Do-it-yourself boiler for a gas boiler. How to make an indirect heating boiler with your own hands: instructions and tips for making

Many private houses do not have hot water supply equipment, and residents experience great problems in this regard. Domestic needs are always solved through the use of hot water, and its production becomes quite troublesome. However, there are several options for getting out of this situation: a gas water heater, a double-circuit boiler, an electric water heater, the purchase and installation of which requires considerable financial investments. But, there is an alternative way to manufacture and install a hot water supply system - a home-made indirect heating boiler. Its advantage lies in the economical hot water supply of residential premises with minimal cash investment.

Where to begin

A boiler is a system that heats water to provide a room with heat and hot water. Accordingly, an indirect heating boiler is a water heater storage device that does not require additional power sources to reproduce hot water supply.

Any design of a water heater consists of a container of sufficient volume, and a heating element located inside it, which is responsible for supplying heat. In the process of increasing the temperature of the heating element, the water filling the container is heated to the required level. More preferable is the parallel connection of the boiler to the house heating system.

When choosing a container for creating a homemade water heater, one should take into account the tendency of the material used to be affected by corrosion. As a suitable option, you can use an aluminum alloy, plastic or stainless steel, as well as simply a steel container that has undergone preliminary external processing with the necessary means of protection against the damaging effects of moisture.

This container is equipped with two openings: one on top of the body - for the return of hot water, the other from below - for the flow of running cold water. Ball valves are built into each of these holes so that operational actions do not cause difficulties in use.

Do-it-yourself coil

An important component of the boiler is the presence of a coil for the movement of the primary coolant. The material used can be a pipe made of metal or metal-plastic of small diameter. The determination of the diameter of the coil depends on the preferences of the manufacturer, the main condition is only that the contact with water is maximum.

For the convenience of creating a serpentine spiral from a tube, you can use any pipe or log of a cylindrical shape that is suitable in diameter. One end of the tube must be fixed on the rod and make smooth rotations, controlling the density and freedom of the turns, so that the resulting spiral can then be removed from the rod.

Since hot water rises when the temperature rises, the tap that supplies it is mounted at the top of the tank.

It is worth noting the fact that the coil tends to form scale, by depositing metal salts contained in water. Therefore, this system requires periodic cleaning at least twice a year.

Implementation of thermal insulation

Thermal insulation in the design of the boiler is necessary to increase the degree of heat retention. For this, any material for thermal insulation used in construction can serve: isolon, foam, polyurethane foam, etc. It is fastened with glue or wire ties, covering the entire perimeter of the container. This casing allows not only to keep the heat of hot water in the boiler for a long time, but also to reduce the time of its heating, which will positively affect the flow rate of the coolant, increasing its efficiency.

Sometimes the double container method is applicable, that is, placing a container with a smaller diameter in a container of a larger diameter. The space created between them also performs the function of thermal insulation.

We make a boiler ourselves

In order to make an indirect heating boiler with your own hands, you need a certain range of knowledge and improvised materials for its manufacture.

For work you will need:

gas cylinder;
nitro primer;
nut with a diameter of 32 mm;
plastic tubes;
coil;
welding machine.

First, we cut the gas cylinder intended for work into two parts.

Attention! Before cutting the balloon, it must be completely filled with water. Otherwise, an explosion will occur when cutting.

It is advisable to use a new cylinder, since the one that has been in use for several months will give the water a peculiar smell. In the event that it is problematic to get a new cylinder, then we use a nitro primer and process the entire inner surface of the gas cylinder with it, followed by a thorough flushing.

Secondly, a nut with a screwed threaded thread is welded into place for installing the coil. The tube intended for hot water is installed to the very top of the device. A tube for cold tap water should have the following scheme: one end is threaded, and the other end is provided with holes and a plug on the sides. Such a system is designed to prevent mixing of hot and cold water.

Thirdly, by welding we form a hole for installing a heat exchanger. Depending on the intended type of installation of this system, corners or lugs can be welded as a means of fixing the boiler to the wall. The next step is the installation of a heating element with a signaling electric sensor.

Fourthly, for greater reliability, it is desirable to wrap the boiler with heat-insulating material. Connect all hoses and pipes to the general system of the house, special attention should be paid to the pipe connected to cold water, it must have a check valve. This measure will protect against water runoff from the boiler and protect the heating element from the possible risk of burning.

Alternative indoor hot water source

A fairly simple and effective way is to create a hand-made indirect water heating boiler from the following materials:

wooden boards;
aluminum sheet;
copper pipe;
copper collector.

A case is constructed from the boards, inside of which an aluminum sheet is lined. Furrows are formed with a copper pipe, and a copper collector is installed. On one side is the entrance, and on the other - the exit. Such a heating system allows heating water in the required volume.

The technological process is practically unchanged, it should only be noted that for better heat absorption it is worth using glass and specialized paint.

The undoubted advantage of making a homemade water heater is the minimum financial and physical costs. In addition, a huge variety of options for possible water-heating structures can be used, depending on the compliance with the conditions of the room where they are installed.

A bulk water heater is an excellent solution for a country house or a country house.

An indirect heating boiler with a volume of 100 liters in a store is unlikely to be found cheaper than 15,000 rubles. And you can assemble it yourself and no more than 3,000 rubles, if you try and work hard ... The main problem - welding pipes into the body can be bypassed by other technical means ....

Conventional design of an indirect heating boiler

In the simplest version, the design of the boiler includes the following.

A tank with a volume of usually 100 - 200 liters, in which water is heated and its supply is stored.
The coil is a heat exchanger inside the tank, through which the coolant moves from the heating system.
The heat-insulating shell of the tank allows you to store the volume of heated water for a long time.
Pressure gauge, thermometer, safety valve - a safety group for the hot water system, installed on the tank.
Electric heater, as an option for summer water heating, when it is possible to turn on the heating boiler, it is not possible

Getting hot water - principles

Hot water costs money, and maybe a lot if it is cooked with electricity. The cheapest water is obtained if heated by heating, which most often runs on natural gas, coal, or wood - no more than 1 rub / kW. In addition, the power of heating allows you to get a lot of water and heat it quickly enough.

An indirect heating boiler of 150 - 200 liters with a heat transfer power from a coil-heat exchanger of 20 kW (and the corresponding boiler power) makes it possible to fill a large jacuzzi with hot water in a sane time and then add more .... In principle, for normal home use, 100 liters of volume is enough, but again, with a heat exchanger inside, no weaker than 15 kW.

How does the boiler heat the boiler

Automated boilers receive information from the DHW temperature sensor and independently switch their work to the boiler connection pipe when it cools down.

For example, single-circuit gas boilers are often equipped with an additional hot water outlet to the DHW boiler. And the switching circuit (based on a three-way valve) is already inside them. The same with electric, and with bunker-solid fuel. But if necessary, you can assemble such a scheme next to the boiler, there is nothing complicated, the information is on the adjacent pages.

If this option cannot be done, or the boiler is not automated, then you will have to manually regulate the removal of the coolant to the boiler, according to the “on-off” or “slightly opened” type, which is not difficult to create on the basis of a control valve.

What you need to make a hot water boiler

Difficulties in creating a boiler with your own hands

The actual assembly of the boiler at home is based on the qualifications of the welder and metalworker. It is necessary to cut holes in the barrel with a diameter of 21 mm:

Pair for coil pipes.
Two more holes for welding in pipes for supply and intake of hot water.
Hole for connecting safety devices
Under the electric heater with a large diameter.

It is necessary to weld the following on the body of the barrel by electric welding.

Weld evenly all these tubes into their holes, scald so that there is no leak.
Weld legs, flat bottom possible, for installation on polystyrene, possibly brackets for hanging on anchors on a solid wall.
Weld a cover, possibly ears, for installing a cover with a bolted seal.

How else can you seal the exit pipes from the boiler

There are a couple of other methods to seal the pipes in the boiler body without resorting to welding.

Use epoxy potting with a rag seal. The parts to be joined are thoroughly degreased, lubricated with glue, without touching them with hands. After that, an omentum is slowly made from a bandage on glue. Usually a daily hardening will mark hermetic gluing. But, it's not reliable.
Use sealed cable glands. In a special electrical shop, it is not difficult to choose a cable entry-gland in diameter, designed to work under water up to a certain pressure - from 4 atm. Tightening the threads guarantees sealing and no leaks, but the method is more expensive.

In this case, the remaining issue of welding the cover is not so difficult to solve ...

What not to forget to do in the hot water supply

The DHW system, as an isolated heated circuit, is supplied with an expansion tank. Selected specifically "for drinking water", for hot water supply. The device makes the system safer, ensures the comfort of work - a constant pressure in the system is maintained at the level of 1.5 - 2.5 atm.
It is rational to make a hot water supply scheme with constant circulation of liquid through the annular pipeline. Then the principle is realized - open the tap and immediately hot water comes out. Similar diagrams and instructions can be found on this resource.

To provide a private house with hot water for household needs, various household appliances are used. It includes instantaneous water heaters and various boilers - electric, gas and indirect heating. The latter are of the greatest interest, since they do not require any energy carriers for their operation. On the other hand, such units in the factory version are very expensive. That is why making an indirect boiler with your own hands is a good solution, and we will tell you how to implement it in this article.

The device and principle of operation of an indirect heating boiler

What makes these units so attractive is the ability to deliver a large amount of hot water to several consumers at once. At the same time, heating occurs without additional connections to the electrical network or gas mains, the heat source is the same boiler that we use to heat the house. The only condition is that the heat generator must have a power reserve in order to have time to work with the heating system and the water heater.

I must say that the device of an indirect heating boiler is quite simple, so if you have some skills, you can do it yourself. In fact, this is a round sealed tank of decent capacity (at least 100 liters), inside of which is placed a copper tube coil. Outside, the tank is covered with a heat-insulating layer that prevents the water in the tank from cooling down quickly. The water heater device is shown in detail in the diagram:

The figure shows a conventional indirect boiler in the minimum configuration, more advanced models are additionally equipped with:

a second coil for connecting an alternative heat source;
electric heater to maintain the water temperature in the event of a boiler shutdown;
thermometer and manometer.

The very principle of operation of an indirect heating boiler is to transfer heat indirectly from the boiler to the mass of water in the tank. The mediator is a coolant heated to a temperature of 70-80 ° C and circulating through the copper tube of the coil. This allows you to bring the temperature of the water intended for domestic hot water to 60 ° C. In order to exclude electrochemical corrosion of the metal tank, a magnesium anode is placed inside, which forms a more active copper-magnesium galvanic pair than copper-steel.

Also, an indirect type storage water heater is equipped with a branch pipe for connecting a safety safety valve and a temperature sensor connected to the thermostat. In the event that it is necessary to provide an instant supply of hot water to the mixers, the boiler is equipped with a branch pipe for connecting the return recirculation line.

To make an indirect heating boiler at home, you will need 2 main elements - this is the tank itself and a copper tube heat exchanger. The ideal shape for a tank is cylindrical, so it is better to use some kind of cylinder, a metal barrel or a thin-walled pipe of large diameter as such. The copper tube should not be too thin, such a heat exchanger will not be effective. A suitable diameter is 15-20 mm.

Advice. For the manufacture of a heat exchanger, a corrugated stainless pipe used for heating and water supply systems is also well suited. It is easier to bend than copper.

Having picked up a suitable tank and decided on its dimensions, you can start winding the coil. For this, it is recommended to use a template in the form of a pipe or a log, whose diameter is half the size of the container. After fixing one end of the tube, wind onto the template as tightly as possible, coil by coil. At the same time, it is necessary to monitor the height of the product so that it subsequently fits inside the boiler, made by oneself.

The finished heat exchanger is installed in the center of the tank so that the tube does not touch its walls anywhere. Now you need to arrange a sealed passage of pipes through the tank, which is done using soldering and threaded connections, as shown in the photo:

Now it remains to insulate the tank with the help of rolled heaters and bandages made of wire or thin steel strip. First you need to finish all the welding work - attach the bottom and cover, cut in all the pipes and weld the supports. A decorative casing made of sheet metal or other convenient material should be put on top of the insulation.

Advice. In order to extend the life of a homemade steel tank, it is recommended to purchase and install a magnesium anode inside the water heater.

Scheme of connecting the boiler to the boiler

Assembling a storage water heater is only half the battle, you still need to properly install the unit and connect it to a heat source. Since the water tank has a fairly large weight, it is better to put it on the foundation and align it vertically. If the floors in your boiler room are filled with a 100 mm thick concrete screed, then you can do without a foundation. After installation, you can start tying the boiler.

Advice. Perhaps someone advised you to connect the boiler to the hot water path of a double-circuit boiler, or you found a similar scheme on the Internet. Remember that these units cannot be connected in this way, the water heater must be connected to the same line as the heating system.

The fact is that a double-circuit boiler heats water for the needs of hot water only up to 60 ° C. And this means that it will heat a large volume of water in the boiler to no more than 50 ° C, while spending a lot of time. There is another point: when the heat generator works for the DHW circuit, it is completely disconnected from the heating system, as a result of which the latter will cool down significantly, and with it the whole house. All the nuances are described in detail in the following video:

In order to properly combine the water heater and the boiler into one properly functioning system, it is necessary to tie them according to one of the diagrams below. In the first, the distribution of coolant flows is organized by installing a three-way valve with a servo drive. When the temperature of the water inside the boiler begins to decrease, the actuator sends the coolant flow to the coil of the unit at the signal of the sensor.

In another connection scheme with two circulation pumps, the indirect heating boiler is loaded by turning on the pump in its circuit. In this case, the heating circuit can function continuously or turn off, which depends on the automation. If the heat output of the boiler is sufficient, then both branches can operate simultaneously. You just need to choose the right pumps so that they do not interfere with each other.

Another way to tie the boiler is used in complex systems with several circulation pumps and a hydraulic separator.

Here, the water heater with its pump is simply connected to the common collectors located behind the hydraulic gun. More details on the correct connection of an indirect heating boiler are shown in the video below.

Installation of a safety valve for a water heater

This small device plays an important role in the boiler connection scheme. When the water in the tank begins to heat up, it expands in volume and as a result, the pressure increases.

When it reaches a critical value, it works and dumps some of the water to reduce pressure. Therefore, the valve nozzle must be connected with a flexible tube to the sewer outlet.

In large-capacity tanks, it is customary to additionally install a membrane expansion tank (expansomat). It is able to compensate for a larger volume of expanding liquid. At the same time, it is important when buying a tank to choose one that is intended for water supply systems, and not heating. You can recognize it by the value of the maximum working pressure of 7-8 Bar (for tanks for heating 3 Bar).

In addition to these elements, other necessary parts must be present in the boiler piping from the water supply side: taps, valves, filters and other fittings. How to properly tie an indirect water heater with the water supply of a private house is shown in the diagram with a reverse circulation circuit:

Conclusion

In fact, the design of a storage water heater is not difficult, so if you wish, you can make it yourself. At the same time, it is possible to equip the boiler with all possible functions and integrate sensors into it to work together with the boiler automation. But you will have to tinker with the strapping, the effective operation of the entire heating of the house depends on the correctness of its implementation.

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 coolant 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

An indirect heating device is a special storage unit that heats water without using any additional power sources. Due to this, hot water supply of private housing construction requires minimal financial costs from their owners.

Indirect heating unit - hot water at a low price

The owners of many private houses are now installing double-circuit boilers in their homes. These devices are able to provide housing construction not only with heat, but also with hot water. Conventional heating units do not have such capabilities. This means that the homeowner has to look for other ways to generate heated water used for everyday household needs.

At first glance, the easiest way to solve such a problem is to purchase and install. It quickly heats the water, without any problems mounted with your own hands. But its cost, as well as space prices for consumed electricity, are not to the liking of every person. In addition, instantaneous water heaters often require a complete replacement of the electrical wiring available in the house. Such events cost a pretty penny.

A reasonable alternative to flow devices that heat water, according to many experts and ordinary consumers, will be an indirect heating device.

It is truly economical in operation and at the same time effectively performs its task. Unfortunately, the cost of a factory boiler is not available to everyone. In this case, home craftsmen have the opportunity to make such a unit on their own. A little later, we will describe in detail the process of its manufacture. But first, let's deal with the principle of operation of the equipment we are interested in.

A boiler is a tank inside which pipes are mounted. They circulate the coolant, which is used to heat the home. There is an inlet tube at the bottom of the tank. It is designed to supply cold water to the described container. The heating of the incoming liquid is carried out due to the moving coolant. Important feature! Outside, the tank is wrapped with a heat-insulating layer, due to which the heated water retains its temperature for a long time. The hot water pipe is usually mounted at the top of the tank. It is recommended to equip it with a conventional ball valve to simplify the operation of the device.

Pros and cons of equipment - the boiler is good, but far from perfect

The cost-effectiveness of using an indirect water heater is an important, but not its only advantage. The boiler has a number of other operational advantages:

Sufficiently high performance. Its specific indicator depends on the cross section of the pipes installed in the unit, as well as on the power characteristics of the heating boiler itself.
There is no load on the household electrical network (if a heating element is not additionally mounted).
The possibility of operating the equipment year-round (requires the installation of a heating element - a special heater) and the use of various sources of thermal energy. In some cases, this is of great importance.
Absence of areas of contact between the coolant containing a considerable amount of harmful salts and heated water.

Now let's deal with the shortcomings of the considered water heaters and with possible ways to solve them. The main disadvantage of the boiler is the large size of the tank. The unit takes up a lot of space, which can cause difficulties when installing it in modest areas. The second drawback is that in a large container, the water heats up for a long time. Moreover, when the liquid in the tank is heated, there is a slight decrease in the intensity of heating of the dwelling.

Strapping installation

From the description of the principle of operation of an indirect water heater, it can be seen that without additional devices it can only be operated when the heating system is working. That is, the boiler is used exclusively in the cold season. And if we want to constantly get hot water, regardless of the temperature outside? It's quite real. You just need to equip the water heater with a heating element. It is built into the tank and connected to the mains. It is clear that you have to pay electricity bills. But then in your house there will always be hot water in the required quantity.

Homemade water heater - popular designs

Craftsmen use various methods of making devices of interest to us. It is really possible to build an indirect heating boiler without extra labor costs with your own hands according to one of the options proposed below:

1. Pipes of a certain diameter are installed inside the tank. They can be placed in the central part of the storage tank or along its side surfaces. In the second case, the water heating rate will be slightly higher.
2. Installation of the coil. The principle of operation of the device will remain the same. But the efficiency of the unit will increase. The coil is usually made from a pipe (metal, plastic). It just needs to be bent to get a spiral element.
3. The use of two (different in geometrical parameters) containers. In this case, pipes are not needed. It is required to insert a smaller container into a tank with a large volume. The coolant in a similar design moves between the walls of the tanks used.

Homemade water heater

Indirect heating systems with a coil are recognized as the most effective in application. The bottom line is that the curved pipe is characterized by a large length. This makes it possible to use the potential of the coolant to the maximum. In addition, it is easiest to make a tank with a spiral element yourself. More on this later.

Container for the heater - what to make and how to prepare?

The water heater tank can be made from almost any material that has some resistance to corrosion. You can use enameled metal, glass ceramics, stainless steel, plastic. When choosing a material, the following should be taken into account: plastic, glass-ceramic and enameled containers do not differ in particular mechanical strength, in addition, enamel and ceramics are prone to corrosion. Because of this, after a couple of years of operation, it may be necessary to replace a tank made of these materials.

But stainless steel containers are many times more durable and reliable. The easiest way is to make an indirect water heater from a conventional gas cylinder. It is advisable to buy a new container. But it is also allowed to use with an old cylinder. It must be cut into two halves, the inner walls must be cleaned of dirt and treated with a primer (usually 2-3 layers are applied). Nuance. Soil is allowed and not used. But then in the first couple of weeks of operation of a homemade boiler, you will clearly smell the gas coming from hot water.

In the balloon prepared in the described way, we will make four holes. Through one, heated water will come out, the second is needed to supply cold liquid. Two more holes will allow you to connect the coolant and the coil. Then you should take care of high-quality thermal insulation of the tank. A homemade boiler must be insulated as carefully as possible. If this condition is not met, the efficiency of the device will be significantly reduced. Water in a warm state in it will not be maintained for very long.

Thermal protection of the container is recommended before assembly of the unit. It is more convenient, simpler and more reliable. The function of a heater can be performed by almost any heat insulator. Some craftsmen use glass wool. It is attached to the cylinder body with wire or adhesive. If desired, you can first glue the cotton wool, and then additionally fix it with a wire tie. It is even better to use polyurethane foam for insulation. Working with it requires minimal labor costs. And the result is excellent.

We make a coil and assemble the device - there will be no problems!

We make a spiral element for a boiler from a plastic or metal pipe. Its diameter should be small - in the range of 0.8–2 cm. We wind the pipe on a rounded log of a larger cross section, a metal tubular product, or on any other strong cylindrical mandrel. We make sure that the coils of the spiral do not touch each other. In this case, we will ensure maximum contact between the heated water and the heating surface.

The number of turns and the length of the coil are determined based on the capacity of the tank. For a boiler made from a 200-liter cylinder, the length of the spiral is about 15 m. The required number of turns is 12 (with a distance between them of about 7 cm). The coil should not be wound on the mandrel too tightly. Every year it will have to be dismantled and cleaned of accumulated deposits without fail. If the spiral is wound too tightly, it will be problematic to remove it.

Now we assemble our water heater:

1. Install the coil along the walls or in the center of the tank.
2. We solder the pipes to the outlet and inlet pipes.
3. We weld ears to the body of the device - fasteners made of a metal corner when the boiler is planned to be hung on the wall. If the heater is installed vertically on the floor, legs must be welded to its bottom. They will ensure the stability of the unit.
4. At the ends of the spiral element, we cut the thread, screw the locknut onto it. Then we bring the coil out of the tank, pull rubber gaskets on its ends, and threaded couplings on them. We connect the coil to the circuit of the heating system.
5. We connect the device to the inlet and outlet pipe.

The final work is the arrangement of piping in different rooms (bathroom, kitchen). Advice. If wiring is not planned, install a valve on the hot water tap. We check all connections for leaks and start using a homemade water heater.