Before the start of the heating season, it is necessary to carry out comprehensive service heating circuit. Such measures include checking the functionality of the equipment. After this, you need to fill the closed heating system and bleed all the air. There are several ways to fill a contour. It is very important to monitor the pressure level while performing work. The optimal values are indicated in the passport of each circuit element.
Selection of coolant
If you fill the circuit with low-quality coolant, the equipment will not last as long as it could. Therefore, before filling the heating system in a private house, you need to select the coolant suitable for your situation. There are only two options - water or. In a house where you live constantly, it is better to give preference to water, since there are fewer problems with it, especially if it is distilled. Such water contains almost no impurities of salts and metals, which negatively affect all elements of the heating circuit.
Non-freezing liquid thickens at sub-zero temperatures. It is used when the heating works from time to time. The characteristics of non-freezing liquid impose some restrictions:
- high degree of fluidity - leakage may appear where water would not leak;
- Do not overheat - when heated to 95 degrees, it decomposes into acid and other elements;
- if the liquid has thickened, then heating should be gradual;
- Anti-freeze has a resource (depending on the manufacturer, on average 2 seasons).
Polymer has one of the lowest thermal conductivity coefficients.
If you do this, the tree will not breathe and will rot very quickly.
Antifreeze cannot be used if you have it installed. Liquid can seep through protective gaskets, so it happens that colored water flows from a hot water tap. In any case, only non-toxic antifreeze based on propylene glycol should be poured into the system. After all, there is also antifreeze based on ethylene glycol - this is car antifreeze. Some people also pour it into the heating system, but we do not recommend doing this.
How to fill a heating system through make-up
Filling a closed-type heating system through make-up is only possible if the circuit is connected to a water supply system. IN autonomous systems– this is the best option, as it does not require the purchase of additional equipment.
Make-up valve.
It is advisable to install not a ball valve on the feed, but a valve that can be used to regulate the flow. Before filling the heating system with water, you need to empty it of old coolant. The water changes because it becomes too dirty. Then you need to open all the Mayevsky taps on the radiators and open the make-up.
As the radiators fill, liquid will begin to flow from the air vents at the ends. As soon as water appears, the tap is immediately turned off. You need to monitor the readings of the pressure gauge - a device that shows the pressure in the heating circuit.
In autonomous systems it should not be more than 2.5 atmospheres. This value is achieved when the temperature of the coolant increases, and when the water is cold, the pressure gauge should show no more than 1.5 atmospheres.
After filling the heating system with water, you need to turn on the boiler. When the coolant heats up, you need to bleed air from all batteries again. IN hot water air separation occurs more intensely than in cold. It may be necessary to remove air pockets several times (the first 2-3 heating cycles of the coolant).
Filling closed heating with a pump
If the circuit is not connected to the water supply, the only option left to fill the heating system is a pressure test pump. This is a small rectangular metal reservoir into which liquid is collected. From the reservoir, the coolant is supplied to the pipes thanks to a pump-action hand pump on which a pressure gauge is installed.
Hand pump for pressure testing.
There is nothing complicated about how to fill a closed heating system. Work algorithm:
- connect the hose from the pump to the circuit;
- pour coolant into the pump reservoir;
- manually pump fluid into the system.
If there is no pipe for draining water from the circuit, then you can connect the pump hose to one of the ends of the battery. To do this, you need to unscrew the plug and put the adapter in its place. Before starting work, be sure to open all air vents so that air can leave the circuit.
There is no point in gluing the roll. A thin layer of thermal insulation will not give the desired result.
When working with thermal insulation in sheets and rolls, it should be used to fix the material.
Watch the pressure gauge reading carefully. Using such a pump, pressure testing of the heating system is carried out. They can pump up pressure to 10 atmospheres (if you have enough strength). When filling the system, such pressure is not necessary, otherwise the boiler will break.
Filling the system through a double-circuit boiler
Now let's look at the simplest method, namely how to fill the heating system of a double-circuit boiler. These units do not require the installation of an additional unit for feeding the heating circuit, since it is included in the basic configuration.
The feed tap is located at the bottom.
Look into the bottom of the boiler. Near the supply pipe cold water There should be a plastic handle for the make-up tap from the water supply. In principle, the procedure is no different from refilling through a water pipe:
- open all air vents;
- open the feed tap and fill the system;
- As the circuit fills, close the air vents;
- we achieve pressure (specified in the boiler passport).
After the pressure in the heating system has reached the required level, the make-up valve closes. He won't be used until next season. It is recommended to change the coolant every year. For more information on how to fill a closed heating system, watch the video below.
Heating a home using liquid coolant is the most popular. Reliability of operation heating systems, consisting of sets of equipment and pipelines, depends on the thermal fluid and its characteristics. The task of the coolant is to transfer the maximum amount of thermal energy at minimal cost.
Replacing one type of coolant with another is done to increase the efficiency of the heating system. But before you pump or replace new coolant into the system, you need to select the coolant itself.
The cheapest coolant is water. But the use of water is not always justified. Water should be used in heating systems that are not subject to corrosion. The use of water as a heat carrier has certain reservations. Such a coolant must be processed by distillation, this will protect the heating system from the formation of scale in it. The use of water that freezes at zero temperatures can destroy pipes in the event of an emergency shutdown.
Injecting special “anti-freeze” agents as a coolant allows you to ensure high-quality operation of the home heating system. The market for heating antifreeze manufacturers offers various types thermal media made on various bases and having certain characteristics on which their final price depends.
Basic requirements for a coolant:
- The degree of viscosity of the thermal fluid with temperature changes;
- Inertness of antifreeze in relation to other materials;
- The thermal fluid must not be corrosive and be safe for residents in terms of toxicity and ignition;
- Thermal conductivity of the material;
- The price of the thermal fluid must correspond to its payback period.
Popular antifreezes for heating
H2_2Ethylene glycol-based antifreezes are divided into two categories depending on their freezing point: - 30 °C and - 65 °C. This type is cheap and cold resistant.
Antifreeze based on ethylene glycol has a significant drawback - high toxicity, which limits the conditions for its use. Ethylene glycol, which is colored red by manufacturers to warn of danger, is not used in open heating systems.
Propylene glycol, colored by manufacturers in green, is safe to use. The coolant has a freezing point of 35 °C and can be used in systems with an open expansion tank.
Antifreeze made from glycerin is safe to use and has a freezing point of 30 °C. In comparison with ethylene glycol and propylene glycol, it has a number of advantages and can successfully replace them:
- protects corrosion nodes and does not damage parts and elements;
- Compared to coolants based on ethylene glycol and propylene glycol, with a service life of no more than 5 years, antifreeze based on glycerin has more long term operation – up to 8 years;
- the liquid is sold in diluted form, ready for use;
Fact! Glycerin-based antifreeze can be used in heating systems as a replacement for another type of coolant, without flushing the pipes.
Before pouring antifreeze into the heating system with your own hands, you need to correctly calculate how much liquid will be needed and how much to buy. To carry out calculations, it is necessary to calculate the volume of the entire heating system.
There are special tables that allow you to accurately calculate how much anti-freeze you need to fill before initial use or replace one antifreeze liquid to another, based on calculations made for one linear meter of pipe. Using such calculations and knowing the diameter of the pipes, you can calculate how much coolant is required per 10 m of the system. It remains to be clarified how much antifreeze needs to be added to fill the battery section. By adding up all the data, you can get the total volume of antifreeze required to fill the system. There is no single formula - filling depends on the diameter of the pipes and the volume of the radiators.
In most cases, the container in which the thermal fluid is sold contains information about the antifreeze sold and its density. Such data allows you to calculate how much water needs to be added to the liquid, which will serve as a heat carrier.
To refill the antifreeze with your own hands, you need to have a pump or special equipment that allows you to carry out the procedures of purging and flushing from used residues. For pouring work you will need: a screwdriver, pliers, adjustable wrench, hoses for pumping coolant, fixing clamps and sealing tape.
Injection of a closed or open type system consists of the following steps:
- Before pumping in a new antifreeze liquid intended for replacement, you need to drain the entire amount of used liquid or water through a special pipe by opening the drain valve. If the liquid does not drain on its own, it is removed using circulation pump;
- If the coolant is replaced with another (with the exception of glycerin liquids), preliminary flushing of the system is necessary;
- Next, new antifreeze is added using a hose and a circulation pump. Two hoses are used for the injection procedure. The first hose is secured to the drain pipe and the pump outlet, securing the ends with clamps. The second hose is used to supply antifreeze from the container to the pump;
- After the hoses are installed, the pump is turned on, which takes the coolant from the tank and fills the heating system with it. When pouring antifreeze into the system, it is necessary to ensure that the end of the hose lowered into the canister is below the liquid level; this is necessary to prevent air along with the liquid from entering the system during the intake of antifreeze. The air that gets in with the liquid forms plugs that will interfere with the operation of the heating;
- For unhindered injection of coolant, the “Mayevsky valve” or a special plug is opened, which will allow air to freely exit when filling the cavities with liquid. After the antifreeze being poured begins to flow out of the plug in a thin stream, filling stops and the plug is closed.
Filling with antifreeze yourself is not a difficult task. When starting work on pumping coolant, you need to decide on the choice of coolant, how much of it is needed, and have the equipment necessary for the work - a pump and tools.
Each heating system includes a number of elements, without which its normal functioning is impossible. One of these elements is an expansion tank; its purpose and structure will be discussed in this article. We will also look at how to choose an expansion tank for heating a private home.
Why is an expansion tank needed?
Even from a school physics course, everyone knows well that any body expands when heated, and liquids and gases increase in volume. Unlike gas, liquid is an incompressible medium, and if it is heated in a closed vessel, such as a boiler tank, this will lead to an increase in pressure inside it, since there is nowhere for it to expand. As a result, the tank walls may rupture.
Imagine a coolant heated in pipelines from a temperature of 20 ºС to 80 ºС. If you do not install an expansion tank in the heating system, then when the liquid medium is heated, the pressure in the network will increase greatly and water may break out at the weakest point. It's good to have safety valve security. The excess water will go through it, since it has nowhere else to go. If there is no valve, the coolant will simply break out at one of the connections.
An expansion tank is needed to accommodate the growing coolant as it heats up. At the same time, during cooling it returns back to the system.
In the case when the safety valve releases water, after cooling it cannot return it back and will allow air to fill the vacated space. This will lead to the formation of an air lock, which will prevent the system from working normally.
Types of expansion tanks
Externally, expansion tanks for heating may differ in shape and size, determined by calculation. Typically this is a tank connected to the heating system via a single pipe. However, different types There are design differences between containers, and they are used in different cases. To choose the right tank, you need to understand these differences, so first we present a list of existing types:
- open type;
- closed, equipped with a membrane.
Note. There are also closed expansion vessels without a membrane, but their use is strictly not recommended. We'll explain why below.
Open type containers
These tanks are used for an open heating system (otherwise - gravity, gravity) and are a metal tank with an open top of any shape. A pipe for connecting a hose or overflow pipe is welded to the upper part of the side wall; the coolant is supplied to the tank from below. The element is installed above the entire system on the supply pipeline, usually in the attic of the house.
Note. Speaking right technical language, an open system is one from which water is directly taken for the needs of hot water supply. It is not used in private homes, only in centralized networks. A scheme with natural coolant circulation is mistakenly called open.
Any expansion tank for open type heating performs 2 functions:
- serves to compensate for the expansion of the coolant;
- removes air from the system, since its top communicates with the atmosphere.
This is its advantage, but it is not the only one. An open container can also successfully and durablely serve in systems with forced circulation, since the design of the tank is very simple, there is nothing to break. However, it also has many disadvantages:
- a tank installed in the attic requires good insulation;
- During the season, it is necessary to constantly monitor the water level in the tank and replenish it in a timely manner;
- the coolant is constantly saturated with oxygen from the atmosphere, which is why the metal parts of the boiler corrode faster;
- additional consumption of materials and difficulties during installation.
Closed membrane tank
A more modern closed expansion tank is a cylindrical vessel with a rubber membrane built inside. It is used in circuits with forced circulation of coolant and is installed in the combustion room. The coolant is also supplied from below; a service spool for pumping air is installed on top of the device.
The rubber membrane (in common parlance – “pear”), which is equipped with a closed expansion tank of the heating system, comes in 2 types:
- in the form of a diaphragm;
- balloon type.
Note. Some manufacturers' containers have a removable bulb, which makes it possible to change it if cracks appear.
The shape of the membrane does not have a special effect on the operation of the device, although the second type of tank holds a little more water. On the other hand, air (sometimes nitrogen) is pumped from the “pear” under a certain pressure; it must be adjusted individually for each system. All closed expansion tanks operate equally simply: when the coolant heats up, the pressure in the network increases, the membrane stretches and releases water inside the tank. When it cools, everything proceeds in the reverse order.
A sealed expansion tank for a wall-mounted gas boiler is often built inside the heat generator, as it is small in size. In addition, the apparatus does not communicate with the atmosphere and the diffusion of oxygen into the coolant is completely excluded. The weak point of such tanks is the membrane; its service life very rarely reaches 10 years, and it is not always possible to replace it.
There is a third type of compensation devices - a vacuum expansion tank for closed-type heating without a “pear”. It is difficult to find them on sale, and there is no point, since this design is the most unfortunate. The role of the membrane in the container is played by the air itself, which leads to its active diffusion into the water, and this is unacceptable. And then, the level in the tank will increase all the time, as a result there will be nowhere to compensate for the expansion.
If a natural circulation circuit is planned or has already been installed in the house, then an open-type expansion tank is just for you. There is no need to play tricks with a vacuum tank here; remember that water in such a system moves only due to the difference specific gravity and the apparatus may not play its role. You can buy an open vessel, or you can make it yourself; the main thing is to correctly calculate the volume of the expansion tank, which we will discuss below.
With vacuum membrane vessels the situation is a little more complicated. There is one caveat: if you find yourself in a store among many similar products, do not confuse a heating tank with a hydraulic accumulator for water supply. Outwardly, they are very similar, even the color can be the same, so selecting a tank based on this criterion is excluded. The tanks differ according to the inscription on the nameplate; for heating, the operating temperature is indicated up to 120 ºС and pressure up to 3 Bar. On the hydraulic accumulator, respectively, up to 70 ºС and pressure up to 10 Bar.
When making a choice, it is also worth paying attention to the possibility of replacing the “pear” in case of its failure. The size of the device is selected based on the calculation results of a closed tank.
Expansion tank calculation
In the technical literature and on the Internet you can find many methods for calculating an expansion tank for a heating system with natural and forced circulation of coolant. But for the most part they contain a lot complex formulas with reference to the boiler power and other parameters. You can't go wrong if you use more in a simple way determining the volume of the tank.
The method is based on the statement that the amount of water in the system at maximum heating will increase by no more than 5%. That is, first calculate the volume of water as follows:
- the amount of coolant in the boiler tank - according to the passport;
- volume of water in pipelines - using the formula for the area of a circle, find the cross-sectional area of each pipe and multiply it by the length;
- The capacity of the radiators is also according to the product passport.
Having summed up the results, you select and calculate the expansion tank with a margin, taking not 5, but 10% of the resulting amount. This will be its capacity.
Conclusion
Calculating the volume and choosing a closed tank is quite simple; all that remains is to install it correctly. You can also do this yourself, following the instructions included with the product.
In a water heating system, one of the components is an expansion tank. This is a small reservoir that is responsible for stabilizing pressure. Without it, damage to pipes, radiators and other system elements is possible. Let's talk further about what an expansion tank for heating is and how it regulates pressure.
Purpose and types
In a heating system, the temperature of the coolant constantly changes, which leads to changes in its volume. It is known that liquids expand when heated and contract when cooled. The expansion tank for heating is precisely designed to absorb excess liquid during heating (expansion) and return it to the system when cooling. This way it maintains a stable .
Open type
There are two types of expansion tanks: open and closed. Open type containers are usually used in gravity flow systems (). It is called this because it is a non-sealed container. This could be a barrel, a pan, or a specially welded tank. In order for the coolant to evaporate less, a lid is installed, but the container itself is not airtight. The principle of operation of an open expansion tank is simple: it is a container into which excess coolant is forced out when the temperature rises and is supplied back when it cools.
Open type expansion tank - any container, for example, a plastic canister
When calculating open-type tanks, take a significant reserve in volume: you can add coolant and not check its level for some time. The container is not airtight, so there is constant evaporation of liquid and a supply will not hurt. If there is a lack of coolant, air will enter the system, which can stop it. The consequences can be sad - if the boiler’s automatic system works (if it has one), there is a possibility of defrosting. If there is no automation, the boiler may rupture due to overheating. In general, this is the case when the stock is really justified.
If the heating system is filled with water, you can make an automatic replenishment based on a float from the toilet cistern. The principle of operation is exactly the same: when the level drops below a certain point, the water supply opens. When the required level is reached, the supply is shut off.
The advantage of this solution is that there is no need to control the amount of coolant; the possibility of airing is minimal. Minus - you have to pull water pipe. Since open systems usually operate on natural circulation, the expansion tank for heating is placed at the highest point of the system. Very often this is an attic, so the route turns out to be long.
And these are not all possible emergency situations. Floats sometimes do not shut off the water supply. If this happens to the toilet, the water simply runs into the drain. In the case of heating, water will flow into the attic, flooding the house... To avoid such a situation, it is necessary to control the overflow. In the simplest case, it is a pipe welded/attached at the required level with a hose connected to it. The hose can be led into the sewer, but then you also need to come up with an alarm system for overfilling the container (at the same time, the level will drop below critical). You can simply lead the hose a meter away from the house or run it into the drainage system. In this case, “traces” of overflow will be visible and it will be possible to respond in a timely manner without an alarm. So an open expansion tank for heating requires some retrofitting.
Closed type
An expansion tank for closed-type heating is installed in systems with forced movement of coolant. In them, the movement of the coolant is activated using a circulation pump. Such systems operate at elevated (relative to atmospheric) pressure. To maintain this pressure, the container must be sealed.
One of the main functions of an expansion tank for a closed heating system is to maintain stable pressure. To do this, the container is divided into two parts. One contains air or an inert gas (usually argon) pumped in at the factory. This part is sealed, there is a small diameter outlet in which a spool is installed (the operating principle is the same as that of a bicycle or car). The other chamber is empty and has an exit of some cross section. Through this outlet the expansion tank for heating is connected to the pipeline. During expansion, coolant enters this chamber.
The closed-type expansion tank is divided into chambers using an elastic rubber partition - membranes. It comes in two types: in the form of a diaphragm (disk) or a pear. There is not much difference, except that the bulb is easier to change. So bulb-type containers are more popular than diaphragm-type ones.
The operating principle of a membrane expansion tank is more complicated than an open one. A certain pressure is created in the “dry” chamber. It is selected depending on the operating pressure in the system, and the standard factory setting is 1.5 Bar. While the pressure in the system is lower than in the expansion tank, the “water” part of the tank remains empty.
When it gets higher, liquid begins to flow, the membrane stretches, increasing the pressure in the “gas” part of the tank. This process occurs until either the pressure in the system begins to drop (the coolant cools down) or the container is completely filled. The first case is normal operation of the heating system, the second is an emergency.
The second option means that the volume of the expansion tank is not enough. And this situation occurs when the size is incorrectly selected (too small) or when the boiler overheats. To maintain the functionality of the system in such situations, emergency valves are installed.
Determining the volume of the expansion tank and its selection
For normal heating operation, the expansion tank must have sufficient volume. There are two ways to determine it: you can calculate it using a formula, or you can use empirical data.
Empirical path
Let's start with the empirical method. Based on operating experience, it was concluded that if the volume of the expansion tank for heating is about 10% of the total volume of the heating system, this is sufficient. The question is how to determine the volume of the system. There are at least two ways:
- Count when filling (if it is filled with water and there is a meter, or when filling with coolant from canisters, you will know exactly how much liquid was pumped in).
- Calculate by volume of system elements. You will need to find information about how many liters fit in one meter of pipe, in one section of the radiator. With this data you can already find out the volume of the heating system.
Knowing how many liters of coolant are in your heating, it is easy to calculate the required volume of the membrane tank - it should be at least 10% of this figure. In the case of an open type tank, the actual volume can be at least doubled - there is less chance that the tank will be empty. At a minimum, you should add half - you will still underfill it by at least 1/3.
A membrane expansion tank for heating is usually taken without overestimating the calculated figure. The fact is that the larger the capacity, the more expensive the expander costs. And the price increase is significant. However, you should not take a smaller one - the pressure will “jump”, which will lead to early wear of components or even shutdown of the system. It is most likely that the heating will fail in cold weather, because in cold weather the coolant is hotter, which means its volume is larger. And it is at these moments that the volume of the expansion tank may not be enough. If you notice such symptoms and the calculation confirms that your membrane tank is of insufficient size, it is not necessary to change it to a larger one. You can put a second one. It is important that their total capacity is not less than the calculated value.
If there is antifreeze in the system
Heating antifreeze has greater thermal expansion than water. Moreover, different brands have different characteristics. Therefore, for this type of coolant, it is advisable to pre-calculate the volume of the expansion tank.
There are two ways: determine how for water, make an adjustment for greater thermal expansion. It depends on the percentage of ethylene glycol (antifreeze). For every 10% glycol, add 10% volume. That is:
- 10% ethylene glycol - must add 10% of the found volume of the water tank;
- 20% ethylene glycol - add 20%, etc.
This calculation is usually justified, but more accurate figures can be found using the formula (shown in the figure).
Once you have decided on the volume, it's time to buy an expansion tank. But in the store they are in different colors. At a minimum, there are blue (cyan) and red. So, membrane expansion tank for heating is always red. Blue ones are for plumbing, and for cold water. They are much cheaper, but the membrane there is made of rubber not suitable for high temperatures. So it will not last long in the heating system.
Pressure in the membrane tank and checking it
For a closed heating system to work properly, the pressure in the expansion tank must be 0.2-0.5 Bar lower than in the system. The larger the system, the greater the pressure difference. But, as already said, at the factory they are pumped up to 1.5 Bar, so before installing the expander, it is better to check it and adjust it to your heating system.
We check the pressure with a pressure gauge by connecting it to the outlet with the spool. If the pressure is higher than you need, bleed off a little. This is not difficult to do - press the petal in the nipple with something thin. You will hear the hiss of escaping air. When the pressure reaches the desired level, release the petal.
If the membrane tank is inflated too weakly (this also happens), it can be inflated with a regular pump. But it’s more convenient to use a car one, with a pressure gauge - you can immediately control the pressure. After verification, you can install it on the system.
Installation location
An expansion tank for closed-type heating is installed in a straight section in front of the circulation pump. Before, in the sense that the pump drives water from the expansion tank, and not into it. In this case, the expander works more correctly.
To install a membrane tank, install a tee, from which comes a pipe to which the container is connected. The installation height does not matter. But it is better to install shut-off valves in front of and behind the tank. The membrane fails every few years. Even more often you have to check it and pump it up. To avoid having to stop and drain the system for maintenance, a shut-off valve is installed. It is blocked off and the tank can be removed, checked, and repaired.
In open-type systems, the installation location of the expansion tank is selected based on other considerations. It is placed at the highest point of the system. In this case, it also works as an air collector. Air bubbles tend to rise, and if there is an expansion tank at the highest point, they rise to the surface, escaping into the atmosphere. So such a tank is deliberately made leaky so that the air from the heating system can escape naturally.
As a rule, the initial filling of the heating system is carried out by the specialists who installed it. However, during operation, situations may arise when this procedure has to be carried out independently. This usually occurs during repairs that involve complete or partial emptying of the system.
The process of filling heating with water largely depends on its design:
- Open. This system uses natural circulation of coolant (usually water) when there is no additional pressure. Its operation is based on the elementary laws of thermodynamics: the liquid circulates slowly here, because an additional pump is not used. At the highest point of the open circuit, a special expansion tank is installed to compensate for the increase in water volume when heated. This container absorbs excess water as it expands, returning it back when cooled. The tank is not sealed, so liquid constantly evaporates from it: its volume must be replenished from time to time. The boiler in an open system, as opposed to the tank, should be mounted at the very bottom of the circuit.
Open heating system
- Closed. A completely sealed system in which the heated coolant moves under the influence of a circulation pump. Closed-type heating is also equipped with an expansion tank, but unlike an open system, it is completely sealed and can be installed at any point in the system, not just on top. Inside the container there are two compartments, separated by a rubber membrane. The lower part of the expansion tank is filled with liquid, and the upper part is filled with air: thanks to its pressure on the membrane, a comfortable pressure level (1.5 atm.) is maintained in the circuit. When the temperature of the coolant rises, it penetrates through the valve into the expansion tank and compresses the air. After cooling, the liquid is pushed back into the circuit by compressed gas.
Closed heating system
The list of situations when there is a need to fill the heating system with water:
- On first launch. As already mentioned, this procedure is usually carried out by the plumbers who installed the heating system.
- Repair. Preliminary coolant discharge is accompanied by repair measures when it is necessary to repair or replace shut-off valves, radiator, pipeline section, etc.
- After seasonal reset. They try to empty systems with cast iron radiators after the end of the heating season, as this reduces the wear of the intersectional paronite gaskets by an order of magnitude. In addition, in some cases, the coolant can be drained for the winter: this usually happens in country houses, which are not used in winter.
- Reduced coolant quality. The liquid inside the system is constantly exposed to critical influences, either heating up or cooling down. This causes sediment to form (if water is used) in the form of lime and rust. For synthetic coolants, such an operating mode can lead to changes in the viscosity level. You should also take into account the fact that in metal circuits the liquid gradually accumulates iron impurities. All this leads to a decrease in heating efficiency and its service life, up to the failure of individual elements. Therefore, there are certain recommendations on the frequency of coolant replacement, depending on the situation. For example, it is recommended to change distilled water in a system with a double-circuit boiler once a year, before the start of a new heating season.
Preparation
Regardless of whether a new, just installed system is being launched, or the circuit has been reset to repair or replace the coolant, utility network Before filling out you must undergo certain training:
- Drain. Before pouring new coolant into the system, the old one must be completely drained. To do this, turn off the boiler and wait until the water temperature drops to room temperature. Next, by opening the drain valve at the bottom of the heating circuit, drain all the liquid: it must be collected in special containers for subsequent disposal. After waiting until the system is completely emptied, open the Mayevsky valve at its top point - this will allow the pressure in the pipes to stabilize.
Mayevsky crane
- Flushing. It is necessary to remove all debris from inside the circuit - chips, scale, limescale, etc. This is done using a pump connected to the network, which pumps the washing solution inside. It often takes several cycles until the water comes out completely clean. The water for the last rinse is enriched with neutralizers to remove additives in the first portions.
Flushing the heating system
- Pressing. It allows you to test how tight all joints and connections of the system are before filling in the coolant. To do this, create excess pressure inside the circuit by pumping air or using a coolant. To carry out the test, you will need a mechanical (electric) pump. There is also an option to connect the water supply, but this kind of procedure is much more difficult. Before connecting the pump to the inlet pipe of the system, you must carefully inspect all joints and connecting nodes. If no defects were found, excess pressure is created inside the circuit (the norm must be exceeded by 1.5 times).
Manual pressure test pump
- Elimination of leaks. All leaks discovered during pressing must be eliminated. If the flaw is at the junction, then it is repacked, installing a new seal. Leaks in the middle of the pipe are solved by replacing the damaged section.
- Checking the complete set. Before filling a closed heating system with water, it must be checked for the presence of the necessary safety equipment. We are talking primarily about Mayevsky taps, bypasses, thermometers and pressure gauges. If any of these elements are missing, it will most likely cause problems with the heating.
Calculation of coolant volume
In cases where water not from a pipeline is used as a coolant, it is important to know exactly how much liquid is needed.
This can be determined in the following ways:
- When resetting the system, measure the drained liquid using a meter or a special container of known volume. The same method can be applied when flushing and pressing the circuit.
- Separately summarize the volume of elements included in the system. The parameters of the boiler, batteries and expansion tank are indicated in the passport documentation for these products, and the volume of the pipeline is determined using special tables from the plumbing reference book.
Thread diameter, inch
Conditional bore, mm Volume, liter
15 0,177 20 0,314 25 0,491 32 0,804 40 1,257 2 50 2 1/2 65 3 80 4 100 The volume of coolant in one meter of pipe
Filling a closed heating system
Having prepared the required amount of coolant, you can begin filling the pre-washed and tested system. The most convenient way to do this is with a vibration pump.
Considering the particular importance of this procedure, care will be required when performing it:
- All joints are checked for defects and leaks for the last time.
- Shut off the shut-off valves through which coolant is removed from the heating circuit. This is done to avoid unnecessary fluid loss.
- Test to see if the air valves are working properly. If it turns out that their level of performance is insufficient, it is recommended to fully open the Mayevsky tap during the entire filling procedure. You can also leave the valve open in the upper section of the network, which will significantly speed up the release of air accumulated in the pipes.
Heating system elements
- Begin to pour water through the pipes adjacent to the boiler. In this case, it is advisable to supply the liquid as slowly as possible: in this case internal air will be able to drain freely through open fittings. Rushing at this stage usually leads to traffic jams. To avoid water hammer, the tap on the pipe through which water is supplied should be opened no more than halfway.
- As the circuit is filled, all taps and valves from which liquid begins to splash are closed: before starting the process, it is advisable to place an empty basin or bucket near each of them. For this reason, water is stored with a certain reserve, taking into account possible losses.
- When pouring water, it is recommended to change the position of the pump from time to time, switching to higher outlets. This is especially true for filling a closed system in houses with several floors.
- Checking the quality of the filling. To fill the amount of coolant, it is recommended to determine not only the total figure, but also the volume of individual sections of the circuit. This will allow for quality control of filling as it progresses using meters on the inlet pipes. This will allow you to monitor the amount of coolant already pumped in, comparing it with the volume of individual elements of the system. If, after filling a certain area, it turns out that less liquid was used than was calculated, it means that an air lock has formed inside. If the filled volume of coolant exceeds the calculated data, you need to look for the location of the leak.
- Draining excess air. Upon completion of the filling procedure of a closed system, all air must be removed from it. The main pipe is deaerated using air valve, which is usually available on the boiler. If the circuit uses a forced coolant circulation method, then bleeding air from pumping equipment This is done using an air valve, which is usually located at the front of the device.
Each radiator must also be freed from air pockets individually, starting with the heating elements on the ground floor. This procedure is very simple: using a key or a screwdriver, open the Mayevsky tap, closing it only after water appears in the hole. Finally, you need to check the return flow using the valves installed on it. Having released all the air, the pressure in the closed system must be brought to 1.5 atm, and only then shut off the water supply.
Feeding the system
To ensure efficient operation of a closed heating circuit, the pressure in it must be kept at a constant level. This is directly affected by the volume of coolant circulating through the pipes and radiators. In any case, it will gradually flow out, despite high level system tightness: to compensate for these losses, liquid replenishment will be required. The issue is solved by special make-up valves, which are equipped in areas of the circuit with the lowest pressure (most often, next to the pump, directly in front of it).
Make-up valve
Small houses with low-power heating systems are usually equipped with mechanical valves. In this scheme, compensation for pressure surges occurs thanks to the rubber membrane of the tank. To avoid the occurrence emergency situations you have to constantly monitor pressure parameters.
Automatic filling
Double-circuit boilers, as a rule, have a device for automatically filling the coolant. This electronic control unit is installed on the inlet pipe. The convenience of this solution lies in the fully automatic regulation of pressure in the system through timely pumping of liquid.
If the pressure in the network is critically low, a signal from the pressure gauge is sent to the control unit. This, in turn, activates the supply valve, which begins to allow water to flow into the system until the pressure is completely stabilized. However, you have to pay for convenience, which is reflected in the high cost of automatic filling devices.
In order to fill the open heating system of a private house with coolant, a slightly different procedure is used. The main difference from closed networks is the internal pressure of the circuit: here it corresponds to atmospheric pressure, which allows the use of an expansion tank as the main control device. In open heating systems it is mounted above all other elements.
Step-by-step instructions for filling an open heating system with water:
- Draining the old fluid and cleaning the circuit. This is done in the same way as in the case of a closed system.
- To pour water into an open system, an expansion tank is used, which looks like an open tank. Having removed the lid, they begin to pour water: filling a small circuit is usually done with a bucket. Filling large systems in this way is quite tedious, so it is better to use a household vibration pump. To do this, you will need a large tank with pre-prepared water. The pump is equipped flexible hoses on clamps: one end is immersed in a container of water, and the other in an expansion tank.
Extended tank
- It is recommended to supply water slowly so that the air has enough time to escape. When using a vibration pump, you need to ensure that the pressure in the circuit during its filling is within 1.5-2 atm. When it decreases, more water is added to the preparation tank so that the suction hose can be immersed deeper. The water supply is turned off after it begins to pour into the expansion tank.
- At the end of the procedure, it is necessary to free the circuit from air pockets. To do this, open the Mayevsky taps on all existing radiators one by one, closing them only after water appears. To avoid getting the floor wet, it is recommended to place a portable container under the taps. Having released the gas from all batteries, add water to the tank. As practice shows, the final release of air from an open system occurs through an expander after the first combustion.
During intensive use of open heating (most often this happens in winter), the coolant will gradually evaporate through the expansion tank. This is explained by the high temperature of the coolant. To maintain the functionality of the system, it must be periodically topped up, making sure that its temperature does not rise above +80 degrees.
There are several types of water poured into the heating circuit:
- Tap water. This also includes liquid taken from a well, a well or a nearby body of water. The main advantage of this option is its low cost. However, the quality of such a coolant is quite low: it has a rather aggressive effect on the internal walls of the circuit due to the salts and oxygen dissolved in it.
- Boiled. Boiling allows you to remove some of the oxygen and salts that precipitate from the water. However, preparing water for a volumetric circuit in this way is quite difficult.
- Purified by reagents. To neutralize harmful impurities Instead of boiling, it is convenient to use special chemicals - reagents. Water prepared in this way needs to be carefully filtered before being poured into the system.
- Distilled. It is sold in plumbing stores in containers of various sizes. Rainwater also has similar properties, which some owners of private houses specially collect for subsequent use in heating networks.
- Antifreeze. They are used instead of water in cases where the heating system is prone to freezing (the crystallization temperature of antifreeze is much lower than that of water). This method of filling the heating circuit is used quite rarely due to its high cost.
How to add water to heating: instructions for closed and open systems