Comparison Bosch Gaz 6000 WBN-18C RN 18 kW vs Vaillant atmoVIT VK INT 484/1-5 48.9 kW

Regarding the installation method, boilers are divided into two main types: wall and floor.

— Wall-mounted boilers, as the name suggests, are designed to be mounted on a wall. They usually have low power, which makes it possible to do without a separate room for their installation, and relatively small dimensions, which allow the boiler to fit into the interior of a kitchen or bathroom.

— Floor boilers usually have more power than wall-mounted ones, which accordingly affects their weight, dimensions and the installation method. The weight is also due to the presence of a cast iron heat exchanger, which is considered more reliable and durable than copper, steel or silumin. Most boilers with a power of 50 kW or more and almost all boilers with a power of 100 kW or more are floor-standing.

— Parapet. They are designed for installation close to the wall; at the same time, the installation itself can be both wall-mounted and floor-mounted, depending on the dimensions and weight of the unit. All parapet boilers are gas-fired (see Energy source) and have a closed combustion chamber (see below); in this case, the flue goes directly through the wall, near which the boiler is located. One of the key advantages of such devices is their small size; a parapet boiler is considered a good option for a small city apartment or a private house with small rooms. Also, the advantages of such dev...ices are that they do not burn the air from the room and immediately remove the products of combustion to the outside. In addition, many of the boilers of this type have convection holes and during operation they also play the role of heating radiators.

Depending on the set of functions, boilers are divided into single-circuit and dual-circuit.

- Single-circuit boilers are equipped with one heat exchanger, in which the heat from fuel combustion is transferred to the heat medium of the heating system. The only function of such boilers is space heating. It is technically possible to use single-circuit boilers to provide hot water, but this requires an additional tank (the so-called indirect water heater).

- In dual-circuit boilers, the primary heat exchanger is supplemented by a secondary one. Due to this, such a boiler, in addition to heating the room, also provides a hot water supply. In this case, both running water and water accumulated in a special tank(see Built-in water heater tank) can be used.

A very conditional parameter that slightly characterizes the purpose based on the size of the room. And depending on the height of the ceilings, layout, building design and equipment, actual values may differ significantly. However, this item represents the maximum recommended area of the room that the boiler can effectively heat. However, it is worth considering that different buildings have different thermal insulation properties and modern buildings are much “warmer” than 30-year-old and especially 50-year-old houses. Accordingly, this item is more of a reference nature and does not allow us to fully assess the actual heated area. There is a formula by which you can derive the maximum heating area, knowing the useful power of the boiler and the climatic conditions in which it will be used; For more information on this, see "Useful Power". In our case, the heating area is calculated using the formula “boiler power multiplied by 8”, which is approximately equivalent to use in houses that are several decades old.

It is the maximum useful power of the boiler.

The ability of the device to heat a room of a particular area directly depends on this parameter; by power, you can approximately determine the heating area, if this parameter is not indicated in the specs. The most general rule says that for a dwelling with a ceiling height of 2.5 – 3 m, at least 100 W of heat power is needed to heat 1 m2 of area. There are also more detailed calculation methods that take into account specific factors: the climatic zone, heat gain from the outside, design features of the heating system, etc.; they are described in detail in special sources. Also note that in dual-circuit boilers (see "Type"), part of the heat generated is used to heat water for the hot water supply; this must be taken into account when evaluating the output power.

It is believed that boilers with a power of more than 30 kW must be installed in separate rooms (boiler rooms).

The minimum heat output at which the heating boiler can operate in constant mode. Operation at minimum power allows you to reduce the number of on-and-off cycles that adversely affect the durability of heating boilers.

The minimum operating temperature of the heat medium in the boiler system when operating in heating mode.

The maximum operating temperature of the heat medium in the boiler system when operating in heating mode.

The maximum pressure in the heating circuit of the boiler, at which it remains operational, and there is no risk of physical damage to the structure. For a heating system, the maximum pressure is usually about 3 bar, and for a domestic hot water circuit up to 10 bar. When the maximum pressure is exceeded, a safety valve is activated, and part of the water is discharged from the system until a normal pressure level is reached.

The maximum pressure in the hot water circuit (DHW) at which it can operate for a long time without failures and damage. See "Heating circuit maximum pressure".