Tank lining
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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.
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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for such containers, the possibility of corrosion is not ruled out — especially when it comes to cheap devices that use outdated welding technologies, and the material of the seams may differ from the material of the tank.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.
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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.Combustion chamber type
Type of combustion chamber of a gas water heater. Combustion chambers are divided into open and closed.
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Open (atmosheric). It works according to the classical scheme: for the combustion of fuel, the air is consumed from the room in which the heater is located, and the combustion products are removed through the flue due to the natural draft. For normal operation of such a heater, the room must have good ventilation, and the flue must be at least 4 m high.
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Closed (turbocharged). The closed combustion chamber draws air for combustion of the fuel from the outside, and the products of combustion are removed there. In this case, gas exchange is carried out forcibly, with the help of a fan, therefore sometimes such combustion chambers are called turbocharged. The main advantage of such heaters is that they take air for combustion from the street without burning oxygen in the room. Thus, comfortable conditions are provided in the room, and the heater itself can be installed regardless of ventilation conditions (for example, in the kitchen or the bathroom). ). However, for turbocharged chambers, there are restrictions on the maximum length of the flue.
Gas consumption
It is the amount of gas a device consumes.
Weight
The weight of the device, excluding the water collected (passing) into it.
