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If safety is important: we select a coaxial chimney for a gas boiler

Modern heating equipment is the most complicated units with economical fuel consumption and high-quality security system. An important part of this system is the coaxial chimney. For a gas boiler, such devices are sold as a set or can be purchased additionally. Today, in the review of the homemaster.techinfus.com/en/ editorial office, you will find answers to the most pressing questions: how does such a chimney work, how does it work and how should it be installed? In addition, we will give you the opportunity to get acquainted with models from the best manufacturers.

The safety of the heating system is an important issue. Coaxial pipe will help you solve this problem

The content of the article [Hide]

1 What is a coaxial chimney and what's new in this device
2 What is so special about the device of a coaxial chimney for a gas boiler
3 How does a coaxial chimney work
4 What is included
5 Coaxial chimney for a gas boiler: materials for manufacturing
- 5.1 Plastic and its advantages
- 5.2 Coaxial pipe for gas boiler made of stainless steel
6 Pros and cons of using a coaxial chimney
7 On which boilers can a coaxial chimney be used
8 Popular manufacturers of coaxial chimneys
9 Basics of installing a coaxial chimney
10 Important rules for installing a coaxial chimney for a gas boiler
11 How much does it cost to buy a coaxial chimney for a gas boiler
- 11.1 The price of components for a coaxial chimney for a gas boiler
12 Outcome

What is a coaxial chimney and what's new in this device

First, a little basic physics: combustion requires air. When the stove burns fuel, it also uses oxygen. For free air access, you can ventilate the room, provide a blowing system. But in this case, you can lose precious heat, because any draft, open window or ventilation hole in the wall will open access to the cold atmosphere from the outside. What is the difference between modern heating boilers? They use a non-standard technical solution that turns them into a closed system that does not require outside air intake.

The device of a modern gas boiler with a closed system

And this technical solution is called a coaxial chimney kit. Its main innovation lies in the fact that air for fuel combustion comes from the street through the same pipe that removes the combustion products. This happens due to the special design chimney... This method guarantees complete safety of the heating boiler operation. Coaxial pipes are installed not only in private houses, but also in modern apartment complexes.

The use of individual heating in an apartment is a guarantee of cost savings and a constantly comfortable temperature

What is so special about the device of a coaxial chimney for a gas boiler

So, we found out that the coaxial design allows you to simultaneously supply and exhaust air from the heater. How is this possible? Such a chimney consists of several parts, which are assembled in such a way that a pipe in a pipe is obtained. To prevent the components of the kit from touching, there are special jumpers inside. Such devices are used not only in boilers, but also in convector devices and radiators, that is, wherever there is a fuel combustion chamber.

The photo shows an example of what a coaxial chimney looks like:

Jumpers fix the inside and outside of the device

How does a coaxial chimney work

As you already understood, in such a design there is a two-way air circulation. The principle of operation of the device is as follows:

cold air mass enters from the street through the outer channel of the pipe and in the process of moving towards the combustion chamber is warmed up by the heat of the inner channel. The access of heated air significantly reduces fuel consumption and increases the efficiency of the boiler;
the inner channel removes toxic combustion products. For more intensive air circulation, the channels are additionally insulated, in some models there is even a layer of basalt wool.

The principle of the chimney of a coaxial structure

Important! In order for the coaxial kit to work with full efficiency, it is necessary to follow the installation standards, carefully calculate the capabilities of the system and correctly assemble the device.

Related article:

Chimneys for a gas boiler in a private house. Selection rules and requirements for the installation of chimneys, their varieties and installation nuances in a special publication.

What is included

The coaxial chimney consists of two pipes of different diameters. Through the large air enters the outside, through the smaller one - combustion products are removed.

An expert's point of view

Andrey Starpovsky

Head of the Heating, Ventilation and Air Conditioning Group, GRAST LLC

“The maximum length of a coaxial chimney for a gas boiler should not be more than 3 meters. Otherwise, turbulence of the air mass will occur, and the circulation process will be disrupted. "

Pay attention to the instructions for the heating device, it must necessarily indicate the parameters of the pipe. In addition to pipes, the coaxial kit includes:

knee or angle from 45 to 90 °;
tee;
adaptive coupling for connection to the boiler;
unit for preventive cleaning;
assembly for condensate collection;
cover for protection from rain and snow;
clamps for fastening;
flange for fastening in the wall;
rings for sealing.

Coaxial exhaust kit

Coaxial chimneys for wall-mounted gas boilers can have a vertical or horizontal outlet. The horizontal version allows you to freely choose a place for the boiler, and much less chimney parts are required.

If you do not want to spoil the facade with a hole in the wall, you can always use the vertical model and traditionally bring the chimney through the roof

Note! Vertical coaxial chimneys for gas boilers can be installed on several heating devices located on different floors. This type of equipment is installed in apartment buildings that use individual heating systems.

Related article:

Chimney cap. In a special publication of our online magazine, recommendations for choosing a weather vane for different types of chimneys and some installation nuances are presented.

Coaxial chimney for a gas boiler: materials for manufacturing

On sale you can find kits made of plastic or stainless metal. Rarely, but there are also aluminum specimens. Let's consider how popular types of materials differ.

Plastic and its advantages

For the manufacture of the chimney, a special plastic is used that is resistant to high temperature exposure. Such material can withstand more than + 200 ° C. Benefits plastic kit are its low weight, simple installation and low price.

Plastic also has drawbacks: it will last a maximum of 5 years and is only suitable for boilers with a low-temperature mode for removing combustion products

Coaxial pipe for gas boiler made of stainless steel

The main advantage of stainless steel is that it can withstand heating up to + 500 ° C! In this regard, a stainless steel coaxial system is much more durable and practical than a plastic one.

Metal structures can be the most primitive, without built-in insulation, with an acid-resistant inner tube, and more complex ones with improved aerodynamic properties and a forced air supply system

An expert's point of view

Andrey Starpovsky

Head of the Heating, Ventilation and Air Conditioning Group, GRAST LLC

"In multi-storey buildings, a common coaxial channel is mounted within the walls of the building and has a warranty period of 30 years or more."

Pros and cons of using a coaxial chimney

Before deciding on the installation of such a device, you need to understand its advantages and disadvantages. The first ones need to be used, and the second ones - be able to cope.

Advantages:

Safety. The operation of the heater will be safer, since the pipe that removes the combustion products is cooled.
Uninterrupted work.The system supplies fresh air to the combustion chamber without interruption.
Increases boiler efficiency. Due to the flow of heated air into the combustion chamber, fuel consumption is significantly saved.
Environmental friendliness. In boilers with coaxial air exchange, the fuel burns out completely, a minimum amount of toxic substances enters the atmosphere.
Comfortable use.Air exchange does not affect the inside of the room, all processes are carried out outside. There is no smell or burning.
Easy installation and long-term operation. The design is lightweight and easy to install in any conditions. Refractory materials will last for more than a dozen years.

Disadvantages:

Not suitable for all boilers. Such pipes can only be installed in systems with a closed gas combustion chamber.
Unaesthetic exit to the facade.Horizontal leads are unlikely to decorate the wall of the house. It is easier to arrange vertical outlets like a regular pipe.
Glaciation.At temperatures below -10 ° C, the pipe outlet is covered with ice due to condensation. To prevent this from happening, additional pipe insulation is required.

Icing is the main problem with such structures

On which boilers can a coaxial chimney be used

Such chimney designs are suitable for condensing and turbocharged boilers with a closed chamber. They can have a natural exhaust system for combustion products or forced air flow. The coaxial pipe can be installed on a convector and a device with an atmospheric burner.

Such air exchange can be connected to almost any modern heating system with one or two circuits.

Important! If a separate combustion product removal system is installed in a turbocharged boiler, it makes no sense to install a coaxial chimney. For such a boiler, you will need to remove two separate pipes: one for the access of fresh air, the other for the output of the exhaust.

Before purchasing and installing a pipe, carefully read the design of the heating boiler.

Related article:

Sandwich pipes for chimneys. What they are for, technical specifications, an overview of ready-made models, do-it-yourself creation, the basics and important nuances of installation, additional recommendations - read our publication.

Popular manufacturers of coaxial chimneys

The technically perfect chimney has become such a popular product that many boiler manufacturers not only began to include it in the set of supplied equipment, but also release it for separate sale. Versatile devices can be connected to almost any gas boiler... Let's consider the most popular brands.

Korean coaxial chimney Navien

These systems are perfect for boilers made in Korea. You can choose the desired diameter and length. Suitable models will be offered to you at the representative office of a Korean manufacturer.

Navien products

Coaxial chimney for Baxi gas boiler

The Italian company offers models made of enamelled steel. The warranty period for such a pipe is not long - only a year, but users note the quality of the product and a rather long service life. For severe Russian frosts, Baxi offers insulated models with an air intake made of composite material. You can buy a coaxial chimney for a gas boiler from Baksi at a price of 3000 rubles.

The cost will depend on the components of the Baxi kit

How much does it cost to buy a coaxial chimney for a gas boiler Proterm

A simple and inexpensive device Proterm is suitable for boilers of the same name. Slovaks offer various extension cords, adapters and adapters for ease of installation. Every year new developments of this company appear on sale.

Proterm pipe

Chimneys Buderus

The German quality of these chimneys is beyond praise. They are made from enamelled steel and sold as a set. These kits can only be used for boilers of the same name.

Buderus kit

Popular Vaillant Kits

The products of this manufacturer are in great demand in the European market. The kits are suitable for Vaillant boilers and must be placed away from places of possible fire.

Vaillant boilers are very popular due to their quality and economy.

Everyone knows Ariston

Household appliances of this company are known to the Russian consumer. Italian quality has earned the trust and respect of millions of buyers around the world. The chimneys of this manufacturer, as they say, keep the brand.

The outer tube of the structure is made of enamelled steel, the inner tube is made of aluminum

Basics of installing a coaxial chimney

Each set of coaxial chimney for a gas boiler has detailed DIY installation instructions. If you study it carefully, there will be no installation problems. If you are planning a horizontal installation, select the right pipe exit location. An important point is the distance from the coaxial chimney to the neighbor's window. If you place it too close, problems cannot be avoided.

The height of the pipe from the boiler to the hole in the wall must be at least one meter for a floor-standing boiler and half a meter for a wall-mounted one.

An expert's point of view

Andrey Starpovsky

Head of the Heating, Ventilation and Air Conditioning Group, GRAST LLC

"The number of rotary couplings with a horizontal outlet should be no more than two."

The horizontal part of the pipe can be up to 5 meters long.Pipe joints should be sealed with couplings, not silicone or other sealants. To protect against frost, horizontal chimneys must be carefully insulated. Vertical installation can be cascade - for connecting several boilers and individual - for one heater. Cascade systems in multi-storey buildings are designed together with the house, their installation is monitored by fire and gas services.

To connect a single boiler, a pipe up to 7 meters long can be used. This height is enough to mount a heating system in a two-story house.

If the house is made of foam blocks, the pipe is mounted in the wall. In a brick house, you can put a pipe outside the building, but it is important to carefully insulate it. About the installation of a gas boiler with a coaxial chimney, floor or wall type in the video:

Important rules for installing a coaxial chimney for a gas boiler

There are recommendations approved by SNiP, without which the gas company may not allow the operation of your boiler. Here are some basic rules to keep in mind:

the horizontal exit must be at least 2 meters from the ground;
the diameter of the hole in the brick wall should be 1 centimeter larger than the chimney, in the wooden one - by 5;
in a multi-storey building, it is impossible to draw a chimney outlet if it is located less than a meter from the neighbor's window on top;

There must be at least 1.5 m from the coaxial pipe to neighboring buildings, doors and windows; trees must not impede the exhaust gas outlet

boilers with forced and natural air supply must not be simultaneously connected to the same air exchange system;
a pipe with a length of no more than 3 meters can be laid through an adjacent room. If the boiler has a turbocharged system, the pipe length can be increased up to 5 meters;
it is important to ensure the collection of condensate from the pipe, it should not fall into the ground. In multi-storey buildings, this issue will have to be coordinated with the sanitary and epidemiological station;
the outlet of the pipe must be at least 30 centimeters from the wall;
in systems with a turbocharged boiler, a constricting diaphragm is mandatory;
once a year it is necessary to clean the chimney from soot and soot. This is usually done before the start of the heating season.

How much does it cost to buy a coaxial chimney for a gas boiler

The cost of a coaxial chimney depends not only on the brand of the manufacturer. In many ways, it depends on additional parts included in the general scheme. The most practical thing is to buy not a ready-made kit, but the units that you definitely need. It is for this reason that we have analyzed the prices of components and offer you a small list that will help you approximately calculate your future costs.

The price of components for a coaxial chimney for a gas boiler

Knot	Average price (as of May 2018), rubles	Best deal
Coaxial pipe, length 110 cm with ferrule, DN 60/100	4515	Teplomarket
Coaxial elbow, 90 °	1832	Thermokit
Horizontal tip for coaxial pipe	249	Thermokit
Pipe element, inner pipe sealing ring	248	Teplovod-Service
Coaxial adapter	1737	ComTermo MSK
Pipe element, boiler adapter vertical coaxial	1841	Teplovod-Service

All of these parts are universal and can fit almost any boiler model.

Outcome

If you plan to install or replace heating boiler - it's time to think that it's time to keep up with the times. You need to use modern inventions that guarantee you safety and comfort. It is for this reason that it makes sense to install a coaxial chimney. With it, you do not have to worry about the smooth operation of the boiler.