How to choose a flueless boiler - what should you pay attention to?

In order to equip a room with water heating devices today, it is not necessary to use a stationary chimney. To do this, you can use a chimneyless gas boiler. Such equipment has an independent smoke removal system and small dimensions, which is a rather convenient factor for many consumers. The smoke removal system itself is somewhat reminiscent of an exhaust hood and this is their main charm. Let's discuss this topic in more detail. Similar boilers appeared quite recently and although they are very similar to classic boilers, some differ from others in the operation of their system, which is called coaxial with a closed chamber.

Operating principle and advantages

A boiler that does not have a chimney completely or has one, but is very simple, has a number of its own unique design features and a certain operating principle, which we will discuss later.
Since gas is used to operate such a heating unit, the main requirement is the presence of a cylinder connected to the device or the presence of an already installed gas line. Also, although the name suggests that such a boiler is chimneyless, it still has a chimney, but in comparison with other large, complex and massive systems it is very simple.

In order to make such a hearth even more useful and powerful, to heat a large house with it, you can connect it to heating radiators and thereby convert it into systems with a water circuit. Heating in this case will be carried out by circulating and heating cold water in the radiators of each room. In the same way, you can get hot water in the house.

A double-circuit gas flueless boiler consists of the following elements:

• Gas lines or systems;
• A heat exchanger through which heated water moves and circulates;
• Return heating circuit;
• Through the input element, cold water enters the system;
• An output element that is used to remove and use already hot water for various domestic needs and purposes.

Such systems are complemented by two circuits at once, each of which is not connected to each other. This allows you to use them separately and for different needs. This variation can be supplemented with coolant, unlike single-circuit ones, which, at most, can be used to simultaneously heat and produce hot water using a device such as a boiler, which is purchased separately.

The most economical and budget-friendly variations are those that have a boiler with indirect heating, due to which closed local recirculation is formed. Thus, you can equip your home not just with hot water, but also get it heated to a certain temperature by simply opening the tap. The disadvantages include the bulkiness of such systems, due to which they will not fit into small houses and apartments. At the same time, the price of products manufactured by well-known and trusted brands is not always the lowest and most affordable.

Before you buy a chimneyless boiler, we recommend that you familiarize yourself in more detail with all its positive qualities and operational capabilities:

1. Double-circuit variations of the modern model are distinguished by their average, and in some cases, quite miniature overall dimensions. Due to this, such a unit easily fits even in the smallest and most standard kitchen or in a specially designated utility room;
2. The functionality of such centers is very large and varied. This is not just a heating device, but also the ability to connect to a water jacket to heat a large area. If you have a boiler, you can get water for domestic purposes;
3. They are economical. The owner of the house can use such boiler equipment himself, as needed, thereby reducing resource consumption;
4. Since double-circuit variations have a simple list of components, unlike single-circuit boiler systems, installation can be done with your own hands and without the help of a specialist.

The disadvantages of this variation are that it is not capable of performing several actions at the same time. For example, when performing the heating function, you will not be able to receive hot water. Also, water heating does not occur immediately, but gradually. Moreover, the smaller the size of the tank for filling and storing water, the less you will be able to provide your home or apartment with hot water

When using such a boiler, it is important to remember that, for example, when using water in the kitchen, it may not be enough for someone who is currently washing in the bathroom

Manufacturers and brands

Equipment of this class is produced by all well-known European companies, as well as domestic enterprises. If we consider its cost in relation to wall and floor options, then it is distributed in the same way as for boilers with an open combustion chamber. Wall-mounted options are cheaper, while floor-mounted ones have the highest price.

If we compare between local and foreign models, then here too there is no particular difference between boilers with an open and closed combustion chamber. Imported samples still have the highest prices, and products from domestic manufacturers are almost 50% cheaper.

If we consider boiler models from one manufacturer, for example, the very popular Italian company Baxi. Then its gas flueless floor-standing units have a price of around 2000, and wall-mounted models - about 1000 euros. The cost of wall-mounted boilers with an open combustion chamber under the brand name of this company is about 700-800 euros.

But, despite the higher price, chimneyless boilers are in great demand, especially when equipping apartment heating systems in multi-storey buildings.

Chimneys and material options for their installation

Current heating equipment powered by gas is characterized by a fairly high efficiency index and low temperatures of combustion products, which implies increased requirements for the materials from which chimneys are constructed. In the construction market, there is a gradual replacement of brick, steel, asbestos pipes, and galvanization with more modern ones. Increasingly, special protective sleeves are used, as well as stainless steel and Hungarian furanflex. Let's take a closer look at the parameters of each of these materials.

Galvanized pipes

Steel pipes are quickly exposed to corrosion, which makes the operation of a galvanized chimney quite short (about 3 years). The use of a specially designed protective coating can extend the service life up to 5 years.

Asbestos cement pipes

This material was widely used in organizing the removal of combustion products, despite the maximum temperature of 300 degrees Celsius. This option has an acceptable cost, but has a number of nuances that would have to be dealt with (for example, installing a chimney on a gas boiler is quite difficult in the vertical plane, insufficient tightness of the joints, the likelihood of rupture or splitting of pipes when they overheat, as well as the ability of asbestos cement to absorb moisture and condensate).

Brick chimney

Brick is far from the best material for creating a chimney, since condensation quickly destroys the integrity of this material. Quite often, in houses equipped with a brick chimney, the ceilings and walls are “decorated” with damp spots, which are formed due to the absorption of moisture and condensation by the brick.

Protective sleeve

The smoke exhaust device, which has equal perimeters of the ventilation duct and the protective sleeve, is a composite multilayer shell. The main function of this design is to protect smoke channels from the adverse effects of thermal gas flows. Special hoses can be used to seal ventilation channels; their use can minimize the effect of combustion products on the chimney, as well as improve draft and increase the operating time of the entire structure.

Furanflex

It is a new option that is used for chimney installations. It is made from reinforced plastic reinforced with special fibers. A distinctive feature of this material is its resistance to interaction with the acidic environment of condensate, low thermal conductivity and efficiency when operating at temperatures less than 200 degrees Celsius.

Stainless steel

This material is characterized by high levels of tightness and fire safety, quickly overcoming the threshold of condensation. Thanks to its round cross-section and smooth surface, stainless steel promotes maximum traction

When purchasing pipes of this type, you should pay attention to their marking data, since they can significantly affect the quality of welded joints, as well as options for connecting disparate elements into a single structure

The influence of pipe material on the occurrence of excess moisture

You can insulate a ventilation chimney pipe using different materials and methods, but you must take into account the quality of the material from which this pipe was made, because it will directly affect the process of moisture formation.

When the gas boiler is turned on, a brick chimney takes a long time to heat up, so a large amount of moisture appears in it. A steel chimney can also form a certain amount of moisture inside, but this problem is quickly solved by installing two nested cylinders (the diameter of such pipes must be different) with insulation between them. This technology is called “sandwich”.

Ceramic pipes are convenient because they warm up quickly and therefore do not form condensate stagnation, especially if they are installed correctly and properly insulated. If you decide to make a pipe for a gas boiler from the polymer material furanflex, there will be no problems with the formation of excess moisture.

Asbestos-cement pipes are already gradually becoming obsolete, because they are harmful due to the formation of asbestos dust and poor heating. The last factor negatively affects moisture formation.

Almost any chimney pipe with insufficient insulation and incorrect, leaky installation can contribute to the formation of destructive moisture. Timely insulation of the chimney with mineral wool, brick chips, slag and other suitable materials will help solve the problem.

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Parapet heating systems

One of the types of gas chimney boilers is parapet. The design resembles the design of condensing equipment. The main difference from the latter is the presence of a closed combustion chamber. During operation, air, which is inevitably consumed during combustion, enters the firebox not from the room itself, but from the street, therefore, overheating does not occur and the oxygen concentration does not decrease. As a result of this method of operation, the efficiency, environmental friendliness and efficiency of equipment increase

It is important to remember that some types of equipment, in addition to the traditional heat exchanger, have a convection casing in their design, which allows you to heat the room, consuming less gas, that is, with greater efficiency. There are mounted types of parapet equipment, which are mostly energy-dependent and also require additional power from electrical networks

At the same time, floor-standing units are completely energy independent.

How to make a chimney for a flueless boiler

The advantages and disadvantages of chimneyless boilers have been discussed more than once in various construction forums. In Europe, the units enjoy a well-deserved reputation as economical and reliable equipment with low installation requirements. Under domestic operating conditions, boilers' efficiency and productivity are somewhat reduced.

Several aspects can be highlighted as advantages:

• There is no need to coordinate with the gas service when installing a turbo boiler, provided that licensed and certified equipment is purchased.
• It is allowed to install the boiler in rooms with limited space, in apartment buildings and private houses. There is no need for forced ventilation of the room.
• Performance – chimneyless units use the temperature of heated flue gases to generate additional thermal energy, which increases the efficiency and efficiency of the devices.

What malfunctions often occur with chimneyless boilers?

Most malfunctions occur due to improper operation or installation of equipment. The specialist will try to find out the reasons why the chimneyless boiler goes out and eliminate them. There are several factors leading to this:

• Poor traction - non-compliance with the requirements for installing a coaxial pipe: exceeding the permissible vertical and horizontal sections leads to shutdown of the equipment.
• Voltage failures - in most cases, sensitive automation is installed in chimneyless units. If there is a voltage failure, the processor gives a signal to shut down.
• Malfunctions in the operation of automation - the design provides a large number of monitoring sensors: draft, heating of hot water and coolant, etc. Failure of any sensor leads to a shutdown.

If you follow the rules for installing chimneyless wall-mounted heating boilers and carry out regular maintenance, the devices will operate without complaints or difficulties throughout their entire service life.

How to deal with blowing out of a chimneyless turbo boiler?

One of the main problems that owners of chimneyless heating equipment face is shutdown due to poor draft or blowing out of the boiler. The danger of chimney backdraft for a boiler with a closed combustion chamber lies in the likelihood of carbon dioxide entering the room, as well as failure of individual components.

There are several ways to troubleshoot the problem:

• Improve the draft in the boiler by installing a deflector that increases the draft by approximately 1.5 times.
• Install wind protection - a block mounted on the head of the pipe reliably protects against wind.
• If the situation is not corrected, the coaxial chimney is redone, taking into account the technical requirements for the location of the chimney, when installing a turbocharged boiler with a closed combustion chamber in a private house.

In Europe, it is mandatory to install a gas detector when operating any gas equipment. In our country, this is a desirable measure that has already saved dozens of lives.

Which boiler is better - chimney or flueless, expert opinion

When answering this question, it should be taken into account that condensing / chimneyless boilers were created for operating conditions in low-temperature coolant heating mode. The 95% efficiency declared by the manufacturer is only possible if the return temperature is no more than 40°C. In the harsh Russian winter, it is quite difficult to fulfill this condition.

Installing a boiler with a closed combustion chamber in a regular chimney when replacing old equipment with new equipment is prohibited. You will have to redo the smoke exhaust system, which is quite expensive. Chimneyless units are optimally suited for well-insulated buildings located in temperate climates.

Methods to combat the blowing out of a flueless turbocharged boiler

To quickly and permanently get rid of the problem of blowing out the flame in a turbo boiler, you must first install a deflector that cools the air and increases draft. If you are in a windy area, be sure to install a windbreak. This is a special block that is mounted on the very top, that is, the head of the outgoing pipe.

We recommend reading: The reason why a gas boiler is blown out by the wind

If none of the methods helps solve the problem, you should remake the chimney pipe in accordance with all the requirements for this type of structure. These standards are established officially and are publicly available information.

Features of the design, operation and installation of floor-standing chimneyless gas boilers

If it is impossible to install a classic vertical chimney, flueless gas boilers are used for heating. For such heating equipment, a separate ventilated room for natural draft is not equipped.

Despite the name “flueless”, such boilers do have a chimney. Its role is played by a compact coaxial pipe, which provides draft and removal of smoke masses from the combustion chamber.

External outlet of coaxial chimney

Design and principle of operation of chimneyless boiler equipment.

Chimneyless boilers, like classic gas boilers, operate in heating mode - single-circuit, and also as water heaters (DHW) - double-circuit.

A distinctive feature of the design is a closed combustion chamber. The burner, through which the gas heats the water in the system, is located in a sealed chamber. Thus, carbon monoxide, soot and smoke from fuel combustion do not penetrate into the room, and the boiler’s operating efficiency increases.

Oxygen-saturated combustion air enters the closed chamber through the external chimney block. The air heated by the burner element heats the copper circuit through which the coolant flows. Then the “exhaust” air, together with the products of fuel combustion, exits through the internal block of the coaxial pipe.

Scheme of operation of a floor-standing coaxial boiler

The coaxial chimney is simple to implement. These are two coaxial pipes of different diameters, fastened together. In this way, the heated gas waste is cooled by the air entering the chamber, making the boiler fireproof and environmentally friendly for the residents of the house. By cooling the combustion products, the air enters the combustion chamber already heated, which saves energy resources.

To prevent insufficient draft, high-power gas boilers are equipped with deflectors that increase the air flow by one and a half times. If there is a possibility of wind blowing, a special wind protection block is installed at the pipe outlet.

Features of installation of gas boilers with a coaxial chimney.

Floor-standing chimneyless boilers for autonomous heating systems are installed in small buildings and in multi-apartment buildings or industrial premises.

Chimneyless gas boilers are installed on a special stand. If the boiler is controlled by an electronic board, it is connected to electricity according to the rules for installing electric and gas equipment by specialists.

They are included in the heating system and gas mains in the same way as chimney gas boilers. The difference is the installation of a coaxial chimney.

Installation diagram of a horizontal coaxial chimney

Requirements for installing a coaxial pipe as a chimney:

1. The chimney outlet to the street runs horizontally through the wall. The length of this pipe section is no more than 1 meter.
2. The chimney is horizontal, but if horizontal exhaust is not possible, a vertical chimney is used. The length of the vertical part of such a chimney is about 3 meters.
3. The outer part of the pipe is located no lower than 2 meters from the ground.
4. The distance from the pipe to window or door openings is at least half a meter.
5. Do not place the pipe outlet under a window.
6. To prevent the accumulation of condensation liquid, it is installed at an angle of 3-5 degrees.
7. Observe the diameters of the coaxial chimney pipes and their ratio for fire safety.
8. The hole drilled in the wall for the pipe is lined with insulation made of non-flammable material.

Compliance with these requirements will ensure the boiler operates safely and efficiently.

Chimneyless boilers - their pros and cons of operation.

The advantage of floor heaters equipped with a coaxial pipe is installation in a living room. To fit the boilers into the interior, the finishing of the walls and the junction of the chimney with the wall is selected.

More details about coaxial chimneys and their use for gas boilers can be found in the video below.

Coaxial boiler in the interior of the apartment

Besides this, other advantages:

• simplicity and low cost of installation;
• there is no need to install supply and exhaust ventilation;
• high power of units of such a design that they heat large areas;
• some gas models are equipped with convection holes, which makes it possible to heat a room without a radiator;
• long service life.

The disadvantages of coaxial boilers are the smoke exhaust system. The length of the smoke exhaust pipe is no more than 5 meters. During frosts, chimneyless boilers operate at high power, which causes more condensation to form in the coaxial pipe, which freezes and blocks the air supply and smoke removal. Blowing out of the chimney occurs if it is not equipped with a wind protection.

What is this equipment?

In terms of their purpose, chimneyless boilers are practically no different from conventional ones. They, like all other models, can be used for heating rooms and preparing hot water, but they have a slightly different combustion chamber. There are differences in the principle of operation.

If the normal functioning of a conventional gas appliance requires the presence of a chimney and draft, then these models use a coaxial pipe to take in air and discharge exhaust gases.

Equipment of this type is designed for heating rooms up to 300 m² and can be connected to the system on one or both sides. Combustion products are removed from them through a coaxial pipe consisting of two elements. Gases are removed through the internal one, and air is supplied to the boiler through the external one.

They are very convenient not only structurally, but also because they are fireproof. Hot combustion products are isolated from the walls of the building by cold air coming from the street.

Another advantage is that the boiler does not require draft and air flow; these operations are performed forcibly, using a fan built into the device.

What we pay attention to

Heating devices with a closed combustion chamber include a coaxial chimney for a gas boiler.
It is designed to ensure smooth operation of the device. And serious requirements are placed on it, because combustion products are released through it, which are very harmful to human health. Therefore, it is recommended to install it through a wall in which there are no window or ventilation openings.

In all other parameters, the criteria for choosing a gas flueless boiler do not differ from others

When purchasing it, you should also pay attention to:

• power
• compactness
• design
• ignition options

The brand of the manufacturer is also an important factor, and since each of them has a wide range of products, it is worth evaluating several different samples to decide which one is best suited for the room.

Flueless boilers are divided into:

Let's start our consideration with floor-standing boilers from the Slovak manufacturer Proterm. They are non-volatile and have an efficiency of 90%, are reliably protected from overheating and are supplied assembled. Floor-standing boilers have high power ratings and can be used for heating large rooms, and also have other remarkable characteristics:

• reliability
• ease of use
• relatively low price
• possibility of changing fuel

The next noteworthy models are gas boilers with a coaxial chimney from a Korean manufacturer; today they are leaders in the sales market and not only because they have a low cost, but also due to a fairly large list of high performance indicators.
When choosing these devices, even the brand is not so important. It can be:

All of them are well adapted for use in the Russian climate and have high quality indicators, a large number of safety sensors and are very easy to operate.

German chimneyless boilers are undeniable in their reliability and quality. Not only are they designed for a long service life, but they also have a lot of advantages, not the least of which is environmental friendliness.

The brand plays a significant role when choosing, but you should not lose sight of other parameters:

They are also important and must be taken into account when purchasing.

Which chimneyless boiler is better to choose for your home?

When choosing one of the types of heating devices under consideration, it is worth considering that chimneyless devices are created to operate a coolant that has a fairly low temperature - about forty degrees Celsius. Thus, normal operation and 95 percent efficiency (efficiency factor) will be ensured if the water temperature does not rise above the specified level.

This is interesting! It has been noticed that with the correct selection of a boiler subtype without a chimney and its proper installation, the efficiency increases and even becomes more than one hundred percent (108-109%).

Russian turbocharged boilers

Turbocharged boilers of Russian domestic production are not so widely represented on the heating equipment market. “Conord”, “ZhMZ”, “Neva” and “Rostovgazapparat” - these devices have already proven themselves, offering lines with different models.

Manufacturers producing boilers of these brands have adapted their devices specifically to Russian realities, taking into account all possible nuances. Domestic coaxial heating units have a great undeniable advantage over their foreign counterparts - they cost on average thirty to fifty percent less. Thus, a device from an Italian company can cost up to two thousand euros, while a Russian one will cost a maximum of 1,100 euros.

Foreign turbocharged boilers

High-quality American and European automation, which is equipped with these foreign units (Vaillant, Ariston, Viessmann, Baxi, Buderus, Ferroli), allows you to trust these brands, because they have already been tested by a large number of users. Korean-made Navien and Daewoo boilers also stand out among other, lesser-known brands.

The Slovak brand Proterm is widely represented on the Russian market. Boilers of this brand require an additional connection to electricity, but are conveniently installed, without requiring assembly or additional preparation. Korean (Olympia) and “Rinnai” are equipped with high-quality sensors that allow full control of the current operation of the device.

Ukrainian flueless boilers

Turbocharged boilers of foreign production are represented on the relevant market by such Ukrainian companies as, for example, Danko and Euroformat. Experts note the units of these two brands, which stand out among others in terms of their long useful life.

This is interesting! Most Ukrainian-made boilers, produced under the Euroformat and Danko trademarks, have in their design parts made in the USA and some European countries. Thus, the Danko device contains inside a micro-flare stainless steel burner and a piezoelectric element for its convenient ignition.

SNiP standards

The manufacture and installation of any chimney structures must comply with all requirements of SNiP 2.04.05-91 and DBN V.2.5-20-2001. Such adherence to standards guarantees the safe operation of the heating system. Violation of the conditions listed in the documents can lead to problematic situations, the solution of which will require the participation of the gas industry.

Abstracts from the main regulatory documents:

1. The structure of the condensate collector should solve the problem of moisture accumulation on the walls of the chimney;
2. Good traction is a must;
3. The head of the chimney must be free and do not allow the presence of deflectors or fungi on it that inhibit the removal of combustion products;
4. A careful fit of all structural elements at their connection points is mandatory;
5. Tight sealing at joints and all kinds of connections is required.

Installation requirements: all according to the law

When installing gas boilers, which have become popular due to their inexpensive fuel, requirements are imposed both on the boiler room itself, if the unit is located in a separate non-residential premises, and on the selection of locations for all elements of the ventilation system.

If a domestic gas boiler has a power of more than 30 kW, it must be installed in a separate room. It can be located both in a residential building and outside it

For units whose power exceeds 150 kW, a separate building is erected or an extension is made to a residential building. Next to the boiler room, through the adjacent wall, there should be a non-residential premises.

The rules for ventilation and air conditioning are set out in SNiP 2.04.05-91. The main requirement concerns air exchange, which must be completed in full at least 3 times within an hour.

Be prepared for supervision by gas service representatives, who will definitely check:

• the presence of a solid foundation and concrete floor;
• laid communications - water supply, sewerage, heating pipes;
• insulation of walls and gas outlets to prevent freezing during cold periods;
• area – at least 15 m³;
• ceiling height – 2.2 m and above;
• mandatory natural lighting - a window of at least 3 cm² for each cubic meter of boiler room volume.

To ensure natural ventilation, the window is equipped with a window, and a small gap is left under the front door for the free flow of air - approximately 2.5 cm high. Instead of a gap, door perforation is used - in the lower part adjacent to the floor or threshold, several holes with a diameter of about 2 cm are made .

If the extension door leads into the house, or more precisely, into a non-residential room, then it is made of fire-resistant material with a high fire safety class.

Often, not natural gas, but liquefied gas cylinders are used as fuel. They must not be stored near the boiler.

Another additional room is equipped for the cylinders, and they are connected to the boiler via a fuel supply pipe.

Requirements regarding chimneys and ventilation:

• Gases are removed and air supplied through separate channels;
• the size of the ventilation window for air flow is at least 1/30 of the boiler room area;
• the boiler is installed at a minimum distance from the exit of the chimney pipe and the ventilation shaft;
• if a coaxial chimney is routed through a wall, then two openings are provided: the first - directly for the pipe, the second - for maintenance.

Ventilation ducts installed in a private house for a floor-mounted or wall-mounted gas boiler must always be open so that air circulates constantly.

Chimney boilers general information

When choosing chimney boilers powered by natural gas, you need to know what types of this equipment are on sale today. Popular types are:

• Parapet boilers;
• Mounted;
• Floor-standing.

When choosing heating equipment, you should pay special attention to the following indicators and parameters:

• Possibility of additional power supply from electricity in case of emergency shutdown;
• The presence or absence of a circuit and/or built-in boiler;
• Performance.

Despite the fact that the equipment produced in our country does not have a wide range of capabilities and the functionality is much more modest than that of analogues from Western countries and Japan, the reliability and durability of all elements allow it to be used for heating rooms of various sizes without loss in performance

It is important that all gas boilers are completely safe, since they undergo preliminary quality control before entering the market