How to choose a dual-circuit floor gas boiler: what to look at first?

Autumn came unexpectedly expected, testing the heating systems, rested during the summer, for strength. For negligent owners, interruptions or a failure in the operation of the boiler may come as a surprise. There is not much time left before the onset of frost, and now some have to hurriedly look for a replacement for non-working equipment. It is not necessary to purchase the first boiler that comes across, it is better to devote two three days to a thorough study of the technical characteristics that the desired model should have. In addition, you can make a small improvement if you buy a double-circuit floor gas boiler or its compact wall modification. In houses where speakers or electric boilers are used to heat water, with such a boiler you can save. On the market, gas double-circuit boilers manufactured in Russia, Italy, China, Germany, Ukraine and South Korea were most widely used. The latter in the economy class range, by the way, get quite a lot of flattering reviews from sellers and buyers and are popular.

What is such an aggregate?

The double-circuit gas boiler is a fully automated unit. In fact, this is a mini-boiler room: a burner, two heat exchangers for domestic hot water and heating, a pump and a control panel that allows you to adjust the temperature of hot water and affect the indoor climate. The temperature of the coolant is maintained by instantaneous heating: with a pump, it is constantly supplied to the burner, then it is driven throughout the system and returned to the boiler. In the same way, a second heat exchanger heats the water for hot water supply. No need to put a boiler, the boiler heats it up very quickly - the faucet is opened, and you can take a hot shower.

A gas boiler, like air conditioning, needs to be bought with a margin of power. This will avoid "work at the limit" and increase the service life. Before making the final choice, you must also study the SNIP. When calculating the power can not be limited to the formula "1 kW per 10 square meters." In addition to the quadrature of the building, the height of the ceilings, number of storeys, the number of windows and external doors, the degree of insulation of the building and roof, and the features of the climatic zone are also taken into account. For poorly insulated houses, you always need to make a choice in favor of boilers with a large supply of power.

A double-circuit gas boiler with a capacity of 16 kilowatts is suitable for heating a house with an area of ​​up to 160 square meters. In this case, we are talking about a well-insulated building, the ceiling height in which is no more than three meters

You can calculate the power more accurately using our calculator:

Differences of the "dual-circuit" from the "single-circuit"

A double-circuit gas boiler allows you to avoid unnecessary costs associated with the purchase and installation of equipment for hot water supply. Two heat exchangers, independently of two, heat the coolant in the heating system and water for sanitary purposes. This is especially true for buildings under construction, or for those who, due to circumstances, decided to completely replace heating systems and hot water supply systems - it's time to carry out optimization.

A double-circuit boiler reduces construction costs. Installation and maintenance of a boiler with a DHW circuit will be cheaper than for two separate systems

Floor-mounted gas boilers, like wall-mounted boilers, can be paired with a flowing water heater or an external or built-in boiler. The latter can be sixty-one hundred liters, and some models are equipped with 150-liter tanks. Wall-mounted boilers cannot boast of such characteristics. A large water heater is relevant for homes with a large number of consumption points.

Most models of wall-mounted gas boilers are available with power up to 60 kW. Much less common are instances that can provide heating for buildings with an area of ​​800-900 square meters. But floor-standing gas boilers are available with power from four to several hundred kilowatts. Agree, there is much more room for choice here. Therefore, for large buildings, in which it is possible to equip a separate boiler room, it is better to buy a floor gas heating boiler.

Floor heating boiler, as a rule, requires installation in a separate boiler room. In this room, it is advisable to install a sensor that immediately shuts off the fuel supply line if there is a gas leak

Double-circuit floor gas boilers with instantaneous water heaters provide hot water consumption of up to 33 liters per minute. This figure can be increased if you additionally install a storage boiler. The most powerful floor boilers are equipped with independent circuits that provide heating medium for underfloor heating and pool water.

Basic classification of gas boilers

Gas boilers are classified according to several criteria:

• according to their functionality, single-circuit and dual-circuit (with a built-in boiler or instantaneous water heater) are distinguished;
• by sight coolant (water or water plus antifreeze);
• as a combustion chamber, they can be chimney or turbocharged;
• according to the ignition method, models with both automatic electric ignition and manual piezo ignition are presented on the market;
• by type of traction - with natural or forced;
• by the method of placement, you can choose between the parapet, floor and wall-mounted boiler;
• according to the heat exchanger material - steel, cast iron, copper, stainless steel or silumin. The last two are used in condensing gas boilers;
• according to electrical dependence, respectively, electrically dependent (with and without self-starting function) and electrically independent boilers are distinguished.

Traditional domestic boilers heat the coolant only due to burning fuel. However, if we are talking about condensation models, then they additionally use the thermal energy released during the condensation of water vapor - one of the constituent flue gases. Such equipment has an efficiency of 10–20% higher than traditional systems, which means a reduction in fuel costs by the same amount.

A boiler with a cast-iron heat exchanger weighs twice as much as its steel mate.It is more expensive, more durable and cools much longer. True, there is one significant drawback - fragility. It must be transported and installed carefully, as cracks may appear on the heat exchanger upon impact.

Such a number of criteria provides buyers with a wide assortment in which it is easy for a non-knowledgeable person to get lost. However, before finally deciding on the model of equipment, it is better to study the entire list. This will allow you to choose the best option at a reasonable price.

Additional selection criteria

In the long list of technical characteristics of gas boilers it is easy to get confused. The main ones affecting the operation of the heating system were given above. We decode the remaining characteristics of double-circuit floor gas boilers:

• Efficiency - coefficient of performance. Most boilers range from 80 to 92%. However, condensing boilers have a ratio from 102 to 109%;
• performance of hot water supply - the volume of water that is heated by the boiler in 1 minute to the set temperature. Typically, this figure ranges from 2.5 to 17 l / min. Powerful heaters can produce more than thirty liters;
• maximum temperature of hot water - usually 55ºС;
• maximum water pressure - for most boilers is 6 bar;
• the maximum temperature in the heating circuit is 80-90ºС;
• pressure in the heating circuit - most manufacturers produce boilers with a pressure range from 1 to 10 bar in the heating system;
• expansion tank volume - we are talking about built-in tanks, the volume of which is 17 or more liters;
• natural gas consumption - a modest 7 kW boiler consumes 0.78 cubic meters / hour. But the unit, designed for heating 1950 sq.m., burns 24 cubic meters of gas per hour. It all depends on the power of the boiler;
• Electricity consumed - the numbers opposite this parameter indicate that this boiler belongs to the category of electrical dependent. Such they, for the most part, are. Electron-independent equipment does not allow adjusting the room temperature so quickly and requires additional installation of an expansion tank.

In the technical specifications, additional options are often found: display, auto diagnostics, frost protection, protection against overheating and protection of the pump from jamming - their availability depends on the price segment of the equipment.

Condensing gas boilers have a much higher efficiency compared to traditional ones. They allow you to save 10 to 30% of fuel

Overview of prices and some manufacturers

Conventionally, the market for floor-mounted double-circuit gas heating boilers can be divided into four price segments: premium, medium (medium), economy and super-economy.

Premium equipment is produced by eminent companies that have been leaders in this market for several decades. Boilers are produced on full cycle lines. These are, as a rule, thick-walled models made of alloy steel or cast iron. Their service life ranges from thirty to fifty years, and during this period, customers have no problems with maintenance. All new products and improvements are the patented developments of the manufacturer. The efficiency of premium-class boilers is about 92-98%. This equipment is able to adapt to various operating conditions, including pressure drops in the gas line, voltage surges. Manufacturers of heating equipment in this segment include companies such as ACV, Buderus, Chappee, CTC / Parca, De Dietrich, Rapido, Rendamax, Vaillant, Viessmann and "Wolf."

Medium class boilers are produced by well-known European brands. Their affordable price is usually associated with entry into the Russian market, the use of common technologies. This equipment is designed for use in “mild” conditions. The service life of equipment in this segment is an average of 10-15 years.Efficiency ranges from 80 to 90%. Not all models can work in conditions of unstable voltage or pressure drops in the gas pipeline. This price segment is shared by Ariston, Baxi, Beretta, Biasi, Dakon, Electrolux, Ferroli, Junkers, Kiturami, Laars, Riello, ACV ”,“ Fondita ”,“ Roca ”,“ Protherm ”,“ Sime ”and“ Viadrus ”.

When choosing boilers economy and super-economy class, be sure to choose analogues from more expensive segments for comparison. So you can evaluate the adequacy of the parameters and offer prices. The main distinguishing feature of economy class boilers is, of course, the low price. This equipment can be inferior in reliability to the representatives of the medium segment, however, their service life and efficiency are on the same level. In this class you will not find boilers with advanced developments, in the production of components often used well-known European concerns. The economy class on the Russian market is represented by Alphatherm, Attack, Fondital, Mora, Navien, Olympia Boiler, Saturn, Therm, Unical and Lighthouse.

When buying a boiler, be sure to study all the characteristics of the model and compare it with similar ones in other price ranges

As for the super-economy class, it is represented mainly by Russian and Ukrainian manufacturers. Some are produced in factories located in China. Here are the cheapest gas boilers. The warranty period for them is 12-24 months. The design of boilers came from distant Soviet times. Service is far from accessible everywhere. There are companies that can service this equipment, but they do it not for free even during the warranty period - hardly anyone will dismantle the boiler for return. The cheapest boilers are produced by “ATON”, “Dani”, “Termotechnik”, “Vektor Lux”, “ATEM”, “Borinskoye”, “Borisoglebsky boiler-and-mechanical plant”, “Volcano”, “Danko”, “Zhukovsky Engineering Plant” , Zvezda-Strela, Kirovsky Zavod, Konord, Lemaks, Mimaks, Novosergievsky Mechanical Plant, Hearth, Rostovgazoapparat, Signal-Mash, Thermolux and Eco -Hydropress. "