and the associated connection to the electrical network. It is less economical and is not capable of heating water to the same high temperature as the storage one.
Flowing water heaters are built-in, vertical, designed only for the crane, only for the shower, for the faucet and shower together. There are compact models for installation above or under the sink.

Flowing water heaters due to their compact dimensions can be installed in any room. On sale there are models capable of supplying water only to one or several water-pumping points. Electric flow-through water heaters use more electricity than accumulators with electric heating, their power can reach up to 27 kW.

Characteristics of instantaneous water heater

The main characteristics are:

Heating water in the tank. The capacity of the flowing water heaters and the heating temperature depend on the temperature of the cold water at the inlet. The temperature difference between cold and hot water is about 25 ° C. At low heating temperatures on the TEN, the scale does not form so intensively, and this increases its longevity. If preheated water enters the water heater, the outlet water temperature rises and this saves electricity. Modern models of instantaneous water heaters even with the change in pressure in the pipeline maintain a constant temperature of water heating automatically. When the water supply stops, the automation switches off the heating. The heating mode can be selected depending on the change in the inlet water temperature and the season. More expensive models of flowing water heaters have several heating modes and 2-stage protection.
Durability. Depends on the quality of the TEN and the flask. "Dry" heating elements are much safer than "wet". Heaters with ceramic coatings heat water faster and have a longer service life. Plastic flasks are considered less reliable, they transmit heat worse than metallic flasks. The most durable are stainless steel flasks. The most effective are copper flasks: they are better than stainless steel flasks, transfer heat.
Electronic control. Flowing water heaters are equipped with a two-color display, where the screen color changes depending on the set heating temperature. Automation provides the flow of water at the right temperature, even in the event of a sudden change in pressure in the water supply. By turning the knob, you can select the desired water heating temperature. The display shows the set temperature.

Connection Requirements electric power supply flow water heaters are the same as the requirements for connecting storage water heaters.

Gas flow-through water heaters (gas columns)

The gas column is economical and safe.

Gas columns can raise the water temperature by 50 ° C. They can be equipped with a piezoelectric ignition of the flame of the pilot burner. For gas columns without a pilot burner, less gas is required. Such models are safer. The flame automatically lights up from an electric spark when the hot water tap is opened and turns off when the faucet is closed.

The modulating burner regulates the flame intensity automatically, depending on the water flow, which allows maintaining a constant heating temperature when the pressure in the water pipe changes.

A gas burner equipped with automatic ignition and temperature regulation of water heating is quite convenient for using a gas water heater. In more expensive models, there are special sensors that will automatically shut off the gas supply if the flame goes out or if the column overheats because of thrust violations.

Flow-through water heaters have all the advantages of running and storage water heaters. They are open-type units, they have compact dimensions, a small tank and a high heating rate. Usually sold complete with a ball mixer, shower head and a faucet.

Gas double-circuit boilers

Two-circuit gas boilers They are used for heating water for domestic needs and for heating premises. Boiler with expansion tank and the integrated pump is fully prepared for connection in the room. A boiler with an open combustion chamber is connected to a traditional chimney, and a boiler with a closed combustion chamber - to a special system of smoke and air ducts. Equipped with all necessary to ensure safety in cases of insufficient or excessive pressure, disruption of combustion and combustion products entering the room.

Built-in electronic sensors shut off the gas automatically if the flame goes out or smoke appears in the room. Presented on the market, water heaters of various models and brands are able to satisfy the demands of any buyer. Having studied the features, advantages and disadvantages of different types of water heaters, you can choose the device taking into account all needs and desires, and thereby not only improve the comfort of your residence, but also save money when buying it and operating it with water heating.

Often in private homes there is no connection to the central hot water supply, and water heaters help to organize the supply of warm water in such cases. In the heating season, the indirect heating boiler will not only ensure uninterrupted supply of warm water, but also provide the owner with significant savings. But what is the indirect heating water heater and what is the principle of its operation? This article will answer these questions.

Indirect heating boilers are appliances that can heat water with a heat source in a house heating scheme. These types of water heaters differ from electric or gas counterparts - their work consists in consuming the energy of the boiler, and not electricity or fuel. This feature is indispensable in the winter or just the cold season.

Pros of an indirect heating boiler

sufficiently rapid heating of the water;
providing multiple water intake points;
compatibility with any boilers;
saving on electricity costs;
provision of hot water recirculation;
reduction of the influence of scale on the capacity of the boiler;

Negative characteristics of indirectly heated water heaters

high cost of a set of equipment (an indirect heating boiler, as well as a single-circuit boiler), in contrast to a dual-circuit boiler;
decrease in the intensity of heating at home during the heating of water;
large volume of boiler capacity, occupying a lot of space.

The design of an indirect boiler and the principle of its operation

The device of the indirect boiler consists of a heat insulating tank having inside a water heating element, namely a coil (a tubular heat exchanger). The latter is a heating element, through which the coolant passes (water or antifreeze), and which is connected through an individual circuit to the system as a whole or to the heating boiler in particular. The time for heating the water directly depends on both the power and the surface area of the coil. Often, the capacity of the water heaters is equipped with a built-in anode, which contributes to its passive protection. indirect heating can be found floor or wall mounting.

The principle of operation of boilers is quite simple. Passing through the water heating element (coil), the coolant (water or antifreeze) transfers some of the heat of the water in the tank. Thus, the walls of the coil serve as a heat exchange surface. In other words, inside the tank is installed something like a radiator of the heating system, only the heating is not air, but our water in the tank.

Criteria for selecting an indirect heating boiler

Firstly, when planning a hot water supply system, it is worth remembering that the use of an indirect heater is justified only when the required amount of hot water is sufficiently large. In other cases it is economically expedient to use another method of water heating, for example, a two-circuit gas boiler.

Secondly, when buying an indirect heating boiler, it is necessary to take into account the capacity of the boiler, which must be sufficient for both heating the boiler water and for heating the house. In the event that the capacity of the boiler is insufficient, the time for heating the water increases severalfold. The power of the boiler must certainly be greater than the capacity of the boiler.

Thirdly, it is necessary to choose the correct volume of the tank. There are many ways to calculate this, so that hot water enough for your needs. We advise you to choose a boiler with a capacity of at least 50 liters if you plan to use hot water by one person, at least 80 liters, if 2-3 people use it, and for families consisting of 4 or more people, you should choose a tank of at least 120 l.

As for the coating of the tank, it should pay special attention, because this will determine the life of your equipment. Of course, boilers with a good and high quality coating are much more expensive, but you should not save on this.

To protect the capacity of the boilers, a special anti-corrosion coating is used, which is most often glassfibre or titanium sputtering. The latter is the most reliable, and a tank with such a sputtering is able to last long enough - up to 5 times longer than their counterparts with a glass-porcelain coating. But accordingly, these tanks and are at times more expensive. There are such tanks with titanium sputtering and their shortcomings, the main one of which is a weak spot in the welding section.

Also the most durable tank is made of stainless steel, which is deservedly a reliable material for protection against corrosion. Containers made using AISI 316 L steel contain a low amount of carbon and have a rather high resistance to intercrystalline corrosion, which in turn prolongs the life of the vessel.

Why you need to install an indirect boiler (video)

Summarizing, we can say that properly selected equipment can quickly warm up the water in the tank to the desired temperature. For example, 500 liters of hot water per hour is able to produce an indirect heating boiler with a capacity of 100 liters. The price of such water heaters starts from $ 270. Such a sufficiently high cost and large dimensions of the devices are the main disadvantages of indirect heating boilers.

Connecting an indirect heating boiler to a gas boiler

Connecting an indirect heating boiler to a gas boiler (video)