Among the entire range of water heaters, it is indirect heating that is considered the most economical. To heat water in such a device does not require additional electricity or the consumption of other fuels, therefore, operating costs are minimized. The principle of operation of the equipment is based on heating water due to the movement of the coolant. In fact, this is a water heating system, where heat is not released into the air, but into the water in the tank.
Considering that the house is heated and water is heated at the same time, such a system is the most rational. With the undoubted advantages of such water heaters, they have one drawback - the price of an industrial model (from 15,000 rubles). We will tell you how to make an indirect heating boiler with your own hands, what is needed for this, and also give recommendations from experts.
Device and principle of operation
The simplest indirect heating boiler is a container where pipes are inserted. When the boiler is turned on, the coolant begins to circulate through the pipes, simultaneously heating the water. The tank initially contains cold water, which heats up as the boiler operates and can be used for its intended purpose.
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This is a kind of storage boiler in which the task of the heating element is performed by a pipe with a coolant. Given that the efficiency of the boiler is used to heat water, the cost of this type of hot water supply is minimal.
Device diagram
As can be seen in the diagram, the indirect heating boiler is a storage tank connected to the boiler by a pipe system. A coil is installed in the tank itself, through which a hot coolant circulates and heats the water. Due to the constant movement of the coolant, the temperature in the tank is kept at a certain level. Even with the consumption of water and the addition of new water, it heats up in a short time and is ready for use again.
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The advantage of using such a device is that hot water can be supplied simultaneously to several points, and the temperature is stable everywhere. If we take for example a double-circuit boiler or instantaneous water heater, then when you turn it on, you must wait a while until the water heats up. If 2 points are connected at once, then while hot water flows in one, cool water flows in the other, since the power of the heating element is not enough to instantly heat water in such a volume. An indirect heating boiler, built on the principle of water accumulation, eliminates such disadvantages and maintains a constant water temperature.
How to DIY
For home-made manufacturing, 3 options for boilers are suitable:
- a container with a coil through which the coolant moves;
- tank, where the pipes are located along the walls - the principle of circulation of the coolant is similar to the first option;
- 2 containers - large and small, where water is poured into the small one for heating, and the coolant circulates into the large one.
The primitive design of the indirect heating boiler gives a lot of room for creativity. If the principle of operation is clear, then you can come up with any of your own design options.
Manufacturing procedure
The list of works can be summarized in 7 main points:
- choice of capacity for the boiler;
- production of a coil or pipe for the coolant;
- tank thermal insulation;
- final assembly;
- connection of the coil with the boiler piping;
- cold water connection;
- hot water faucet installation.
Capacity selection
As a storage tank, any container of the appropriate size, resistant to temperature changes and having protection against corrosion, can be used. It can be plastic, stainless steel tank, cast iron construction, etc. A tank made of stainless steel 3-4 mm thick will be optimal.
In order to make such a tank yourself, take a sheet of steel and weld a cylinder out of it. Separately, you need to weld the bottom. This is possible if you own arc welding.
You can use a used gas cylinder. This is generally an ideal option, since it has a high degree of strength. In order to completely get rid of the remnants of gas and its aroma, it is enough to fill the balloon to the eyeballs, and drain the water after a few hours. Next, you need to cut the balloon, sand it from the inside with sandpaper and apply a primer. Leave to dry for a day.
Do not use enameled containers under the tank. Constant contact with water will quickly render the walls of the structure unusable and after a year and a half the tank will have to be redone.
Tank manufacturing
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In the tank (gas cylinder) by welding, make 4 holes:
- 2 for hot and cold water;
- 2 for pipe or coil mounting.
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Holes for the coil are made according to the pipe-to-pipe principle. In this case, all parts are interconnected by electric arc welding.
Hinges for wall mounting are separately welded to the tank. The loop can be made of reinforcement or a corner.
thermal insulation
To reduce heat loss, wrap a thermal insulation balloon. As such, any heat-insulating material, up to polyurethane foam, can be used. Fix the insulation on top with foam or foam rubber, tighten it with wire, after which the tank can be hung on the wall.
A large container in which the boiler is placed can also be used as thermal insulation. The space between them is filled with loose or lumpy heat insulator.
Coil manufacturing
The coil is mainly made of copper pipe. It is copper that almost does not react with water, does not resonate to a temperature difference, gives off heat well and can be operated for several decades.
Sand is collected into the pipe to prevent a break or a change in diameter, and it is wound onto a container of a suitable diameter.
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The pitch between the turns depends on the diameter of the coil and can vary from 2 to 5 centimeters. The threads do not touch.
The more turns in the coil and its total length, the faster the water in the tank will heat up.
At least once a year, clean the coil from lime deposits and plaque. It is known that our water is not of the best quality, so do not forget to carry out timely prevention.
Final assembly and connection
Install the boiler on the wall near the boiler. Connect the supply and output hoses of cold and, accordingly, hot water.
On the pipe through which cold water will flow, make a check valve so that the tank does not leak.
During the assembly process, it is important not to damage the heat-insulating layer, otherwise the water in the tank will cool down very quickly. Check before starting how even the layer is and if there are any tears anywhere.
All the details on how to make an indirect heating boiler with your own hands on the video:
The problem of heating water in a private house can be solved in various ways: by installing a gas column, a double-circuit boiler, a water heater, as well as an indirect heating boiler, which can be done by hand.
The principle of operation of an indirect heating boiler is based on the use of a system, its general or separate circuit. The boiler is a storage tank with a coil installed inside it, through which the coolant passes. The geometric dimensions of the coil are determined in accordance with the volume of the tank, which, in turn, can be any and depends on the family's need for hot water. The water to be used is piped into the boiler via an inlet pipe, usually located at the bottom. The water from the coil is heated evenly throughout the entire water column. The outlet pipe is usually located at the top so that there are no sudden temperature changes during use. Outside, the boiler must be well insulated to avoid heat loss from the walls of the tank.
An indirect heating boiler is usually installed in the same room as the boiler in order to reduce the cost of installing the circuit and heat loss. Install the boiler on a solid, level base, providing easy access to all taps and the lid.
R Calculation of the volume of the indirect heating boiler and design of the coil
The volume of the tank directly depends on the need for hot water. It is generally accepted that 50 to 70 liters of hot water is enough for each family member daily. Therefore, for a family of 3-4 people, a 200-liter boiler is enough. As a tank, any suitable heat-resistant container made of anti-corrosion material is used: stainless steel, aluminum, plastic. In the tank, inlet and outlet ball valves are installed.
The diameter and length of the pipe for the coil are calculated based on the volume of the tank, pipe material, coolant flow rate and temperature. For every 10 liters of tank, about 1.5 kW of heat output of the coil is needed. The coil is usually made from a brass tube with a diameter of 8 to 20 mm, coiled into a spiral so that the turns do not touch - this ensures maximum contact of its heating surface with heated water. To determine the total length of the tube, it is necessary to calculate the required coil power, and then determine the length of the pipe using the formula:
where P is the thermal power of the coil in kW;
d is the pipe diameter in meters;
ΔT is the temperature difference between the coolant and the heated water, °C.
For example, for a tank of 200 liters, a coil with a heat output of 30 kW is required. The diameter of the tube for the coil is 10 mm, or 0.01 m. The temperature of the heat carrier is 80 ° C, the temperature of the incoming water is 15 ° C. According to the above formula, we calculate the length of the coil:
The coil in this case is made in the form of a spiral with a diameter of 40 cm. With a tank diameter of 0.5 m and a height of 1 meter, such a coil will have 12 turns with an interturn distance of 6-8 cm. For convenience, winding is done using a template - a pipe of the appropriate diameter . It is more convenient to enter and exit the coil from one side of the tank.
How the system works
Indirect heating boilers are widely used due to their simplicity, efficiency and economy. In the cold season, they are powered by heating systems, and in spring and summer, heating is performed by a heating element. Many people design such boilers on their own. You ask - how to make an indirect heating boiler with your own hands? We answer - if you understand the principle of operation of the boiler, then you can assemble it yourself using improvised materials and tools.
The principle of operation of the storage water heater of indirect heating
A classic storage electric water heater heats water through a built-in heating element, providing water storage in a tank with thermal insulation. Since the heater operates around the clock, turning on and off, the cost of electricity is quite high. As for indirect heating boilers, there are large coils inside them that are connected to the heating system. The heated coolant, flowing through the coil, provides fast preparation of hot water.
An indirect heating boiler heats water through a coil through which hot water flows from the boiler.
In cold weather, heating is always on in houses and apartments, so the heat generated by it can be spent on heating water - gas costs are always less than electricity. It turns out that the use of an indirect heating boiler will lead to savings when paying electricity bills. In warm weather, heating is carried out with the help of electricity - there's nothing you can do about it. But in general, the annual savings are tangible.
In order for the savings to be even more tangible, you should assemble an indirect heating water heater with your own hands. We will need:
- Steel container of suitable volume;
- Copper tube for the manufacture of the coil;
- Electric heater;
- Welding machine;
- Fittings with threaded fasteners;
- Threaded fittings;
- Check valve;
- Faucet on the water supply pipe;
- The crane on a pipe of giving of the heat carrier;
- Pipes for connection to the water supply and heating system;
- Thermal insulation.
Finding all this is not difficult. Our tank will store water, and the coil will heat this water. In the warm season, when the heating is turned off, the heating element will turn on.
When assembling an indirect heating water heater with your own hands, choose reliable and durable materials. In particular, this applies to the tank - the service life of the entire system depends on its durability.
Tank preparation
Do-it-yourself drawings for assembling an indirect heating boiler can be found on our website. It should be noted that the assembly procedure can be dispensed with without any drawings, since special accuracy is not needed here. The work is carried out in several stages:
An indirect water heater tank can be made from a gas cylinder, but you will need a welding machine for this.
- Tank preparation;
- Coil manufacturing;
- Installation of a coil and heating element;
- Creation of thermal insulation.
The process of preparing the container is extremely simple. If necessary, it must be washed from dirt and coated with a primer. Lucky to find a stainless steel tank? Then you can get by with a simple wash - you need the inner surface to be clean, otherwise the water may have an unpleasant odor. Next, you need to consider a sealed cover, since our entire structure will be under pressure. For sealing, you can use a rubber gasket on which the lid itself will lie.
Ensure that the lid is firmly pressed against the tank itself. For example, this can be done with locks purchased from a hardware store. Only in this case the design will be as tight as possible.
For connecting the supply and discharge pipes, as well as for connecting to the heating system, we recommend using fittings with threaded connections that are welded into the tank walls. They will help ensure a sufficient level of tightness. Pay attention to the placement of fittings:
- The cold water inlet must be at the bottom;
- The hot water outlet is located on top, as hot water always rises;
- The fittings for connecting the coil can be located anywhere.
You also need to remember that subsequently a heating element must be built into a home-made indirect heating boiler.
Installation of the coil and heating element
Next, we proceed to the manufacture of the coil - we recommend choosing copper tube, because copper bends easily and resists corrosion well. The recommended tube diameter is 10-20 mm. To calculate the length, we will use the special formula l=P/π*d*Δt, where l is the tube length, P is the heat output of the coil, d is the tube diameter in meters, Δt is the temperature difference. Thermal power should be 1.5 kW per 10 liters of water. The temperature difference is calculated by subtracting the supply water temperature from the heating medium temperature.
Let's try to calculate using an example in which we will have a copper tube with a diameter of 0.01 m and a tank of 100 liters. The required thermal power of the coil is 15 kW, the inlet water temperature is +10 degrees, the coolant temperature is +90 degrees. Using the above formula, we find out that the length of the coil should be approximately 6 meters.
Wrap the copper tube around the plastic tube. The rate of heating of water in the tank will depend on the number of turns of the resulting spiral.
To make a coil, we wind a copper tube on some kind of base, for example, on a plastic sewer pipe. Winding with force is not needed, otherwise it will be problematic to remove the coil from the base. In conclusion, we solder the fittings to the coil - with their help we connect to the fittings inside the tank. This completes the work with the coil, and we just have to install a heating element at the bottom of our homemade boiler, embedding it in a convenient way.
Combined indirect heating water heaters are designed so that the heating elements are located in the lower part, from where the heated water can rise up, gradually mixing. As for the coil, it is advisable to expand it a little and install it so that the water is heated throughout the entire volume - this will ensure faster heating.
Creation of thermal insulation and connection of the boiler
The more carefully you approach the issue of insulating your water heater, the more money you can save.
Our boiler is almost ready, it remains only to attach the lid and create thermal insulation. We have already talked about the cover, and as for thermal insulation, here any insulation that can be purchased in specialized stores will do. Some are used as additional insulation mounting foam. After the thermal insulation is finished, we connect the boiler to the heating system and the water supply.
Do not forget to connect the heating element, although in winter it is not needed - an electrical cable of a suitable section is used for this. It is desirable to embed an RCD in the cable. Also, do not forget about the taps with which you can shut off the supply of water and coolant.
If necessary, you can build a thermometer into a self-made indirect heating boiler that will show the temperature of the water heating. In the process of testing the system, carefully evaluate the tightness - no leaks are allowed.
Do you think it is enough to choose the right water heater? For successful operation, it is equally important to connect it. In the article you will learn how to tie an indirect heating boiler. Our recommendations will help to carry out the installation so that the equipment works as efficiently as possible and does not break.
Types of water heaters and the principle of their operation
Unlike models that run on electricity or gas, an indirect heating boiler (BKN) operates due to an external heat source. If the system is connected to heating, then the coolant is heated by solid fuel. This approach helps out in the winter, but what to do in the summer, when the heating season is over?
Manufacturers produce combined systems: in addition, a heating element is placed in the tank, which can be powered by electricity or a solar collector. , read in a separate publication.
There are two types of water heaters:
- managed;
- without control.
The first ones are more expensive and easy to use, they work automatically. All that is needed:
- Connect hot water inlet and outlet.
- Organize the supply of cold flow to the tank.
- Install a liquid dispenser.
Even appliances with a thermostat cannot heat up more than the coolant allows. For example, the boiler heats up to 40 degrees, which means that the coolant will warm the water by a maximum of 40 degrees.
Devices without control work automatically, depending on the parameters of the boiler. You will have to mount the temperature sensor yourself and connect it to the heating system. After that, the strapping is performed, which we will discuss in more detail below.
When choosing, pay attention to additional functionality - it can be useful during operation. More expensive models may be equipped with accumulation system. Thanks to improved insulation and a large tank volume, the liquid retains heat well in the absence of electricity.
There are also devices recycling. Fast heating is provided by three nozzles. Two of them move a hot stream, one cold. An additional pipe can be used to connect things to the dryer.
Features of tanks and their installation
There are also indirect water heaters. Wall-mounted reach a capacity of up to 150 liters. The shape of the tank is most often round. Mounted on special brackets that come with the kit.
Tanks with a displacement of 200 to 1500 are installed on the floor. They have side or rear hose connections. The base often rests on legs. For large equipment, you will have to allocate a separate room.
Nuances of installation and strapping of the device
It is best to tie the water heater together with the installation of the boiler and other equipment than to embed the device into an already finished system. There are two main connection principles:
- with priority. This scheme requires a powerful boiler. It provides rapid heating of the contents of the tank, pumping the entire volume through the coil. Thus, hot water enters the radiators, which does not allow the temperature to drop.
- no priority. It is characterized by prolonged heating, since not all water passes through the coolant.
Binding rules:
- Choose a place to install the tank as close to the boiler as possible. This way you can reduce heat loss.
- Installation must be carried out on a flat and stable surface.
- For the normal functioning of the system, an expansion tank must be installed at the outlet of the water heater. It neutralizes thermal expansion.
- Each individual device (circuit) must be equipped with taps. This will allow you to disable them individually, independently of the rest of the system.
- Required installation.
- To reduce water hardness, .
- Do not place tanks larger than 150 liters on the wall, especially if it is made of drywall.
How to tie a boiler
There are several strapping schemes, which we will give below. Choose the most convenient for you.
Forced circulation and three-way valve
The scheme is suitable for strapping or with a boiler. If a gas boiler is already installed at the moment, place the BKN nearby. A circulation pump is mounted on the supply. After that, a three-way valve is connected, which is controlled by a temperature sensor.
A tee cuts into the inlet pipe in front of the body, to which a hose is connected to drain fluid from the heat exchanger. How it works:
- As soon as the temperature sensor informs the control board that the temperature has been reduced, the valve turns on the water heater's coolant. The heating system starts up.
- The content of the coolant passes through the heat exchanger, heats up in the tank.
- As soon as the heating reaches the set temperature, the valve switches to heating operation.
Convenient scheme for regular use of the water heater.
Use of two pumps
If the BKN is installed at a great distance from the boiler or you rarely use it, it is better to include a circulation pump in the system.
Connection diagram for an automatic boiler:
One pump is mounted on the inlet pipe, and the other on the heating body. The piping is done with tees, without a three-way valve. The thermostat controls the start and stop of the pumps.
Non-volatile boiler
For this scheme, it is better to use wall-mounted models, since the boiler should be located above the rest of the appliances.
Installation and floor model is possible. But in this case, the heating of water will be slower.
Priority is provided by a large circuit that is connected to the water heater. It should be one step larger than the one that is supplied to the heating system.
Temperature and flow switching is provided by a thermostatic head with a sensor. It sets the desired parameters. If the sensor indicates that there is cold water in the tank, the heating switches to the boiler - and vice versa.
Hydraulic connection application
Suitable for installations with multiple circuits and large tank volumes. Similar schemes are used in apartment buildings, when, in addition to heating, it is necessary to provide, for example, floor heating.
The hydraulic distributor (hydraulic arrow) helps disperse the pressure so as to avoid thermal shock. It is risky to carry out independent installation, it is better to contact a specialist.
Recycling equipment
If you want to turn on an additional heating device, a towel dryer, you need to organize the connection so that water constantly circulates in the pipes. You can immediately buy a device with a recirculation function or turn it on using tees. However, such a connection has negative aspects:
- Large consumption of electricity, fuel. Passing through the pipes of the dryer, the water cools down, so the device needs to be turned on more often.
- Blending layers. During normal operation, hot liquid rises. The flow that comes out of the pipes mixes the layers, and at the exit you get a lower temperature liquid.
Connection steps
Make the necessary calculations, mark the pipe layout, the installation location of the boiler and the boiler on the floor plan. Prepare a solid foundation for the water heater, especially if it is designed for large volumes. Next, do this:
- Run the wiring, marking the location of the hot and cold nozzles.
- Install tee, relief valve. The latter allows you to get rid of excess pressure.
- Seal all connections securely.
- Connect to electricity, install an RCD.
- When finished, adjust the thermostat settings. Perform a test run.
Watch the connections, pipes. There should be no leakage or suspicious noise. Remember that the source of heat can be not only a boiler, but also a solar collector. Sometimes its installation is much more profitable.
To finally understand the principles of strapping, watch the video
The indirect heating water heater is designed so that it can work from the heating system. To make the device yourself, you need a calculation. You will also need an old gas cylinder, which will serve as a system tank and copper pipes that act as a coil.
The system is not powered by electricity, but is powered by a heating system. With the right design, the water heater has high performance at minimal cost. The advantages also include the durability of the device by isolating the device from running water. At the same time, there is always hot water in the bokeh, just open the tap. can work from a boiler or central heating, the sources can be changed.
Cons of the indirect system:
- Re-equipment of the system requires financial investments;
- An indirect heating device is more expensive than a gas or electric boiler;
- The first heating may take several hours, which may affect the heating system;
- With large volumes of the system, the design takes up a lot of space.
When buying a boiler, first pay attention to its size. Next, take into account the material of manufacture of the inner tank. It is he who determines the quality and durability of the device. It is best when the inner walls are made of stainless steel.
How an indirect heating boiler works
An indirect heating boiler is mounted next to the boiler and connected in parallel to the main wiring and heating devices. This connection provides the device with a sufficient amount of coolant to heat water. This reduces the cost of temperature spread when the water heater is turned on.
Scheme of indirect equipment:
- Frame;
- Tank made of steel with thermal insulation;
- Thermal insulation;
- Pipe for water circulation;
- Openings for cleaning and inspection;
- Copper heat exchanger;
- Thermometer.
When the temperature in the tank drops, a signal is given to start the circulation pump. The coolant passes through the coil and shares heat with the cold liquid. After heating the water, the coolant goes back. It is important to insulate the outer casing well. Then the heat loss through the walls will be negligible.
If you open the tap on the mixer, cold water begins to dilute the hot. The temperature in the system drops and the heating cycle is repeated.
The system provides for the installation of a check valve on the supply of cold tap water. It does not allow it to drain when the supply is turned off. Heated water expands. If the flow valve is closed, the check valve prevents the flow of cold liquid, then the pressure in the system increases. In order for these indicators to be within the normal range, a safety lever is mounted between the tank and the check valve. It diverts some of the water into the sewer.
Boiler design elements
The indirect heating boiler provides a large thermos. There is a heating element in the tank - a heating element. In addition, the design includes a number of other important details.
Water heater device:
- Outer case with fixing details;
- Thermal insulation;
- Thermostat or thermoelectric sensor;
- Security group;
- Air outlets;
- magnesium anode;
- Inlet and outlet pipes.
Some elements include a recirculation circuit. Combined models are equipped with a tubular electric heater with piping. Boiler pricing may vary. Much depends on the material of manufacture, method, design and additional functions.
For the outer case I use a steel sheet or durable plastic. If the boiler is installed on the floor, then the design provides for special legs. Brackets are required to fix the device on the wall. The space between the tank and the body is filled with polyurethane foam, which acts as a heater. The outer casing is equipped with a thermometer to control the heating of the water.
The inner tank must be resistant to corrosion. Stainless steel does an excellent job with this task, but it is an expensive material. The design with anti-corrosion glass-porcelain coating has many advantages.
When used for an internal tank with enamel coating, the device will not last long.
The heat exchanger has the form of a coil, which is made of steel or brass. The heat exchanger can be located along the entire contour of the tank or only at the bottom. Some boilers are equipped with two coils at once. One is connected to the boiler, and the second to the pump or manifold.
The magnesium anode protects the internal elements of the boiler. The device works on the replacement of electrons that participate in ion exchange. This stops the process of corrosion and the parts will last longer. But the anode itself needs periodic replacement.
Water inlet and outlet pipes are located at the bottom and top, respectively, so that the liquid does not mix. Horizontal systems can have pipe connections on the right or left. The safety group includes a safety valve, a thermal relay and a thermostat.
Do-it-yourself drawings and calculation of an indirect heating boiler
Do-it-yourself manufacturing of the device takes place, based on the drawn up drawings. You will also have to carry out certain calculations of the system. But first you have to decide on the design parameters.
Necessary characteristics of the boiler for operation:
- Water consumption and storage tank dimensions;
- The position of the coil and its dimensions;
- Additional structural elements - thermostat, heating part.
This data will help determine the device of the boiler. Given them, a drawing of the future design is created. The optimal capacity for the tank and the material for the construction of the boiler are also selected.
The volume of the tank is determined by calculating the daily water consumption. It is believed that each family member spends 50-80 liters of water per day. This amount will be enough for bath procedures, washing, washing dishes.
For an average family of 3-4 people, it is necessary to have a boiler with a tank capacity of 200 liters.
If the hot liquid is used exclusively for household needs, then a smaller water heater will be required. A boiler for 50-70 liters will be enough. No need to purchase a larger tank unnecessarily. Precious heat is spent on heating water, and this increases the cost of operating the device.
Do-it-yourself boiler case from a gas cylinder
The body of the product is made of steel. The walls can be thin, since the water temperature should not exceed 70 degrees. A homemade boiler can be made from a gas cylinder or a plastic barrel. To clean the tank, you will need to weld a large flange from one end. But this is not a prerequisite.
Required holes in the case:
- Heating connections;
- Hot water supply;
- hot water circulation;
- Supply of tap fluid;
- heating element and magnesium anode;
- temperature sensors.
The heat exchanger can be located below or over the entire surface of the internal structure. The hot water outlet is located at the top, and a pipe for circulation is found a little lower. Cold water is supplied from below. The heating element must always be in the water, so it is mounted at the bottom. Temperature sensors occupy a place in the middle of the structure.
The magnesium anode protects the elements from corrosion. Its installation is necessary, even when the heating element is not planned to be installed.
A metal pipe is welded to the holes that work with water and sensors. The diameter of all nozzles must be the same. A large tube is provided under the anode, a cover, a bolt and an anode are mounted on it.
The heat exchanger is fastened with a shackle or nuts. The first option is considered more reliable. It is not necessary to install a drain. For these purposes, you can use a tee, which is mounted on the fluid supply.
Do-it-yourself coil for a boiler
For the heat exchanger, a copper or brass tube is used. The diameter of the nozzle can be from 8 to 20 mm. At the same time, the pipe molding is calculated so that there is enough power to heat the tank.
Data for calculation:
- Diameter (the parameter is taken in meters);
- Fluid temperature in the heating system;
- Temperature indicators of tap water.
To determine the length of the heat exchanger, a special formula is used. In this case, the thermal power is divided by the number Pi, then multiplied by the diameter and the temperature difference between the heating and the water supply. It is better to round up the data obtained and take the pipe with a margin.
To give the heat exchanger a spiral shape, the pipe is wound onto a blank. The diameter of the coil must match the diameter of the tank. There is a small distance between the spirals. The end of the coil is equipped with fittings. Before welding the system, its performance is checked.
Do-it-yourself indirect heating boiler (video)
Making a boiler yourself is quite realistic, since the principle of operation of an indirect water heater is quite simple. To work, you will need a metal barrel, copper pipes and some elements of the system. The fabrication includes the equipment of the outer casing, the coil and the connection of pipes.
