A gas boiler is a complex technical device, the efficient and safe operation of which depends on many factors. Therefore, the transition to autonomous gas heating requires homeowners to strictly follow the rules for the safe operation of gas heating equipment. Ventilation for a gas boiler is one of such key aspects of its correct operation and, regardless of the type of heating unit, is arranged without fail.
For residents of city apartments using compact mounted gas boilers, the issue of ventilation is not so acute, since modern models of heating boilers are equipped with a closed combustion chamber, the normal operation of which is ensured simply by installing a coaxial chimney.
The situation is more complicated for the category of residential facilities in which powerful gas-fired hot water boilers are installed — such units for burning fuel in the furnace need more air.
Basic requirements for ventilation of gas heating equipment
The basis of any heating system is project documentation. Even at the stage of project development, it is necessary to make thermal calculations, accurately calculate the parameters of the exhaust system. For private houses in which it is supposed to use gas boilers of high power, a prerequisite is the allocation of space for the boiler room.
The boiler room for gas equipment must comply with state regulations and standards, which is explained by the increased danger of using natural gas in everyday life. Let’s get acquainted with the requirements for residential facilities when installing autonomous heating and gas boiler ventilation equipment when installing a heating system in a private house.
Why is gas boiler ventilation necessary?
The main task assigned to ventilation is to remove combustion products from the interior. Even a slight ingestion of carbon monoxide can have an extremely negative impact on the well-being of the inhabitants of the house. No less dangerous are leaks of natural gas, which easily accumulates in a closed space and, at a certain concentration, is an explosive combustible mixture.
The lack of normal ventilation also significantly affects the performance of the heating gas boiler. Only a constant inflow of the required volume of air ensures the normal combustion of fuel in the combustion chamber. As a result of insufficient extraction efficiency, the fuel burns worse, the heat release decreases and the gas consumption increases accordingly.
Important! For powerful floor-mounted gas boilers, poor exhaust operation causes rapid clogging of the furnace compartment. Accumulated soot and soot also cause a decrease in the internal diameter of the duct. As a result, part of the combustion products is not drawn out, but enters the interior of the room.
The ventilation system has certain requirements, so its parameters must correspond to those calculated in the project — a lot depends on the diameter of the duct, its length and the method of air supply. The parameters of the supply ventilation system for a heating gas boiler, in order to maximize the efficiency of the heating system, are calculated individually for each situation and model of gas equipment. At the same time, it is necessary to take into account the design features of the building, which also play an important role in ensuring the ventilation of the boiler room.
Basic requirements for ventilation equipment in the boiler room
A number of requirements are imposed on the building planned for equipping with autonomous gas heating, including the presence of a separate, specially equipped room in accordance with GOST standards for installing a gas boiler — a boiler room. The boiler room can be equipped in the following places (the list is compiled in the direction of decreasing preference):
- in a separate building;
- in an annex to the main building;
- in the attic;
- in the basement of the house.
Important! The use of the basement of the house or the basement under the boiler room, especially when the boiler is running on liquefied gas, is allowed in extreme cases and only when two ventilation systems are equipped — the main and backup. Liquefied gas has a higher specific gravity, so its leakage will lead to gas accumulation in the lower air layers of the boiler room and the creation of an explosive situation.
Wall-mounted boilers have a power of up to 30 kW and a closed combustion chamber. The supply of air for the operation of such a unit in a city apartment is simply provided — for exhaust, it is enough to install a coaxial air duct in the hole of the required diameter in the wall, which is capable of performing two functions at once — through it atmospheric air enters the closed combustion chamber of the boiler, and at the same time combustion products are expelled .
Installation of wall-mounted gas boilers is carried out in the utility rooms, bathroom or kitchen. Under the installation of the boiler, if the thickness of the wall allows, to save space, you can build a special niche.
This heating system is quite suitable for heating private houses of a small area or in the country. At the same time, the premises for installing an autonomous gas boiler must be equipped with ventilation.
Coaxial chimneys are also used for ventilation equipment for powerful floor-standing boilers, but additional requirements are imposed on the installation of such heating units.
The use of heating equipment designed for installation on the floor (with a power of up to 30 kW) for heating requires the allocation of a separate room for the installation of the boiler, which, in accordance with SNiP 2.04.05.II-35, must be equipped with ventilation. In addition, this boiler room must meet the following requirements:
- minimum area — 4 sq. m.;
- the volume of the room is over 8 m3;
- ceiling height — from 2200 mm;
- door width — at least 80 cm;
- the presence of opening windows in the room;
- the device of a special permanently open eyelet;
- the glazing area must exceed 0.05 m2 per 1 m3 premises (standard for easily dropped structures in explosive premises — SNIP 31-03-2001).
Air with oxygen necessary for fuel combustion and boiler operation enters the heating unit from the outside through the ventilation duct. In the boiler room, the location of the duct is the upper part of the room, the wall or the ceiling. For the convenience of cleaning the air duct, an inspection hatch is made 30 cm below the main channel, which is closed with a flap or a plug cover.
Important! The operation of the supply ventilation is calculated as follows: 1 kW of boiler power requires 8 cm2 cross-sectional area of the vent channel; with natural ventilation due to internal air mass, 1 kW will require 30 cm2 its sectional area.
The main types of ventilation for the operation of gas heating boilers
There are two types of ventilation arranged for the efficient and safe operation of heating gas boilers:
For clarity, the action of these two types of ventilation can be depicted schematically.
Let us briefly consider the device and application of these ventilation systems.
The average area of a private house is 80-100 m2, therefore, for the normal operation of autonomous heating, natural draft is quite enough. For a boiler with a power of up to 30 kW, it is necessary to have an air vent with a diameter of 15 cm. The ventilation duct is equipped with a plastic pipe and is closed from the outside with a metal mesh that blocks access to rodents and prevents debris from entering.
Ventilation for a gas boiler in a private house is mounted as follows. The upper edge of the exhaust pipe is closed with an «umbrella» that protects the exhaust channel from atmospheric precipitation. A non-return valve is installed on the inside of the pipe, which prevents arbitrary air from escaping to the outside.
The hood is placed directly above the heating boiler, while the air duct is mounted behind the fuel chamber.
Important! In accordance with the requirements and standards, the efficiency of ventilation is determined by its ability to update the air mass in the boiler room three times within an hour.
On a note: it is impossible to calculate the exact parameters of natural ventilation of a gas boiler installed in a private house, since the intensity of air exchange depends on too many factors — atmospheric pressure, wind strength and direction, ambient temperature, etc.
The efficiency of the hood depends on the design of the chimney, and the requirements for chimneys are fixed in the relevant SNiPs — the diameter of the chimney is determined by the power of the boiler.
Example: for a boiler with a power of 24 kW, it is enough to have a chimney with a diameter of 120 mm. With an increase in boiler power, the diameter of the chimney increases. Gas boilers with a power of over 100 kW are equipped with chimneys with a diameter of 230 mm. An important role is played by the length and degree of elevation of the upper point of the chimney above the ridge of the roof — the pipe must rise above the ridge by at least 0.5 m. Otherwise, air may be sucked into the room.
For reference: the diameter of the chimney recommended for each boiler model is indicated in the technical data sheet of the gas equipment.
If the parameters of natural exhaust do not meet the requirements specified in the boiler operating instructions, you can use equipment equipped with a forced draft fan. In most cases, duct fans are installed on gas boilers. Air is supplied to the combustion chamber by means of a fan. A working blower creates an area of low pressure, due to which air is sucked into the room.
For high power boilers with high combustion intensity and the formation of a large amount of harmful substances, a forced ventilation device is necessary. Calculating the performance of forced ventilation of a gas boiler installed in a private house is quite simple. Let’s consider a specific example.
Boiler room dimensions:
- length — 3.0 m;
- width — 2.0 m;
- height — 2.2 m.
By multiplying the parameters, we determine the volume of the room:
3m x m2 x 2.2m = 13.2 m3 Rounding up to integer units, we get 14.0 cubic meters.
In an hour, the air in the boiler room should be changed three times, therefore:
14.0 x 3 = 42 m3 That is, the exhaust fan in ideal conditions should be 42 m3 / h. But part of the power will be spent on overcoming the resistance when passing through the chimney, so 40% should be added to the resulting value:
42 x 1.4 \u003d 58.8 (m cube / hour).
We round the value up to tens and get the final value of 60 cubic meters / hour.
You should be aware that the intensity of supply ventilation
In order to get a better idea of what ventilation looks like in an apartment or what residents of a private house should pay attention to, watch the video.