Comparison Proskuriv AOGV-7PG 7 kW vs Danko 7 USV 7 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.

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".

The performance of a dual-circuit boiler in the DHW supply mode when the water is heated by 25 °C above the initial temperature.

Performance is the maximum amount of hot water the unit can produce in a minute. It depends not only on the power of the heater as such, but also on how much water needs to be heated: the higher the temperature difference ΔT between cold and heated water, the more energy is required for heating and the smaller the volume of water with which the boiler can handle in this mode. Therefore, the performance of dual-circuit boilers is indicated for certain options ΔT — namely 25 °C, 30 °C and/or 50 °C. And it’s worth choosing according to this indicator, taking into account the initial water temperature and taking into account what kind of hot water demand there is at the installation site of the boiler (how many points of water intake, what are the temperature requirements, etc.). Recommendations on this subject can be found in special sources.

We also recall that water begins to be felt by a person as warm somewhere from 40 °C, as hot — somewhere from 50 °C, and the temperature of hot water in central water supply systems (according to official standards) is at least 60 °C. Thus, for the boiler to operate in the ΔT=25 °C mode and produce at least warm water at 40 °C, the initial temperature of cold water must be at least 15 °C (15+25=40 °C). It is a rather high value — for example, in a centralized water supply system, cold water...reaches 15 °C, except in summer, when the water pipes warm up noticeably; the same applies to water supplied from wells. So this performance is a very conditional value. The boiler does not work so often with a temperature difference of 25 °C. Nevertheless, the data for ΔT=25°C is still often given in the specifications — including for advertising purposes since it is in this mode that the performance figures are the highest. In addition, this information may be useful if the boiler is used as a pre-heater, and heating to operating temperature is provided by another device, such as an electric boiler or instantaneous water heater.

The efficiency of the boiler.

For electric models (see "Energy source"), this parameter is calculated as the ratio of net power to consumed; in such models, indicators of 98 – 99% are not uncommon. For other boilers, the efficiency is the ratio of the amount of heat directly transferred to the water to the total heat amount released during combustion. In such devices, the efficiency is lower than in electric ones; for them, a parameter of more than 90% is considered good. An exception is gas condensing boilers (see the relevant paragraph), where the efficiency can even be higher than 100%. There is no violation of the laws of physics here. It is a kind of advertising trick: when calculating the efficiency, an inaccurate method is used that does not take into account the energy spent on the formation of water vapour. Nevertheless, formally everything is correct: the boiler gives out more thermal energy to the water than is released during the combustion of fuel since condensation energy is added to the combustion energy.

It is the optimum gas pressure supplied to the inlet of the boiler system. Most often indicated for natural gas and is about 15-20 mbar. This parameter must match the specs of the gas supply system. However, the pressure in the latter may be higher, which may require the installation of a special gas regulator.

Maximum gas consumption in the boiler with the corresponding energy source (see above). Achieved when the gas heater is operating at full capacity; with reduced power and consumption, respectively, will be lower.

Note that boilers of the same power may differ in gas consumption due to the difference in efficiency. While the more fuel-efficient models tend to cost more, the price difference pays off in gas savings.