How to install a magnesium anode in a water heater? Magnesium anode for a water heater: operating principle, purpose, installation Why do you need an anode in a water heater
Sooner or later, any owner of this device will have to replace a burnt-out heating element in a storage electric boiler. Don’t think that it will serve you for decades, no matter how high-quality and expensive the model is.
Heating elements fail for two reasons:
- scale formation and burnout of the working element (heating coil)
- corrosion and mechanical failure
Scale and cleaning of heating elements
Scale forms primarily in the presence of hard water. Just 1mm of scale gives 75% additional thermal insulation. Thus, the heating element under such a large layer of salts simply begins to overheat.
The first sign of scale formation is a distinct hissing or whistling noise.
When the noises become louder, but the boiler continues to work properly, do not delay cleaning, otherwise it may be too late. 
Disassemble the boiler, as shown below, and begin cleaning. This can be done in two ways:
Cut off the neck plastic bottle 1.5 l and dilute the solution in it:
- warm water 60 degrees
- 7 teaspoons citric acid
Soak the heating element in it overnight. After which, in the morning you clean off all excess. The result is sometimes simply amazing. 
Corrosion water heating element
Why does the heating element body corrode and collapse? The fact is that the heating element in the boiler is equipped with a magnesium anode. 
Without it, a galvanic couple is formed inside the titanium:
- tank - heating element
And with a magnesium anode:
- heating element - anode
Through this anode, all stray currents flow to the ground, gradually taking with them some part of the anode body. When it is completely destroyed, these currents begin to flow down the body of the heating element. 
The growths on the heating element do not form evenly. Because of this different areas its copper shell acquires different expansion coefficients. As a result, surface tension is created, which breaks the shell of the heating element. 
In many service centers, in the event of a major breakdown of the boiler, you may even be denied a warranty if there is no receipt for timely replacement of the anode.
Ultimately, corrosion becomes through and the working element burns out.
By the way, with the anode intact, the water from the tank may have a slight odor. When the smell disappears, this may be some kind of sign of corrosion of the electrode.
Modern models have special sensors that monitor the condition of the anode. 
With timely replacement of the anode and mandatory cleaning, your heating element will actually last several times longer. Grounding the housing also increases the service life of the heating element by at least two times. 
However, for some reason many people lose sight of this point. Meanwhile, during intensive work, it is recommended to clean the boiler at least once a year.
It cannot be said with certainty that some models, for example Electrolux, Ariston or Gorenje, have a longer service life than Thermex or Indesit. It all depends on many factors:
- amount of water consumed
- the average heating temperature of this water, its chemical composition
- is there grounding or not?
Checking the serviceability of the heating element
How can you understand that the heating element has burned out and it’s time to change it? If the indicator lights light up and show that the boiler is on, but it does not heat, this is only an indirect reason. 
You can also check the presence of potential between zero and the body of the device. When the heating element is destroyed, its current-carrying spiral comes into contact with water, and through it the voltage reaches the boiler body. 
It is better to take measurements with a multimeter in AC voltage measurement mode. The dial can show either a couple of tens of volts or all 220V. This already indicates a 100% malfunction and the need to change the heating element. 
If you have an RCD, as it should be in a normal circuit, then it begins to knock out when you try to turn on and supply power. 
The correct RCD (not 30mA, but max 10mA) is required element circuits when connecting any boiler, otherwise you could easily get voltage on the faucet, tap water in the kitchen and in other unexpected places. 
Draining water and disassembling the water heater
And so, when you decide that you still need to open it, the first thing you do is turn off the power by unplugging the plug from the socket. Then drain the water from the titanium. To do this, turn off the hot and cold water supply taps. 
Unscrew the cold water hose, placing a suitable container for drainage.
If water does not flow from the removed hose, this indicates air lock. We need to remove it. To do this, just slightly loosen the nut at the connection point of the pipe. hot water to the pipe. 
After draining, completely unscrew both valves from the titanium (hot + cold) to open the bottom cover and gain access to the heating elements. 
There are modern models where the bottom cover is collapsible and to remove it, it is not necessary to touch the valve. It comes in the form of a plastic insert secured with several screws. 
Disconnect the power wires, first remembering or marking with a marker which one is connected where. Better yet, draw a diagram. As a rule, all wires are colored and this will be easy to do. Otherwise, you can get confused in such a pile of wiring. 
If you don’t want to draw anything, then just take a couple of photos on your cell phone. You will know exactly the location of all elements and wires. 
After this, unscrew the nuts or screws securing the heating element itself around the perimeter.
You can unscrew them in any order, but you need to screw them in the same way as the engine head or the wheels on a car, that is, crosswise.
If you immediately tighten a nut all the way, this will cause the flange to bend and there will not be the required tightness. Consequently, the gasket will not hold and will leak.
Carefully pull the heating element out. It will be all covered in rust, and from the magnesium anode, except for a thin burnt piece of iron, there may be nothing left at all. 
Flushing
After the heating elements are removed, the boiler itself must be washed clean water from all the rust and dirt that has accumulated inside. Therefore, for a quality replacement, the water heater still has to be removed from the wall. 
Rinse the inside with a regular tap hose. Pour only a little water, since the boiler with a volume of 50-80 liters will still have to be lifted manually to drain all the scraps. Someone adds citric acid when washing, some don't.
Washing tip: It is best to rinse the tank in the bathroom, placing it vertically on a linen board. Twist the watering can from the mixer shower and insert the hose into the hole where the heating element was.
Replacing heating element and anode
After all cleaning procedures, proceed to reassembly. Keep in mind that the anode may not be included with the new heating element. Be sure to buy it separately and screw it into your seat.
It is especially worth noting that if two heating elements are installed in the boiler, then it is not always necessary to install two anodes.
One is enough for one electric titanium, even if you have at least five heating elements inside. The anode is not an accessory or component of the heating element. This is an element of protection for the boiler. 
Please note that in the factory version, during the first disassembly, on the second heating element there is no place at all for mounting this anode. 
Some claim that on tanks with stainless steel you can do without an anode, the main thing is to have them in specimens with walls made of glass porcelain. 
However, the pattern of failure of boilers is usually the same: first the anode, then the heating element and then the housing.
You can install heating elements not only from the direct manufacturer of the boiler. For example, there is a company called Thermowatt, which produces some of the best heating elements on the market. The main thing is to match the power overall dimensions and a seat. 
Practice has shown that there is not much difference. The main thing here is the quality of the product (China or Italy). 
When repairing, be sure to change the flange gasket. Here are some of their varieties for boilers Thermex, Ariston, Indesit, Gorenje, Electrolux:
Thermex Ariston Indesit Gorenje Electrolux
Some people are trying to save money here. Remove the old one and replace it with the new element.
However, a leak that will inevitably form in a month or two will make you regret such savings.
The flange nuts, as mentioned above, are tightened in a cross pattern. In this case, there is no need to use excessive force; you can inadvertently break the thread or tear the pin out of the body. 
According to the marks sketched on the diagram, connect the power wires and put them in place protective cover-cover. Before closing the cover, be sure to double-check all terminal blocks; they should fit tightly and not loosen.
Filling with water and checking functionality
Hang the electric titanium in place. Connect the hoses and open cold water, start filling the tank. The hot water tap must also be open to allow air to escape.
At the same time, make sure that there are no leaks anywhere. As soon as water comes out of the “hot” tap, the boiler is full. There is no need to close the tap immediately; let all the “slurry” spill out and finally flush the tank and pipes. 
Only when it goes clean water, turn off the mixer.
After this, the water heater must stand for at least half an hour or an hour so that condensation leaves all surfaces and there is confidence that there are no leaks. 
You can then apply voltage by plugging the titanium into an outlet. To check the operation of the thermostat, use the control knob to force the adjustment to maximum and minimum.
In this case, the boiler on/off lamp should light up.
If the boiler operates quietly, without making any sounds, and it is not clear to you whether it is heating or not, you can check the energy consumption using the meter.
At maximum heating power of the heater, the counter will spin or blink much faster. This means that the heating elements work as they should.
The entire repair with the purchase of spare parts will cost you around 1500-2000 rubles. In any workshop calling a plumber to your home, for such work they will ask for at least 3000-5000 rubles, and this does not include materials.
So do-it-yourself repair can save you a significant amount of money, the main thing is not to make some mistakes.
Errors when replacing heating elements
1 Tighten the heating element fastening nuts in a circle.
As discussed in this article, this method will lead to bending of the flange and subsequent leakage. That is, you will have to remove the boiler from the wall again, unscrew everything and reassemble it again.
2 Application of sealant when installing the gasket.
No sealants should be used when replacing heating elements. Tightness should be created only by uniform pressing of the gasket material.
3 Using an old gasket.
No matter how intact it may seem, in any case, every time you open the heating elements, be sure to replace the sealing elements.
4 Replacing only the heating element without replacing the magnesium anode.Even if you don’t find a suitable anode in your store, never install heating elements inside the tank without it. Not only does this reduce the service life of the heating elements, but ultimately it all ends in burning out the body of the boiler tank. 
True, some expensive boiler models have titanium anodes with electronic potential removal. 
They just don't require replacement. Therefore, before unscrewing anything, carefully study the product data sheet.
5 Control board.
When washing the tank and draining the water, be very careful; you can accidentally flood the electronic control board with the display, which is located on the side of the case, with water. In this case, the boiler simply will not start after switching on.
You will search for the cause for a long time, ringing all the terminals, but it will lie literally on the surface. You can soak this board even with the boiler upside down. 
Look closely at the hole where the lone control wire goes. 
Water can simply flow through it directly to the electronics. So, it is best to close this hole initially, even before pulling out the heating elements, by pushing any seal there.
Many owners DHW water heaters have no idea what it's for magnesium anode in a water heater and what functions it performs. The fact is that the boiler tank during operation requires regular cleaning of metal oxidation products and scale. You should know how to deal with these negative processes and ensure long term boiler service.
Since the steel from which the internal tank of the storage water heater is made is an alloy of iron and carbon, this factor is decisive for the service life of the unit. The oxygen contained in water interacts with the material of the tank walls, causing the formation of corrosive deposits.
How is the inside of the boiler protected?
The inner surface of the tanks is protected by the manufacturers by applying a glass porcelain or glass ceramic coating. But it is not capable of serving even a third of the time. regulatory period water heater services. The coating is destroyed due to temperature fluctuations - microscopic cracks gradually form, their number and size increase. As a result, the material of the internal walls is completely deprived of surface protection.
The use of stainless alloys cannot guarantee long-term operation, because food grade steel, which is regulated for production in this case, does not have the necessary resistance. It is susceptible to corrosion, although it can last a little longer.
The main problems with water heaters made of stainless steel are associated with the need to use welding. When it is performed, heating the metal promotes the burning of additives that protect the material from corrosion, resulting in leaks along the welds.
Functions of magnesium anode
The magnesium anode is just an additional protection inner surface boiler from corrosion.
In addition to protecting the housing, this unit allows you to extend the life of the heating element. Due to the formation of salt deposits, the heating element may soon fail. A magnesium anode cannot prevent such an impact, but due to its use, these deposits acquire a less dense structure, and therefore are easier to remove during preventive maintenance without causing destruction protective coating heating element.
This element is a steel rod coated with a magnesium alloy. This element is fastened using threaded connection. It is located next to the heating element.
Operating principle of magnesium anode
Let's imagine what would happen in the absence of such protection.
This situation causes the formation of a so-called galvanic couple. This phenomenon was discovered back in the eighteenth century. Iron reacts with oxygen in water. Surface layer steel is destroyed with the formation of oxide. Thus, it is gradually destroyed. This happens because the material of the walls of the water heater is characterized by a significantly lower electrochemical potential than the rest of the tank parts.
When installing a magnesium anode, it takes on all oxidative processes because it has a much lower electrochemical potential than the body.
Almost all models of water heaters include this element in their design. Initially, the surface of this part is smooth silver color. As a result of long-term use, clear traces of corrosion deposits appear on it, but the integrity of the boiler walls is ensured.
The sacrificial anode is made from magnesium because this metal has a weak electrochemical potential. In addition, the low cost of magnesium alloy does not lead to a significant increase in price finished product, therefore it is advisable to use this particular component. Using it as consumables much more profitable than if corrosive wear of the walls of the water heater occurs. The salts contained in the water settle on the surface of the magnesium anode without affecting negative impact for other details.
Replacing the anode
Since the anode for the boiler is a consumable item, it needs to be periodically replaced. This procedure does not require significant time or special qualifications. To do this you will need:
- Buy this part at a store or service center.
- Remove the bottom cover of the tank.
- Remove the flange and thermal sensor, which will then become accessible.
- Remove the heating element by slightly stirring it. The resulting deposits may prevent its dismantling. This procedure should be performed carefully to avoid damaging the assembly.
- Remove the spent sacrificial anode.
- If the replacement has not been made for a long time, instead of the whole product, only its rod may be present. This is due to complete destruction magnesium alloy layer.
- The heating element is cleaned and installed in place. If necessary, you can replace it.
- Install a new anode and assemble the water heater in reverse order.
Replacing the anode is not difficult. It is necessary to periodically clean the internal tank of the water heater from deposits and promptly replace the magnesium anode. This will ensure long-term operation boiler
Owners of boiler water heaters often come across references to a magnesium anode. But not everyone knows what this part is, what its function is and why a magnesium anode is needed in a boiler.
Let's figure out how this element works and how to know if it's time to replace your magnesium anode for your water heater.
Corrosion of the internal walls becomes a problem during the operation of a water heating tank. Because of this, after some time the equipment fails. To understand why an anode is needed in a home water heater, let’s consider what happens to the boiler during operation.
Causes of corrosion of a water heating tank
- Weak anti-corrosion coating of the material
Modern boiler tanks are made from stainless steel, which should reliably protect the mechanism, which is constantly in contact with water, from corrosion. However, high-quality grades of stainless steel are expensive and are not profitable to use in mass production.
Such water heaters would become a luxury for many people. To establish flow output and make water heating products accessible, food grade stainless steel is used. But this type of steel has a less durable coating and begins to gradually fail after three to four months.
- Metal deformation during operation
Water heating devices are constantly in a changing state. The hot liquid acts on the metal, causing it to expand, after which the walls contract again.
In addition, devices, as a rule, consist of two parts that fit tightly together at the joint. Temperatures and high blood pressure affect this seam. In all these cases, the integrity of the stainless coating is compromised, microcracks appear in the material, and it is less resistant to corrosion.
- Savings on production
Some manufacturers are not interested in their products lasting long. Only industrial equipment withstands heavy loads and prolonged use.
Home tanks are made from cheap alloys with the expectation that people will change them frequently. Naturally, this approach is beneficial to the manufacturer - and completely uncomfortable for users. Conscientious brands produce products with optimized quality at low cost of water heaters.
- Water quality
Another negative factor is water hardness. In some regions, the quality of the water supply is so poor that water heating tanks become clogged with salt deposits within a few months, which prevents the normal use of the boiler.
Because of heavy metals Scale settles on the walls of the tank and heating element, which destroys the metal.
For these reasons, heaters are improved, and the shock is directed away from the central parts of the device. To do this, use a magnesium anode for the boiler.
How does the anode work in a water heater and what is it for?
The magnesium anode in the water heater is metal cylinder, made of the named material, which is designed to attract heavy salts from water in order to increase the life of the device.
This is a consumable item and needs to be changed periodically. This part wears out so that the rest of the housing and heater continue to function properly.
The walls of the heater deteriorate because the electrochemical potential of the material is lower than that of the other components used in the assembly. Therefore, without an anode, scale salts settle precisely on the inner layer of the tank, corroding the surface. The potential of magnesium is even lower.
The inner insert attracts destructive sediment towards itself. Here's how an installed magnesium anode works in a water heater.
Of all the metals that can provide such protection against corrosion, magnesium is the most accessible. It is used in production without raising the price of the finished product. At the same time, periodic replacement of such a part will cost the owners inexpensively.
How to replace the anode in a water heating tank
This part must be replaced regularly as the metal deteriorates over time. During such reassembly, it will not hurt to descale the heating element.
If the replacement was not made on time and the magnesium anode for the water heater has completely “dissolved,” corrosion will begin to attack the tank.
Replacing the anode on a boiler is easy; even an inexperienced user can do it. To do this you need to follow several steps:
- Shut off the water supply. Unscrew the cold water supply hose and drain the remaining liquid from the tank. For this purpose, an outlet tube is used.
- After this, you need to remove the protective casing and remove the heating element and other internal elements. Sometimes after prolonged use metal parts difficult to dismantle. If the heating element is stuck, apply some force, but act carefully so as not to damage the mechanism. Rock the rod from side to side.
- Then the anode is removed. Don't be surprised if after prolonged use all that's left is the base.
- After installation new part It is advisable to descale the device and then assemble it.
Ideally, the anode should be replaced approximately once every 12 months. This is a fairly economical procedure, considering the benefits of the device. Often the service life of a part depends on its thickness, the characteristics of the tank and the hardness of the water in your area, so check the water heater periodically.
Which anode to choose for replacement in the boiler
Today on the market of parts and components for plumbing you can purchase copper or aluminum anode. In the majority modern models a magnesium rod is installed because it has best characteristics. These columns differ from each other in thickness and height.
Typically, the parameters of the anode depend on the type, shape and volume of the boiler and are selected taking into account these parameters in order to serve effectively for as long as possible.
When choosing an anode for foreign-made water heaters, it is better to take with you an old dismantled rod to purchase the appropriate type. If this is not possible, ask a consultant for help by naming the brand of your water heating tank.
That is why it is better to buy components for the boiler in specialized stores - if not branded ones, then at least professional ones, or in the service department. Such centers employ competent craftsmen and experienced salespeople who will select the necessary part for you.
Each water heater has a sacrificial anode. However, many people not only do not know why it is needed there, but also what it looks like.
Because of this, boilers fail much earlier than the manufacturer expected.
A magnesium anode is a thick rod of this non-ferrous metal installed inside the boiler tank.
Most often, it is mounted next to the heating element on one base, so that in case of maintenance, both the electrode and the heating element can be removed with one movement. But in some models it is installed separately.
Why is it needed?
The magnesium anode performs two functions in a water heater:
- protects the device body and additional elements from corrosion;
- makes the scale on the heating element loose and less durable.
The first function is the main one, the second is a nice bonus. Modern boilers are made with galvanized or stainless steel bodies. Additionally, their surface is protected with special paints.
It may seem: why is this element there if the steel is already well protected? But in any case, sooner or later the metal begins to rust. Even stainless steel is susceptible to corrosion at the welding site or under the influence of acids and salts.
With constant heating and cooling, protective paint eventually becomes covered with small cracks, through which water gets into the metal, after which the destruction of the metal is a matter of time. Galvanization also has its resource.
Thus, without additional protection, the water heater tank begins to become covered with rust within a couple of years.
The exact service life before a leak appears depends on the intensity of use and chemical composition water. The service life is negatively affected by the presence of salts and acids and the richness of water in oxygen.
The operating principle of the sacrificial anode is based on the galvanic interaction of conductors. Iron is less electronegative than magnesium, so if there is an electrical bond, the former will not oxidize in the presence of the latter. In other words, the magnesium anode “pulls” oxygen ions onto itself.
As a result, as long as there is magnesium in the water heater tank, the steel body remains intact.
At the same time, this element facilitates the fight against scale.
The main element that contaminates the surface of heating elements is calcium salts, most often carbonates.
Magnesium cannot protect against this scourge, but it does make it less problematic.
When the anode interacts with carbonates, substitution occurs; as a result, magnesium salts are deposited on the heater, which have a loose and soft structure.
They are very easy to remove mechanically, without the risk of damaging the heating element itself.
Replacement
The magnesium anode protects iron from oxidation by drawing oxygen towards itself. Thus, during operation, it gradually oxidizes itself, dissolving and breaking down.
That's why the second name this method protection - “sacrificial electrode”.
To ensure that the protection does not weaken, the electrode must be changed periodically.
But this period can vary greatly depending on how intensively the device is used, how many liters of water are distilled through it per day or week.
Another very significant factor is water hardness. The more hydrogen cations in water, the lower its pH, the more intense the oxidation of the metal occurs. An additional destructive effect is exerted by mechanical particles that scratch the surface of the water heater body and electrode, reducing its service life.
Therefore, it is advisable to install in plumbing system a water softening filter and almost always a coarse filter.
Personal electrode service life is calculated empirically - at first the condition of the magnesium anode is checked every 4-5 months. By finding out how long your electrode lasts, you can reduce the number of checks.
The check is performed as follows:
You should not use a boiler without a sacrificial anode, because without it the service life of the device is reduced several times.
Monitoring the condition and periodically replacing the sacrificial anode is a small concern that can greatly increase the service life of the heating device.
The cost of this element, 150-700 rubles, is negligible compared to the price of the boiler itself. At the same time, do not forget that rusting of the container ends with its leakage, which can lead to flooding of neighbors. As a result, an attempt to save money on a small electrode can result in losses of many thousands.
You can purchase magnesium anodes for water heaters in our store at favorable and low prices. We ship to any point in Russia, both cash on delivery and courier or transport company. We deliver goods to shopping center free of charge. An order for the post office, namely, cash on delivery, as well as delivery by courier or pickup, imply payment upon receipt of the order. Payment by Sberbank card, delivery by transport company is prepaid. Our branches are located in many cities of Russia, so getting an anode will be even easier and more convenient. Valid in the online store flexible system discounts, which can be found in the "Discounts" section. If questions arise regarding sizes, compatibility of anodes with water heater models, etc. you can consult in online help, by phone in the "Contacts" section, or write to feedback on email. We are always ready to help and choose the right magnesium anode for your boiler model, be it Ariston, Thermex, Garanterm, Etalon, Polaris or any other brand.Description of anode rods
Magnesium rod prevents corrosion internal walls tank, and also softens the scale that forms on the heating element during operation of the water heater. It is a rod made of magnesium alloy on a metal stud with a thread and is screwed to the flange of the heating element, together with which it is inserted inside the water heater tank. The hole thread diameter ranges from M4 to M8 depending on the size and weight of the magnesium alloy on the stud. How larger sizes and weight, the thicker the magnesium anode pin. The diameter of the magnesium anode varies from 14 to 25 mm. The length of the magnesium part without the pin varies from 140 to 660 mm.Operating principle
The water entering the water heater contains soluble calcium and magnesium bicarbonates, which are present in it in the form of Mg2+, Ca2+, HCO3- ions. Magnesium is the first to react with water, since it is more active than iron and binds free oxygen formed during heating due to a multiple increase in the number of Mg2+ cations. When an anode is installed in the tank, it is not hard scale (CaCO3) that is formed, but soft scale (MgCO3 or Mg(OH)3), which is easier to remove when cleaning the water heater, or which itself falls to the bottom of the tank during operation of the water heater due to thermal expansion or contraction of the heating metal element. Over time, the anode will dissolve, so it is advisable to check or replace the magnesium anode once a year or follow the water heater manufacturer's instructions.Is it necessary to install a magnesium anode in a water heater?
Modern boilers have tanks made of stainless steel, with titanium, porcelain glass, and enamel coating. In this case, the tank undergoes corrosion in the welds and begins to leak over time, so it is necessary to regularly replace the magnesium anode. If it was not present in the water heater initially, then it must be installed in the event that scale forms on the heater. In this case, the manufacturer most likely performed welding according to special technology or even made the tank one piece, without welds. Without an anode, hard scale forms, which has lower thermal conductivity. At the same time, the heating time and the amount of energy consumed increase, the efficiency decreases, and the metal of the heating element constantly overheats. Ultimately this leads to its rupture and failure. Therefore, timely and regular replacement of the anode will allow your water heater to operate for many years.What to look for when choosing a magnesium anode?
The main selection criterion is the diameter of the thread on the stud so that the anode can be mounted on the flange of the heating element or nearby, if such fastening is provided. The second criterion is the length, since meter ones, for example, simply may not fit. The next criterion is thickness. Anodes with a large diameter may interfere with the heater tubes, although in this case the plate with the mounting hole can be bent. The next criterion is the length of the hairpin. This choice is rare, as certain electric heaters require a long stud to avoid hitting the heating tubes.Let’s summarize and list the criteria for finding a suitable anode:
- thread diameter on the stud;
- length;
- thickness or diameter;
- threaded stud length.
