Reliability and long service life
The water heater should work for a long time without any problems. Of course, it doesn't have to work flawlessly only within the warranty period. What does the long life of a water heater depend on:
4.1. The quality of the enamel coating.
Years ago, the water tanks of the water heaters were galvanized. It was some protection against corrosion, but not effective enough. In addition, water in contact with the galvanized surface of the water container is harmful to human health. The enamel (or in other words "glass-ceramic") coating of the inner part of the water container is essential for resistance against stubborn corrosion processes. Enamel in the form of a liquid or powder substance is mechanically applied to the inner surface of the water container. After firing in enamel ovens, this substance adheres tightly to the water-contact surface of the wax holder. This process is called adhesion . Thus, the black steel from which the water container is made is isolated from the aggressive effects of water.
The enamel frits and clays used in world enamelling practice are almost identical. However, the addition of some components to the enamel formula increases its resistance to high temperatures and wear. Such, for example, is the zirconium that we put in in the enamel coating of ELDOM water heaters .
4.2. Availability of cathodic protection and its effectiveness.
Cathodic protection is used for additional prevention against corrosion processes in the water reservoir. It is something as simple as a construction as it is difficult to explain as a physico-chemical process.
For effective cathodic protection, it is important to know only the basics: the active protection elements are one or two anode protectors. They are most often made of a special magnesium alloy. All other alloys do not provide sufficiently effective protection! Located at opposite ends of the water container, the anodes imperceptibly but reliably protect its entire volume. How does this happen?
No matter how perfect the glass-ceramic coating (enamel) is, there is always a risk of micro-pores appearing, as well as defects at the weld seams where water has access to the base metal. Then corrosion processes begin to take place in the water reservoir.
The cause of corrosion always lies in the difference between the electrode potentials of the metals. In the specific case - the black steel of the water container and its environment (copper electric heater, stainless pipe, brass couplings, etc.). Corrosion is an electrochemical process in which the surface of a metal is gradually destroyed. As a result, leaks appear in the water tank, which lead to a leak in the water heater .
Cathodic corrosion protection is an active method of protection and, unlike passive methods, directly attacks the cause of the problem. The method is based on the interdependence between the potential and the rate of corrosion development. Anodes also create potential. Very weak currents flow between them and the defective surface, opposite to the corrosion currents. Thus, cathodic protection leads to a delay and, under certain conditions, to the prevention of corrosion.
- The size of the anode is essential. It is considered that 200 gr. an anode mass with average statistical water parameters can successfully protect 1 square meter of an enameled surface with no more than 7 square cm for 3 years defects. From this point of view, 350 gr. anode mass in ELDOM water heaters provide truly reliable protection. For boilers with a volume of 50 to 750 liters and for boilers with coils, where the coil is a kind of screen, we have, after repeated tests, arrived at the effective solution of using protection with 2 anodes. Unfortunately, such solutions are not implemented by many manufacturers.
- Checking the operation of the anti-corrosion protection by means of an anode tester.
During the operation of the cathodic protection, part of the mass of the magnesium anode is lost - it gradually melts. That's why specialists call it a "sacrificial anode". When we put protective anodes in the water heater and customers pay for it, there has to be a way to evaluate or measure their performance. Only ELDOM water heaters provide this possibility due to the isolated installation of the anode, as well as the strong galvanic connection to the housing by means of a cable, and not by direct contact. The performance of cathodic protection can be evaluated by a service technician.
There is another, much more convenient solution, using an anode tester built into the water heater. This is a simple and inexpensive milliammeter that, at the push of a button, shows the condition of the anode protectors. If the indicator is in the green zone, it means that anti-corrosion currents are flowing. The red area showing means you need to call your service technician. Anode replacement manipulation is quick and cheap. This way you increase the life of your water heater by at least another 3 years.
It is interesting that most water heater brands do not have the option of checking with an anode tester. Therefore, their customers , even if they want to , cannot evaluate the performance of cathodic protection. One possible answer is that most manufacturers are reluctant to do this since they are unsure of their design decisions.
4.3. Quality of the electric heating element
The electric tube heater is the "heart" of an electric water heater. That is why we pay special attention to it. In order to guarantee and control the quality of the heaters we put in our appliances, we manufacture them ourselves. This is done on a last generation line covering the entire production process of both copper and stainless steel heaters of different power, working voltage, purpose, shape and length (up to 3 meters). The modern technology we use allows maximum automated 100% process control.
- All the materials we use are of guaranteed quality, supplied by leading companies. The resistance wire is a special Kanthal chrome-nickel alloy. The Kantal D used by us allows a heating temperature of up to 1300°C. For the temperature regime at which our heaters operate, it is reinsured with a 40% range;
- We rely on impeccable magnesium oxide (MgO) insulation, which is a significantly better insulator than the quartz sand used in many mainstream heating elements. We use MgO class H with 99.97% purity, which allows the dielectric characteristics of the heater to be preserved even at temperatures of 1300°C.
- We use a hard pin made of special steel with a nickel coating.
- To pressurize the heaters, in ELDOMINVEST we use a special brand of epoxy resin. It is a better solution than the widely used silicone, whose characteristics deteriorate over time, and this leads to dangerous depressurization of the heater.
- We use ceramic insulating bushings, not the commonly used plastic ones.
- The copper tubes for our heaters are calibrated to a very high degree of accuracy and are supplied by German and English companies.
- We make the stainless steel pipes at ELDOMINVEST. We use 321S grade with a high content of alloying additives (NiCr and Mo), extremely resistant to work in water and air environments.
- Our heaters are designed with a longer length and a longer cold zone. Despite the higher consumption of expensive materials, this provides the customer :
- Greater resource (longer life) and longer life of the heater, due to the lower load, resp. less stress on the tube and spiral;
- High resistance even with incorrect use of the device in which they are installed.
- Resistance to calcareous waters. The remoteness of the heating zone also protects tires, bushings, etc. flange sealing elements from scale build-up.
- The heaters in the ELDOM appliances are manufactured in accordance with BDS EN60335, part 1 and have been tested in a certified SGS laboratory.
Perhaps this is the place to clarify the issue of heater power and electricity costs. The water heating time depends on this. It is a misconception that the smaller the power of the electric heater, the more economical the water heater. The thermal energy that a heater gives off is equal to the consumed electrical energy. A 2 kW heater takes longer to heat 80 liters of water than a 3 kW heater. However , the final result and the consumption of electrical energy are the same.
