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How to fill in an indirect heating boiler properly

Indoor heating boiler strapping schemes

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

It is advisable to consider as an example traditional attitudes with a classic coil that work (receive thermal energy) from hot water. First you should deal with the term “indirect heating” in more detail. Classic installations use an electricity connection or natural gas to receive heat. Boilers do not have such advantages. They are connected to the hot water and use the heat of water or other coolant.

fill, indirect, heating, boiler

Standard installations have the shape of a round barrel (although today there are already more convenient and compact square models). If you look closely at the product line from well.known manufacturers, you can notice a certain tendency. They all have the same design. This applies to both boilers and gas boilers. You can significantly save space when they are placed by installing one unit on another.

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

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

Magnesium anode is one of the most important elements in modern boilers. The part serves to prevent corrosion on all internal surfaces, and the rod itself is inside the structure in its upper part. Thanks to this, the unit serves several times longer. The design must have a thermostat and built.in valves, since they are fuses from a strong increase in pressure as a result of failure of the entire system.

A common myth states that boilers are not effective 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. It is quite large in the BKN, so the water heats up effectively even at a seemingly low temperature not exceeding 70 ° C.

The device works very simple. The boiler capacity is completely filled with cold water for heating. Inside is a coil, into which hot water from the boiler is launched at this moment. Cold water after a certain time heats up and becomes suitable for taking a shower, washing dishes and other household needs.

What is an indirect heating boiler and why it is needed

It is customary to call a boiler a heater or a tank supplying an apartment or house with hot water. In general, there are 2 types of such units: direct and indirect heating. The main difference between the last version of the water heater is that this boiler releases the heat produced by the heating system. The appearance of an indirect heating tank causes an association with a barrel. But in the modern market you can find models that have the shape of a cube or parallelepiped. The first, being made with an indirect heating boiler in a single style, are usually installed directly under it. This solution ensures the savings in the utility room.

An indirect heating boiler can be connected to both a gas and electric boiler

Indirect heating boiler: principle of operation

Water is supplied to the unit for 2 contours. The first is heating, which is connected to the heating system of the dwelling. In the second, water is heated, coming from the water supply and subsequently distributed to the points of water intake.

The contours of heating are implemented in the considered unit with two methods:

  • “Tank in the tank”. From the name it is clear that this is such a boiler of indirect heating, the design of which provides for the formation of the circuit due to the placement of a smaller steel tank in the main tank;
  • The coil is mainly mounted.

Indirect heating boiler connection diagram

Both circuits are connected in parallel to the housing heating system. The coolant gets from it into the boiler through the pipeline. To organize effective circulation of the coolant, such a pipeline must be equipped with a pump-mixing system.

Helpful advice! When buying a boiler for a gas boiler, evaluate the power of the last unit. It should be enough to ensure the simultaneous operation of the heating system and the boiler is heated for heating.

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Cold water is supplied to the heating container, and hot water is taken by consumers. It should be borne in mind that many manufacturers produce such an indirect heating boiler with several heat exchangers. A similar design works more efficiently, but on sale are extremely rare.

Pros and cons of the boiler for hot water of indirect heating

The pluses of the technical solution implemented by this device can be attributed:

hydronic heating system antifreeze added to system

  • In the heating season, the wiring is not overloaded, since the device does not work from the mains;
  • both the coolant and the internal system of the heater into contact with tap water do not enter. It follows that such an indirect heating boiler will last a long time;
  • Hot water will begin to flow into the crane immediately after the launch of the unit, because the process of recirculation is based on its work;

The diagram of the design of the indirect heating boiler design

  • A well.designed water heating system will operate effectively with the optimal cost of exploitation on the basis of this device.

But here it was not without flaws. Of these, experts highlight:

  • The installation of an indirect heating boiler with recirculation requires significant preparatory work requiring considerable financial expenses, which will adversely affect the family budget;
  • There is a much larger boiler than electric or gas counterparts;
  • The initial heating of water requires about 1-2 hours. During this period of time, the quality of the heating system can noticeably deteriorate;
  • Having bought at an affordable price a 100-liter boiler of indirect heating, for its installation you will have to highlight a separate room. The fact is that even with a seemingly large volume of internal capacity, the external dimensions of such a device are very impressive. Not to mention the 200-liter boiler of indirect heating. But industry produces even 300-liter samples;

One of the disadvantages of using an indirect heating boiler is the ability to reduce the efficiency of the heating system

fill, indirect, heating, boiler
  • Got water, providing a house with hot water depends on whether the heating system is currently working. But for obvious reasons, there is no need for the year in it in the summer. There are two of the following exits from this situation: the installation of an individual coolant supply system that serves only a boiler, or install a combined boiler of indirect heating with an electric heater.

On the last option, we will dwell on somewhat more details. The most inexpensive and for this reason that has become traditional in the boiler is a copper heating. However, due to the intensive formation of scale at high temperatures in hard water, it quickly fails. In addition, these deposits reduce the degree of heat transfer of the heater, as a result of which the energy consumption increases.

Helpful advice! Buying a combined boiler of indirect heating with a “dry” heating element will save on paying for electricity bills.

Advantages and disadvantages, choice of BKN

Indirect heating boilers have a number of the following advantages:

  • The presence of a stock of hot water;
  • Do not require a permit for installation (unlike a gas boiler);
  • Simplicity of device and operation;
  • The possibility of using different heat sources;
  • The possibility of independent manufacture (in the presence of equipment and skills);
  • High.quality provision of hot water at any point of water clearance (in the case of the recirculation circuit).

The equipment has few disadvantages, but still they are available:

  • Large overall dimensions and weight of spacious models;
  • Dependence on the availability of electricity;
  • The initial heating of water requires a certain time, while the power released on the heating system is significantly reduced.

In the case of its own BKN boiler, it is unambiguously considered the best solution to ensure the needs of the hot water. It is not required to purchase water heaters having a more complex design, requiring the implementation of conditions for installation, the presence of other energy resources. gas or electricity. Compared to most water heating equipment, indirect heating boilers in terms of level and quality of hot water are considered the best.

The choice of the BKN model depends on the following factors:

  • The intensity of hot water consumption;
  • Manufacturing materials;
  • The possibility of integration with heat generators;
  • Manufacturer’s reputation;
  • Price.

The main selection criterion is the volume and frequency of water consumption. The volume of the BKN tank is usually determined by the average indicators of hot water consumption:

Number of persons BCN tank volume, liters Approx.
one 2 3
one fifty
2 50. 80
3 80. 100
4 100 or more
5 and more 120. 150 and more

An important technical indicator. the power of the heat exchanger. The rate of water heating depends on it. Recommended value. at least 70. 80% of the rated power of the heat generator. With lower values, the duration of the initial heating increases, this negatively affects the operation of the heating system.

The duration of the equipment service directly depends on the quality of manufacturing materials. It is recommended to purchase boilers made of materials that are not prone to corrosion or with maximum protection from it. Corrosion is the main negative process that affects the integrity of equipment.

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You should also pay attention to the possibility of integration (mutual work) of the boiler and boiler of various manufacturers. Such an opportunity is not always available. for joint work it may require the purchase of additional automation and complication of the scheme.

An important factor. the reputation of the manufacturer and the cost of the device. The issue of price depends on the financial capabilities of the buyer. As for the manufacturer, it is recommended to purchase units of proven brands. BKN have a decent cost. therefore, it would be irrational to purchase a low.quality product.

An indirect heating boiler. pros and cons of

Compare the indirect heating boiler and other types of water heaters:

  • Gas column. its installation requires a project, building a chimney and preliminary approval with government agencies. The maintenance contract for the gas column is required. The main minus of this type of water heaters is the inability to maintain a stable water temperature.
  • Gas heater, accumulative. similar to most characteristics with an indirect heating boiler, but requires the same preliminary measures as the installation of a gas column.
  • Castle electric heater. rapid heating of water, but low performance due to lower power than that of indirect heating boiler.
  • The accumulative electric heater. as in the case of a flowing electric heater, has a lower power, which is why it is not capable of providing a new portion of water in a short time. Serious Minus of any electric heaters. a large electricity consumption.
  • Double.circuit boiler. the performance of this water heater is small, and the temperature of heated water is not constant. The main disadvantage in solving the problem of the hot water using double.circuit boilers is the overgrowing of the serpentine in which water circulates with lime deposits (scale). As a result, a double.circuit boiler loses power, t. to. The scale prevents the heat transfer, the cross section of the snake’s tube decreases, which is why the water when opening the tap flows with a weak stream. it is extremely difficult to remove the scale inside the coil.

Installation and circuit of a strainer of indirect heating boiler

There are three options for connecting to the heating system and all of them involve the installation of a boiler at a minimum distance from the boiler. The boiler should be placed on a sufficiently strong base and strictly in level. The input of the coolant should be performed on top, the withdrawal from below. The fence of hot water, on the contrary, is performed on top, and the feed is based on.

Option 1. The heating pipe is divided into two branches, each of which is on a locking reinforcement or a three.way crane. One branch passes through the boiler, the other shakes the highway if the water is not needed. This method is optimal with constant use of a boiler or seasonal operating mode. In this case, you can adjust the temperature in two electromagnetic valves with self.return connected through a three.pin r all of a thermostat.

supply of cold water; 2. locking reinforcement; 3. mesh filter; 4. check valve; 5. security group; 6. heating radiator; 7. heating boiler; 8. boiler security group; 9. circulation pump; 10. three.way crane; 11. electromagnetic valve; 12. expansion tank of the DHW system; 13. hot water to consumers

Option 2. The feed pipe has a branch to which the circulation pump and a boiler are connected sequentially, on the other hand, the connection is made to the reverse flow pipe. The pump is enabled through the thermostat relay circuit, thus, when the water temperature drops inside the boiler, it activates forced circulation and accelerates the heating. The heating circuit has its own pump installed on the feed pipe after the boiler insertion place. This option is optimal if the boiler is used infrequently or the water temperature is required lower than in the heating system.

supply of cold water; 2. locking reinforcement; 3. mesh filter; 4. check valve; 5. security group; 6. circulation pump of the DHW system; 7. boiler thermostat; 8. radiator; 9. heating boiler; 10. boiler security group; 11. circulation pump of the heating system; 12. expansion tank of the DHW system; 13. hot water to consumers

Option 3. The boiler is sequentially connected to the boiler supply pipe through the circulation pump. With this connection, the boiler always works in the heat accumulator mode, the option is optimal for recirculation devices. The presence of a bypas connecting the fluorine outlet from the boiler with the boiler is accessed to use the DOS system in the summer.

fill, indirect, heating, boiler

supply of cold water; 2. locking reinforcement; 3. mesh filter; 4. check valve; 5. security group; 6. bypass; 7. heating radiator; 8. heating boiler; 9. boiler security group; 10. circulation pump; 11. expansion tank of the DHW system; 12. hot water to consumers

With any connection diagram, it is necessary to install shut.off valves on all the boiler pipes and the circulation pump. Connecting the boiler to the DHW system necessarily requires installation from the water supply of the expansion tank with a membrane to compensate for the pressure of the heated fluid. A mesh filter and a check valve must be installed on the cold water supply pipe to the security group.

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Scheme of electrical connections

The combined version of the tank, equipped with a heater, must be connected to the house network, taking into account the transition to the summer mode, in which the main coil will stop receiving heat from the boiler. We offer to use the universal scheme where the pump control module is included by the thermostat.

The colors of the wires depicted in the figure correspond to the generally accepted classification: blue-neutral, brown-phase, yellow-green-grounding and so on

The circuit involves the second security thermostat, which works at the time of overheating of sanitary water. Lamp. indicator signals the inclusion of the heater.

Advantages of homemade heaters

Why the hosts still often prefer to make a boiler with their own hands? A homemade boiler has a lot of advantages over factory:

  • Connects to the heating system.
  • It is placed next to the boiler.
  • Costs much cheaper than purchased
  • Allows you to save energy resources.
  • Allows you to maintain a constant water temperature.

If we talk about the minuses of the boiler with your own hands, then they are:

  • You need a rather spacious room to put or hang a heater.
  • If the device is not powerful enough, water heats up for a long time.
  • Scale is quickly formed, so it is better to soften water

Important! A homemade unit is also good because it works from central heat supply during the heating season, and in the summer. from the mains.

Boiler device

Indirect heating in these boilers is carried out due to heat partially selected from the heating system. To do this, their device provides for spiral heat exchangers made of copper or brass. They have a fairly large area to ensure a faster warming up of the internal contents. All this farm is included in the tanks of one or another volume. Types of used tanks:

How to Install an Indirect Water Heater on a Boiler | Ask This Old House

In terms of price/quality, glass.ceramic boilers are the best solution.

  • Enameled. differ in the maximum cheapness and not the longest service life;
  • Glass.ceramic. more advanced tanks characterized by increased endurance. But they cost more than enamel tanks;
  • From stainless steel. almost eternal, very hardy and persistent to corrosion. This is really the best choice, but characterized by a high price.

In addition to everything, thermostats are present on board. they control the flow of coolant, adjusting the temperature of the water in tanks within the established limits. For servicing indirect heating boilers, audit holes (flanges) are provided in their design.

For work in the summer, indirect water heaters can be equipped with heating elements. They are purchased separately or are supplied by already built.in. There is also an automation on board, which controls the shutdown and turning on electrical heating elements. For the protection of tanks and welds, replaceable magnesium anodes are provided. External covers are made of plastic or steel.

Any accumulative tank of indirect heating contains another important detail. this is the thermal insulation that protects water from too fast cooling.

Often there is a situation when there is a heated towel rail in the bathroom through which water should constantly circulate. Both boiler and boiler can be involved in this process.

In this case, the heated water will constantly circulate through the closed circle using a pump. The advantage of such a scheme is that the water from the crane will spill immediately hot (you do not need to lower it).

But there is a drawback: during recirculation, fuel consumption is increased. Moving along the heated towel rail, the water will be rapidly cooled, the boiler will have to “be distracted” more often on the hot water and at the same time spend additional fuel. This will be especially felt in diagrams where a solid fuel boiler and an indirect heating boiler participate.

But not even this moment repels many from the use of this method. During recirculation, the water layers are mixed, and the total temperature of the heating of the water in the DHW contour drops. In normal mode, the upper layer of water in the tank is first used, and it is hotter. But the towels will always be dry.

How to avoid these shortcomings? There are special models of boilers with indirect heating water with already provided for recirculation. The heated towel rail is connected to the boiler nozzles intended for this. Devices are much more expensive than similar options for water heaters with the same volume, only without a recirculation system.

Author

Kerariel

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