Connecting the boiler to a double-circuit boiler. Wiring diagram for an indirect heating boiler - which one is easier to do yourself? Wiring diagram for indirect heating boiler

12.11.2019

Boiler indirect heating installed in conjunction with single-circuit gas and solid fuel boilers, heat pumps, solar collectors. For normal operation of the water heater, piping is required, made in accordance with the manufacturer's instructions.

Connecting an indirect heating boiler to a single-circuit boiler requires special skills, a clear understanding internal device capacitive storage. There are several options for piping, which allows you to take into account the technical conditions for the operation of the BKN.

Fittings for binding BKN

The principle of operation of the boiler is associated with the use of heat taken from the heating system to heat domestic hot water. The binding of the BKN should solve several important tasks:

ensure continuous circulation of the coolant from the boiler to the water heater;
prevent hydraulic and thermal shock;
maintain the set temperature of water heating in automatic mode.

When installing the boiler, the following shut-off and control valves are used:

Diaphragm expansion tank- designed to compensate for thermal expansion in the DHW system and prevent accidents. At connecting BKN installed with the security group. The expansion tank must contain at least 10% of the total volume of the indirect heating boiler.
Safety valve- needed for emergency draining of water from the BKN. With an excessive increase in pressure, it opens and discharges water from the boiler. The valve is used during maintenance to fill the tank with descalers.
Indirect heating boiler safety group- Includes pressure gauge, relief valve and air vent. The unit is designed to normalize the pressure in the hot water supply and prevent water hammer. The installation of a safety group and an expansion tank is a requirement made by manufacturers for the BKN piping.
Boiler temperature sensor- connects to a circulation pump that controls the pressure in the coil. The immersion thermostat works on the principle of a relay. When sufficient water heating is reached, the sensor gives a signal to turn off the pumping equipment. The water stops heating up. After cooling, the automation for the boiler starts circulation.
Three-way valve- works as a mixing unit, opening and closing the flow of water to the boiler from the heating system. There are simple mechanical devices and precise servo operated three-way valves.
Circulation pump- depending on the selected strapping scheme, one or two modules are installed. The pump is used to create constant pressure and recirculation in the DHW system.

The connection kit may vary depending on technical conditions, building features, actual hot water demand and other parameters. Additional equipment may be present in the piping: a hydraulic switch, a filtration system.

Pipe material for piping BKN

Cold and hot water supply, supply and return of the heating system are connected to the boiler. The heating temperature and pressure on the pipes determine which material is preferable to use when tying:

Cold water - normal water can be installed polypropylene pipe. The material is suitable for soldering the entire cold water system.
Hot water supply - DHW temperature supplied to the user is maintained at 65-70°. It is allowed to use polypropylene with fiberglass (reinforced) or aluminum reinforcement, intended for hot water supply.
Another option: tie copper pipe. When laying a copper pipe, the use of thermal insulation is mandatory. Copper is a good heat conductor, which will inevitably lead to a decrease in the temperature of heated water during transportation to the end consumer. Thermal insulation of pipes will protect against heat loss.

An alternative to polypropylene can be a metal-plastic pipe. Material withstand high pressure and heating up to 95°C. Mounted using crimp and press fittings.

The installation location of the boiler is immediately after the heating boiler, in front of the radiators and warm floors. This connection scheme is due to the fact that in order to heat the DHW, the coolant must be heated to 90-95 ° C. Serious thermal load observed in the area between the boiler and the boiler. This section of the strapping is recommended to be made with a steel or copper pipe.

Options for piping an indirect heating boiler

Several conditions affect the choice of connection scheme. The source of heat, the number of water points, the presence of underfloor heating, heating radiators in the system are important. The piping methods are selected individually in each case, with an emphasis on the technical conditions of the hot water supply and heating systems.

Another important factor to consider when choosing the type of connection is volatility. There are ones in which the circulation of water and coolant occurs independently, as well as schemes with the creation of forced pressure (pumping). The latter cannot work without electricity. BKN manufacturers in the operating instructions indicate the recommended piping scheme, which is also taken into account when connecting.

BKN piping with a three-way valve

Scheme with mixing unit- connection with DHW priority, successfully used when several heat sources are simultaneously connected to the boiler (boiler, solar collectors, heat pump). BKN is mounted immediately after the heater. A circulation pump is cut into the supply, a three-way valve is installed.

There are several advantages of the solution:

rapid heating of hot water;
savings with constant use of the boiler;
the possibility of automating water heating.

The three-way valve redirects the flow of coolant from the heating system to the BKN until the temperature in the boiler reaches the set values. After heating the DHW, the coolant is fully returned to the heating system.

Dual pump piping

A good solution in cases where the boiler is planned to be used only from time to time. Requires the connection of two circulation pumps. The first is put on heating, the second is directly on the water supply to the BKN. A constant circulation of the coolant in the heating system of the building is maintained.

The circulation pump for the accumulator is connected to a thermal sensor. When the DHW heating temperature drops, a signal is given to turn it on. A sufficient pressure is created to change the movement of the coolant and direct it through the BKN. In order for the system to function normally, an accurate calculation of the pump for the indirect heating boiler is needed.

Connection via hydraulic arrow

The scheme is used for industrial purposes, as well as for tying large drives over 200 liters. Connection through a hydraulic arrow is also used for branched complex heating systems: combining underfloor heating and radiators, a solid fuel boiler, together with solar collectors.

The implementation of the strapping requires preliminary competent thermal engineering calculations. The connection scheme is complicated, so it is better to seek professional help to complete it.

Tying in a gravity system

Hydraulic connection schemes used in non-volatile heating boilers. The boiler and related equipment is raised above the boiler. The distance between the level of the boiler heat exchangers and the water heater must have a gap of at least 1 m in height.

The gravity system has several disadvantages associated with the peculiarity of the work. Water warms up more slowly, the heating temperature and the water supply in the tank will be less than in systems with forced circulation. The main advantage: the ability to work in the absence of electricity. With frequent power outages in the network, a gravity system is out of competition.

Installation of DHW recirculation with BKN

In normal use hot water some of it constantly remains in the pipeline between the BKN and the draw-off point. In difficult DHW systems, without recirculation, this segment can contain several tens of liters of liquid.

When the faucet is opened again, the already cooled water first flows out of it, which reduces the comfort of using the boiler. Recirculation is needed to ensure instant supply hot water consumer. An additional advantage is the ability to connect a heated towel rail.

The piping scheme for an indirect heating boiler with recirculation practically does not fundamentally differ from a conventional connection. The difference is that a tee connected to the return pipe is installed in front of the mixer itself or the tap. The DHW recirculation line through an indirect heating boiler will operate exclusively with the use of pumping equipment.

Recycling has several disadvantages:

decrease in DHW heating temperature;
increase in fuel costs;
energy dependence.

In the design of European indirect heating boilers, companies, ACV,
A common question with no definitive answer. Connecting an indirect heating boiler to a double-circuit boiler will solve the problem of waiting: from the moment the tap is opened until the actual supply of hot water. In practice, the following happens:

When the tap is opened, the double-circuit boiler heats the DHW heat exchanger, spending the maximum amount of thermal energy on this. It takes time for the coil to warm up. For this reason, hot water is supplied to the user not immediately after the tap is opened, but after some time (the period depends on the distance of the draw-off point and the boiler power).
Frequent starts and stops in the supply of hot water create a load on the heating elements, which can lead to a quick failure of the equipment.

According to some estimates, only 1 draw-off point with intensive use wastes about 70 liters of water. A double-circuit boiler with an indirect heating boiler in normal mode works in the same way as a single-circuit one. Heat from the heating system enters and accumulates in the storage. When DHW is turned on, hot water is immediately supplied to the consumer. The piping of the boiler and indirect heating boiler provides for the installation of a recirculation system.

The main disadvantage of the scheme: the dependence of the operation of the BKN on the throughput of the boiler. The parameter affects the speed of hot water preparation. Heat transfer in this case will be lower.

BKN is better to initially connect to a single-circuit boiler. Connection to a double-circuit boiler is inefficient and is used mainly if it is necessary to modify an existing heating and hot water system.

If you do not know how to connect an indirect heating boiler to a double-circuit boiler, the diagram on this page will help you deal with this issue.

The most simple circuit connecting an indirect heating boiler to a double-circuit boiler implies the use of a second boiler circuit for heating hot water for domestic hot water.

In the case when you do not have a BKN, hot water is heated in the "streaming" mode. If you need a "cumulative" mode, then there is only one option - the use of BKN, since there are no storage tanks no hot water storage.

At the same time, a double-circuit boiler, the diagram of which is given on this page, is implemented in exactly the same way as if it were a single-circuit boiler.

The question arises - why then use a double-circuit boiler? The answer is not obvious. But someone may have such a situation that there is already a 2-circuit boiler and there is a BKN. And at the same time, a person wants to implement a hot water supply system in a "cumulative" mode.

Scheme of connecting an indirect heating boiler to a double-circuit boiler

So, here is a simple scheme for connecting an indirect heating boiler to a double-circuit boiler, when you have the opportunity to implement a "storage" mode for the DHW system even when using a 2-circuit boiler.

What is an indirect heating boiler and how it works

The design of this type of unit is relatively simple. It is an indirect heating boiler, a small heat-insulated metal "barrel", covered from the inside with two layers of enamel. As a heating element in such units, a conventional coil is used.

Cold water enters the indirect heating boiler from below, passes upward through the spiral, heats up and exits through the upper pipe. The heat carrier of the heating system is responsible for heating the coil itself in such devices. Hot water from the boiler is supplied to the heating coil from above, and is discharged from it from below.

What rules should be followed when connecting

Do-it-yourself piping of indirect heating boilers is carried out in compliance with the following recommendations:

taps are installed on the pipes supplying the coolant to the coil and draining it;
at the entrance cold water a check valve is installed in the unit;
an expansion tank must be used in the boiler piping.

Valves on the pipes connecting the water heaters with the boiler are mounted in order to facilitate repairs if necessary. In the future, it will be possible to remove the unit in the presence of such fittings at any time without turning off the main equipment. check valve when installing the boiler, it is used in order to avoid the flow of hot water into the "cold" water supply when the pressure in the system drops.

An expansion tank in the piping of indirect heating units serves to prevent their body from breaking during operation. After all, as you know, when heated, water can expand quite a lot. Consequently, the pressure inside the unit can rise to high limits.

The main stages of installation

The piping of the water heater, therefore, should include the following steps:

connecting the unit to the water supply from the well;
tie-in line supplying heated water to consumers;
connection of the coil to the pipes of the boiler, inlet and outlet of the coolant;
installation of the expansion tank and safety group.

Simultaneously with the boiler in boiler rooms, a recirculation system that increases the usability of hot water supply is usually mounted.

Step-by-step installation of a boiler in a forced-type heating system

In networks of this type, the piping of indirect heating units is carried out as follows:

after the circulation pump, a three-way valve crashes into the supply pipe;
a water heating temperature sensor is screwed into the sleeve on the boiler body;
one of the outlets of the three-way valve is connected to the boiler pipe receiving the coolant;
a tee crashes into the return pipeline;
a branch pipe for the removal of the heat carrier of the coil is connected to the tee;
a valve is installed behind the tee;
an expansion tank is mounted on the hot water pipe next to the boiler.

Indirect heating sensors are usually initially supplied with single-circuit boilers. When the water in the boiler cools down, they simply switch the three-way valve to supply coolant to its coil. As a result, the boiler switches to hot water heating mode. The heating system is temporarily switched off.

As soon as the water temperature in the boiler reaches a certain value, the three-way valve switches the boiler back into space heating mode.

Stages of installation of a water heater with a pump

Sometimes indirect heating boilers, when inserted into the system, are supplemented with their own circulation pumps. Typically, such a piping scheme is used when the unit is not installed next to the boiler, but at some distance from it.

In this case, the installation is carried out according to the following technology:

a pipe is connected to the boiler coil from above, supplying the coolant from the boiler;
a section of the boiler return line cuts into the cold water supply to the boiler;
in front of these segments, a check valve is mounted in the cold water pipe;
a pump is installed on the heater return;
the pipe is connected to the coil;
an expansion tank is installed.

A three-way valve in such a scheme, as you can see, is not used. The boiler circuit is connected through conventional tees. In this case, the pumps and the temperature sensor are responsible for switching the flow, which, depending on the degree of water heating, closes the contacts of the boiler or boiler pump.

Step-by-step piping in gravity systems

Installation of a water heater in networks of this type is carried out in such a way that it is located above the radiators. Therefore, they buy for gravity systems usually not floor, but wall hanging boilers.

Includes correct installation water heaters in networks with natural circulation of the coolant, the following steps:

supply from the boiler is connected to the boiler coil using a pipe of a larger diameter than in the heating system;
further, the supply of the heating system is cut into this segment between the boiler and the water heater;
between the boiler and the resulting branch, a thermostatic head with an overhead sensor, powered by batteries, is mounted;
the boiler is connected to the boiler with a return pipe;
a line for removing the cooled coolant from the radiators is cut into the return pipe;
an expansion tank is installed closer to the boiler on the return line.

Water is heated when using such a scheme due to the difference in the cross section of the supply pipes of the boiler and the heating system. The water heater in this case is a priority. As soon as the water in the boiler is heated to a certain temperature, the sensor is activated and the pipeline is blocked. As a result, water begins to flow into the heating system.

Is it possible to connect to double-circuit boilers

It is quite convenient to use double-circuit boilers capable of heating water both in the heating system and in hot water supply in country houses. However, this equipment has one fairly serious drawback. When using a double-circuit boiler as a heater, the water from the DHW taps can go either too hot or cool. Equipment of this type, as already mentioned, is not capable of providing its uniform heating.

In this case, you can correct the situation with the help of a boiler. Connect such equipment to double-circuit boilers is of course allowed. The piping of the water heater with such units is carried out in the usual manner. At the same time, on the boiler itself, the pipes responsible for hot water supply simply overlap.

Installation of an indirect heating boiler in the collector network

Such modern systems water heaters are also very commonly used. Boilers are mounted in collector networks, usually on a comb as close as possible to the supply. That is, where the coolant has the highest temperature.

Indirect heating boilers are connected in such systems according to the following scheme:

the supply from the comb of the heating system is connected to the water heater;
the return line, expansion tank, safety group are connected;
water supply and outlet pipes are installed.

When installing the supply line of the coil in collector systems, shut-off valves are mandatory.

Installation instructions for the recirculation system

It often happens that plumbing fixtures are located in the house at a considerable distance from the boiler or on the upper floors. In this case, the owners of the building, in order to get hot water, usually have to wait until stagnant and cooled in the pipes drain from the taps in the bathrooms. And this, of course, is inconvenient and not particularly economical.

You can fix this situation by building in country house recycling systems. The installation of such a network is approximately as follows:

as close as possible to the consumer, a tee cuts into the pipe supplying hot water to it;
a pipe of the required length is connected to the tee;
the extended line is connected to the boiler through the recirculation pipe;
next to the boiler at the branch pipe, an additional pump of not too high power crashes into the circuit.

When using such a scheme, the water in the pipes between the boiler and the consumer, after turning on the pump in the electrical network, will not stagnate and, accordingly, cool. That is, residents of the house will be able to use hot water immediately after unscrewing the tap valves.

Heating equipment is now quite diverse. But understanding all its intricacies is extremely important, because otherwise you can allow fatal errors. This fully applies to water storage devices that heat it by an indirect method.

Peculiarities

The main feature of the connection scheme for any indirect heating boiler (the brand and model can be ignored here) is that it is devoid of its own heating unit. Water takes a thermal charge from external heating systems.

They may receive thermal energy due to:

combustion of mineral or organic fuels;
electrical resistance effect;
contact with the central heating system;
accumulation of sunlight.

Device

With any type of external sources of thermal energy, the operation of the boiler is the same, with rare exceptions. And even private innovations of individual firms, protected by patent law, do not change the essence of the long-established scheme. A portion of the heat carrier received from any source goes through a coil built into the storage. The circulation is maintained by a pump. In close contact with the tubes or the tank, where the initially colder water is located, it heats up.

Since even one joule of heat, radiated out in vain, has an extremely negative effect on the operation of the system, it must be equipped with thermal protection. Polyurethane or polystyrene is usually chosen as the material impervious to the outflow of heat. The flow of new doses of cold water naturally comes from the general water supply system. Each new portion passes through specially designed nozzles. As soon as the cycle of movement in the coil is completed, the coolant enters the heating system of the house - a very special pipe is provided for this.

Then there are certain differences: Although most boilers are designed to supply cold water from the bottom, there are some that supply it from the top. In such a design, the liquid must first pass completely through the system to the lowest point. Variations with the withdrawal of the heated coolant are noticeably smaller, in almost 100% of cases it is removed from above. It is difficult to find a reason why one should do otherwise. After all, the top location allows you to supply hot water for as long as possible, while there is at least a small portion of it in the tank.

In order for the coil to occupy the largest possible space within the body, it is usually made in the form of a spiral. When the coolant passes several cycles through this pipe, the temperature becomes equal to the heating of the liquid in the boiler itself. At the command of a special relay, a special circuit that feeds the pump stops. With the subsequent cooling of the coolant to the set value, the relay gives another command - to close the circuit - and the heating resumes. The advantages of such a device are fairly well known. All these points must be taken into account before work begins.

Installation principle

If you want to mount a tank with a capacity of up to 200 liters, it can be a wall-mounted product. For its fastening, brackets of a special kind are provided, which must be located on even and strong vertical surfaces. Ordinary drywall partitions for mounting even such a “light” drive are of little use. You need to choose between saving on the arrangement of interior space and saving on the boiler. Floor units are preferred to meet the needs of large households, sometimes they even put products with a capacity of over a thousand liters and allocate a special boiler room for them.

In private homes, you can limit yourself to indirect heating boilers that accumulate from 250 to 300 liters of water. The exact choice of capacity should be made taking into account real and predicted needs. When connected to a double-circuit boiler equipped with a built-in pump, the coordination of the valve operation according to signals from the thermostat is taken over by the boiler automation itself. This is very important, because a double-circuit heating apparatus, unlike a single-circuit one, must supply hot liquid both to the heating system and to the hot water supply circuit.

If a three-way valve is installed, the water heater will have an advantage in the system compared to the heating circuit. This approach is acceptable when the tank is installed large capacity. For your information: a similar connection method is also practiced with the forced use of hard water, which makes it difficult normal use hot water systems. Although, of course, it would be much more correct to take care of softening the incoming coolant. But sometimes you have to reluctantly adapt to it.

Problems may arise due to the fact that a significant consumption of hot water can complicate the operation of this scheme. At the same time, the method of generating heat, including using a pellet or other solid fuel boiler, is not essential. And here the boiler comes to the rescue, which smooths out fluctuations in two circuits. Thanks to him, even the intensive consumption of the coolant has little effect on people's daily lives. Installers must consider which function will have the highest priority.

Connecting indirect heating boilers to a single-circuit boiler can be done using a pair of pumps. Then the water flows with their help are distributed through two pipelines. It is usually assumed that the hot water circuit will come first. The algorithm of the boiler operation in conjunction with a single-circuit apparatus is also adjusted accordingly. So that liquid flows of different heating do not change the main parameters of each other, both pumps must be preceded by a check valve. Hot water is supplied exclusively from the boiler.

Mounting

High-quality piping of a boiler connected to a double-circuit boiler implies docking the water heater with one of the heat exchangers. An annular system is formed when the inlet pipe of the boiler communicates with the initial link of the heat exchanger. Everything is designed in such a way that the water coming from the water supply system bypasses the boiler heat exchanger. It will begin to pass immediately into the boiler, and from there it will penetrate into the DHW route. To plug electric boiler it is possible approximately according to the same scheme, but the water supply is connected to the first branch pipe of the second node that exchanges heat, and the second branch pipe is already connected to the boiler.

It is recommended to install the water heater as close as possible to the energy source in order to simplify their connection using automation. When the device is mounted, it is the docking turn. Important: A properly installed and connected water heater must only take a fraction of the heat. Excessively high consumption can paralyze the heating system. It is most often possible to solve such a problem if you install an automatic circulation pump with your own hands or with the help of professionals.

Only at the very last turn is the thermal block mounted. It is almost always recommended to entrust the assembly of the circuit to specialists. The nuance is that indirect heating boilers with a control unit must be connected exclusively to heating systems that receive water from uncontrolled boilers.

Only required:

tighten the giving and taking moves;
dock the drive with the water supply;
put a comb on the top outlet that distributes hot water;
fill the reservoir and start heating immediately.

The simplest boilers interact mainly with automated heat sources. When installing, you will have to take care of connecting a sensor that measures the force of heating. This sensor is supposed to be associated with a strictly defined input to the boiler. It is allowed to connect boilers independent of the mains to autonomous boilers, but this immediately complicates the work and requires a special scheme. It should be borne in mind that it is possible to heat the water inside the boiler a little weaker than the heated liquid in the coil.

Therefore, when the boiler is switched to a low heating mode and can supply a coolant warmed up to 40 degrees, only combined-type heaters will be able to raise the temperature higher. They necessarily include an electric heating element, which helps to add heat. If, when setting up a system that controls recirculation, priority is given to heating hot water in a tap, the movement of the entire coolant is directed through the storage exchange unit. As a result, the total time required to obtain a liquid with the required temperature is noticeably reduced.

As practice shows, if the designers and installers of the boiler room give preference to the option with priority, it is possible to provide comfortable conditions for residents. To warm up the entire volume of liquid in the tank, it should take from 20 to 40 minutes. And if we talk about temperature stabilization against the background of coolant consumption, this time is reduced several times more. Even a small dwelling is unlikely to have time to cool down enough to be discovered by those in it. But a lot depends on the installed boiler and boiler: their power must match, and ideally it is recommended to install a boiler with a power reserve of 25%.

To guarantee the stable operation of devices connected to hot water distribution manifolds, it is necessary to supplement the outlet from the boiler with a special expansion tank. The recommended value is 10% of the main tank to help dampen the effects of thermal expansion. All connected branches are supposed to be equipped with ball-type shut-off valves. With their help, any node succeeds in right moment disconnect from the main and check or repair.

The pipelines through which the liquid is supplied are usually equipped with check valves. With their help, the opposite course of the coolant is prevented, the convenience and safety of installation is increased. It may be necessary to place a boiler next to a boiler, on the supply side of which a circulation pump is mounted. In this embodiment, it is very important to provide a separate circuit through which water will flow into the heater from the boiler. In essence, a parallel type of connection is created.

If there is a pump in both the boiler and the boiler, a three-way valve must be installed immediately after the circulation pump, one channel of it is connected to the water heater pipe. This ensures the normal operation of the heating. A tee must be installed on the return pipe up to the point of entry into the boiler. And already in this tee a branch pipe is connected, which draws the liquid from the heat exchanger. Such a simple system easily and elegantly solves the tasks.

As soon as the sensor gives a signal that the coolant temperature drops below the set mark, the valve transfers fresh flow to the boiler. Wherein heating system stops. When the normal value is restored, the same valve switches back. The minimum number of components reduces the risk of breakage. And ease of execution allows you to quickly find a problem if it does occur.

When a utility-independent boiler is used, boiler priority is not achieved as easily as in other options. It is recommended to place the water heater higher in relation to the floor of the room than the radiators. It is advisable that the lower point of the wall model is also raised above the boiler. But it is possible to strictly comply with such a requirement only in individual cases. When it is partially executed, it is still worthwhile to raise the drive to as high a height as possible.

Putting the boiler on the floor, immediately reduce the rate of heating of the liquid. Even worse, the lower part of the tank is in principle unable to warm up normally in this mode. If you connect the boiler according to the classical system, then any power outage will deprive you of access to hot water. You can solve the problem by using a larger pipe for the circuit associated with the water heater than on the heating link. Immediately at the beginning of the heating branch, a thermostat head is placed and a sensor is applied. Energy is provided by batteries.

An indirect heating boiler is installed in conjunction with single-circuit gas and solid fuel boilers, heat pumps, solar collectors. For normal operation of the water heater, piping is required, made in accordance with the manufacturer's instructions.

Connecting an indirect heating boiler to a single-circuit boiler requires special skills, a clear understanding of the internal structure of the capacitive storage. There are several options for piping, which allows you to take into account the technical conditions for the operation of the BKN.

Fittings for binding BKN

The principle of operation of the boiler is associated with the use of heat taken from the heating system to heat domestic hot water. The binding of the BKN should solve several important tasks:

ensure continuous circulation of the coolant from the boiler to the water heater;
prevent hydraulic and thermal shock;
maintain the set temperature of water heating in automatic mode.

When installing the boiler, the following shut-off and control valves are used:

Diaphragm expansion tank- designed to compensate for thermal expansion in the DHW system and prevent accidents. When connected, the BKN is installed together with the security group. The expansion tank must contain at least 10% of the total volume of the indirect heating boiler.
Safety valve- needed for emergency draining of water from the BKN. With an excessive increase in pressure, it opens and discharges water from the boiler. The valve is used during maintenance to fill the tank with descalers.
Indirect heating boiler safety group- Includes pressure gauge, relief valve and air vent. The unit is designed to normalize the pressure in the hot water supply and prevent water hammer. The installation of a safety group and an expansion tank is a requirement made by manufacturers for the BKN piping.
Boiler temperature sensor- connects to a circulation pump that controls the pressure in the coil. The immersion thermostat works on the principle of a relay. When sufficient water heating is reached, the sensor gives a signal to turn off the pumping equipment. The water stops heating up. After cooling, the automation for the boiler starts circulation.
Three-way valve- works as a mixing unit, opening and closing the flow of water to the boiler from the heating system. There are simple mechanical devices and precise servo operated three-way valves.
Circulation pump- depending on the selected strapping scheme, one or two modules are installed. The pump is used to create constant pressure and recirculation in the DHW system.

Pipe material for piping BKN

Cold water - an ordinary polypropylene pipe can be installed. The material is suitable for soldering the entire cold water system.
Hot water supply- the temperature of the DHW supplied to the user is maintained at 65-70°. It is allowed to use polypropylene with fiberglass (reinforced) or aluminum reinforcement, intended for hot water supply.
Another option: tie a copper pipe. When laying a copper pipe, the use of thermal insulation is mandatory. Copper is a good heat conductor, which will inevitably lead to a decrease in the temperature of heated water during transportation to the end consumer. Thermal insulation of pipes will protect against heat loss.

An alternative to polypropylene can be a metal-plastic pipe. The material withstands high pressure and heat up to 95°C. Mounted using crimp and press fittings.

The installation location of the boiler is immediately behind the heating boiler, in front of radiators and underfloor heating. Such a connection scheme is due to the fact that in order to heat the DHW, the coolant must be heated to 90-95 ° C. A serious heat load is observed in the area between the boiler and the boiler. This section of the strapping is recommended to be made with a steel or copper pipe.