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Comparison BAXI Eco-4s 18 F 18 kW vs BAXI Eco Compact 18 Fi 18 kW

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BAXI Eco-4s 18 F 18 kW
BAXI Eco Compact 18 Fi 18 kW
BAXI Eco-4s 18 F 18 kWBAXI Eco Compact 18 Fi 18 kW
from $484.88 up to $489.98
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from $460.44 up to $593.00
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Energy sourcegasgas
Installationwallwall
Typedual-circuit (heating and DHW)dual-circuit (heating and DHW)
Heating area144 m²144 m²
Technical specs
Heat output18 kW18 kW
Min. heat output9.3 kW
Power supply230 V230 V
Power consumption130 W110 W
Coolant min. T30 °С30 °С
Coolant max. T85 °С85 °С
Heating circuit max. pressure3 bar3 bar
DHW circuit max. pressure8 bar8 bar
Consumer specs
DHW min. T35 °С35 °С
DHW max. T60 °С60 °С
Performance (ΔT=25°C)13.7 L/min10.3 L/min
Performance (ΔT ~30 °C)9.8 L/min7.4 L/min
"Summer" mode
Heated floor mode
Circulation pump
Control busOpenTherm
Boiler specs
Efficiency92.5 %92.8 %
Combustion chamberclosed (turbocharged)closed (turbocharged)
Flue diameter
60/100 mm /80/80 mm for separate/
60/100 mm /80/80 for split flue/
Inlet gas pressure20 mbar
Max. gas consumption2.11 m³/h2.05 m³/h
Expansion vessel capacity6 L8 L
Expansion vessel pressure0.5 bar0.5 bar
Heat exchangercopper
Connections
Mains water intake1/2"
DHW flow1/2"
Gas supply3/4"
Central heating flow3/4"
Central heating return3/4"
Safety
Safety systems
gas pressure drop
water overheating
flame loss
draft control
water circulation failure
frost protection
gas pressure drop
water overheating
flame loss
draft control
water circulation failure
frost protection
More specs
Dimensions (HxWxD)730x400x299 mm700x400x298 mm
Weight30 kg29 kg
Added to E-Catalogaugust 2016august 2014

Min. heat output

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.

Power consumption

The maximum electrical power consumed by the boiler during operation. For non-electric models (see Energy source), this power is usually low, as it is required mainly for control circuits and it can be ignored. Regarding electric boilers, it is worth noting that the power consumption in them is most often somewhat higher than the useful one since part of the energy is inevitably dissipated and not used for heating. Accordingly, the ratio of useful and consumed power can be used to evaluate the efficiency of such a boiler.

Performance (ΔT=25°C)

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.

Performance (ΔT ~30 °C)

The performance of a dual-circuit boiler in hot water mode when water is heated by approximately 30 °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 ΔT — namely 25 °C, 30 °C and/or 50 °C. And it is 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 mode ΔT ~ 30 °C and give out at least warm water at 40 °C, the initial temperature of cold water should be about 10 °C (10 + 30=40 °C). A similar temperature can be found in wells in the warm season, and cold water in the ce...ntralized water supply system often warms up to 10 °C in the warm season. However, boilers, including dual-circuit boilers, are switched on mainly in cold weather, when the initial water temperature is noticeably lower. Accordingly, if the boiler is used as the main water heater, heating to the claimed temperatures (see "DHW min. T", "DHW max. T") often requires a greater ΔT than 30 °C, and the performance is less than indicated in this paragraph. But when operating in the preheating mode (when the water is heated to the desired temperature by an additional device like a boiler), this parameter describes the capabilities of the unit very reliably.

Control bus

The control bus with which the boiler is compatible.

The control bus is a communication channel through which control and controlled devices can exchange data. Support for such a channel greatly simplifies the connection of thermostats and other control automation. It is enough that such devices are compatible with the same bus as the boiler. In addition, many types of tyres allow you to create very extensive monitoring and control systems and easily integrate various devices into them, including heating boilers.

In modern heating technology, the most popular tyres are OpenTherm, eBus, Bus BridgeNet and EMS. Here are their key features:

— OpenTherm. A fairly simple standard with modest functionality: it allows only a direct connection between the control and the controlled device and is not designed to create extensive systems. On the other hand, this bus has quite advanced capabilities for controlling heaters: in particular, it allows you to control the temperature not just by turning the boiler on/off, but by changing the power of the gas burner. This mode of operation contributes to saving fuel/energy, as well as reduces wear and increases the life of the heater; and in many cases, a system of two devices (boiler and thermostat) is quite enough for effective heating control. At the same time, the OpenThe...rm standard is simple and inexpensive to implement, which makes it extremely popular in modern boilers. For several reasons, it is mainly used in gas models.

— eBUS. A control bus that has some pretty impressive features. Allows you to combine up to 25 control and 228 controlled devices in one system, with a data transmission distance between individual components up to 1 km. At the same time, eBUS is an open standard, its implementation (at least within the framework of the main functions) is freely available to everyone. And although nowadays eBUS support can be found mainly in Protherm and Vaillant equipment. However, in boilers, this is the second most popular type of control bus, after OpenTherm. It is mainly due to slightly higher cost, while advanced eBUS capabilities are not needed as often.

— Bus BridgeNet. Hotpoint-Ariston proprietary development, used exclusively in boilers of this brand. One of the advantages is a high degree of automation: the user only needs to set the temperature parameters (and for different zones, you can choose custom options) and, if desired, a weekly programme, the rest of the necessary calculations and adjustments will be carried out by the system. However, such features are available only in special control devices such as temperature controllers; in boilers, Bus BridgeNet support usually means only compatibility with such automation.

— EMS. A control bus used primarily in Bosch and Buderus equipment. In general, it is characterized by wide functionality, a high degree of automation and the ability to create extensive control systems. However, note that nowadays you can find both the original EMS and the modified EMS Plus, and these standards are not initially compatible with each other (although support for both of them may well be provided in some devices). So the specific version of the EMS bus should be specified separately. We note that in Bosch devices there is mainly an original version, and in Buderus devices — EMS Plus (although exceptions are possible there and there).

Efficiency

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.

Inlet gas pressure

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.

Max. gas consumption

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.

Expansion vessel capacity

The capacity of the expansion tank supplied with the boiler.

The expansion tank is designed to drain excess water from the heating system when the total volume of liquid increases as a result of heating. It consists of two parts connected by a flexible membrane: in one, hermetically closed, there is air under pressure; in the other, excess water enters, compressing the membrane. In this way, a catastrophic increase in pressure in the heating circuit is avoided. The optimal volume of the expansion tank depends on several system parameters, primarily the volume and composition of the coolant; detailed recommendations for calculations can be found in special sources.
BAXI Eco-4s 18 F often compared
BAXI Eco Compact 18 Fi often compared