Magnesium anode for a water heater - what is it and how to replace it? Magnesium anode for a water heater: principle of operation, purpose, installation Magnesium anode for what it is needed

Modern storage water heating tanks (boilers) are usually made of stainless steel, less often of copper. This allows you to use the heater for a long period, but still, over time, the tank becomes unusable due to corrosion. To extend the life of the tank, you need a magnesium anode in the water heater. Why it is used, you can understand if you know how cathodic protection works.

Extend the life of your water heater with a magnesium anode

Anode device

The water heater element is a round steel rod coated with a magnesium alloy layer 10-15 mm thick. The electrode is attached to the threaded connection to the bottom of the tank body next to the heating equipment.

In some boilers, they are mounted on the top of the tank. The working length of the anode is from 14 to 66 cm. In addition to magnesium, titanium, zinc are used for their manufacture, or active electrodes connected to the electrical network are used.

Due to their electrochemical properties and low cost, magnesium anodes have gained great popularity. The boiler needs a kind of protector metal parts tank from exposure to oxygen and salts resulting from the heating process.

In this video, we learn the anode devices:

Purpose of the element

During the operation of the water heater in the water, substances are released as a result of chemical reactions. cathodic protection implies the settling of all foreign matter on the passive anode. For this, this element is needed in the water heater. It performs the following tasks:

protects the tank and its parts from corrosion;
prevents the formation of scale on the heating element;
reduces water hardness.

With prolonged operation of the magnesium electrode, its gradual destruction occurs, but the chemical composition of water does not change. This suggests that its use is absolutely safe for human health.

Therefore, it is very important to replace this part on time. In order to perform this procedure less often, it is necessary to monitor the quality of the water. The frequency of use of the boiler also affects the duration of the anode.

Depending on all factors, this device can last from 1 to 7 years. It is possible to operate a water heater without an anode, but then the boiler will fail very quickly. By the way, when purchasing a new item, you should pay attention to the quality of the product.

An electrode made of cheap technical magnesium will fail very quickly, and during operation, the water will acquire a characteristic smell of hydrogen sulfide.

Principle of operation

The principle of operation of the electrode is based on its activity, since magnesium in all compounds is a divalent metal, and the iron from which the tank is made is trivalent. In addition to corrosion, during the heating of water, scale is formed due to the settling salts of heavy metals.

Since magnesium has increased activity, then the salt atoms interact with it, and not with iron. Therefore, the magnesium anode binds oxygen atoms and attracts, as magnetic material , iron salts. At the same time, the formation of calcium carbonate salts is sharply reduced, and carbonic acid salts are formed from magnesium.

As a result, the scale becomes looser, and it can be easily removed during cleaning of the unit. Thus, corrosion of the tank and coating of the heating element is prevented. This process is called sacrificial protection, and the electrode is called anode-protector.

Currently, almost all manufactured boilers have a magnesium anode. For its long-term operation, it is necessary to observe certain measures. Here is some of them:

During the operation of the heating element, there should be no extraneous sounds. If the boiler emits a quiet hiss, these are the first signs of scale and an anode failure.
At least twice a year it is necessary to check the condition of the magnesium anode. If minor damage is noticed on it, then it is better to replace it with a new element.
In the heating system, it is best to use softer water, which will greatly extend the life of the electrode.
If the boiler turns on and off periodically, and the water does not heat up, or it heats up very slowly, these are clear signs of scale on the heating element.
Before proceeding with the replacement of the anode, it is necessary to close all taps and turn off the power to the boiler.

Hi all! I want to tell you about such a specific thing as replacing the magnesium anode in a water heater. Specifically, the model for 80 liters of Termex 80YS-RE. But in principle, in terms of dimensions, it can fit many others. Who is interested, welcome to the laboratory :-))) Many bad photos
Perhaps I'll start with how I decided to open my water heater (after it served faithfully for about 3 years) for cleaning.

A bit of theory

What is a magnesium anode for? To protect the water heater tank from corrosion. Extends the life of the water heater. With timely replacement of a worn out (min. 30%) magnesium anode, the water heater lasts 20-30 years, without an anode - 1-3 years.
Principle of operation: if two metals are placed in water, then one of them, namely the more active Magnesium, will begin to emit electrons and attach hydroxyl groups (OH) from water to the formed ions, and the other, less active Iron, will accept electrons, attaching them to their ions. As a result, more active metal- the anode - will be oxidized, and the less active metal - the cathode (water heater tank) - will be restored. Thus, the anode will protect the tank from corrosion.

Too bad I didn't take a photo when I first opened the tank. Having scooped out almost half a basin of scale flakes and sand-like deposits from it. An autopsy showed that the anode needs to urgently look for a replacement. Having rummaged through the expanses of the local "Belarusian Internet" - I saw a price of about $ 12 per piece. I decided to try my luck on Ali. But one piece was not there, but there were large ones, but 5 for almost the same price, but three. The toad still won, and thinking that this stub would last another month, I assembled the unit back. Having made an order, I sat down to wait at the window, I rejoiced at my economy - "it's three for the price of one"
And now, less than six months later, 26 days later, I received the coveted package.

It looks like nothing, but we'll check. Here's what's on the site:

But in real life:

And now the decoding of the black box of bad photos: Length - 190 mm, "body" diameter - 16 mm, shank diameter - 5 mm. In general, the Chinese did not get into one of the sizes, plus or minus a kilometer. Moreover, there is also a thread on the shank (sorry, not 6 mm, which is needed). Having shown "fe" to the seller, through a dispute and recaptured part of the money for new reagents, he set to work.

Crazy Hands™

1. Disconnect the boiler from the network and shut off the water supply to the tank, and proceed to drain the water:

2. First, unscrew check valve With cold water(innings):

We fasten the hose back, and unscrew the other end of the hose from the supply and throw it into the bath, toilet bowl, container, etc. or as I have on the mixer.

3. Open the tap with cold water and unscrew the hose hot water from the tank (we create a vacuum):

While we are going to taste new reagents, drink tea-coffee-juice-kefir-whatever you like, the process of draining by gravity is not fast.
4. After a while, we come and admire the result:

5. We proceed to the opening of the patient. In the hole on the right under the plug there is a cross screw:

"MO-O-O-ZGI-I-I!"

6. Carefully cut out the brain, turn everything off and unscrew the wiring fasteners (do not forget to capture for posterity or for the service department :-), how it was, to assemble it back):

With these thermal sensors, they are more careful, they are on capillary copper tubes, they cannot be crushed and strongly bent:

7. Well, we got to the heart iron man unscrew all the nuts in a circle (the rest of the water will flow out, you need to substitute the container):

Distorted inside (you can sanitize the abdominal cavity to clean the tank from the inside - a thin hand will crawl through (hello to your wife))):

Not much dirt in a month.
8. We start transplanting a Chinese donor organ. BEFORE:

AFTER:

9. Putting it back (and if everything worked out, go to step 10):

10. Enjoy the result)))))):

PY.SY. Too few photos, I have them:

magnesium anode for a water heater - a special element of water heating equipment designed for effective protection internal elements device from salt deposits and destruction.

Thanks to the anode, the risk of developing corrosive changes on the inner walls of the water heater tank is greatly reduced, and the amount of scale on the main heating element, the heating element, is minimized.

Water from natural and artificial plumbing systems does not always have the optimal quality composition.

Very often, water containing a large number of soluble calcium bicarbonates Ca (HCO 3) 2 and magnesium Mg (HCO 3) 2.

Such elements are dissolved in water, and only the presence of a magnesium anode, which increases the amount of Mg2+ cations, contributes to the main chemical reactions:

binding of free oxygen, protective protection of the inner surface of the tank and heating element from destructive corrosion changes;
reduction in the formation of insoluble salt CaCO 3 and loosening of scale, which allows it to easily separate from the heating element, as well as settle on the bottom of the storage tank.

Spent and new anode

The operation of water heating equipment without a magnesium anode is accompanied by the accumulation of scale on the heating element, which causes an increase in the time of heating the water to the specified values, a decrease in the coefficient useful action and increased energy consumption.

It is important to remember that the magnesium anode for the boiler is a passive corrosion protection that is not subject to changes under the influence of grounding and affects the total amount of scale formed on the heating element, therefore, untimely replacement of this element has Negative influence for the total life of the domestic water heater.

Design and types of anode

In hot water equipment accumulative type, characterized by tanks made of ordinary metals, the installation of magnesium or so-called "sacrificial" anodes is strictly mandatory. The appearance of such elements may vary.

For example, conventional suspended water heaters are most often equipped with anodes having appearance ordinary rod, with a threaded stud installed in the inside. Depending on the design features boiler, the hairpin can differ not only in diameter, but also in length.

Magnesium anode and heating element in the assembly

In floor gas or electric water heating equipment with a large volume storage tank, large-sized “sacrificial” anodes are installed, which can somewhat complicate them self-replacement. For example, in boilers two meters high, most often, meter-long protective magnesium anodes of a multi-section type are installed.

A novelty is flexible plastic anodes, which are a plastic tube with special microscopic pores. The inside of the structure is filled with special magnesium granules.

Anode new - from below and anodes after operation

The main advantage of flexible anodes is the complete absence of sediment, represented by oxidized magnesium. Among other things, as it is used, magnesium powder is added, which reduces the cost of acquiring a new protective element and replacing it.

Protective magnesium anodes, installed inside any storage type water heating equipment, are most often represented by a steel rod, very richly coated with a layer based on a magnesium alloy.

How to change the magnesium anode in a water heater

If high-quality titanium protective elements do not require replacement throughout the entire period of operation of water heating equipment, then magnesium anodes are very important in without fail subject to a standard preventive check annually.

Daily use of the boiler requires more than frequent check and systematic replacement of the magnesium protective anode, according to the following rules:

disconnection of the water heater from the electrical supply network;
shutdown of the cold water supply system;
complete drainage of water through the underwater pipe;
unscrewing and removing the protective cover from the device;
removal of fasteners with removal of the sensor and flange;
careful loosening of the tubular electric heater;
removal of scale deposits from the surface of the heating element and internal parts storage tank with a solution of citric acid;
unscrewing the protective magnesium anode and replacing it with a new element;
assembly of the entire internal structure in reverse order.

Quite clearly indicate the need to replace the anode by frequent switching on and off of the water heater, hissing during the operation of the boiler, as well as too long water heating.

When replacing the anode, it is imperative to remove all scale accumulated on the inner surface and heating elements, which helps to extend the overall service life of the heating equipment, and also increases quality characteristics heated water.

Where to buy?

Magnesium anodes are included in the package of storage-type water heating equipment, and are most often installed with inside flange, near the heating element.

In some models of the boiler, the protective element may be located on the upper part on the inside of the storage tank.

As a rule, if it is necessary to perform a replacement, a magnesium anode for a water heater is ordered on fairly favorable terms in specialized online stores. However, in this case it is necessary to know all the main parameters of the ordered device.

When purchasing a boiler anode in retail network the consumer has the opportunity not only to get expert advice, but also to verify the quality of the products sold by checking all the accompanying documentation.

Price

At present, magnesium anodes are produced and sold, which differ in length not only of the anode itself, but also of the inner stud. Standard length of the purchased anode for water heating equipment can vary in a fairly wide range - 10-60 cm with a hairpin length of 1.0-23 cm.

Among other things, anodes differ in terms of overall diameter - 1.4-2.2 cm, and in diameter threaded connection hairpins - "M-4", "M-5", "M-6" and "M-8".

The average cost of the most common models of protective magnesium anodes for domestic storage boilers:

100 mm with D14 + 20 mm and "M-4" - 200-220 rubles;
100 mm with D18 + 180 mm and "M-6" - 230-250 rubles;
100 mm with D18 + 230 mm and "M-6" - 250-270 rubles;
110 mm with D21.3 + 10 mm and "M-5" - 320-330 rubles;
120 mm with D16 + 10 mm and "M-6" - 150-160 rubles;
140 mm with D14 + 20 mm and "M-4" - 130-140 rubles;
145 mm with D25 + 10 mm and "M-5" - 290-310 rubles;
200 mm with D16 + 35 mm and "M-6" - 280-290 rubles;
200 mm with D18 + 180 mm and "M-6" - 290-310 rubles;
200 mm with D16 + 10 mm and "M-4" - 290-310 rubles;
210 mm with D22 + 10 mm and "M-6" - 360-380 rubles;
210 mm with D18 + 10 mm and "M-4" - 310-320 rubles;
230 mm with D22 + 10 mm and "M-5" - 380-400 rubles;
300 mm with D21 + 10 mm and "M-8" - 440-460 rubles;
660 mm with D21.3 + 13 mm and "M-8" - 810-830 rubles.

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Do not know which electric towel warmer is better to choose in the bathroom? Read.

Such a tangible variation in dimensions and cost is not accidental, and makes it quite easy to independently choose the most best option magnesium anode for hot water appliances that differ in length, shape and design characteristics.

Developer shortcomings and the problem of hard water

In general, it will be justified to shift the blame for the poor resistance to corrosion of the tank on the shoulders of the manufacturer. After all, it is he who is responsible for the observance of all specifications and must consider every aspect. Moreover, if the developer was dishonest and saved on materials, this can lead to formation of microcracks. Once they occur, the process can no longer be reversed.

There is an intense oxidation of the metal, caused by interaction with oxygen that has penetrated into the faults.

Looking at the table of electrochemical potentials, you can see what can start with such a process. But unscrupulous companies do not waste time on this. As a consequence of economy or trivial misunderstanding chemical processes, in the production of heaters, a variety of materials are used that are not able to withstand the load. Needless to say, such boilers will stop working pretty soon.

But not only manufacturers are responsible for this. Chemical composition water, which determines its quality, in some regions is very far from ideal. But it is she who constantly interacts with the heating element and the walls of the boiler. It is to compensate for adverse inclusions in the water that a magnesium anode is needed in the water heater.

Tank corrosion

Working principle of the anode

Imagine for a second that the tank is not equipped with an anode. In such a situation, there is galvanic couple. This effect was discovered in the eighteenth century far from us. The hull coating will take over the functions of corrosion protection and for this reason will soon begin to collapse. This is due to the fact that the electrochemical potential of the material of the tank walls is much weaker than that of the others used during the assembly of the unit.

Why such a part as a magnesium anode for a water heater, needed in the system? Its electrochemical potential will be even less than that of the case. It follows from this that the oxidation process will be directed to it.

The magnesium anode for the boiler is included in the design of almost all models. If we consider a new part, it will have flat surface silver color. After long work traces of corrosion formation will be visible in the tank on the pin. But the most important point- the walls of the tank will remain intact.

Why Magnesium

Finding an answer to this question worries many minds. The secret lies in the electrochemical potential. In a substance such as magnesium, it is rather weak. Together with this, material cost allows it to be used in mass production without increasing the price of the final product. Apply it like consumable much more effective than sacrificing tank walls. Why exactly do you need a magnesium anode in a water heater? He collects salt. Coming into contact with magnesium, it settles on the surface of the anode without harming other parts.

Replacement process

Since the part is a consumable item, periodic replacement of the anode is necessary. It won't take long and anyone can do it.

Obtain the necessary part from a specialized shop or service center.
Remove the protective cover from the bottom of the water heater.
After dismantling the casing, you will see a temperature sensor and a flange. They also need to be carefully removed.
Slightly shake and pull out the heating element. It may not give in due to the deposits formed. Apply a little force, but be careful not to damage the equipment.
Dismantle the old anode from a special nest near the heating element.
Quite often, instead of a whole anode, you can find there empty pin. Why is this happening? Due to the gradual destruction of the magnesium layer. Pull out this pin and free the socket.
At the same time, clean the heater from scale or install a new one.
Insert a new anode and carefully assemble the boiler to its original state.

As you can see, replacing a spent magnesium anode in a water heater is not as complicated as it might seem. Remember to clean periodically inner surface of the tank and also change the anode regularly. This will help maintain the effective performance of the device and increase its service life.

Now you will find out why you need a magnesium and titanium anode in a water heater (boiler). We will also consider how to replace the anode with your own hands.

It often happens that the time comes for the owners of water heaters to clean the tank from scale and corrosion, it is required to replace the anode. But what is an anode, a person does not know. From the article you will learn what it is and in general why it is needed in a water heater.

Check price and buy heating equipment and related products you can from us. Write, call and come to one of the stores in your city. Delivery across all territory of the Russian Federation and the CIS countries.

Water heater anode

To begin with, let's clarify that the anode is a boiler element in the form of a thick metal rod (magnesium or titanium).

The main material used for the production of internal tanks is stainless steel (an alloy of iron and carbon). Heated oxygen, being in the water, begins to be released and interacts with the capacity of the steel tank. After all, the formation of oxide begins.

In order to protect the inner surface of the water heating structure, protective enamel is used. It makes the service life longer and at the same time safer.

The benefits it gives enamel coating, the following:

resists disintegration in any water, even in sea water or with the content of nitrogen compounds;
inseparable from the metal, and this prevents the formation of corrosion under the coating;
does not age, it is wear-resistant;
enamel is resistant to temperature extremes;
non-toxic and hygienic;
enamel is biologically neutral (this is not the best breeding ground for bacteria);
coating technology is such that it is possible to apply enamel in containers of any volume.

To prevent rust from appearing on the tank, anodes are installed - magnesium or titanium. Their fastening occurs with the help of a threaded part with a heating device.

What is it needed for

Let's try to figure out why you need a magnesium anode for a water heater.

From the anode itself, current flows to the damaged areas. Thus, due to the decay of the more active material, corrosion does not occur.

The anode, which is built into the tank, consists almost entirely of magnesium, so it is enough to check the design once a year. It is necessary to observe the verification, because due to poor quality water product life may be shortened.

Magnesium and iron are in contact with water, but magnesium is more active than steel. Magnesium atoms leave the anode and produce oxide. Thus, the steel atoms remain intact, and the tank does not corrode. That's the whole principle of its work.

The magnesium anode for the water heater has a low price, and its use will be quite effective. When interacting with such a rod, the salt will not disappear, but simply remain on its surface.

Titanium coated (active anode)

The operation of a titanium coated anode is slightly different. AT this case current is supplied by an external voltage source. A stable current, which is needed to prevent corrosion, is supplied and regulated by an external electronic control. The active anode functions as a supply and measuring electrode.

From time to time the power supply stops. In these minutes, the anode analyzes the state of the internal part of the structure for damage, and precisely regulates the strength of the current supply for restoration.

During the operation of a water heater with a titanium anode, it is not subject to destruction, therefore it does not need to be replaced throughout the entire life of the water heater.

On sale you can find an externally powered titanium anode from Austria Email. Model - CORREX. It costs a lot - more than 15,000 rubles.

Replacing the magnesium anode

How often you need to change the anode in the water heater, you already know: titanium - does not require replacement during the entire period of use, but magnesium should be checked on average once a year. With frequent use of the device - more than once a year.

New and corroded anode

During the replacement process, it is also worth removing scale from the inner surface of the tank and the heating element. This will extend the life of the heater and improve water quality.

Now let's look at how to change the magnesium anode in the water heater with your own hands. It doesn’t matter which manufacturer’s device you purchased, the cleaning process will not be radically different.

It is worth saying that the replacement of the anode in the water heater should occur if there are the following signs of a contaminated tubular electric heater:

the boiler turns on and off more and more often;
there is a slight hiss during operation;
the water heats up for a long time, or does not heat up at all (after all, if it is covered with lime, then it takes more time and electrical energy to heat the liquid).

DIY

To replace the anode, the following work is required:

It is worth disconnecting the boiler from the power supply and blocking the flow of cold water. Drain completely through the water supply (it is recommended to connect a hose, as the flow of water will be difficult to control and there is a possibility of flooding everything around).
The next step is to unscrew and remove the protective cover. It's better to take a picture after taking it off. heating element with all the connections, so that after all the work not to get confused and restore the structure to its original form.
Then you need to unscrew all the nuts, remove the sensors, the flange and begin to carefully loosen the tubular electric heater. After you take it out, put the bowl where the water will drain.
The heating element in working condition is easier to clean, since the plaque has not yet hardened and can be easily removed with a flat screwdriver. If, nevertheless, the plaque has become solid, then it is dissolved in citric acid(50 grams of citric acid per liter of water - soak in solution for about two days).
After carrying out all the cleaning work, you need to unscrew the magnesium anode for the water heater and insert a new one. Assembly must be done in reverse order.

Now you are aware that you need to monitor the condition of the anode in the water heater and change it in time.