A properly selected and installed chimney for a geyser not only ensures its reliable operation, but also does not allow combustion products to get inside the house. Therefore, special attention should be paid to this issue, because cases of burnout from improper operation of instantaneous water heaters are not so uncommon.
To figure out how to choose a gas chimney for different types of columns and install it yourself in accordance with the rules, the following material will help.
Varieties of chimneys
The primary criterion for choosing a particular type of exhaust pipe is the principle of operation of the column itself. Most of them have an open combustion chamber and take air from the room, entering the burner naturally. But there are more modern and expensive models of water heaters - turbocharged. Their combustion chamber is of a closed type, and air is forced into it by a fan. Accordingly, chimney pipes for these two types are used different.
Flowing gas heaters with an open combustion chamber are called atmospheric, since the burner in them operates at natural air pressure. In turbocharged columns with a closed furnace, forced air injection occurs, as a result of which the burner operates under pressure. Hence the second name of the water-heating units - supercharged.
To remove gases from the atmospheric column in private houses and apartments, it is allowed to use exhaust pipes from the following materials:
- Vertical brick channels with ceramic or metal insert. They are arranged in the thickness of the wall during the construction of the house.
- Chimneys made of stainless or galvanized steel - ordinary or insulated (sandwich).
- Enameled steel chimneys - for indoor installation.
- Corrugated stainless steel pipes - for connecting the column to a vertical exhaust shaft (in the common people they are called "corrugated stainless steel").
Often, homeowners use the cheapest option to connect a geyser using an aluminum foil corrugated pipe. On the one hand, a flowing water heater is a batch device and a foil corrugation can last quite a long time.
On the other hand, thin aluminum can burn out at any time, which is fraught with waste for residents. Therefore, it is not recommended to use such gas flues for connecting speakers to vertical channels.
Flue gases from supercharged water heaters are removed through the so-called coaxial (double-circuit) chimneys. Their design is simple: a smaller diameter chimney is placed in the sleeve so that there is a sufficiently large gap between the walls for the passage of air. As a result, 2 streams move along the channels towards each other, exchanging heat.
The combustion products exit the gas column through the internal channel of the coaxial chimney passing through the wall, and the outside air moves from the street, sucked in by the fan. The structural circuit of the dual-circuit channel is shown in the photo:
Which chimney to choose for a geyser
Oddly enough, but choosing a coaxial chimney for a turbocharged hot water column is quite simple. Here the requirements for the chimney are as follows:
- the length of the channel should be enough to pass through the wall and outward at least 300 mm;
- the diameter of the inner chimney pipe must correspond to the size of the connecting pipe on the column.
If we talk about how to choose a chimney for an atmospheric column, then the rule for matching the diameter applies here.The only exception is when the column and gas boiler are connected to the same chimney, then its diameter increases based on their simultaneous operation. Ideally, the smoke channels from different units are separated.
If there is a finished chimney mine in a private house or apartment, it remains only to select a pipe section for connecting a column to it. Stainless steel corrugation is suitable here, as well as a galvanized or enameled steel pipe. When there is no such shaft, you will have to install a chimney outside, for which a chimney insulated sandwich made of galvanized steel or stainless steel will work best. Warming will dramatically reduce condensation from temperature differences.
How to install a chimney
For all gas-using installations, including gas boilers and columns, unified chimney design rules apply. Therefore, the installation of a chimney in a private house is carried out taking into account the following requirements:
- When connecting water-heating units with an outlet pipe on top, a vertical section of 250 mm in length should be provided, if the ceiling height is 2.7 m. When the ceilings are higher, then the section length increases to 500 mm.
- The interval from the chimney to the combustible wall structure (for example, in a wooden house) is at least 250 mm, to the fireproof - 5 cm. If there is a screen made of asbestos sheets and roofing steel, the distance to the combustible wall can be reduced to 10 cm.
- The sum of all horizontal sections should not exceed 3 m.
- When installing a vertical chimney, you can make a protrusion of 1 m with a slope of 30 ° C to bypass building structures or roof overhangs.
- The number of pipe turns is not more than 3, the diameter is not less than that of the outlet pipe of the water heater.
- When connecting the gas boiler and column to the vertical section of the chimney in series, it is necessary to maintain an interval between taps of at least 75 cm.
In addition, the horizontal sections should have a slope towards the heat source, and a pocket with a revision hatch and a tap for condensate drainage is arranged at the bottom of the vertical channel. If you want to pass through a fireproof wall through a chimney, you must make a hole of the appropriate diameter in it, lay a pipe and seal the gaps with non-combustible material.
It is somewhat more difficult to make a passage through the outer wall in a wooden house. You will have to cut a through opening, whose dimensions are 38 cm larger in each direction than the diameter of the chimney. And this is provided that a two-layer sandwich with a non-combustible insulation is used. Then the aperture is sewn on one side with a sheet of galvanized metal, stuffed with basalt wool and then closed with the same sheet on the other.
Important. If the floor of the house is made of wood, then you should maintain a distance from the gas duct to the ceiling of at least 0.5 m.
Installation of an attached chimney from a sandwich is carried out on brackets with clamps. It is not permissible for the mounting location to coincide with the junction of the two sections. The minimum height by which the top of the flue must be raised is 5 m, counting from the level of the combustion chamber of the unit. It is important that the end of the pipe does not fall into the area of wind support above the roof, this will lead to a decrease in traction. When installing, you must be guided by the following scheme:
The installation of a coaxial chimney mounted by yourself is somewhat different. The slope of the gas duct must be provided not towards the gas-using unit, but outward, so that condensate can leak out. In addition, it will correctly remove the chimney horizontally along the shortest path out. If you lay it vertically on the roof, then the length of the gas path and its resistance will increase. It is not known whether the regular fan installed in the column will cope with it.
The chimney device in the apartment
When installing and connecting a gas water heater in the apartment there are some nuances that you will not encounter in a private house.For example, in apartment buildings it is rarely possible to meet a chimney mine, only ventilation. And you can’t connect the gas outlet from the flow heater to them, although many residents do so. And different inspections simply turn a blind eye to this.
The question arises - how to correctly install and connect the chimney from the column, if there is no special channel in the wall? The surest solution that allows you to sleep peacefully is to buy a supercharged water heater and lay out a coaxial chimney. It is important to maintain all the distances from it to windows and other structures, so as not to have problems with neighbors. Normalized intervals are indicated in the table:
When the chimney channel in the apartment is still there, the task is greatly simplified. There are no combustible structures in prefabricated houses, so you can safely lay a corrugation from a stainless steel from the apparatus pipe to the mine entrance so that it does not sag. A special flange for the chimney is mounted on the wall, and fastening is carried out using clamps.
Conclusion
In how to choose and mount a chimney from a gas water heater, there are no big tricks, you just need to perform work in accordance with the established rules. Finally, the recommendation: you should think about the method of laying the chimney at the stage of buying the column itself. So you can successfully place the unit in the house and purchase the required chimney parts.