Gas boilers with water heater. Gas boilers of indirect heating. How to make a stratified heating boiler from an electric boiler

Now we will figure out how to choose a gas boiler with a built-in boiler and what is the difference between single-circuit and double-circuit ones. In the end, let's see who produces the best models in this segment.

There are various ways to establish and equip a hot water supply system in a house. One option is to install a gas boiler with a built-in boiler.

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Boiler with built-in boiler

Differences and advantages of single-circuit and double-circuit boilers

A single-circuit gas boiler is designed exclusively for heating the house - it does not have a built-in water heater that provides residents with hot water. If you connect a boiler to it, it will heat water for various domestic needs.

The mechanism of dual-circuit units is more complex and their price is higher.

The main advantage of a gas boiler with a built-in storage tank is that you do not have to buy and install additionally. In addition, the water in it heats up much faster than in single-circuit boilers.

For devices with two circuits, you can connect a separate boiler so that there is more hot water. If you already have a single-circuit boiler, then in addition to it you can buy a special one, which is equipped with a fluid flow heater.

If you are the owner of an apartment that is small in size and you need to save space, then the best option would be a single-circuit boiler with a built-in boiler.

To avoid all sorts of problems that may arise due to incorrect installation of equipment, installation should be carried out by specialists.

Currently, you can find the following models of double-circuit boilers:

• with a flowing water heat exchanger;
• with a built-in boiler for 40-60 l;
• with built-in boiler for 80-599 l.

The main characteristics of wall-mounted boilers with flowing water:

• they can simultaneously heat rooms with a total area of ​​​​up to 300 m²;
• they are compact, you can mount them in a niche in the wall;
• acceptable price;
• differ in simple installation;
• simple and convenient control.

Gas boiler device with built-in boiler

Advantages of gas heating boilers with a 40-60 l boiler:

• they can heat an area up to 300 m² and simultaneously supply water to 4 draw-off points at once;
• easy to manage;
• have a self-diagnosis system.

Units with a boiler for 80-500 liters are of three types. The first two include devices that include all the necessary parts, they are compact and allow you to fully control the system. The third type includes boilers for which you need to install additional equipment and buy other parts. As a result, in order to purchase all the missing elements, you will have to spend a lot of money.

As already noted, most users prefer single-circuit gas boilers with a separate boiler.

We note the main advantages of such devices:

1. The large internal section of the heat exchanger, due to which scale is formed much less.
2. Differ in reliability.
3. The mechanism and principle of operation of the device is simple.
4. Thermal energy is expended expediently, as a result of which the efficiency increases, and fuel is consumed more economically.
5. They are easy to service.
6. With a gas boiler and boiler, you are guaranteed to be provided with hot water at any time of the day.

Manufacturers

Today, the leading manufacturers of gas boilers with a built-in boiler are: Electrolux, Ariston, Viessmann, Baxi, De Dietrich, Vaillant, Wolf, Chaffoteaux, Biasi.

Thus, by purchasing a gas boiler with a built-in boiler, you can achieve significant cost savings without losing functionality and ease of use.

People who do not have enough space in an apartment or house to equip a boiler room often try to save space and purchase a double-circuit boiler. This is a smart choice, however, in order to provide the family with hot bath and household liquids, care should be taken to have additional equipment. Choosing a suitable tank is not difficult, you can take a tank or other container. However, to make the task easier, you can simply buy a special gas boiler with a boiler.

Possibility to connect a boiler

A boiler for a gas boiler is a storage tank, inside of which a heat exchanger is placed. This model, in fact, is a double-circuit, as it has a connection for both the heating system and the hot water supply.

Double-circuit models have a built-in flow-type water heater, which single-circuit models cannot boast of. The advantage of a gas boiler with a built-in storage tank is that there is no need to create an indirect heating boiler. In addition, water is heated much faster than in single-circuit versions and does not reduce the efficiency of the heat carrier for heating.

A separate boiler can also be connected to double-circuit boilers to provide more hot water. Such equipment belongs to the technique of layer-by-layer heating. You can also buy a double-circuit gas boiler with a built-in indirect heating boiler. Such devices are combined with the boiler, although separate devices can be purchased. Depending on what is best for you: ease of transport and installation or compact placement - you can choose a separate or adjacent model.

If a single-circuit boiler is already installed, a special layer-by-layer heating boiler can be purchased for it, which is equipped with a flow-through liquid heater. If you need to save space in the apartment, you can opt for a single-circuit boiler with a built-in indirect heating boiler.

Heater power

Depending on the power of the gas burner, the flow rate of the liquid in the instantaneous water heater varies. Also, the rate of water heating depends on the design features of the heat exchanger. A feature of heating the liquid is its short contact with the heat exchanger, therefore, in order to warm the coolant to the desired temperature, a lot of heat is needed. To increase the performance of the heating element, it is necessary to increase the power of the burner and increase the gas flow.

In order for the water temperature in the shower to be 40 degrees, you will have to adjust the burner to a generated power of 20 kW, but if the burner is not designed for such power, then it is impossible to take a warm shower. The bath also needs a powerful burner, as the water must be heated quickly in large volumes for a normal set.

Most boilers have a capacity of about 20–30 kW, and 10 kW is enough to heat a house. Thus, all the difference can be used to provide domestic hot water. Modulating burners have been developed for boilers with water heating, which cover the range from 30 to 100 percent of the maximum power.

However, even the weakest boilers have excess power, which leads to frequent switching on and off of the burner. This process leads to rapid wear of equipment and increases fuel consumption. These problems make buying a more powerful boiler model to provide more hot liquid an unprofitable and unjustified solution.

That is why in dual-circuit models a boiler is provided that contains hot water, which allows it to be given out in large volume while taking a shower or bath. Thus, layer-by-layer heating of water is optimal: it ensures the normal operation of the equipment and does not lead to burner wear.

In double-circuit models with stratified heating, water is heated using a plate radiator or a tubular water heater. The presence of an additional heat exchanger is beneficial in condensing models, since it provides additional heat from the combustion products. The liquid enters the boiler with layer-by-layer heating already heated, which allows you to quickly prepare the hot liquid in the required volume.

Floor double-circuit gas heating boilers with a boiler have a number of advantages.

1. The flow of hot water into the upper layers of the boiler allows you to take a shower 5 minutes after turning on the heat exchanger. In contrast, boilers with an indirect heating boiler provide longer heating of the liquid, since time is spent on the convection of warm water from below the heat source.
2. The absence of a heat exchanger inside the storage tank allows you to collect more warm water for domestic needs. The performance of such boilers is 1.5 times higher than in models with indirect heating.

Work of a gas boiler with a boiler - video

Frequently asked Questions

Most often, people do not understand why there is also a boiler in the boiler. The fact is that the built-in model allows you to ensure comfortable use of warm water. This allows you to quickly ensure the availability of hot liquid when opening several points of water intake, which a conventional double-circuit boiler will never cope with.

Moreover, there are cases when a small pressure of warm water is needed, which a boiler with an instantaneous water heater is not capable of, since the lower pressure limit is limited in it.

Floor models with a built-in storage tank look like a refrigerator. They hold up to 100 liters of liquid, which is quite enough to provide warm water to the whole family.

The connection diagram of a double-circuit gas boiler with a boiler practically does not differ from the standard connection. An important difference is the need to connect not only to the heating system, but also to the water supply. It is necessary to crash into the system before the water exit points, but after the toilet bowl. This will ensure that hot liquid exits from all water intake taps. It is best to consult with the masters to connect everything correctly.

For the installation of a hot water supply system (DHW), there is Several variants, some of them are double-circuit and single-circuit boilers with a separate boiler.

If a in a dual device a small heat exchanger has already been built in that heats water for hot water supply, then in a single-circuit system with a boiler, the task of heating water for domestic needs is entrusted to it.

Double-circuit boilers are usually equipped with relatively small capacity for hot water, therefore, they cannot provide the desired temperature for many consumers for a long time.

Types of gas boilers with indirect heating boilers

There is two options water heaters for domestic hot water:

• indirect heating (BKN);
• direct heating.

BKN is connected to the installed gas boiler. Inside it is a heat exchanger (it can be a pipe twisted in a spiral or a tank-in-tank scheme).

Hot water from the heating system circulates through this heat exchanger, heating the water in the boiler. The latter is connected to the cold water supply network (CWS), and hot from the collapsible pipe goes to consumers.

Direct heating boiler can be compared with conventional gas boiler heating. It also has a gas burner and a water tank. The burner heats the water in the tank independently of the central heating system.

Important! When installing the BKN, it is necessary to estimate the power that will be spent on hot water supply. If there are many consumers and water is used frequently, boiler power may not be enough for heating, and the room temperature will be lower than the set temperature.

In this case, it is advisable to replace the boiler with a more powerful one, or use a different type of water heater.

Schemes for connecting a boiler to a single-circuit boiler

Exist three ways connecting the boiler to the boiler.

Direct connection of the water heater to the heating system

In this version, the BKN is included in the heating system, in series or in parallel with other radiators. The simplest and most inefficient scheme, not recommended for use and given for reference.

Photo 1. Scheme of direct connection of a water-heating gas single-circuit boiler to the heating system.

If the boiler temperature is set below 60 °C, this scheme becomes even less economical, and the water heats up for a very long time.

Temperature increase

Added to the wiring diagram three-way valve- a special device that switches the movement of the coolant when the temperature in the water heater tank drops to DHW and vice versa.

Thus, if the DHW water cools down, heating is temporarily switched off.

All boiler power is redirected to DHW.

The temperature on the device in this circuit is set higher ( typically 80-90°C).

And the heating temperature is regulated by a three-way valve.

Reference! The boiler temperature must be set at 5 °C above the required DHW.

Using a thermostat in a water heater and automation

If a thermal relay is installed in the BKN (a device that gives a signal when the set temperature is reached), and the boiler controller has contacts for connection boiler thermostat, then this scheme is the most preferable.

In this case, the boiler electronics is aware of the temperature of the water in the DHW system, and it decides itself where to direct its power: for heating water in BKN or for heating.

Photo 2. Thermostat for a water heater in the heating system, with it you can find out data on the water temperature.

Materials and tools

Materials:

• Pipes, valves, check valves- there are no special requirements for them: use the same materials as for working with hot water or heating systems.
• Expansion tank- a separate one is required for the domestic water supply system, it serves to prevent sudden pressure drops when opening / closing taps.

Attention! The tank must be designed for use with hot water, usually such devices are indicated special marking.

• Circulation pump- as a rule, a separate pump is installed in the heat exchange circuit with the water heater.

In addition, in DHW systems with recirculation, a separate pump is required to circulate the water in the DHW circuit.

This eliminates the need to wait for hot water to flow through pipes of great length from the installation site of the water heater: the water will immediately be hot.

• Wires and small electrical piping- if you plan to connect the water heater thermostat to the boiler automation.
• fasteners– especially in the case of wall mounting, also for fixing pipes and pumps.
• Standard plumbing set of sealants, seals, gaskets.

Tool:

• gas key;
• wrenches of various diameters;
• Adjustable wrench;
• building level;
• perforator, screwdrivers, screwdriver;
• minimum set of electrician: knife, wire cutters, electrical tape, phase tester.

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Installation process: how to connect

Ideally, the boiler should be as close as possible closer to the boiler to minimize heat loss.

Cold water is always supplied to the lower pipe of the boiler, and hot water is taken from the upper one.

1. Choose the location of the water heater so that it does not interfere and is easy to maintain. Mount the brackets, stands, fix it on them.
2. Connect to the HVS network: make a tap, put a stopcock and a coarse filter.
3. Take the cold water line to consumers through the tee, connect the second outlet to the boiler through a safety valve.
4. Connect the domestic hot water line to the boiler, not forgetting about the expansion tank on it. In addition, install bypass valves so that you can disconnect it from the circuit for the duration of the service.
5. Now connect the boiler to the gas boiler according to one of the above diagrams. Do not forget to turn off the boiler and shut off the system before connecting!
6. Connect electronics, sensors, pumps according to the instructions.

Startup and verification

All their pros and cons will become more clear in comparison with similar models in which hot water is “prepared” in a flow heat exchanger.

Advantages

1. Providing the house with hot water, regardless of the pressure in the HV line. The peculiarity of double-circuit gas boilers is that their automation, with a sharp decrease in pressure in the circuit, may not transfer the unit to the DHW mode. This happens during the hours of increased water intake. As a rule, in the evening, when the housewives cook, wash, bathe the kids. For models with a built-in boiler, all this is not critical - they will provide a hot water house in any case. Even if the automation of the protection circuit closes the gas fittings and the boiler stops for a while, hot water will still flow from the boiler.
2. When connecting this heater no additional hardware required, according to people who don't know enough. By analogy with conventional models, it joins two main communications - water supply and industrial / voltage networks.
3. Extended operating period. This is due to the fact that traditional double-circuit wall-mounted boilers, if necessary, constantly switch from one mode to another. As a result, increased wear of individual components. In this regard, heating installations with a boiler are more durable, that is, their non-repair period is somewhat longer.
4. Optimal combination indicators such as boiler power and tank capacity for water. Those who choose the option of providing hot water supply with a single-circuit unit with the connection of a separate boiler, moreover, on their own, are most often not satisfied with the result. The reason is in the irrational distribution of thermal energy, which is caused precisely by the wrong selection of equipment. In boilers with a built-in boiler, its capacity exactly corresponds to the power of the installation, so there are no problems with heating, increased gas consumption for such models.
5. The DHW tank protects the HW circuit from overheating, as it performs the function of a kind of "buffer" capacity, taking part of the thermal energy for the preparation of hot water.
6. The consumption of "blue fuel" double-circuit boilers with a built-in boiler is somewhat less. But with the expectation of the future, the savings can be quite impressive.
7. Lack of inertia of the DHW circuit. Hot water comes out immediately after opening the tap.

disadvantages

In fairness, it should be noted that not all the disadvantages of wall-mounted boilers with a boiler are of great importance in terms of installation and further operation. A serious analysis of the relevant information allows us to conclude that some of them are contrived (as a rule, by competitors), while others come from a superficial understanding of the essence of the issue. How significant the existing shortcomings are, everyone will be able to assess on their own, knowing the features of their home and their own capabilities for caring for the RH system. What is put in minus double-circuit boilers with a boiler?

1. Built-in tank increases the dimensions heating system and its weight. Fair, but only partly, since we are only talking about an increase in a few cm and kg(depending on the model).
2. Small boiler volume. And this means that such a unit will not fully provide the need for hot water with its large analysis. Double-circuit wall-mounted boilers with a tank for domestic hot water are available in several modifications. The minimum capacity of the boiler is 10 liters, the maximum is 60. For a family of 5 - 6 people, 35 - 40 is enough. This will be confirmed by any specialist, since it is unrealistic, for example, for all households to take bath procedures at once or to open all the hot water taps at the same time . The already marked “Baxi” boiler is equipped with a 40-liter boiler. As they say, in most cases, "behind the eyes." In addition, many models have the ability to connect a storage boiler (for example, 250 or even 500 liters). Therefore, talk about the fact that hot water will go literally a matter of minutes, at least, is incorrect.
3. Maintenance becomes more difficult heating unit. This is due to the need for regular cleaning of the DHW tank. Quite rightly, if not for a single nuance. In any house there are other devices (except for the boiler heat exchanger), one way or another related to water in their work. A zealous owner, in order not to engage in systematic repairs of the same washing machines, dishwashers, and so on, always thinks through water treatment issues. Depending on the quality of the liquid in private homes, various modifications of filters or treatment plants are installed. So to say that some special problems will arise with the boiler boiler is completely pointless.
4. High price. Significant drawback. But you have to pay for any convenience, and hardly anyone will argue with that.
5. The complexity of choosing an acceptable model and its strapping. Undoubtedly. The main difficulty that many experience when assessing the feasibility of purchasing boiler equipment is determining the optimal capacity of the installation. The most common recommendation is a proportion of 1 to 10 (kW / m 2). But this ratio is averaged, and does not take into account many factors - structural features (wall material, layout), its location on the ground, and a number of others. With regard to double-circuit boilers with a boiler, such a formula does not work at all, since part of the thermal energy is spent on preparing hot water.