Comparison Electrolux EWH 50 Heatronic Slim DryHeat vs Electrolux EWH 50 SL

The regular way to install a water heater.

The choice for this parameter depends primarily on how much free space is available for installing the device and what shape this space has. Therefore, when there is a lot of space (for example, the user has an entire wall in the boiler room of a private house at his disposal), this parameter can be ignored. But in cramped conditions, each installation method will have its nuances.

— Vertical. Vertical arrangement devices, elongated in height. This option is well suited for narrow cramped spaces — for example, a bathroom in a small city apartment.

— Horizontal. The horizontal layout is less suitable for tight spaces than the vertical one but in some conditions, it may be optimal — for example, if the place under the device looks like a low horizontal niche. Also, note that many instant water heaters are produced in this design (see "Type") — they do not take up much space, and horizontal orientation is considered optimal for such devices for several reasons.

— Floor. Floorstanding models (as opposed to all of the wall mount options described above). The main advantage of such an installation is simplicity: there is no need to drill walls and prepare other special fasteners; it is enough to have free space on the floor. In addition, weight restrictions are not so critical for floor water h...eaters, and this method can be used even for the most powerful, capacious and, accordingly, large models. On the other hand, free space on the floor is not always available, and this installation method is not suitable for cramped conditions.

— Universal (wall mounted). Devices that can be placed in any position — both horizontal and vertical (see above for details). The advantage of this option is obvious: the user can choose the installation method of his choice, depending on the situation.

The shape of the water heater.

The traditional options are cylindrical and rectangular, but nowadays there are more specific options — flat cases, slim cylindrical devices. Here are the features of each of these options:

— Cylindrical. This form is traditional for storage water heaters. It is because with the same total volume, less material is needed for a cylindrical tank than for a rectangular one; and in production, such tanks are simple and cheap, which allows them to be used in water heaters of any price category. The disadvantages of this form include, first of all, some bulkiness in comparison with other options.

— Rectangular. The case is rectangular in shape, with pronounced front and side faces; the corners can be both sharply defined and rounded. It is the traditional form for instant water heaters, primarily gas, but it can be found in a fairly large number of storage models. Accordingly, the features of a rectangular case will be different — depending on the type of heater. So, in instant water heaters, the “rectangle” is simply one of the most convenient options in terms of the overall layout. But in storage water heaters, this shape differs from the flat one (see below) only with a slightly greater thickness and, in some cases, pronounced angles.

— Flat. A variant found mainly in s...torage electric heaters. Such devices look as if the classic cylindrical body was flattened at the back and front, reducing its thickness by increasing the width (and sometimes height). Thus, such a boiler does not protrude as much in front of the wall as a cylindrical one; in some cases, this point may be fundamental — for example, when installed in a bathroom, where a cylindrical device would hang over the toilet bowl, creating discomfort.

— Slim. A variety of cylindrical cases are characterized by a reduced diameter. In other words, boilers from this category are also round, but with the same volume, they have a noticeably smaller width and thickness than traditional cylindrical ones. In cramped conditions, this can be very useful. However, it must be borne in mind that the price for reducing the diameter is an increase in height.

Electrical power consumed by the heater during operation.

This parameter is of key importance for electric models (see "Energy source"). In them, the power consumption corresponds to the power of the heating element and, accordingly, the heat output of the entire device. The overall efficiency and flow rate of the water heater directly depend on the useful power. Accordingly, high-flow rate models inevitably have high consumption. At the same time, we note that the heating power is selected by the designers in such a way as to guarantee the necessary flow rate and water temperature. So when choosing a device according to flow rate, you need to look primarily at flow rate and temperature. Power must be taken into account when connecting: for example, if a 220 V model (see "Power source") consumes more than 3.5 kW, it, as a rule, cannot be plugged into a regular outlet — connection is required according to special rules. And the most productive and high-powered models — 10 kW or more — are connected only to three-phase mains.

The power consumption has a similar value for combined boilers — adjusted for the fact that in them the electric heater is an additional source of heat. For gas and indirect models, this parameter describes the power consumption of control circuits and other auxiliary structural elements; this power consumption is usually very small — on the order of several tens of watts, less often up to 1.5 kW.

The highest water temperature provided by the device. The standard temperature of hot water in the water supply is 60 °C, and this value is actually the minimum for modern water heaters: models with more modest rates (usually from 40 °C) are extremely rare. But higher values can be found much more often: for example, water heaters of 75 °C and 80 °C are very popular, and in the most powerful models in this regard, the temperature can reach 95 °C and even higher.

On the one hand, strong heating requires appropriate power (which is especially noticeable in the case of instant electric heaters). On the other hand, the higher the temperature of hot water, the less it is needed for a comfortable outlet temperature, after mixing with cold water; this reduces the consumption of heated water, which is especially important for storage boilers. In addition, many models have thermostats (see "Features").

Also, note that heating to operating values may involve different ΔT (degree of temperature change) — depending on the initial temperature of the cold water. The actual performance of the heater directly depends on ΔT; this moment is described in more detail below, in the paragraphs devoted to performance at different ΔT.

— Enamel. Like plastic, enamel is chemically neutral and does not affect the taste and smell of water, while it is considered more durable. Theoretically, this material is prone to the appearance of microcracks, including due to temperature differences (which eventually lead to water contact with metal and corrosion). However, high-quality heat-resistant enamels are most often used in boilers, which have the same coefficient of thermal expansion as the material of the tank and are damaged only in case of violation of operating conditions (or with strong impacts). So the mentioned drawback is typical mainly for the most inexpensive models with appropriate quality materials.

— Stainless steel. Due to its high strength, stainless steel is considered the most reliable and durable material today. Unlike enamelled ones, such tanks are absolutely not afraid of temperature changes, and they also normally withstand hits including pretty strong ones. On the other hand, steel is noticeably more expensive than enamel. At the same time, for such containers, the possibility of corrosion is not ruled out — especially when it comes to cheap devices that use outdated welding technologies, and the material of the seams may differ from the material of the tank. To eliminate this phenomenon, cathodic protection is required, which further affects the cost.

— Glass ceramics....Material, in many respects similar to the enamel described above. On the one hand, glass ceramic does not react with water, does not affect its taste and properties, and is also considered quite reliable. On the other hand, this material is more brittle and prone to the appearance of microcracks and the loss of its properties — both as it wears out and due to strong heating. Because of this, such water heaters usually have a recommended temperature limit of 60 °C.

— Plastic. Plastic is chemically resistant, not subject to corrosion and practically does not affect the composition of water, besides it is inexpensive. The main disadvantage of plastic coating is considered to be fragility.

— Copper. Copper coating is used exclusively in instant water heaters (see "Type"); more precisely, in such devices, the entire tank is usually made of copper. This material is not suitable for a storage tank: copper is too heavy, and it has a corrosive effect on some materials (aluminium, cast iron) due to its electrochemical properties, even if these materials are used outside the heater, in other parts of the water supply system. However, in a small tank in an instant water heater, these moments are invisible, while copper perfectly tolerates compression and tension during temperature changes.

— Titanium-cobalt alloy. A special alloy, characterized by the highest strength and resistance to corrosion, but also very expensive. It is extremely rare, only in top-level heaters.

Time to heat the storage tank (see "Type"), filled with cold water, to operating temperature.

It is worth remembering that this characteristic is not 100% accurate. Manufacturers usually indicate the heating time for certain conditions: a filled tank, maximum heating intensity, and temperature rise (∆T) by a certain number of degrees. In practice, the heating time may differ, both one way and the other. For example, if the heating time for the device is 20 minutes at ∆T = 50 °C, then when the water is heated from 15 °C to 60 °C, the time will be shorter (∆T = 45 °C). Nevertheless, this indicator allows us to evaluate the overall flow rate of the boiler, and with equal ∆T and volumes, different models can be compared in terms of heating time.

The safety of water heaters can be carried out by such functions as overheat protection frost protection, dry heating protection, surge protection, electrical protection (RCD), anti-legionella, gas control and draft sensor. More about them:

— Overheat protection. Water heater safety system that automatically turns off the power supply or gas supply (depending on the type) when the heating element reaches a critical temperature. It avoids overheating and the troubles associated with it, ranging from heater failure to fire.

— Frost protection. Function to prevent freezing of water in the circuits, tank and/or heat exchanger of the water heater. It will be useful when the device is installed in a room with a low temperature and works with long breaks. Frozen water expands, which can damage the device; to avoid this, the frost protection monitors the temperature of the water in the device and turns on the heating when this temperature drops to a critical level.

— Dry heating protection. A safety system that prevents the heater from being switched on without the presence of water in it. Since the heating element does not transfer heat to the water when turned on, it heats up very q...uickly and, in a short time, reaches a high temperature that can lead to damage to the heater and even to a fire. The presence of protection against switching on without water allows you to avoid such unpleasant consequences.

— Voltage surge protection. System for protecting the heater from power surges. Electronically controlled models are usually equipped with such protection (see Control) since it is the control electronics that are most sensitive to problems with the power supply. Note that the capabilities of such systems are noticeably more modest than those of specialized stabilizers or protective systems: the “hardware” of a water heater can smooth out relatively weak power surges, but in case of serious failures, it will most likely simply turn off the device to avoid damage. However, this feature will be useful; except that in very unstable electrical grids, prone to frequent fluctuations, such a heater may require an external stabilizer.

— Electrical protection (RCD). Built directly into the heater, the RCD is a residual current device. Such a device is primarily intended to protect people from electric shock — for example, if the insulation is damaged and electricity leaks into the case or water. When a person comes into contact with this electricity, a so-called leakage current occurs. The RCD reacts to it and almost instantly turns off the power to the boiler, preventing electric shock.
Note that such safety devices are standardly installed directly in switchboards. However, the presence of an RCD in the water heater provides additional security. Naturally, such equipment is found mainly in electric models.

— Safety valve. A safety system that prevents a critical increase in water pressure in the heater. Usually, this protection is based on a safety valve that opens when a certain pressure level is reached and drains excess water, avoiding damage to the heater.

— Gas control. Gas heater safety system that automatically shuts off the gas supply in the event of a burner flame failure. It avoids filling the room with gas and possible unpleasant, and even tragic consequences. Resuming the gas supply after the protection is triggered must be done manually.

— Draft sensor. A sensor that monitors the presence of draft in the flue of a gas water heater. This function is especially important for models with open combustion chambers: in the absence of a draft, combustion products will fill the room where the heater is located. And this, in turn, can lead to a deterioration in people's well-being, health problems and even deaths. To avoid such consequences, this sensor, when detecting problems with the draft, turns off the gas supply and issues a warning about the problem. However, such equipment can also be found in models with closed combustion chambers. In them, the draft sensor performs mainly a diagnostic function, allowing you to determine what interferes with the normal operation of the burner.

— Anti-legionella. A function that prevents the growth of pathogenic bacteria in the tank and water heater circuits. Some types of such bacteria can live and multiply in fairly hot water — up to 60 °C. To avoid this, the anti-legionella system monitors the temperature of the water in the tank and periodically raises it to a level of about 65 °C. The specific methods of operation of such systems can be different: for example, some work strictly according to a set schedule (for example, once every two weeks), others turn on additional heating only if for some period (for example, a month) the water has not been heated to sufficiently high temperatures.

The direction from which pipes are connected to the heater. The choice for this parameter depends primarily on the characteristics of the place where the device is planned to be placed. Note that in universal models (see "Installation"), the place of connection of pipes depends on the method of installation, while specific options in different models may be different, this should be specified separately.

The warranty period declared by the manufacturer for the storage water heater tank (see “Type”).

This parameter is important for the reasons of maintenance terms. The tank is the most complex element: other parts of the water heater are relatively easy to repair and change, and if there is a problem with the tank, it is often easier to replace the entire boiler. In the most advanced models, the warranty on the tank can be 10 years or more.