How to clean the boiler from scale. Signs indicating the cleaning of the AOGV or AGV boiler. Preparing the cleaning solution

Modern water contains a large number of harmful chemically active substances, which contributes to the rapid deposition of scale on various heating elements. Scale is the first enemy of such important units as, for example, a gas boiler. First of all, the heat exchanger inside the boiler will suffer. Consequence: costly repairs or the need to purchase a new element.

It is possible to prevent such consequences. It is enough to clean the heat exchanger in a timely manner, and it is quite possible to perform this procedure on your own.

What is a heat exchanger?

The heat exchanger is an important component of a gas boiler. Its main function is to transfer heat from a heated element to a secondary one.

There are several types of heat exchangers:

Combined or bithermic heat exchangers. In many modern double-circuit heating boilers, bithermic heat exchangers are installed, which combine two heat exchangers in one design: for heating and for hot water supply (DHW).

A bithermic heat exchanger is also called a dual heat exchanger. The section shows that structurally it represents a "pipe in a pipe".

Hot water flows through the inner pipe, and through the outer pipe
heating system coolant

Single-circuit or double-circuit boiler - is there a difference?

Varieties of boilers do not affect the time period through which it is necessary to flush the heat exchanger. It is much more important which liquid () circulates in the heating system and which one enters for hot water supply.

When using process water that has undergone standard treatment, the boiler can be flushed no more than once every four years. This removes a layer of scale (which still forms) and deposits that have more complex structure. If you do not filter the water before pouring it into the system, but use ordinary water from a centralized water supply, then flushing should occur more often, at least once every two years. This is due high content chlorine in the liquid, which, upon contact with the heating element, settles in the form of scale.

Some users prefer to use antifreeze as a coolant. This liquid is of better quality: it does not freeze even at low temperatures, it releases heat more slowly, but heats up quickly. Unfortunately, antifreeze is poisonous, and breaking up into components, leads to damage metal structures. The heat exchanger through which antifreeze circulates should be cleaned at least once every 1.5-2 years.

Therefore, both a single-circuit and a double-circuit boiler require timely cleaning of the heat exchanger, the breaks between which are the same in all systems.

In order to clean the bithermic heat exchanger less often, it is necessary to take care not only of the quality of the coolant in heating circuit, but also about the quality of water in the DHW system. Water should be cleaned and filtered first. It should also be taken into account that the process of scale deposition starts at a temperature of 70°C, its rate increases by a factor of 2 for every 10°C increase in temperature. In this case, the progression of the process occurs, since the growing layer of calcium impairs heat transfer and the temperature of the heat exchange wall increases.

Basic cleaning methods

The heat exchanger can be cleaned in several ways:

Mechanical. The heat exchanger is a system of pipes of small diameter, which is quite possible to clean with a small brush and cable.
Using chemicals. Such reagents should be selected very carefully, too strong drugs can lead to damage to internal surfaces and leaks.
By supplying water under great pressure. Before this procedure, the liquid is best heated to 70-80 ° C.

If you clean the heat exchanger yourself, then the third option may require serious costs, since you will need an installation that can provide high water pressure. When cleaning with your own hands, you should use a mechanical or chemical method.

The sequence of dismantling the boiler and removing the heat exchanger

It should be remembered that this procedure should not be performed at the height of the heating season. Because there are certain time frames for which it is necessary to remove the heat exchanger, rinse it and install it in place. During this time, the heating system will not maintain a constant temperature, and in severe frosts this is fraught with serious consequences or a sharp cooling of the house, which will lead to additional expenses for heating it.

The sequence of cleaning the gas boiler:

Dismantle the burner. Immediately it is necessary not only to remove the part, but also to clean it. For high-quality cleaning of the burner, it is most convenient to use a toothbrush. This personal hygiene item will allow you to get to hard-to-reach places.
Next, the supply wires are disconnected from the gas valve and the thermocouple is removed from the combustion chamber. To remove the thermocouple, you must first remove the capillary tube connecting it to the gas valve.
Disconnect the pipes through which gas is supplied to the device. Now it remains only to unscrew 4 bolts (nuts are used in some models). After undocking, the entire assembly can be pulled out and cleaned.

The main element is the heat exchanger. To get to it, you need to remove the protective cover of the device and undock 2 sensors: draft and chimney. Next to the sensors, you need to remove the heater. With long-term operation of the boiler, it is best to replace the insulation with a new one. Its poor quality condition is the cause of energy loss during operation.

After the above operations, the casing is dismantled, and the heat exchanger remains open. To remove it, only turbulizers interfere. This is a device that slows down the movement of exhaust gases. The temperature of the gases can be too high and at the right speed, such exhaust can damage the internal surfaces of the heat exchanger.

Disassembly and flushing of the BAXI Mainfour 24 wall-mounted boiler.

Cleaning the heat exchanger mechanically

After removing the heat exchanger, you can start cleaning it. mechanically. Of course, you can choose the second option (using chemically active substances), but it will be described below.

After going through the removal process in stages, and taking the heat exchanger out, an unattractive picture opens up to users: a large amount of deposits and soot both inside the pipes and between the cooling plates. The mechanical cleaning method involves the use of a metal cable with a brush at the end, as well as various scrapers and spatulas. With this tool, harmful deposits are removed from both internal and external surfaces.

To make the process of removing dirt faster, you can “soak” the device in water, with the addition of detergents. Then plaque or scale will be removed much easier and without effort. When using a cable, it must be slowly pushed into the device, while turning it clockwise.

After inner part is cleaned, it is necessary to flush the heat exchanger with a hose that can be connected to a centralized water supply. Not required here great pressure, even an ordinary stream of water is enough to wash away dirt, plaque and other deposits.

Remove dirt from the outer surface, especially between the blades, carefully, as this may damage the heat exchanger and disrupt its operation.

What is a booster and how to mount it yourself

When cleaning with chemically active substances, it does not require a lot of effort, but you should purchase or make your own solution that will remove harmful deposits. Using chemical substances booster.

A booster is a device that creates a certain pressure in the heat exchanger and allows the cleaning fluid to be pumped through it. Such a device can be purchased at a specialized store for a substantial amount or you can make it yourself.

Booster mounting sequence:

Purchase 2 metal plates, no more than 2.5 mm thick. Attach them to the heat exchanger and drill holes opposite the terminals of the device.
Buy 4 water faucet like "American". For better tightness, you should also buy washers on them.
The valves must be installed in the holes on the plates, which are located below and, using 4 bolts, connect the plates to each other.
Now you need to find a suitable container. It can be a durable plastic canister or the same bottle. The main condition is a perfectly clean surface inside.
An adapter is mounted at the bottom of the canister, to which the hose will be connected in the future. The adapter must have sufficient tightness.

If desired, and if there is an extra tap, it can be installed on the adapter, but the heat exchanger can be flushed without it.

A variant of a homemade booster with a circulation pump is presented in the video.

Another option is to use a circulation pump.

How to clean a heat exchanger with a booster

This procedure requires skill and compliance with some safety rules:

All connections of the system must be as tight as possible to avoid contact of chemically active substances with the skin or eyes.
The solution for washing should be prepared only in protective equipment (gloves and, if required, goggles).

Now you can start cleaning the heat exchanger with a booster. This will require a pump. low power, for example, from washing machine or heating systems, and a device whose manufacturing sequence was indicated above. The pump should be connected to a container, into which then pour at least 6 liters of water. Before this, the water is heated to a temperature of at least 50 degrees.

After preparatory phase, the hoses from the tank are connected to the inlet and outlet of the heat exchanger and the pump is started. It is enough to drive the liquid through the system once, and turn off the pump. Now you need to make a thorough inspection to make sure that the system is highly tight. If no leaks or drops of water are noticed anywhere, then cleaning can be done in full.

A special solution is added to the system and the pump is started for at least 40 minutes. It should be remembered that both the main and secondary heat exchangers require thorough flushing. Then the total time should be at least 1 hour 20 minutes (40 minutes for each circle).

After the cleaning agent has been run through the system for a specified time, the booster can be turned off and a hose from the centralized water tap connected to the heat exchanger outlets. 3-5 minutes are enough, and the device can be installed back on the gas boiler.

The video shows how to flush the primary and secondary heat exchangers of the Ariston boiler with a booster.

Flushing with booster and hydrochloric acid.

Heat exchanger cleaners

It is best to use for this procedure products that are sold in household or other specialized stores. But, to save money, such a composition can be made independently.

The first thing that is used most often is a solution of 10% sulfuric acid. Such a tool can be used, but this should be done very carefully, since sulfuric acid is very active and can quickly burn through the thin walls of the heat exchanger. Result: the need to contact a master who can solder the hole or purchase a new device. Both the first and second options will cost the user a substantial amount.

You can resort to a more gentle and folk way: for 20 g of citric acid dissolve in 1 liter of water. If the result is not immediately noticeable, then the concentration should be slightly increased. Citric acid qualitatively removes scale and dirt, but at the same time negatively affects rust-damaged areas.

The video below shows how to disassemble the Baxi Ecofour 24F boiler and clean the heat exchanger with citric acid.

Therefore, it is best to spend a little more money, but clean the heat exchanger with tools specially designed for this. For example, a preparation for cleaning gas boilers Detex. This composition has never damaged the inner surface of the heat exchanger and has earned a large number of positive reviews from users.

Benefits of using DETEX liquid:

Removal of a layer of scale, biological deposits, oxides, salts.
The composition of the liquid does not destroy the surface of the heat exchanger.
Contains surfactants, antifoaming and corrosion inhibitor additives.

Summing up

Cleaning the heat exchanger is an important and mandatory procedure, which must be carried out at certain time intervals. Only then the life of the gas boiler will be long, and its operation will be reliable. Before cleaning, it is necessary to carefully study the information presented above and strictly follow the tips and recommendations.

To save effective work gas boiler, it is necessary to take timely measures to care for it. The most difficult and time-consuming is flushing the heat exchanger of the unit. During prolonged operation, especially if there is no water filter, lime deposits will accumulate in the heat exchanger. To prevent this problem from putting the gas boiler out of action, it is necessary to periodically clean the circuit. Therefore, many users of the units are interested in how to clean the heat exchanger of a gas boiler.

The heat exchanger of a gas boiler is a curved pipe made of metal or cast iron. It's heated by the flame gas burner, and then transfers heat to the heat transfer fluid, which moves throughout the heating system. If the heat exchanger is clean, then it effectively transfers heat. When salt deposits accumulate in it, its thermal conductivity decreases. Then the gas boiler has to heat the coolant longer, which entails an increase in fuel and electricity consumption.

If the element is heavily contaminated, in order to maintain the desired temperature, it needs to be in the maximum heated state for a long time - this leads to overheating of the heat exchanger and its failure.

Deposits and scale also prevent the coolant from moving along the circuit. As a result, the load on the circulation pump increases.

Thus, a contaminated heat exchanger threatens to fail not only the element itself, but also other important nodes unit. To prevent damage, the boiler should be cleaned regularly.

Note! In double-circuit models, the secondary heat exchanger, which works for heating, often fails. hot water.

How often should the heat exchanger be cleaned?

The frequency of cleaning the gas boiler heat exchanger is usually indicated in the operating instructions. If at the input water pipe there is a filter, then you can do cleaning less often. If there is no filtration and there is hard water in the region, then the heat exchanger will clog faster.

Usually, without a water filter, cleaning is done once or twice a year. With filtration tap water it is enough to take care of the heat exchanger once every 4 years.

Exist signs that urgent circuit cleaning is needed:

Fuel consumption has increased - with a clogged circuit, gas consumption can increase by 15-20%.
Decreased performance heating system. Signs of this may be the following: weak heating of the batteries, the unit cannot reach the required temperature and works continuously.
Weak water pressure from the DHW system or insufficient heating.
Noises in the heat exchanger.

If at least one such “symptom” appears, the heat exchanger should be cleaned as soon as possible, otherwise inaction will lead to costly repairs.

Gas boiler cleaning options

There are several basic methods for cleaning gas boiler heat exchangers:

manual;
chemical;
hydrodynamic.

Which method of them to apply depends on the degree of blockage. Let's take a closer look at each of these methods.

Not all users of gas boilers know how to clean the heat exchanger of a gas boiler themselves. Manual cleaning is the easiest way to do it yourself. There are two ways to execute this method:

mechanical - with a brush and a brush;
flushing with active solutions is a more efficient option, especially relevant for boilers with two circuits.

For heavy soiling, two methods of descaling are used - first rinsing, and then mechanical cleaning. This process is carried out in the following steps:

turn off the gas and disconnect the unit from electricity;
open the lid of the gas boiler;
dismantle the heat exchanger;
place it in an active substance, for example, a solution of hydrochloric acid;
pull the heat exchanger out of the solution and clean the dirt with a brush or brush;
rinse the element with water inside and out;
dry and install the circuit back.

Chemical cleaning

Dry cleaning is distinguished by the use of a booster or its analogues, as well as aggressive chemicals. An important condition chemical cleaning is to maintain a safe concentration of the substance so that it does not corrode the surface of the heat exchanger.

Dry cleaning is carried out using a booster, but many craftsmen create it cheap analogue with your own hands. To do this, take a container of 10 liters and attach two hoses and a pump to it.

If the scale layer is too large, you can use substances based on sulfuric or hydrochloric acid for cleaning. The simplest cleaning solution is made from citric acid: 200 grams of powder is diluted with 5 liters of water.

The chemical cleaning process is quite simple:

the chemical solution is diluted in containers and poured into a booster;
two hoses are connected to two pipes of the boiler - inlet and return;
turn on the device and run the liquid through the heat exchanger several times.

Factory boosters have a heating function, which allows you to flush the circuits with greater efficiency.

After the procedure, it is necessary to drain the reagent and flush the system again with a neutralizing agent or clean water.

Of course, dry cleaning is more effective than manual cleaning, but the active substances contained in the solutions can lead to corrosion. Therefore, this method cannot be used often.

Solutions for cleaning the heat exchanger

Some owners of gas boilers on the forums are interested in how to flush a gas boiler from scale at home. Typically, the following products are used for dry cleaning:

Cleansing gel - it is considered the mildest remedy. After it, it is enough to rinse the heat exchanger running water. Despite the gentle effect, the gel copes well with scale and lime deposits.
Adipic acid - in order to flush the gas boiler heat exchanger with acid, it is important to dilute it with water in the correct proportion, otherwise the substance will damage metal surface. Adipic acid well softens all deposits inside the heat exchanger. After flushing the system with this agent, the neutralizing liquid should be driven through it.
Sulfamic acid - well helps to cope with complex pollution. The substance is diluted with water and filled into a booster. After completion of the process, it is necessary to flush the heat exchanger with a neutralizing liquid.

Note! When performing dry cleaning, rubber gloves should be worn on the hands, and the body should be protected with overalls through which the acid solution cannot get on the skin.

Hydrodynamic cleaning

This method of cleaning the heat exchanger is carried out only by specialists. It is unnecessary to disassemble the boiler and remove the heat exchanger for its implementation. The principle of hydrodynamic cleaning is as follows: the liquid is pumped into the system and driven under pressure several times. For greater efficiency cleaning agents are added to the water. It turns out that due to the rapid movement of water, scale disappears and pollution is washed off.

However, with this method, it is important to correctly calculate the pressure force - if it is too large, a pipe break may occur. Therefore, hydrodynamic cleaning cannot be performed independently.

What is the difference between cleaning a double-circuit gas boiler?

How to wash the secondary heat exchanger of a gas boiler with your own hands? There are no fundamental differences between flushing the DHW circuit and the heating heat exchanger. It's just that in the case of a two-circuit model, you will have to clean not one, but two elements.

Double-circuit gas boilers can be equipped with two types of heat exchangers:

removable secondary;
bithermic.

The first option is cleaned in the same way as the primary circuit using manual or dry cleaning using a booster:

connect the booster hoses to the supply pipes cold water and outlet hot;
the apparatus is put into operation with heating of the reagent (t=50-55ºC).

During manual cleaning, the secondary circuit is dismantled and immersed in a solution of citric acid. Then brush the outside and dry.

A bithermic heat exchanger consists of two pipes inserted one into the other: a coolant flows through one of them, hot water flows through the other. It is much more difficult to clean it, especially since such a circuit cannot be dismantled as a separate analogue. Therefore, flushing of the bithermic circuit can only be carried out using a booster. If such an element is heavily contaminated, then it is simply impossible to clean it. Then you have to buy a new bithermic heat exchanger and install it instead of the old one.

What is the best way to clean the heat exchanger?

Some people get lost in the variety of contour care products and often choose the most powerful ones, which, if used regularly, negatively affect the metal. Experts say that such tools are best used in last resort if more gentle solutions did not fit. The most versatile tool is lemon acid- it cleans scale no worse than all kinds of expensive products, but it does not damage the surface of the heat exchanger.

If you flush the circuit in time, and not wait until the pipes are completely overgrown with salt deposits, then aggressive substances will not have to be used to clean a small layer of scale.

It is best not to carry out the work yourself, because there is a high probability that, due to the lack of necessary experience, instead of descaling the boiler, you will have to purchase a new boiler. In the article, we will talk about how important timely cleaning of the boiler is. We will also tell you what is traditionally included in such a procedure.

Cleaning methods

Boiler cleaning involves a standard set of separate methods, which includes both mechanical and chemical cleaning. Another possible way out- preliminary cleaning of the boiler from the dirt that may settle on its walls in the future. Since preliminary operations are very expensive, they are now rarely preferred. Regular cleaning of the boiler from the formed scale is enough to prevent the occurrence of possible emergencies. Much more expensive will be the consequences of the lack of timely descaling, when things can end up not just repair work, but also a complete replacement of heating equipment.

Reagent cleaning of boilers from the formed scale

Such cleaning traditionally includes methods that imply surface treatment with chemical reagents (hence the name). Among such reagents, strong acids are currently especially popular, because they cope with such common types of scale as carbonate and ferruginous with great efficiency. Used for cleaning boilers from scale and other solutions. So, silicate scale can be easily removed if you turn to solutions with high alkalinity for help. In any case, it is very important to choose a washing agent on an individual basis, because the choice is influenced by both the nature of the pollutant and the properties of the pollutant.

Varieties of chemical cleaning

An important step in flushing boilers indiscriminately is the supply of a cleaning solution to the system. The booster pump is responsible for this task. It is very important to be able to regulate the system pressure, because this is associated not only with the supply of cleaning solution, but also with an increase in pressure during the reaction between plaque and acid.

In the case of collapsible cleaning, the system is initially dismantled, and dirty parts are placed in a separate container with a solution for several hours. After that, the elements are washed and reassembled into a single whole. Traditionally, chemical cleaning of the described collapsible type is carried out together with mechanical cleaning from scale. It is best to refer to such an operation if the scale has become significant.

Physical cleaning methods

If we are talking about cleaning the boiler from scale in the complex, then mechanical cleaning is initially performed, and only then chemical. Among the main disadvantages of the physical method, one can single out that inner surface the boiler is negatively affected, therefore it quickly deteriorates, especially if, through carelessness, too sharp tools are picked up. Once the cleaning of the boiler is completed, it is important to thoroughly rinse all removed parts with water and reassemble them correctly.

Hydrodynamic cleaning of the boiler heat exchanger involves the removal of contaminants by means of a jet of water high pressure. This method differs from the mechanical one in that it excludes any kind of damage to parts. Although hydrodynamics is very efficient, it is not used as often due to its high cost.

There are two ways of physical methods for cleaning boilers from scale. Both options require a mandatory analysis of the system, which means that it is extremely important for anyone who is interested in such work to purchase necessary tools and provide complete equipment. Since scale is formed mainly on the surfaces of the boiler from the inside, it is impossible to interact with contaminated areas directly. Since the disassembly of the system is a time-consuming and complex process, the cost of physically cleaning the devices from scale is also high.

Noticed that Lately Do you have problems with heating and hot water? One of the likely reasons for this may be the incorrect operation of the heat exchanger, which, as you know, is one of the main components of any gas boiler. After washing it this problem should disappear.

Causes and types of pollution of heat exchangers of gas boilers

The most common cause of their contamination is the plaque on the surface that occurs as a result of the operation of the boilers. As a rule, the formation of plaque is associated with an increased content of salts and metals in the water. These deposits contribute to the blockage of the passages, as a result of which the thermal processes are much worse. Scale formed during water heating contributes to boiler malfunctions, poor water heating, etc.

Types of errors in the operation of gas boilers

malfunctions of boilers, software failures;
poor water heating;
more gas consumption with less heating.

If you notice that software failures have begun to occur in the operation of the equipment, you should first of all check the control panel and identify problems. If such a check did not give the expected results, then it can be stated with 99.9% accuracy that failures occur as a result of deposits and scale on the heat exchanger. In this case, the boiler can be washed by disassembling it completely or without dismantling using chemical reagents. As practice shows, the first method of cleaning the boiler manually is the least expensive. For these purposes, you will need a brush and a vacuum cleaner.

Manual cleaning process

The very first thing you will need to do is shut off the gas and electricity supply for safety reasons. Next, in order to access the inside of the boiler, you will have to remove the front front cover. As practice shows, this process is not at all complicated and any user can cope with this task. As a rule, the front cover of a gas boiler is fastened with four bolts.

The combustion chamber has additional protection, which must be removed, and then proceed with the removal of the combustion chamber cover.

After opening the combustion chamber, a thorough cleaning should be carried out with a vacuum cleaner. As for the burners and nozzles located in its lower part, you need to wipe them with a wet cloth, but if these elements are very dirty, you need to clean them with a brush. Your main task will be to improve the throughput of gas in the nozzles, and for this, to carry out their maximum cleaning. To flush the heat exchanger, it will be necessary to remove it, depending on the model and manufacturer, the methods for removing it may differ from each other. The most important thing is that it is not at all difficult to do this, and even an inexperienced user can cope with this task.

Flushing the gas boiler and its heat exchanger

Flushing must be carried out, both inside and outside. For these purposes, it is necessary to fill the pelvis cold water to which to add special means from scale and corrosion, and then immerse the heat exchanger in it. After he has been there for some time, it must be washed under the pressure of water, both inside and out, and thereby remove the remnants of contaminants. In the case when the parts are very heavily soiled, a brush should be used to remove them. Usually after thorough cleaning appearance heat exchanger and boiler is greatly improved. After that, you can start assembling the boiler in the reverse order.

How to properly clean a floor-standing gas boiler

First of all, the gas supply is shut off and the boiler door is removed, as a rule, it is bolted and can be located both on the front side of the boiler and on its back. Next, carefully disconnect the wire of the piezoelectric element and remove the thermocouple. Before you remove the nozzles, it will be very important to make marks on them that will indicate the depth of their immersion in the burner, because if this is not done, then you can knock down the basic settings. Next, you should unscrew the boiler ignition system, as well as the tube mount. We twist all the nuts that fix the boiler cover and remove the cover itself. Next, you should remove the gas duct and carry out the cleaning itself. After cleaning is carried out, it will be necessary to assemble the boiler in the reverse order, however, pre-spread the joints and pipe fasteners soapy water to check for possible gas leaks.

Cleaning a gas boiler with flushing

This method involves soaking the constituent parts of the heat exchanger in a variety of special mixtures and solutions. Here the main requirement is the utmost care in order not to lose or damage small parts. After washing, you can proceed to reassembly, but you need to focus on the tightness of its parts and components. This is especially true of joints and pipe fastenings.

Cleaning a gas boiler with a chemical solution

With the help of a special “booster” device, a special mixture is pumped into the system, which includes acid, which is used to flush the boiler. This cleaning method is considered one of the most effective, due to the fact that it allows you to clean the dirt as much as possible and increase the throughput in the boiler. After that, a special solution is poured that neutralizes the acid.

Hydrodynamic cleaning

Another method that is also very popular on the market. Its main feature is simplicity, since you do not have to disassemble the gas boiler at all. Its disadvantage is the cash investment for the purchase of special equipment, which is attached to the water supply and increases its pressure, as a result of which the boilers are cleaned mechanically.

How often should boilers be flushed?

Many owners of gas boilers are wondering how often they need to be flushed and cleaned. Of decisive importance in this matter is the quality of the water that is supplied to your home. If you have a high-quality filter installed and the water does not have hardness, then it is enough to carry out such washing every four years. In the case when the water in your water supply is saturated with salts, you need to flush the boilers once a year. It is very important to keep the surface of the equipment clean in order to avoid an increase in gas consumption. In addition, you need to check the water level in the boiler and the water pressure in the system.

Video

Photo: gidotopleniya.ru, proekt-tmn.ru, boyler.org.ua

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Content

Why does scale form?
How often is flushing required?
Popular cleaning methods
Fluids for flushing heat exchangers

Introduction

The service life of a gas boiler depends not only on careful operation, but also on the timely cleaning of its components and assemblies. A heat exchanger that is constantly in contact with a hot coolant is most susceptible to the formation of scale and various deposits. In this article, we will talk about the causes of plaque formation, symptoms of the need for cleaning, how the gas boiler heat exchanger is flushed and what reagents are used.

Flushing is necessary for all types of heat exchangers: tubular and plate, primary and secondary, shell-and-tube and bithermic. Copper and steel, aluminum and cast iron - all of them are more or less susceptible to the formation of deposits and scale.

Why does scale form?

The main reason for the appearance of scale on the walls of gas boiler heat exchangers is the use of hard lime water. As a rule, the water supplied to the heating system is not well purified and contains calcium and magnesium salts, as well as ferric iron, in dissolved form. Under influence high temperature these impurities crystallize on the walls of the heat exchanger, forming a layer of deposits and rust.

Photo 1: Deposits inside a bithermic copper heat exchanger

If the coolant used in the heating system undergoes at least some filtration, then water sometimes enters the hot water circuits of double-circuit boilers and bithermic heat exchangers without any purification. That is why these elements are especially susceptible to scale formation.

What is the danger of scale on the walls of the heat exchanger? There are several factors of the detrimental effect of deposits on the operation of the heating system as a whole and its individual devices in particular:

Increase in gas consumption

The mineral deposits that are part of the scale have a much lower thermal conductivity in comparison with the metal from which the heat exchanger is made. Based on this, more energy will be spent on heating the coolant, and, consequently, the volume of burned gas will increase. Just 1 mm of deposits increases heating costs by 10%.
Heat exchanger overheating

It is laid down that the coolant coming from the return line cools the heat exchanger, removing heat into the heating system. Scale prevents normal heat exchange and the boiler automation gives the command to heat up more in order to reach the required temperature in the supply line. Working for a long time in the mode of extreme temperatures, the heat exchanger quickly wears out and fails.
Additional load on heating equipment

The formation of scale on the walls of the heat exchanger reduces the effective diameter of the channels and prevents the normal circulation of the coolant. As a result, the load on the circulation pump increases, which leads to its premature wear and failure.

Photo 2: Scale and rust on the walls of the pipes of the heating system

The problem of scale formation in gas boilers quite serious and can hurt the owner's pocket if it is not eliminated in time.

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How often is flushing required?

Many popular manufacturers of gas boilers such as Navien, Baxi, Ariston, Vaillant indicate in the operating instructions the frequency of flushing the heat exchanger. However, real operating conditions often make their own adjustments. Practice with hard water shows that the heat exchanger should be flushed every season. In order not to encounter this problem in the middle of a cold winter, it is recommended to flush immediately after or before the start of the heating season. The following are typical signs by which you can judge that the heat exchanger of your gas boiler needs to be cleaned:

Increased gas consumption

The resulting scale reduces the thermal conductivity of the heat exchanger, thereby forcing the gas boiler to burn more fuel to reach the set temperature.
Permanent burner

An increase in the burner operating time may also indicate the presence of scale that prevents the normal heating of the coolant.
Hum and interruptions in the operation of the circulation pump

Reducing the effective diameter of the heat exchanger channels makes it difficult to pump the coolant circulation pump. Its operation in the limit mode may be accompanied by a hum and interruptions in operation.
Pressure reduction in the DHW circuit

A sign of the presence of a scale layer in the secondary circuit of a double-circuit boiler can be a decrease in pressure in the hot water supply line.

If one or more of the above signs can be traced in the operation of your gas boiler, it is urgent to flush in order to avoid breakdowns of expensive heating system components and high costs for their repair or replacement.

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Popular cleaning methods

There are several technologies for flushing heat exchangers, which can be divided into two groups: collapsible and non-collapsible. The collapsible flushing technique consists in the fact that the heat exchanger is removed from the gas boiler and washed separately. When using CIP technology, nothing needs to be removed, and the cleaning process is carried out using special equipment. Let's take a closer look at the main flushing methods:

Manual cleaning

Manual flushing is a collapsible type and requires the heat exchanger to be disconnected from the gas boiler. Its body is cleaned of external contaminants metal brushes and soaked for several hours in an acid solution or a special flushing fluid. The main disadvantages of this technology are the lack of reagent circulation during the flushing process and the detrimental effect of reagents on gaskets and other sealing joints. When starting the washed gas boiler, make sure that all connections are tight and that there are no leaks under pressure.

Photo 3: Collapsible cleaning of the gas boiler heat exchanger

Chemical flush

Chemical (hydrochemical) flushing can be performed without dismantling the heat exchanger from the gas boiler. To remove rust, scale and other deposits, the heater is connected to special device called a booster. This special device, equipped with a pump, pumps the chemical reagent through the heat exchanger in various directions for several hours. During this time, the chemistry that is part of the washing liquid completely removes the most difficult contaminants without damaging the metal.

Photo 4: Chemical flushing of the heat exchanger with a booster

Hydrodynamic cleaning

This cleaning method also applies to in-place methods. Its essence lies in the fact that by connecting special installation, water under high pressure is driven through the heat exchanger. Sometimes, in order to achieve best result, the aqueous solution contains an abrasive filler. The increased flow rate of the flushing fluid contributes to effective removal deposits from the walls of the heat exchanger.

Attention! It is better to entrust hydrodynamic cleaning to professionals and not to do it yourself at home, since the wrong choice of pressure can lead to ruptures and damage to the heating system.

Most often, owners of gas boilers use chemical flushing of the heat exchanger with a booster. To do this, they conclude an agreement with a company that performs this type of work, or purchase special equipment and do the cleaning with their own hands.