Two-circuit wall-mounted gas boiler. What is the difference between wall-mounted gas heating boilers - technical characteristics and operational features of devices
A heating gas boiler is a device that, by means of the combustion of fuel (natural or liquefied gas), heats the coolant.
Device (design) gas boiler : burner, heat exchanger, thermally insulated housing, hydraulic unit, as well as safety and control devices. Such gas-fired boilers require a chimney to be connected to remove combustion products. The chimney can be either a conventional vertical or coaxial ("pipe in pipe") for boilers with a closed combustion chamber. Many modern boilers equipped with built-in pumps for forced circulation of water.
The principle of operation of a gas boiler- the coolant, passing through the heat exchanger, heats up and then circulates through the heating system, giving the received thermal energy through radiators, underfloor heating, heated towel rails, as well as providing water heating in an indirect heating boiler (if it is connected to a gas boiler).
Heat exchanger - a metal container in which the coolant (water or antifreeze) is heated - can be made of steel, cast iron, copper, etc. The reliability and durability of a gas boiler depends on the quality of the heat exchanger in the first place. Cast iron heat exchangers are resistant to corrosion and have a long service life, but are sensitive to sudden temperature changes and are quite heavy. Steel containers can suffer from rust, so their internal surfaces are protected with various anti-corrosion coatings that prolong the “life” of the device. Steel heat exchangers are the most common in the manufacture of boilers. Corrosion is not terrible for copper heat exchangers, and due to the high heat transfer coefficient, low weight and dimensions, such heat exchangers are often used in wall-mounted boilers, but of the minuses, it should be noted that they are more expensive than steel ones.
In addition to the heat exchanger, an important part of gas boilers is a burner, which can be various kinds: atmospheric or fan, single-stage or two-stage, with smooth modulation, double.
To control the gas boiler, automation is used with various settings and functions (for example, weather-compensated control system), as well as devices for programming operation and remote control of the boiler.
The main technical characteristics of gas heating boilers are: power, number of heating circuits, type of fuel, type of combustion chamber, burner type, installation method, pump and expansion tank, boiler control automation.
To determine required power gas heating boiler for private country house or apartments used simple formula- 1 kW of boiler power for heating 10 m 2 of a well-insulated room with a ceiling height of up to 3 m. the gas boiler output must be increased. It is also necessary to increase the power (about 20-50%) when providing a gas boiler and hot water supply (especially if water heating in the pool is necessary).
The peculiarity of calculating the power of gas boilers: the nominal gas pressure at which the boiler operates at 100% of the power declared by the manufacturer, for most boilers is from 13 to 20 mbar, and the actual pressure in gas networks in Russia can be 10 mbar, and sometimes even lower . Accordingly, a gas boiler often works only at 2/3 of its capacity, and this must be taken into account when calculating. In more detail with a table for calculating the power of a heating boiler, you can
Most gas boilers can switch from natural gas operation to liquefied gas (ballooned propane). Many models switch to liquefied gas at the factory (check these characteristics of the model when purchasing), or nozzles (jets) are additionally supplied to the gas boiler to switch to bottled gas.
Pros and cons of gas boilers:
Boiler piping- These are devices for the full operation of the heating and water supply system. It includes: pumps, expansion tanks, filters (if necessary), collectors, return and safety valves, air valves, valves, etc. You will also need to purchase radiators, connecting pipes and valves, thermostats, a boiler, etc. The issue of choosing a boiler is quite serious, so it is better to entrust the selection of equipment and its complete set to professionals.
What is the best boiler? The Russian market of gas boiler equipment has its own leaders in quality and reliability. The best manufacturers and brands of gas boilers are presented in the assortment:
"Premium" or "Lux"- the most reliable and durable, easy to manage, the kit is assembled as a "constructor", more expensive than the others. These manufacturers include German companies
With the development of gasification of the country, more and more consumers are switching to heating residential premises using natural gas.
If for heating industrial enterprises, public buildings and apartment buildings, boiler rooms are being built, then a private household or a cottage is heated using a gas boiler.
At heating system design all stages of work are important from project development to its installation at the consumer, but the most important part is the choice of a gas boiler.
- What should you pay attention to when choosing it?
- How to determine the optimal parameters of the boiler for your home?
To do this, you need to know the general characteristics of gas boilers heating. Let's try to figure it out.
1. Power of the gas boiler (characteristics of gas boilers)
First of all, it is necessary to determine the power of the boiler, since this one of the decisive technical characteristics. It is selected based on the magnitude of the heat loss of the building. The calculation of the heat balance of the house, taking into account the features of its design, should be carried out by a specialist, however, for an approximate assessment of this parameter, if the house building is designed taking into account building codes, you can use the following formula:
Q = k V ∆T
1 kWh = 860 kcal/h
Where
Q - heat loss, (kcal / h)
V is the volume of the room (length × width × height), m3;
ΔT is the maximum difference between the air temperature from outside and inside the room in winter time, °С;
k is the generalized heat transfer coefficient of the building;
k \u003d 3 ... 4 - building from boards;
k = 2…3 - brick walls in one layer;
k \u003d 1 ... 2 - standard masonry (brick in two layers);
k \u003d 0.6 ... 1 - well-insulated building;
Calculation example:
For a building with a volume of V = 10m × 10m × 3m = 300 m3;
At ΔT \u003d (Tvn - Tnar) \u003d 20 - (-30) \u003d 50 ° С;
The heat loss of a brick building (k = 2) will be:
Q \u003d 2 × 300 × 50 \u003d 30000 kcal / h \u003d 30000 / 860 \u003d 35 kW
This will be the required minimum power of the boiler.
Usually, a 1.5-fold power reserve is selected, however, factors such as constantly working ventilation of the room, open windows and doors, a large glazing area, etc. should be taken into account. If you plan to use a double-circuit boiler (space heating and supply hot water), then its power should be further increased by 10-40%. The additive depends on the amount of hot water consumption.
2. Factors affecting the power of a gas boiler (characteristics of gas boilers)
- First of all, these are seasonal peak loads. With an increase in gas consumption by consumers, the working gas pressure in the network may decrease and the boiler will not produce the parameters stated in the passport.
- Strong salinity, hardness of the supplied water (scale on the inner surface of the heat exchanger).
- Long-term operation of the boiler without preventive cleaning of scale in the heat exchanger, soot and soot on surfaces from the gas side. Usually the first cleaning is carried out after 3 years of operation, however, the timing largely depends on the quality of the water and the intensity of operation of the equipment.
- Frequent use hot water. You should be aware that when heating water for household needs, up to 85% of the boiler's power is spent.
3. Which boiler to choose wall or floor? (characteristics of gas boilers)
This issue is discussed in detail in the article:. But to put it in a nutshell, then by its design floor gas heating boiler differs from wall, first of all, the parameters of the heat exchanger, the material from which it is made and the range of generated space heating power.
Floor boilers have a massive heat exchanger made of cast iron or high-alloy steel. Cast iron heat exchanger is more fragile than steel, but it is more durable in operation. Boilers with a steel heat exchanger are lighter, less damaged during transportation and installation at the consumer. The power of floor boilers reaches thousands of kW. The weight of the boiler is about 100 - 150 kg. Large capacity boilers are supplied with additional external equipment (pump, security system, expansion tank). Most often they are in a separate room of the house (boiler room). Here is a detailed one with a brief description and evaluation of the brands presented on our market.
heat exchanger wall boiler made of copper tubes, so it has a shorter service life. The power of wall-mounted boilers does not exceed 35 kW, weight 30 - 50 kg. The wall-mounted boiler can be installed in the household premises of the house: kitchen, bathroom. It is quiet and does not take up much space. Actually - this is a miniature boiler room with a heat exchanger, an expansion tank, pumps for pumping water, a ventilation system and a control unit.
New direction - condensing boilers. They are more powerful than traditional wall boilers are produced with a capacity of up to 100 kW), have a heat exchanger made of steel pipes, whose resource is 2.5 times greater than copper, however, condensate must be drained into the sewerage system. The efficiency of such boilers is higher than that of conventional ones. You can read more about this in the review article, which describes their principle of operation.
4. Gas boilers according to the type of combustion chamber design (characteristics of gas boilers)
For closed combustion chamber(turbocharged boilers) oxygen is supplied through an external coaxial pipe, which is a two-loop pipe (pipe in a pipe), brought out through a hole in the wall. Exhaust gases are removed through the internal contour of this pipe.
For open combustion chamber oxygen comes from the room in which the boiler is installed, the products of combustion of gas fuel are removed through the ventilation system of the building. This method requires the flow of air into the boiler room.
5. Single and double circuit gas boilers(characteristics of gas boilers)
In the presence of a gas boiler, it is natural to satisfy the need for hot water using its power. To heat water for domestic needs, a double-circuit boiler is most often used, in which a flow heat exchanger is installed, sometimes with a small boiler. For a single-circuit boiler, an external boiler is mounted and hot water is taken from it.
6. Profitability and safety of operation of gas boilers (characteristics of gas boilers)
Natural gas boilers are characterized by high efficiency. fuel usage: 90 - 95%. The gas boiler control system has several degrees of protection:
- Burner flame control. The gas is turned off if the flame goes out.
- According to the pressure of the supply gas. When the gas pressure drops below the critical value, its supply will be turned off.
- In the event of a power failure, the gas supply valve closes.
- According to the required air temperature in the room. In the thermoregulation mode, the boiler is switched on / off when the limit values of the air temperatures in the room, set by the user, are reached.
Depending on the type of performance ( economy, comfort or elite), additional features or improved hardware design are possible.
What affects the efficiency of the boiler, what parameters you should especially pay attention to, how to achieve the maximum return from the boiler, we described in the article.
It should be noted that the price of gas boilers of the same class is somewhat different from different manufacturers, however, it is determined primarily by the type of manufacture of the product. The most expensive will be a boiler in an elite version.
Afterword
Now, having understood and determined for yourself the optimal characteristics of the gas boiler suitable for your needs, you can safely proceed to the search and selection of a specific model, which allows you to make ours, where each model has detailed description and reviews of users who have purchased a particular model. Having wandered through the catalog, you will get an idea of the cost and range of models presented on our market, which is important. Also, when choosing, pay attention to - what exactly is the warranty, its terms, operating rules for the warranty period, specifics of service.
Remember that the boiler is the center of the heating system of the building, therefore, when choosing it, be sure to consult with specialists, however, it is better to consult a specialist with basic concepts about options and characteristics, on the basis of which the price is formed.
If the article was useful, as a thank you use one of the buttons below - this will slightly increase the ranking of the article. After all, it's so hard to find something worthwhile on the Internet. Thank you!The most profitable and definitely the right decision in the period heating season- arrange well independent heating own house. This allows you to improve the microclimate and achieve maximum cost savings. Gas can help double-circuit boilers heating, equipped with all the required systems responsible for safety and automation.
There will be no doubt about the financial feasibility of the decision to replace outdated equipment with more modern equipment in the first months of its use. At the same time, the house will be as comfortable as possible, without interruptions in hot water and heat in batteries.
A little about gas boilers: advantages and disadvantages
The market share of heating gas equipment is about 75%. The rest includes solid-state, liquid, electrical or universal counterparts. A large category among them are dual-circuit models, represented by a wide variety on the market. Each of the devices is characterized by similarities and differences in design features.
Introductory video lesson
If you choose the right model, taking into account all its main indicators and characteristics, it will provide heat to all rooms in the house. One of the main advantages of double-circuit gas boilers is versatility. Among other positive aspects, it is worth noting:
- The ability to automate the boiler saves the owner of the house from worries about heating
- Provides maximum security
- The boiler supplies the house not only with heat in heating radiators, but also with hot water supply (DHW)
- The boilers are compact in size, some models can be hung in a convenient place on the walls, while they do not need a separate boiler room
- Relatively low cost
However, looking at the positive aspects, it is worth highlighting several disadvantages:
- Even with the ability to easily organize hot water supply, you will have to wait until heated water flows from the tap
- Normally, a double-circuit boiler is capable of providing hot water only one point in a certain time period
- At the same time, the equipment is not able to heat the premises and provide the DHW line, priority belongs to the second operation
- Installed in modern models heat exchangers are very unstable against hard water: the higher the pH value, the shorter their service life
The device of a double-circuit gas-fired boiler
The market is rich in a variety of models, which are gas double-circuit heating boilers from a variety of manufacturers. Some of them are similar to each other, others have many important differences.
One of the main differences between double-circuit heating boilers is how the heat exchanger is arranged, which transfers the heat released by the combustible fuel to the coolant. This element in most models is placed at the top of the equipment, under which the burner is located.
When the fuel burns, it releases upward heat. The latter heats the heat exchanger through which water circulates. Heat exchangers can be made of stainless steel, aluminum or copper. However, stainless steel models are considered the most common and resistant to aggressive coolant.
Conventionally, double-circuit boilers can be divided into the following two categories:
- With bimetric heat exchanger
- With two heat exchangers
Bimetric heat transfer models are a "pipe in pipe" system. The main external circuit is necessary to ensure the heating of the coolant flowing inside the second circuit. The main advantage is low cost, however, too high a thermal load can disable the equipment after a short 6-7 years.
Dual circuit gas installations heating systems with primary and secondary heat exchangers are much more reliable, but they are characterized by a more significant cost. This construct works like this:
- As a primary heat exchanger, a system of copper tubes is used, on which copper plates are soldered - it is necessary for heat transfer
- A secondary type heat exchanger (its second name is plastic) is designed to transport heat between the coolant and water to provide a DHW line
- When hot water is needed, the coolant moves along closed loop inside the boiler, without entering the heating system and giving off heat to the DHW line
Classification of gas double-circuit boilers
It is possible to classify gas double-circuit heating boilers according to various characteristics:
- Design options
- According to the heating method
- How to remove liquid
Design options
The main classification of gas boilers is design features. Depending on the installation method, the equipment on the market is divided into 2 types:
- wall
- outdoor
The most common are wall-mounted models that can be mounted anywhere (in the corridor, in the kitchen or in a separate small boiler room). Low cost and high performance are their main positive features. Such equipment can heat a house up to 350 sq. m.
Any wall-mounted model is equipped with everything required for stable and reliable operation. There is no need to purchase additional expensive large units that expand functionality.
The cost of floor models is slightly higher, but the difference in the money spent will quickly pay off due to high efficiency. Installations of this type are capable of exceeding a power of 20 kW, allowing you to heat a spacious cottage several floors high.
Significant disadvantages of floor models are:
- Large dimensions and weight due to the use of a cast-iron heat exchanger
- The need for a separate room for the placement of equipment and arrangement of interchanges
- More complex care and the need for regular preventive examinations
According to the heating method
Depending on the method of heating water for hot water supply, a gas heating boiler can be of one of two types:
- Boiler
- flowing
Models that use separate boilers to heat water to the DHW system are less common. In them, the liquid, before entering the mixer, must be heated in a separate tank.
Flow models are more popular. They are characterized by high power, due to which hot water enters the mixer much faster.
The first type of water heaters is more often used in conjunction with floor models. Flow heaters are installed in wall-mounted units to make them more compact.
How to remove liquid
Depending on the method of smoke removal, double-circuit gas boilers can be divided into two main categories:
- With natural traction
- Forced draft
To organize natural draft, you need a boiler with an open chamber. It will receive oxygen directly from the living quarters. But since this is not always possible, forced draft or turbocharged models are most common.
Calibrated boilers have some advantages over analogues:
- They use air that is pumped from outside, and not from living quarters
- High power, thanks to which you can heat up to 12 liters of water per minute
- Profitability and autonomy - all work operations are controlled by automation, which eliminates human influence
- Good tightness
Power is the main selection criterion
Considering and choosing gas double-circuit heating boilers, it is necessary to pay special attention to their power. If it is too small, the equipment will not be able to fully provide heat for hot water supply and the heating system. Too powerful equipment, in turn, will cause increased costs, failures, condensation, etc.
The easiest way to calculate is to take for every 10 sq. m of residential heated premises, an indicator of specific power equal to 1 kW. In modern insulated houses, this value can be 20-25% less due to reduced heat loss. Toward the north, the situation is diametrically opposite.
Specific power, as a rule, is chosen equal depending on the regional location in which the house is located:
- In the northern regions- about 1.5-2 kW
- In Moscow and nearby areas - 1.2-1.5 kW
- Central Russia– 1-1.2 kW
- Southern areas– 0.7-0.9 kW
In cases where the ceiling height exceeds the standard 2.7-3 m, it is recommended to enter a correction factor of 1.1-1.2.
Several installation features
For a double-circuit boiler with a boiler, any of the piping provided in the project of the house is suitable heating system. Some features must be followed when installing equipment with instantaneous water heaters.
It must be remembered that double-circuit flow-type boilers are capable of operating exclusively in the "either heating - or hot water" mode. Priority is given to the DHW line, so if it is used for a long time, the house may become colder.
To make the work of a double-circuit boiler the most practical, it is necessary to adhere to a number of rules:
If there is a nightly electricity tariff, you should consider installing a second electric boiler. Such a solution may seem expensive, but from the point of view of economy, it is justified.
Detailed installation instructions can be
average cost
One of the main exciting questions - how much do gas double-circuit heating boilers cost today? The price range for equipment is quite wide - from $500 to $2000. They depend on the technical characteristics and the manufacturer of the installation in question.
If we talk about popular manufacturers, it is worth highlighting the following market leaders:
- DAEWOO (Korea)
- Ariston (Italy)
- Junkers (Bosch, Germany)
- Rinnai (Japan)
- How to calculate the power of the equipment?
- Single and double circuit boilers
- Varieties of boilers by type of burner: characteristics
- Condensing and convection boilers
- Floor and wall boilers: overview of models
- The method of removal of combustion products
- What should be the chimneys for boilers?
Today, in private housing construction, special equipment is in demand, which allows for uninterrupted supply of hot water and heating of rooms of different sizes. Boilers are connected to common system water supply and heating of the house, they provide water supply in internal systems at home. Such equipment can run on a variety of fuels, including electricity, solid fuel, gas. The most economical are gas boilers, which can be easily installed in a private house of any size, in a city apartment. To make it easier to understand the selection of suitable equipment, you should pay attention to the above review of gas boilers. Such equipment is classified according to a variety of parameters:
- power;
- burner type;
- method of removal of combustion products;
- the principle of operation and the specifics of connecting the entire system.
Before any purchase, it is imperative to review boilers and heating systems, familiarize yourself with the characteristics of the equipment.
How to calculate the power of the equipment?
In addition to an overview of heating systems, it is important to mention how to calculate the power of the purchased equipment. For gas boilers, this can be done in several ways:
- the first way is very simple. It is enough to take into account that for every 10 m² of room area, 1 kW of equipment power is required. This is with a ceiling height of up to 3 m and in the presence of excellent insulation of the entire room. It is enough to calculate the area of \u200b\u200bthe house to find out which one, running on gas, is required;
- the value obtained by the first method must be multiplied by special correction factors. These values depend on the geographic location of the region. For Moscow, this is 1.1-1.5, for the Urals - 1.2-1.8, for the northern regions - 1.5-2. The second value depends on the level of thermal insulation: for well-insulated houses, the coefficient is 0.6-0.9, for the average level - 1.0-1.9, for summer buildings and country houses – 3-4;
- the third option is in demand only among specialists; they use special programs for counting. This method is the most reliable and accurate, but it is used only when the boiler and piping are installed by special companies during the construction of the house.
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Single and double circuit boilers
For an overview, it is necessary to mention the number of circuits that the equipment can have. According to this parameter, single-circuit and double-circuit boilers are distinguished, which differ from each other in the following characteristics:
- a single-circuit gas boiler is a conventional device that is intended only for space heating, hot water supply is not provided;
- double-circuit heating equipment is more complex, there are already 2 circuits that provide heating and hot water supply. Such devices are further divided into 2 types: boilers with boilers, which allow you to constantly have some supply of hot water with a volume of 40-60 liters, and boilers with a flow heating method. In the first case, the equipment is more economical. Flow heaters consume more fuel during heating, although they allow you to get water of the required temperature almost instantly. But their cost is higher, and installation is more difficult. Boilers with boilers are most often used for heating; they are more suitable for apartments, small country houses.
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Varieties of boilers by type of burner: characteristics
For a complete overview of gas boilers and greater awareness, you should pay attention to the type of burner that ensures the operation of the equipment.
All burners are classified into pressurized and atmospheric.
For wall-mounted equipment, built-in burners are most often used; for floor equipment, they can be located separately. In this case, it is necessary to select devices based on the power, the required operating parameters.
Atmospheric burners provide the supply of a gas mixture by creating excess pressure. This is the simplest and cheapest option and is often used for smaller boilers. Pressurized burners are more complex, they already have built-in fans, which provide the gas mixture to the equipment. The advantage of such heating devices is that the draft in the chimney does not matter much. Their efficiency is higher, such burners are most often used for condensing equipment. Their dependence on gas pressure, or rather its decrease and increase, is very small.
Forced burners also have disadvantages - this is a high cost, additional noise from the operation of the equipment, energy dependence, since the fan must be connected to the mains for operation. The review should also mention such differences as the use of piezoelectric and electronic ignition for gas boilers. In the first case, the boiler must be turned on only manually, i.e. for this, you must press the button. If electronic ignition is provided, the equipment turns on automatically. There is no igniter, which means that a constantly burning flame is not required. This saves not only gas, but also electricity.
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Condensing and convection boilers
Today, gas boilers of 2 types are produced: condensing and convector. Any review would be incomplete without mentioning such a division. Convector boilers are more common, but part of the heat is lost in them, the efficiency is 90%. When buying a gas boiler for 20 kW, heating water or coolant will be only 18 kW. It is possible to increase the efficiency, but this process is rather complicated, requiring additional efforts and expenses.
Such boilers have a negative phenomenon - the appearance of condensate, which forms at a temperature of 57 ° C. Water vapor turns into a liquid, which settles on the walls of the equipment. Therefore, during installation, it is necessary to take into account this feature, use chimneys that are not afraid of condensate. In this case, plastic coaxial pipes come to the rescue, they are not afraid of condensate. Why is condensation dangerous? When heated to temperatures of 100-200°C, gases can destroy the walls of chimneys in just a couple of seasons. And this means only one thing - the received heat will literally go into the pipe, that is, the losses will become significant, the equipment will be ineffective.
Condensing boilers are more modern and economical, the process of condensate formation occurs directly in the boiler, i.e. heat is used during gas combustion and when condensate itself appears. This procedure is called the higher calorific value. For heating boilers, this indicator is very important, the increase can be up to 11%. Condensing boilers operate with an efficiency of 106-109%. Therefore, such equipment is so popular today, it is being installed more and more often in private housing construction.
Why can't all gas boilers be replaced with condensing ones? Everything is not so simple here. Their installation differs in some features, the control system is much more complicated than for other equipment designed for heating and supplying hot water. It turns out that the cost of such a boiler is more than the traditional one, plus it is necessary to additionally address the issue of disposal of the resulting condensate.