Rules for connecting a dual-circuit gas boiler to gas

The main purpose of domestic gas boilers is to provide housing with heating and hot water. It is impossible to deal with the installation of such equipment on your own, since installation work and the operation of gas appliances involve certain risks.

However, the owner of the house is directly involved in the design of the boiler room, the layout of the heating circuit, etc. In order to be able to control the performers, you need to understand how the unit works, what is the scheme for connecting a dual-circuit gas boiler to the central gas pipeline and blue fuel cylinders.

The answers to these questions are detailed in the article. In addition, we have identified technical requirements that are important to observe during the design of the boiler piping, its installation and use of gas equipment.

How do double-circuit gas boilers work?

As a rule, gas appliances are installed under the heating closed systemwhere the value of the water pressure is not higher than 0.3 MPa. If we talk about how to properly connect a home gas boiler, the answer is obvious.

The scheme of artificial circulation of a coolant with an expansion vessel is traditionally used. To prepare hot water with gas equipment, a centralized supply of cold water with a pressure of 0.02 - 1.0 MPa is used.

A gas apparatus installed in a private house according to the double-circuit operation scheme. Similar systems are widely used at the objects of suburban housing construction, as well as in urban private buildings

True, the exact values ​​are determined by the specific brand of equipment and the manufacturer. Choosing a double-circuit boiler made according to specific installation conditions.

Boiler heating circuit diagram

The gas boiler heating circuit is by default designed to fill the cold water supply of the central water supply.It is also allowed to operate heating equipment when glycol-based water with antifreeze is used as a heat carrier (C₂H₄(OH)₂) certified according to GOST.

Structural diagram of the operation of equipment designed to work with two circuits. With one (centralized) cold water inlet, the functioning of efficient heating and hot water for residential and other premises is ensured (+)

The coolant coming from the return line of the heating circuit is sent through a filter to the heat exchanger, the design of which allows the initial filling and periodic replenishment of the heating circuit with water from a centralized water supply.

Further movement of the coolant activates the circulation pump, the design of which contains an automatic air vent. Then, the water flow passes the zone of the minimum flow rate sensor and is fed to the input of the first (external) coil of the coaxial type heat exchanger.

Moving along the heat exchanger, the water is heated due to the energy of combustion of the gas.

The internal contents of the dual-circuit gas system is built from a set of the following components: combustion chamber (closed type), heat exchanger, gas burner, circulation pump, heat exchanger (+)

At the outlet of the heat exchanger, on the coolant supply pipe, there is an immersion temperature sensor. It is mounted here safety valve spring action equipped with a pressure relief mechanism.

The upper limit for opening the safety device is 0.3 MPa. A diaphragm expansion tank is also included in the supply line.

DHW circuit function

The DHW scheme works something like this: cold cold tap water under pressure from a centralized water supply is fed through a strainer to the water block. The block design made of brass provides the possibility of initial filling and periodic replenishment of the DHW system.

Appearance of household equipment for heating water from gas with a closed and open housing. This is one of the widespread designs of gas boilers for domestic use, which are used in private households (+)

Further, through the installation area of ​​the water flow sensor and through a magnetic anti-scale device, water enters the internal channel of a coaxial heat exchanger made of copper. Due to the selection of heat from the walls of the heat exchanger heated by the heat carrier passing inside the heating circuit, cold water is heated.

The hot water preparation mode provides for a temporary shutdown of the boiler circulation pump. An immersion temperature sensor is located at the outlet of the heat exchanger, which records the operating parameters of the supply line.

Here, on the boiler feed line, a second spring-loaded safety valve with a pressure relief mechanism is installed. The response limit is usually 1.0 - 1.1 MPa.

Natural Gas Connection

The gas boiler is designed to connect natural gas, the technical characteristics of which correspond to GOST 5542. Fuel, as a rule, is supplied from a low pressure gas pipeline of 0.0013 - 0.0020 MPa. A filter screen and a control valve of the flare ignition device are installed on the supply line.

The classic connection option, typical for most gas equipment designs with two working circuits. As shown in the photo, polypropylene pipelines were used as trunk pipelines

The electromagnetic gas valve maintains gas pressure stability at the inlet to the boiler burner mechanism. Therefore, regardless of gas pressure fluctuations on the line, stable, safe functionality with high efficiency is ensured.

The electronically controlled gas burner power is regulated within 40-100% of the declared rated power.

The method of connection to the gas line

Before considering options for connecting natural gas to the boiler, you should recall the established rules for the operation of such equipment. Gas-fired boilers are hazardous technological facilities.

Installation, connection and operation of such systems requires compliance with established safety standards.

An example of the correct installation of the heating system and hot water supply, when the equipment is mounted in a separate room with the status of ancillary. The installation of such equipment, in accordance with all the rules and regulations, implies just such an approach

Gas boilers are mounted only inside suitable premises for installation (kitchens, corridors, utility rooms). This refers to the premises of public production buildings, private houses, cottages. All of these properties must comply with the requirements for the presence of effective ventilation.

As a rule, compliance is determined by SNiP 42-01-2002 and SNiP 2.04.08-87. When solving the problem of how to connect the boiler to the gas line, you need to remember that the operation of the equipment requires the construction of a mechanism smoke exhaust to the atmosphere. In addition, it is necessary to provide atmospheric air for an efficient combustion process.

The installation connection affects several points of different purpose - gas, water, air. Each node is connected in accordance with established standards, as well as in accordance with the requirements of the equipment manufacturer

Gas boilers supporting the function of the natural withdrawal of combustion products are to be installed in close proximity to chimneys with natural draft.

For equipment whose design provides for air intake directly at the installation site, a normal level of air discharge should be ensured. Inside such rooms, the air should be cleaned of dust and chemical impurities.

Technical nuances of connection

The process of connecting a gas boiler to a gas pipeline using a flexible hose is accompanied by its technological and technical features. So, laying the gas pipeline and subsequent connection to the boiler is permissible only for gas specialists.

Work with the gas main and actions aimed at connecting the gas are coordinated with organizations responsible for the operation of gas systems. In addition, work on gas pipelines is permitted only to gas specialists. All statements about a possible independent connection are unfounded

Before connecting the gas boiler, it is necessary to clean the failed section of the gas pipeline from foreign substances, impurities, and contaminants. This requirement is especially relevant for mounting on used systems.

The gas inlet must be equipped with shut-off valves designed to work in a gas environment, supplemented by a thermal blocking device (TAE). Before connecting the gas pipeline to the boiler, it is required to check the tightness of all connections and gas pipeline connections with a test pressure of at least 0.15 ATI.

The cross-section of the exhaust gas pipeline must correspond to the diameter of the nozzle on the flow protection device. Narrowing the passage of the exhaust gas pipe is allowed, but only if the calculations justify (according to GOST standards) the correct functioning of the line.

The exhaust gas pipeline is shortened (if possible), with some bias in the ascent to the chimney.

Checking gas connections for leaks - a procedure mandatory in case of installation, connection to the gas main and operation of the boiler. Only after a successful check is it permissible to put the equipment into operation

The line supplying gas to the boiler is usually made on the basis of a metal pipe. It is allowed to construct supply lines on the basis of steel and copper pipes.

Meanwhile, permitted installation by polymer pipes (multilayer, with a metallized layer) is not excluded. True, polymers are allowed to be used only inside buildings with a height of no more than three floors.

Using a flexible hose

It is permissible to connect the gas source to the boiler using flexible hose.

The condition for the use of a flexible sleeve:

• resistance to the gas environment;
• conformity to working (test) pressure;
• compliance with the working (test) temperature.

The marked characteristics and parameters can be taken from the boiler data sheet. In this case, the flexible hose used must have a diameter of 20 mm or more, and the sleeve length can be no more than 1.5 m.

An example of connecting a gas line of an equipment to a central line using a flexible hose. In such cases, special sleeves are used, which from all others are primarily distinguished by a characteristic color. Flexible gas hoses are designed for high pressure and temperature

Connection with flexible hoses (sleeves) must be carried out in full accordance with the installation rules specified in the accompanying documentation of the product manufacturer.

Features of connection with cylinders

Flexible hoses (sleeves) often connect SG cylinders with a boiler installation. However, to turn the boiler on precisely in this mode of fuel replenishment, a number of settings are required to transfer the equipment to operation with bottled gas.

If the boiler design supports this type of supply, the instruction describes the sequence of operations.

Here, the technological requirements for sleeves of a flexible structure practically do not differ from the requirements for connecting to a centralized highway. Also, the sleeve diameter is not less than 20 mm with a length of not more than 1.5 m. However, the gas cylinder should be equipped gearboxset to a pressure of 2.9 kPa (vapor medium).

An example of an unacceptable installation of a gas heating system, when cylinders of liquefied gas are placed next to the equipment. This connection option is contrary to existing rules. Cylinders are always located in a separate area, outside the premises

Separate standards have been approved for cases of boilers supplying liquefied gas with liquefied gas, in particular those related to the storage and operation of cylinders. For example, it is forbidden by these standards to place vessels in areas exposed to sunlight, near heat sources and open flames.

One of the main prohibitions is the taboo on installing gas equipment directly inside buildings.

An overview of LPG gas boilers is given in this article.

Thus, the use of gas boilers in practice, including the domestic sphere, must be considered a responsible action, the accuracy of which determines the degree of safety.

Conclusions and useful video on the topic

A few useful tips for installing a gas boiler will help you verify the correct installation of the equipment.

With all the perfection of gas equipment, in the presence of automation and serious technological protection, connecting the system requires compliance with established rules and norms. Without this, it is impossible to guarantee the reliability of gas boilers.

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