Enamel or glass-ceramic. which coating is better in a water heater

What water heaters are better with internal stainless steel tank or coated with enamel from glass ceramics, this question often becomes before the buyer when choosing a specific model of the device. To be honest, it is almost impossible to give an exact answer, the choice will be yours, but we will try to most specifically explain the pros and cons of each option.

  • Stainless steel water heater not afraid of sudden changes and temperature. Even if the water heater accidentally overheats due to lack of water in the tank, it will not suffer, you will have to replace the heating element and other parts damaged due to high temperature.
  • Also no damage to the coating from impacts and concussions, which can peel off enamel that is poorly adhered to the base.
  • We often talk about the toxicity of iron that comes into contact with water. In fact, only bivalent iron is toxic, which practically does not form when water contacts steel; in a water heater, even a large capacity, it is not detected by ultra-precise instrumental methods, if tap water did not become its source. But There is a danger of having an allergies for alloying metals (for example, vanadium), although it is also scanty.
  • Despite the fact that the stainless steel container does not corrode, welding joints differ in composition from the base metal if the simplest welding method with filler material was used. Therefore, if outdated technologies were applied, oxidation at the seams may appear, aggravated by the fact that any chemical reactions proceed faster when heated. To eliminate this effect, cathodic protection is used, but it complicates and increases the cost of the water heater (but additionally reduces corrosion on metal pipes galvanically connected to the water heater).
  • Another argument in the dispute is the best glass-ceramic or stainless steel tank coating price. We must agree, enamel-coated water heaters are cheaper. But this difference is significant only for cheap models.

Stainless steel tank device. Photo 01

  • Vasily Shpudeko. “All the time he used the heater with enamel, as a rule, cracked on cover appeared in 3-4 years. I bought stainless steel, I did not notice the difference. Including the taste of water, which scared everyone.
  • MAX. “They said that stainless steel allows you to heat water faster but spoils its quality. I took Thermex IBL 10 with such a tank, for six months there are no differences, probably, I overpaid after all.

Types of interior coatings

At the moment there are two types of coating: glass fiber with enamel and stainless steel. The first varieties are somewhat cheaper. But this does not mean that steel, if more expensive, is better. Each option has its own characteristics, which you need to understand.

Enamelled glass fiber

When water heaters just started to appear, their inside was covered with ordinary enamel. It was also used for steel and cast iron bathtubs and sinks. However, in the course of operation, a serious disadvantage was identified. cyclic temperature loads became the cause of rapid cracking of enamel.

Important! The steel on the inside of the tank could not withstand electrochemical corrosion, which led to equipment failure. Even with plastic coatings, the service life did not exceed 3-4 years.

After analyzing the situation, manufacturers have identified what determines the life of the enamel. the protective enameled layer had a completely different value of thermal expansion, when compared with the values ​​of the temperature coefficients inherent in steel. To even out the indicators, the protective composition was modified. titanium powder was added.

As a result, the enamel “turned” into another material called glass fiber. Such a tank for new water heaters quickly became popular due to increased strength, elasticity and resistance to temperature deformations. The glass-faor coating keeps the water clean and fresh longer, as scale on the walls of the device is less likely to form.

Water heaters with top-ceramic coating are made like this: steel sheet is taken, from which the welding makes the container. Further, its inner surface is covered with glass fiber and fired at a temperature of up to 900 degrees Celsius.

As for the glassfaor itself, it is a substance in the form of a powder. It can be applied to the walls of the tank in different ways, which will affect the life of the device. Beginner manufacturers use the liquid method. the powder is mixed with liquid substances, then it is sprayed onto a tank, which is left to dry, and then sent to the kiln for firing.

Important! World-famous companies use a different method. dry, which is an electrostatic spraying. Particles with a charge “stick” better to the surface of the tank, and evenly. Liquid enameling, in turn, causes the enamel to run down the tank, due to which the coating in its upper part is thinner. But the upper area of ​​the water heater is most susceptible to corrosion, because an aggressive environment is formed due to the air gap.

When deciding which tank coating is best for a modern storage water heater, do not forget about new protective technologies. Not so long ago, silver began to add to the glass factor, which allows you to saturate water by the ions of this metal. As a result, such tanks decreases the likelihood of bacteria, and the preventive cleaning they need much less.

To understand which tank is better in the water heater, it is necessary to highlight the advantages and disadvantages of each coating. The glass faulty units are characteristic of the following advantages:

  • affordable price;
  • Ease of preventive work. To remove the sediment, it suffices to take advantage of a good detergent;
  • Enamel. inert to many chemicals material. For damage to the glass-ceramic structure, a truly aggressive composition will be required, for example, a floator acid.

Such an internal coating has cons:

  • Ceramics and boiler himself differ in composition. Permanent temperature drops are able to resolve materials. However, glass-ceramic practically eliminates this moment;
  • coloring pigments are often added to bulk enamel. As part of the latter, arsenic and lead were found. substances dangerous to humans. This applies only to devices that were manufactured more than 20 years ago;
  • fragility of ceramics. If the indirect water heater is “shaken”, it will damage the coating.

Important! Enamel and glass fiber are sensitive to temperature changes, which causes microcracks to form on them.

Steel

For a better understanding of which water heater to choose. enamel or stainless steel, you need to consider the features of steel products. It includes non-magnetic stainless steel. And thanks to chromium, a dense protective film is formed on the metal surface, which prevents corrosion from developing. In pure steel or cast iron products, this film is not strong enough, which can cause the metal to crack.

In theory, stainless steel does not corrode. Therefore, additional enamel coating is not required for such tanks, as well as a magnesium anode. But in order to make a water heater, welding is necessary, which violates the structure of the metal in the places of processing. The result is intergranular corrosion. To eliminate this point, new welding technologies have been developed.

The price of stainless steel is 30-100% higher compared to an enameled tank. Such tanks are more durable, they do not need to change the magnesium anode. When wondering which water heater is better. stainless steel or enamel, it is necessary to consider the conditions under which it will be used. In Russia, the quality of cold water is far from ideal, so stainless steel is more in demand as a coating.

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Stainless steel is often chosen in view of the following advantages:

  • resistance to sudden temperature changes. For example, there is no water in the tank, but the boiler continues to heat up. nothing bad will happen to it, it will not deteriorate. The only thing is that the high temperature will damage the heater and other components, which will only have to be replaced with new ones;
  • shocks and shocks are not terrible for the coating.
  • they say that iron in contact with water is toxic. This applies only to ferrous iron. As for steel, there is no such problem;
  • if the tank is made according to the old technology, then its seams may oxidize during operation. The solution to the problem. cathodic protection. But such equipment is more complex and expensive;
  • another controversial point in the choice of glass ceramics or stainless steel in a domestic water heater is the price. Enamel devices are more affordable, but we are talking only about cheap models.

Types of interior coatings

At the moment there are two types of coating: glass fiber with enamel and stainless steel. The first varieties are somewhat cheaper. But this does not mean that steel, if more expensive, is better. Each option has its own characteristics, which you need to understand.

Enamelled glass fiber

When water heaters just started to appear, their inside was covered with ordinary enamel. It was also used for steel and cast iron bathtubs and sinks. However, during operation, a serious drawback was revealed. cyclic temperature loads caused rapid cracking of the enamel.

Important! The steel on the inside of the tank could not withstand electrochemical corrosion, which led to equipment failure. Even with plastic coatings, the service life did not exceed 3-4 years.

After analyzing the situation, manufacturers have identified what determines the life of the enamel. the protective enameled layer had a completely different value of thermal expansion, when compared with the values ​​of the temperature coefficients inherent in steel. To even out the indicators, the protective composition was modified. titanium powder was added.

As a result, the enamel “turned” into another material called glass fiber. Such a tank for new water heaters quickly became popular due to increased strength, elasticity and resistance to temperature deformations. The glass-faor coating keeps the water clean and fresh longer, as scale on the walls of the device is less likely to form.

Water heaters coated with glass ceramics are made as follows: a steel sheet is taken, from which a container is made by welding. Further, its inner surface is covered with glass fiber and fired at a temperature of up to 900 degrees Celsius.

As for the glassfaor itself, it is a substance in the form of a powder. It can be applied to the walls of the tank in different ways, which will affect the life of the device. Beginner manufacturers use the liquid method. the powder is mixed with liquid substances, then it is sprayed onto a tank, which is left to dry, and then sent to the kiln for firing.

Important! World-famous companies use a different method. dry, which is an electrostatic spraying. Particles with a charge “stick” better to the surface of the tank, and evenly. Liquid enameling, in turn, causes the enamel to run down the tank, due to which the coating in its upper part is thinner. But the upper area of ​​the water heater is most susceptible to corrosion, because an aggressive environment is formed due to the air gap.

When deciding which tank coating is best for a modern storage water heater, do not forget about new protective technologies. Not so long ago, silver began to be added to glass fiber, which allows saturating water with ions of this metal. As a result, in such tanks, the likelihood of bacteria formation is reduced, and they need preventive cleaning much less frequently.

To understand which tank is better in a water heater, it is necessary to highlight the advantages and disadvantages of each coating. The glass faulty units are characteristic of the following advantages:

  • affordable price;
  • Ease of preventive work. To remove the sediment, it suffices to take advantage of a good detergent;
  • Enamel. inert to many chemicals material. To damage the glass-ceramic structure, you need a really aggressive compound, such as hydrofluoric acid.

Such an internal coating also has disadvantages:

  • ceramics and the boiler itself differ in composition. Constant temperature fluctuations can lead to delamination of materials. However, glass-ceramic practically eliminates this moment;
  • coloring pigments are often added to bulk enamel. As part of the latter, arsenic and lead were found. substances dangerous to humans. This applies only to devices that were manufactured more than 20 years ago;
  • fragility of ceramics. If the indirect water heater is “shaken”, it will damage the coating.

Important! Enamel and glass fiber are sensitive to temperature changes, which causes microcracks to form on them.

Steel

For a better understanding of which water heater to choose. enamel or stainless steel, you need to consider the features of steel products. It includes non-magnetic stainless steel. And thanks to chromium, a dense protective film is formed on the metal surface, which prevents corrosion from developing. In pure steel or cast iron products, this film is not strong enough, which can cause the metal to crack.

In theory, stainless steel does not corrode. Therefore, additional enamel coating is not required for such tanks, as well as a magnesium anode. But in order to make a water heater, welding is necessary, which violates the structure of the metal in the places of processing. The result is intergranular corrosion. To eliminate this point, new welding technologies have been developed.

The price of stainless steel is 30-100% higher compared to an enameled tank. Such tanks are more durable, they do not need to change the magnesium anode. When wondering which water heater is better. stainless steel or enamel, it is necessary to consider the conditions under which it will be used. In Russia, the quality of cold water is far from ideal, so stainless steel is more in demand as a coating.

glass ceramics

Homeland of glass-ceramics, otherwise called glass-ceramic, USSR. For the first time this composite material was discovered by the Soviet physical chemist Isaac Ilyich Kitaigorodsky (1888-1965). As a professor at Moscow Chemical Technology Institute named after D. And. Mendeleev, Kitaygorodsky devoted his whole life to the search for especially durable glass, wrote a textbook on this topic, which was subsequently translated into several languages.

By combining raw materials, different types of glasses and impurities, the professor obtained a unique product that is used in a wide variety of industries. The professor’s followers expanded the list of glass-ceramics through experiments with different types of materials, various combinations of impurities and additives, experiments with the proportions of the feedstock.

Most glass-ceramics are a series of materials that are durable and thermally stable; glass-ceramic structures do not change their original size when exposed to high temperatures.

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Such a coating is the best suited for a metal tank of a water heater, as it does not attract lime particles, but repels them. The composition of the material prevents the occurrence of a tank of limeths on the walls. The most famous example of sitalla. the surface of the electrical cooker.

The strength of the finished product also affects the method of applying powder sitals for metal. To date, there are two ways: liquid and dry.

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Liquid method is cheaper. That is why in this way it is often used in the manufacture of budget water heaters. Cons of liquid fashion. unevenness. The liquid has a function to drain under the weight of its own weight, so at the top coating felt, and at the bottom it becomes thicker. The danger of a thin coating is due to the presence of an aggressive air-water cushion at the top of the water heater tank, which leads to rapid corrosion of the material.

The dry method is more accurate, glass ceramic is distributed evenly over the walls, using electrostatic spraying. After firing at 90 degrees Celsius, the coating tightly adheres to the surface of the tank and successfully protects the water heater from scale for 10-12 years, with proper care.

Rating of accumulative electric water heaters

What electric boiler chose or would you advise you?

As mentioned above, water heaters can be selected by different criteria. But since our article is devoted to comparing boilers with different types of heating tank, 4 models are selected for this principle.

The most common water heaters are devices with enameled tanks, and first of all they will be considered.

boiler, glass-ceramic, stainless, steel

Electrical Boiler “Electrolux EWH 50 FORMAX”

ELECTROLUX EWH 50 FORMAX is a model of development of a Swedish company, domestic production. The boiler is granted a neat ergonomic rectangular shape with rounded corners. The water heater is equipped with a system independent from each other by the “X-HEAT”. Each of them is closed with its hermetic flask preventing water contact. In the event of failure of one of the heating elements, the second continues to function, that is, the boiler does not lose working capacity.

Electric storage water heater “Electrolux EWH 50 Formax”

The device is easy to operate. for this purpose, there are two knobs on the front panel that allow you to adjust the maximum temperature and set the economy mode.

The boiler has protection against overheating, running dry. The power cord has an RCD.

As thermal insulation, a layer of CFC-Free polyurethane foam was used, which for a long time allows you to keep the water in a heated state.

The quality of the enamel coating of the tank will probably be indicated by the manufacturer’s warranty period of 7 years. True, with the annual replacement of the magnesium anode.

What users say about this model?

  • The heating elements are hermetically sealed with a protective flask from contact with water, which eliminates the risk of scale overgrowth and quick failure.
  • Boiler heats up quickly.
  • The cost can be considered quite affordable.
  • Economy mode available.
  • The flat shape of the body makes it easier to search for a place suitable for hanging the device.
  • Easy to change heaters.
  • Lack of a display (although the “complainer” did not really explain why such an absence is inconvenient for him).
  • Started leaking after 5 years of use. This is serious!

Electric boiler “Timberk SWH FEX1 80 V”

The Swedish company produces electric water heaters with both enameled and stainless steel tanks. Therefore, having stopped your choice in advance on one of these materials, you should carefully study the characteristics before buying a specific model. Chinese-made models mainly enter the Russian market.

Electric boiler “Timberk SWH FEX1 80 V”

Model shown. with enamelled tank walls. Uses a high quality glass-ceramic compound that will not collect scale. Products have strong welding seams covered with a protective layer, as well as reliable thermal insulation.

The boiler has all the requirements for modern models.

  • Ergonomic shape that allows you to install the boiler both horizontally and vertically.
  • Stylish case design
  • Effective protection against leaks and corrosion.
  • Rapid heating of the collected water volume.
  • Convenient instrument control.

However, most believe that the price corresponds to the quality. That is, the period guaranteed by the manufacturer the product will work according to the “full program”.

Electric boiler “Zanussi ZWH/S 50 Smalto”

Accumulative water heater of Italian production. “Zanussi ZWH / S 50 Smalto”. It is designed to heat 50 liters of water, which is enough for a family of two. Or the heater is capable of a backup source of hot water in case of emergency shutdown of domestic hot water. The temperature range for heating water in the boiler is between 30 and 75 degrees.

Rating of manufacturers of water heaters

The company was founded in 1968 by two engineers of the Rada field and Pierre Lyamur on the west coast of France. This is a family business, the company is still run by the children and grandchildren of its founders.

Photos from the French factory of Atlantic

Atlantic is the undisputed leader of the European market for water heaters with a share of over 50% in unit terms. In Ukraine, for the last approximately 10 years, the company has been a leader with 40% of the boiler market. In Russia, Atlantic ranks fourth. At the same time, the company demonstrated literally reactive growth from 25th place in 2013 and earned the title of the fastest growing brand among boiler manufacturers.

Atlantic has a total turnover of 2.3 billion euros and employs 7,200 people at 23 factories worldwide. 4% of annual income. about 70 million euros. allocated to research and development.

Photos from the Ukrainian plant Atlantic near Odessa

Dry water heaters. the revolutionary invention of the Atlantic. Patented development still has no analogues and has become the only effective alternative to wet-widespread in boiler wet. Atlantic water heater, namely steatite models. the most profitable and most hassle-free, the most energy-efficient and the quietest in Russia.

Steatite dry heating element for boilers Atlantic

I note that in the case of Atlantic we are talking about a purely European development. no Chinese. Atlantic owns 23 factories in Spain, Belgium, Egypt, Poland, Turkey, Georgia, Thailand, UK and other countries. In France alone. 12 productions. But none in China. Apparently, the company is well aware of the experience of other brands that spend too much effort in an attempt to make Chinese citizens work in good faith. And produce consistently high quality products.

Well-known Italian company to the Russian consumer. Its products actually opened the boiler market for Russians. Up to the present, Ariston, more by inertia than by the presence of innovation and advanced products, has ranked first in Russia in sales of water heaters with 5 million units per year. It is known that Ariston flat boilers are manufactured at the company’s own factory in China.

Ariston has a full-cycle production facility in the Leningrad Region. Judging by the materials available on the Web, only boilers with a cylindrical body are produced here

Unfortunately, there is not as much information about the brand as we would like. For example, on the Russian-language official website in the “About Us” section, nothing is said about technologies or achievements in the field of water heaters. The history of the company ends in 2010 with a little meaningful phrase “The development of our brand positioning in thermal comfort begins with the creation of a new visual concept. Global growth continues, in all parts of the world from America to Asia”. Informative, yes.

The brand was founded in 1949 in Italy. Since 1995, it has been actively developing its presence in Russia, by 2020 it ranks second in unit sales of boilers. In 2007, in the city of Tosno, themex factory began to work in the city of Tosno. In 2015, it was already about the production of a full cycle with 90% automation. To compare the scale of work: let me remind you that the staff of the French Atlantic is 7,200 people, while more than three times less work on Thermex boilers around the world, 2,000 workers. Unfortunately, the “Italian trace” was lost over time, since the development of the company’s products is carried out exclusively by specialists in China.

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In Russia, Thermex is primarily remembered for its large-scale advertising of flat stainless steel domestic water heaters. Initially, the company produced really high-quality products of this type. Now in the assortment of Thermex there are many models in the budget segment from 6 to 15 thousand. However, at a price in this range, it is impossible to ensure either the use of high-quality stainless steel or the necessary technologies in production. In other words, stainless steel tanks. Rather, marketing tricks and are not always able to resist corrosion.

Commercial and industrial holding “Rusclimat” is an extremely talented organization. It owns the rights to manufacture and distribute climate equipment for more than 50 brands. This is explicitly stated, for example, here. Electrolux, Zanussi, Ballu, Boneco, Royal Thermo, Weger, Shuft, Biasi, SFA, De Dietrich and many others are brands that have nothing to do with their real founders.

Several pictures from the participation of Rusclimat in the Aquatherm Moscow 2020 exhibition. I would like to look at the photos in more detail, but On the official website of the holding, only frames in a small resolution of 650×488 pixels are published

Enamel

Enamel is a protective glass coating with impurities, which is applied to metal at high temperatures. Enamel glass must have a lower melting point than the metal it is applied to.

Liquid enamel spreads a thin layer for metal and frozen when cooled. To achieve greater strength, enamel is applied in several layers.

Testing a water heater with an enamel coating for the first time, engineers have established that such a coating is not reliable enough, since it does not tolerate high temperatures. When water heated above 60 degrees Celsius in enamels appear microcracks, which contributes to its rapid destruction, since the heat expansion of the coating is straightened by the temperature of the extension of the tank itself. Water heaters with such a coating rarely work longer than 3-4 years.

But progress does not stand still, and manufacturers have found a way to extend the life of their creation. In enamel began to add titanium powder, thoroughly observing the proportion. If there are more than 4% of titanium powder in enamel, it becomes fragile. But 3-3.5% of the titanium powder in enamel show a wonderful result, extending the service life of 7-8 years, that is, two and a half times, due to the equalization of the enamel and metal expansion temperatures.

Enamel

Enamel is a protective glass coating with impurities, which is applied to metal at high temperatures. Enamel glass must have a lower melting point than the metal it is applied to.

Liquid enamel spreads in a thin layer over the metal and solidifies when cooled. To achieve greater strength, the enamel is applied in several layers.

Having tested an enamel-coated water heater for the first time, engineers found that such a coating is not reliable enough, as it does not tolerate high temperatures. When water is heated above 60 degrees Celsius, microcracks appear in the enamel, which contributes to its rapid destruction, since the thermal expansion of the coating is strikingly different from the expansion temperature of the steel tank itself. Water heaters with such a coating rarely work longer than 3-4 years.

But progress does not stand still, and manufacturers have found a way to extend the life of their creation. Titanium powder began to be added to the enamel, carefully observing the proportions. If the enamel contains more than 4% titanium powder, it becomes brittle. But 3-3.5% of titanium powder in enamel shows a wonderful result, extending the service life up to 7-8 years, that is, two and a half times, due to equalization of the expansion temperatures of enamel and metal.

A few words. about the fundamental design of an electric boiler

To correctly represent the problem, you should at least in general terms understand the device of an electric storage water heater. The design is simple, and its study does not take much time.

According to this or a scheme close to it, electric storage water heaters are arranged. boilers.

All boilers are always assembled according to the “tank in the tank” principle. But the outer (pos. 1) plays only the role of a protective casing and gives the device the desired visual appeal. With water, it does not contact any way, therefore, the material of its manufacture, learn, is not important. Most often it is painted thin steel, but the option of polymer is not excluded.

But inside there is a “working” tank (pos. 2), in which water is heated. About this capacity, we will just talk to them the main conversation further.

The boiler should heat water, and not spend expensive energy on heating the room. That is, the outer wall of the device should not heat up to any high temperatures. For this, a layer of thermal insulation is necessarily located between the containers (pos. 3). In modern boilers, most often it is polyurethane foam, a very effective and safe insulation.

The heating tank on the inside can have an anti-corrosion coating (pos. 4). We will also talk about it below.

Water enters the boiler through the inlet pipe (pos. 5), on which a non-return and safety valve is installed without fail. Inside the tank, the inlet pipe is designed so that water does not spurt out (pos. 6). the flow is cut, “calms down”, and the filling goes smoothly from below. But the intake of hot water is always carried out only from above (pos. 7). Cold water entering from below displaces heated water, which, in strict accordance with the laws of physics, rises to the upper region of the tank.

The heating element is responsible for heating (pos. – tubular electric heater. It can be open, such as in the illustration, that is, in direct contact with water, or closed, located in a sealed metal “capsule”.

Particular attention should be paid to the magnesium anode (pos. nine). Completely ridding water of various salts is both difficult and expensive. And these salts are very aggressive or, more often, capable of causing a rapid increase in insoluble scale on the heating element and on the walls of the tank. And scale is a sharp decrease in the heat transfer of the heating element, overheating and failure of the heater. Due to the fact that magnesium is significantly ahead of both iron and copper in the activity line of metals, this anode seems to “cause fire on itself”. All redox reactions take place near it, and the overgrowth of the walls of the tank or the tubes of the heating element does not occur, or it goes very slowly. Naturally, the anode from this eventually collapses, at the same time collecting mountains of insoluble precipitation around it. From time to time, the boiler tank is cleaned and the anode is replaced with a new one.

This is how the anode gradually becomes. and this is still far from the most terrible picture!

As a rule, not far from the inlet pipes and the installation site of the heating element, there are indication and control devices (conditionally. pos. ten). They can be of varying degrees of complexity and ease of use, but today we are not talking about them. One of the mandatory control devices is a thermometer (pos. 11), which removes the heating temperature, usually in the hottest layers of water. at the top.