When designing a heating system, measures must be taken to control temperature and pressure. To do this, it is necessary to install special fittings and devices. How to properly adjust the heating system: radiators, pressure and other elements? First you need to understand the principles of organization of these sections of the system.

Heating control methods

When the coolant is heated, it expands and, as a result, increases in volume. Therefore, before entering the apartment, it is necessary to ensure general control of the operation of the system.

Several types of devices are designed for this. They are conventionally divided into regulating and controlling. The first ones are designed to change the current characteristics of the system (pressure and temperature) towards decreasing or increasing. They are installed on a specific section of the pipeline or for the entire system as a whole. Control devices include pressure gauges and thermometers, mounted together with control devices or separately.

How to adjust the pressure in the heating system when operating solid fuel and gas boiler? To do this you need to be guided the following principles design of control systems:

• Installation of pressure gauges (thermometers) before and after the boiler, in distribution manifolds in the highest and lowest parts of the system;
• If there is a circulation pump, the pressure gauge is installed before it;
• Mandatory installation of an expansion tank. In closed systems it can be of the membrane type, in open systems it can be leaky;
• The safety valve and air vent will prevent critical excess pressure in the pipes.

The average water temperature in the pipes should not exceed 90 degrees. The pressure should be in the range from 1.5 to 3 atm. It is possible to make a system with parameters exceeding the specified ones, but in this case you will need to select special components.

If you cannot adjust the heating radiators in your apartment using a thermostat, there is most likely an air lock. To eliminate it, a Mayevsky crane is needed.

Regulating the heating of a private house

For owners of private houses, a pressing question is: how to adjust a two-pipe heating system. Unlike district heating, the parameters of autonomous heating are affected only by internal factors.

The main one is the design of the boiler, the types of fuel used and its thermal power. Also, the ability to adjust coolant parameters directly depends on the following system indicators:

• Pipe diameter and material. The larger the cross-section of the line, the faster the water will expand as a result of rising temperature;
• Radiator characteristics. Before adjusting the heating radiator, you need to make it correct connection to the pipeline. In the future, using special devices, you can reduce or increase the speed and volume of coolant passing through the heating device;
• Possibility of installing mixing units. They can be installed for a two-pipe heating system and with their help the water temperature is reduced by mixing hot and cold flows.

In order to find out how to adjust the heating system in a private home, it is recommended to consider all possible options.

The installation of pressure control mechanisms in the heating system must be provided for at the design stage. Otherwise, even a small error during installation can lead to loss of efficiency of the entire system.

Stabilization of pressure in the heating system

Expansion of water as a result of heating is a natural process. In this indicator, the pressure may exceed a critical value, which is unacceptable from the point of view of heating operation. In order to stabilize and reduce pressure on the internal surfaces of pipes and radiators, it is necessary to install several heating elements. Adjusting the heating system in a private home will be much easier and more efficient with their help.

Adjusting the expansion tank

It is a steel container divided into two chambers. One of them is filled with water from the system, and air is pumped into the second. The air pressure value is equal to normal in heating pipes. If this parameter is exceeded, the elastic membrane increases the volume of the water chamber, thereby compensating thermal expansion water.

Before adjusting the pressure drop in the heating system, you need to check the condition and settings of the expansion tank. You can adjust the pressure in the heating system by purchasing a tank model with the ability to change it in the air chamber. As additional measure install a pressure gauge to visually monitor this value.

However, if there is a significant surge in pressure, this measure will not be enough. This way you can adjust the pressure drop in the heating system if it does not exceed a critical value. Therefore, it is recommended to install additional devices.

How to adjust a security group

This group of devices includes the following elements:

• Pressure gauge. Designed for visual monitoring of the heating system operation;
• Air vent. If the water temperature exceeds 100 degrees, excess steam acts on the valve seat of the device, releasing air from the pipes;
• Safety valve. It works in the same way as a water drain, but is needed to drain excess coolant from the pipes.

How to adjust a heating radiator using this unit? Alas, it is designed to prevent emergency situations throughout the entire system. Batteries require another device to be installed.

Mayevsky crane

Structurally, it is similar to a safety valve. Features are small sizes and the ability to mount on a radiator pipe with a small diameter.

In order to correctly adjust heating radiators, you need to know in what cases the Mayevsky tap is used:

• Eliminating air pockets in radiators. By opening the valve, air is released until the coolant flows;
• Setting the critical pressure value parameters. If an emergency expansion of water occurs, the valve opens and the pressure in the radiator stabilizes.

The last function is optional and is most often not used. This task is best handled by the security team. Proper adjustment of heating in the house should include all of the above elements.

When independently regulating a two-pipe heating system while the boiler is running, you need to constantly monitor the readings of thermometers and pressure gauges.

Heating temperature control

An important parameter of any heating system is the optimal temperature regime for its operation. A ratio of hot and cooled coolant of 75/50 or 80/60 is considered suitable. However, this value is not always acceptable for certain parts of the network. How to properly adjust the heating in the house in this case? Installation of special equipment is required. Some of them are designed for adjusting heating radiators.

Mixing units

Their main element is a two or three-way valve. One of the pipes is connected to a heating pipe with hot water, the second to the reverse. The third is mounted on a section of the main line where it is necessary to ensure a lower level of coolant temperature.

As additional options, the mixing units are equipped with a temperature sensor and a thermostatic control unit. A signal is received from the sensor about the heating level of the coolant and it opens or closes the mixing valve, thereby regulating the two-pipe heating system. Most often, such mechanisms are installed in water-heated floor collectors.

If you need to adjust the heating of a water heated floor in an apartment building, you need to take into account the temperature conditions of the pipes. Most often it does not exceed 45 degrees.

Servo drives

How to adjust the heating in an apartment building if it is not possible to independently change the temperature of the water in the pipes? This requires installation of a special shut-off valves. You can limit yourself to installing simple taps - with their help, the flow of coolant into the radiators is regulated. However, in this case, the adjustment will have to be done independently each time. The best option There will be installation of servos.

The design of this device includes a thermostat and a servo drive. To work, you must perform the following steps.

1. Set the desired temperature value on the thermostat.
2. The servo drive will automatically open or close the flow of coolant into the radiator.

In addition to similar models, you can purchase an economy version that includes only a thermostat. In this case, the level of adjustment will not be as accurate. But how to adjust the heating system in an apartment building if old radiators are installed? There are models of thermostats that are designed for installation in cast iron radiators. This measure will make the adjustment temperature regime to the apartment more accurate.

Thermostats cannot be used to regulate the pressure drop in the heating system. They will only limit the flow of coolant into the radiator without affecting the temperature regime of the entire system.

All of the above devices and appliances are necessary for normal heating operation. But in addition to them, you need to know the basic rules for installing individual elements, since they directly affect the operation of the entire system. Regulation of heating radiators in an apartment begins at the installation stage.

First of all, you need to choose a connection method. The efficiency of the device and the possibility of installing a thermostat depend on it.

You should also take into account the pipe layout. In a single-pipe system, a bypass (jumper) must be installed, which is necessary to redirect the flow of coolant in the event of repair or replacement of the radiator. In a two-pipe connection of each heating element happens in parallel. Therefore, it is easiest to properly adjust the heating batteries.

In this way you can regulate the heating in an apartment building. But for autonomous system It is important to know the correct settings of the boiler.

Installing thermostats on radiators

Each heating system has a unique set of interconnected technical characteristics, which determine its effectiveness, reliability/uninterruption and safety. The most important indicators can be considered the temperature of the coolant in various areas and, of course, the operating pressure. For many users, high pressure in the heating system seems to be a phenomenon that is not entirely clear and even dangerous. However, it's not easy by-effect, which needs to be monitored every minute and maintained at a given level, but a tool with which you can monitor the performance of the heating.

A little theory about pressure in the heating system

Where does pressure come from and what does pressure depend on?

While the pipelines, radiators and heat exchangers are without coolant, the system experiences normal Atmosphere pressure(1 bar). As the heating installation is filled with water or antifreeze, the indicators will immediately begin to increase, albeit slightly. This is due to the fact that air is displaced, and liquid begins to act on the walls of all elements of the system from the inside. Cold liquid. This pressure appears due to gravity, even when the boiler has not yet been turned on and the pumps have not started pumping. The higher the pipes are spread, the larger it will be.

During the startup of the heat generator, the situation changes rapidly. As the temperature increases, the coolant expands and the pressure begins to rise sharply. The load on the walls becomes even greater when pumping equipment is activated for circulation.

It turns out that the water pressure in the heating system depends on the performance of the heat generator (heating temperature) and power pumping equipment. It is very important what heating scheme is used, how hydraulic calculations are made, whether the components are correctly selected and installed, and how accurately the system is adjusted. For example, the smaller the cross-section of the pipe passage in a certain area, the greater the hydraulic resistance there will be, and the higher the pressure will be. Any narrowing will act this way, including blockages or air plugs.

Note that the pressure in the autonomous heating network is different areas are never the same. The reasons are simple:

• the return temperature is lower than in the supply pipeline (especially at the outlet of the boiler);
• the energy/initial speed that water receives from the pump as it moves along the circuit decreases;
• pipe cross-section for different areas is selected differentially, and the flow force can be regulated by shut-off valves.

What types of pressure are considered in thermal engineering

To understand the essence of the issue and not get confused, you need to understand the terminology. There are several definitions in popular publications:

1. The static pressure of a heating system arises from the force of gravity acting on cold coolant. When the installation height increases by 1 meter, the pressure of the water column on the walls of pipes, instruments and devices increases by 0.1 bar.
2. Dynamic. Appears when the coolant is pumped by a pump, or the liquid begins to move under the influence of heat.
3. Working. It consists of static and dynamic. It will differ for different objects.
4. Excessive. This is the positive difference between the measured pressure and the atmospheric pressure (barometer reading). It is this difference that we determine with pressure gauges installed in heating system.
5. Absolute. The sum of atmospheric and excess pressure.
6. Nominal (conditional). An indicator characterizing the strength characteristics of equipment, which guarantees the service life declared by the manufacturer.
7. Maximum. The maximum pressure at which the heating system can operate without failures or accidents.
8. Crimping. After assembly or maintenance, the system is tested under load. What pressure is the heating under? Usually exceeding the working one by 1.2-1.5 times.

Pressure testing of pipelines

How to use pressure information

Optimal pressure in the heating system

The pressure is calculated in each case individually. For example, for structures with natural circulation it will not be much more than static. IN one-story cottages, where implemented forced circulation pumps, the operating pressure is set within 1.5-2.5 bar. As the number of floors increases, the pressure must be increased so that the coolant circulates normally. So for a five-story building it reaches 4 bar, in a nine-story building - up to 7 bar, and in high-rise new buildings - up to 10 bar. Depending on these indicators, the type of pipes for distribution and the model of heating devices with a given nominal pressure are selected.

Pressure control and regulation

For monitoring, pressure gauges are used, which allow real-time recording of excess pressure. These devices can have either a purely informative function or have electrical contacts that switch auxiliary devices or block the operation of the system in the event of pressure deviations.

Pressure gauges are installed using three-way fittings so that the device can be replaced or serviced without stopping the system. Considering the fact that the actual pressure will differ in different areas, several pressure gauges are needed. Usually they are mounted:

• at the boiler outlet and at the inlet,
• on both sides of the circulation pump and regulator,
• on both sides of the filters rough cleaning(you can determine their critical contamination),
• at the highest and lowest point of the system,
• near branches and collectors.

It is better to use several pressure gauges

To compensate for the volume of expanding coolant (for example, when the boiler, after a “sleep mode,” goes into operation at full power) and to prevent a sharp rise in pressure, membrane expansion tanks are used in closed systems. In systems with natural circulation, an open-type expansion tank is used, which is mounted at the highest point of the system.

The “safety group” plays a vital role in maintaining work pressure. A pressure gauge, air vent and safety valve. The pressure gauge shows the existing water pressure. An automatic air vent is used to remove air pockets. A certain amount of coolant is released through the valve until the pressure returns to normal.

In large buildings, to automatically maintain pressure and control coolant flow, the pressure must be actively manipulated. To do this, pressure regulators are installed into the system, operating on the “after” or “before” principle.

Diaphragm expansion tank design

Why does the network pressure fluctuate?

What does an increase in coolant pressure in the heating system indicate:

• Significant overheating of the coolant.
• Insufficient pipe cross-section
• A large number of deposits in pipelines and heating devices.
• Air jams.
• Pump capacity too high.
• Make-up is open.
• The system is “regulated” by taps (perhaps some valve is closed, valves or regulators are not working correctly).

Security block assembly

What does the pressure drop mean:

• Depressurization of the system and leakage of coolant.
• Failure of pumping equipment.
• Expansion tank membrane rupture.
• Security unit malfunction.
• Flow of coolant from the heating circuit to the make-up circuit.
• Clogged pipes, filters, radiators. The duct is blocked by a shut-off and control device. In both cases, a loss of pressure in the heating system is observed after the obstacle.

As we see, there are objective technical specifications, by changing which, it is possible to establish the optimal operating pressure at the project implementation stage and control it during operation. But sooner or later the pressure gauge needles deviate from the set values. Significant pressure drops in the same areas indicate that the system has started to work incorrectly, and you need to look for the cause of the problem.

Video: pressure from the boiler expansion tank

Following a failure of pressure in the heating system, a problem comes - the quality of heating the premises in the house decreases. You can, of course, adjust the heating operation once and for a long time, but this period will not be indefinitely long. One day, the normal pressure in the heating system will change, and significantly.

We will tell you how to keep the physical parameters of the coolant under control. Here you will learn how to ensure a stable speed of movement of heated water through the pipeline to the devices. You will understand how to obtain and maintain a comfortable indoor temperature.

The article proposed for consideration describes in detail the reasons for the pressure drop in closed and open systems. Given effective methods balancing. The information presented for review is supplemented with diagrams, step by step instructions, photos and video tutorials.

Depending on the current principle of coolant movement in the heat pipeline of the circuit, in heating systems main role performs static or dynamic pressure.

Static pressure, also called gravitational pressure, develops due to the gravitational force of our planet. The higher the water rises along the contour, the more its weight presses on the walls of the pipes.

When the coolant rises to a height of 10 meters, the static pressure will be 1 bar (0.981 atmosphere). An open heating system is designed for static pressure; its maximum value is about 1.52 bar (1.5 atmospheres).

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The dynamic pressure in the heating circuit develops artificially -. As a rule, closed heating systems are designed for dynamic pressure, the contour of which is formed by pipes of significantly smaller diameter than in open heating systems.

Normal value of dynamic pressure in a heating system closed type– 2.4 bar or 2.36 atmospheres.

Consequences of instability in circuits

Insufficient or higher pressure in the heating circuit is equally bad. In the first case, some of the radiators will not effectively heat the rooms; in the second, the integrity of the heating system will be compromised and its individual elements will fail.

Correct piping will allow you to connect the boiler to the heating circuit as necessary for high-quality operation of the heating system

An increase in dynamic pressure in the heating pipeline occurs if:

• the coolant is too overheated;
• the pipe cross-section is insufficient;
• the boiler and pipeline are overgrown with scale;
• air jams in system;
• a booster pump that is too powerful is installed;
• water replenishment occurs.

Also high blood pressure c is caused by incorrect balancing of the taps (the system is over-regulated) or malfunction of individual regulator valves.

For monitoring operating parameters in closed heating circuits and for their automatic adjustment security group is set:

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The pressure in the heating pipeline drops for the following reasons:

• coolant leak;
• pump malfunction;
• rupture of the expansion chamber membrane, cracks in the walls of a conventional expansion tank;
• security unit malfunction;
• water leakage from the heating system into the feed circuit.

The dynamic pressure will be increased if the cavities of the pipes and radiators are clogged, if the catch filters are dirty. In such situations, the pump works under increased load, and the efficiency of the heating circuit decreases. The standard result of exceeding pressure values ​​is leaks in connections and even pipe ruptures.

The pressure parameters will be lower than required for normal functionality if a pump of insufficient power is installed in the main line. It will not be able to move the coolant at the required speed, which means that a somewhat cooled working medium will be supplied to the device.

The second striking example of a drop in pressure is when the flow is blocked by a tap. A sign of these problems is the loss of pressure in a separate segment of the pipeline located after the obstacle to the coolant.

Since all heating circuits contain devices that protect against excessive pressure (at least), the problem low pressure happens much more often. Let's consider the reasons for the drop and ways to increase pressure, and therefore improve water circulation, in open and closed heating systems.

Pressure in an open heating system

Unlike a closed thermal circuit, a properly constructed open heating system does not require balancing over years of operation - it is self-regulating. Boiler operation and static pressure ensure constant circulation of water in the system.

The density of the heated water following the supply riser is lower than the density of the cooled coolant. Hot water tends to occupy the highest possible point of the contour, and the cooled one tends to be at its very bottom.

The pressure required for water circulation is achieved by the pressure in the supply riser or by a booster pump (+)

The pressure developed by the water column in the supply riser promotes the circulation of the coolant and compensates for the resistance present in the circuit pipeline. It is caused by the friction of water on the inner surface of the pipes, as well as local resistance (turns and branches of the pipeline, boiler, fittings).

By the way, pipes of increased diameter are used for assembly precisely to reduce friction.

To understand how to increase pressure in an open heating system, you must first understand the principle of achieving circulation pressure in the thermal circuit.

Its formula:

R c = h (p o -r g),

• R c – circulation pressure;
• h – vertical distance between the centers of the boiler and the lower heating radiator;
• r g – density of the heated coolant;
• p o – density of the cooled coolant.

The static pressure will be higher if the distance between the central axes of the boiler and the battery closest to it is as significant as possible. Accordingly, the intensity of coolant circulation will be higher.

To achieve the maximum possible pressure in the heating circuit, it is necessary to lower the boiler as low as possible - into the basement.

The closer the radiator is to the boiler on the supply circuit, the better it warms up. Regulators allow you to distribute heat between all radiators of the heating system

The second reason for the drop in pressure in an open heating system is related to its self-regulation. When the heating temperature of the coolant changes, the intensity of its flow changes. By increasing the heating of water for the heating circuit on cold winter days, owners sharply reduce its density.

However, when passing through heating radiators, water gives off heat room atmosphere, while its density increases. And according to the formula presented above, a high difference in the densities of hot and chilled water helps to increase the circulation pressure.

The more the coolant is heated and the colder it is in the rooms of the house, the higher the pressure in the system will be. However, after the atmosphere of the premises warms up and the heat transfer from the radiators decreases, the pressure in the open system will drop - the difference between the supply and return water temperatures will decrease.

Balancing a double-circuit open heating system

Gravity heating systems are made with one or more circuits. In this case, the horizontal length of each looped pipeline should not exceed 30 m.

But to achieve optimal pressure and the pressure in the open coolant, it is better to make pipelines even shorter - less than 25 m. Then it will be easier for water to deal with hydraulic resistance. In a circuit with several rings, in addition to limiting the length, the condition for heating radiators must be observed - the number of sections in all rings must be approximately equal.

Lack of pressure in an open double-circuit thermal system occurs due to design errors or contamination of the pipeline (+)

Balancing of the horizontal rings included in the vertical circuit is required at the design stage of the heating system. If the hydraulic resistance of any ring is higher than that of the others - static pressure there will not be enough in it and the pressure will practically stop.

To maintain the required pressure in a double-circuit heating system, it is necessary to reduce the cross-section of the pipes approaching the radiators. You can also install valves in front of the radiators that perform thermoregulation (manual or automatic).

You can balance an open-type dual-circuit system:

• Manually. We start the heating system, then measure the temperature of the atmosphere of each heated room. Where it is higher, we screw the valve, where it is lower, we unscrew it. To adjust the heat balance, you will have to perform temperature measurements and adjusting the valves several times;
• Using thermostatic valves. Balancing occurs almost independently, you just need to set desired temperature in each room on the valve handles. Each such device will control the supply of coolant to the radiator itself, increasing or decreasing the supply of coolant.

It is especially important that the value of the total hydraulic resistance of the heating system (all rings in the circuits) does not exceed the value of the circulation pressure. Otherwise, warming up the coolant and attempting to balance the system will not improve circulation.

Circulation pump for open heating system

It happens that measures to balance the heating circuit of a gravity system have no effect. Not all causes of low pressure can be solved by adjustment - choosing the wrong pipe diameter cannot be corrected without a complete reconstruction of the circuit.

Then, to increase the pressure and improve the movement of water without significant modifications to the heating system or booster pumping device. The only thing that its installation will require is moving the expansion tank or replacing it with a membrane expansion tank (closed tank).

In case of a serious drop in pressure, not a circulation pump, but a more powerful booster pump is needed. However for open systems heating booster pumps are not suitable, because develop significant dynamic pressure

The energy consumption of circulation pumps does not exceed 100 W. Therefore, there is no need to fear that it will push the coolant out of the circuit.

The volume of water in the heating system is more or less constant, provided that the filling of the open circuit is controlled. Therefore, no matter how much water the circulation pump pushes along the circuit in front of it, the same amount will flow into it from the return pipe.

By bringing the pressure in the thermal system to the required level, the pump will make it possible to lengthen it, reduce the diameter of the pipeline and achieve circuit balance with high hydraulic resistance.

Pressure in a closed heating system

Installing a modern boiler, especially a double-circuit boiler, is called by sellers the ideal solution for home heating. With high-quality installation, a new boiler will serve you well for several years, but one day the pressure in it drops sharply or gradually. How to find the cause of low dynamic pressure?

A closed heating system requires close attention. A drop or rise in pressure is equally dangerous for her. Being left without heating in winter is a homeowner's worst nightmare.

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First of all, both the boost and the ones present in the thermal circuit are checked. This device wears out faster than a boiler, expansion tank or pipeline, so its condition is determined first. It is important to make sure that the “silent” pump is receiving power and only then take measures to replace the device.

In general, it is more rational to integrate two pumps into the heating circuit in advance - one in the main pipe, the second in the bypass. A closed heating system cannot operate at low dynamic pressure. Therefore, a spare pump, turned on in time, will protect the house and pipeline from freezing.

If the pump is working properly, the source of the pressure loss is in the boiler or piping system. We check the boiler last, first the heating circuit.

Steps to find a coolant leak

It is possible to independently detect leaks in the heating system if the pipes are installed openly and there is access to the taps and all connecting elements. It is also necessary to remove decorative cladding heating radiators.

You need to walk along the entire thermal circuit with a flashlight, carefully studying every connection, every element of the system (boiler piping too). We are looking for puddles of water, wet spots on the floor, traces of dried water, rusty streaks on pipes, batteries and shut-off valves.

We take a small mirror, illuminate it with a flashlight and inspect the back side of each section. If the batteries are prefabricated, made of cast iron or aluminum, you should inspect the connections between the sections. Corrosion and streaks of rust are a sign of a leak, even if the floor is dry under the radiator.

There are situations when the pressure in the circuit drops slowly, day by day. Moreover, there are absolutely no visible traces of leakage on the elements of the heating system or on the floor. Or rather, there are leaks and there are a lot of them, but they cannot be detected.

Flowing water evaporates on a pipe, radiator or on the floor surface, i.e. no noticeable puddles are formed. It is necessary to identify places where coolant may leak, place sheets of soft paper under them - napkins or toilet paper. After a few hours, check the paper for moisture. If it's wet, that means there's a leak here.

The serviceability of the boiler safety group lies not only in the operation of the pressure gauge, safety valve and air vent. None of its elements or detachable connections should leak.

In a house equipped with a partially hidden heating piping system, it is impossible to find leaks on your own. All that remains is to call heating engineers who will search for leaks in the heating circuit using special equipment.

Thermal technical search for leaks in the heating system is performed in a certain sequence. First, the coolant is drained from the circuit.

Then a compressor is connected to the entire heating pipeline or to its individual segments equipped with shut-off valves via a threaded connection. As a last resort, you can connect a car pump to the pipeline.

A few minutes after the start of pumping air into the heating circuit, a distinct sound of escaping air will be heard in places of leakage. Each section of the heating system embedded in a wall or floor with a leak detected by sound must be opened from the cement screed.

Pressure drops in the heating boiler

Let us note right away that only a heating engineer from the service department can determine the exact breakdown of boiler equipment. Those. The homeowner will not be able to independently find out and, moreover, eliminate a serious breakdown that caused a drop in pressure in the heating boiler.

Let's consider possible reasons“creeping” change in pressure on the boiler pressure gauge, which occurs when the boiler is in external condition.

Crack in the heat exchanger. Over the years of operation, the walls of the heat exchanger in the boiler may develop microcracks. The reasons for their formation are wear of the unit, weakening of strength during washing, pressure testing (water hammer) or manufacturing defects. The coolant flows through them and the boiler requires water replenishment every 3-5 days.

The leak cannot be detected visually - the water flows weakly, and when the burner is turned on, the moisture accumulated in the boiler evaporates. The heat exchanger needs to be replaced, less often it can be soldered.

The three-way valve is ideal for multi-ring heating systems. However throughput of such a faucet is strongly linked to how often it will be cleaned of contaminants

The pressure rises due to the open make-up tap. Against the background of low dynamic pressure in the boiler and more high pressure in the water supply system, “excess” water enters the heating system through the make-up tap. The pressure in the heating circuit increases to the point where it needs to be released through the safety valve of the boiler unit.

If the pressure in the water supply drops, the coolant of the heating circuit will transfer its flow into the boiler, then the pressure in the heating system will decrease. A similar problem occurs with a faulty make-up valve. You need to either close the tap or replace it.

Increase in pressure due to three-way valve. If a valve installed on a double-circuit boiler malfunctions, water from the “household” heating sector will flow into the heating system. Three way valve requires cleaning or replacement.

The boiler pressure gauge readings do not change. If, when the operating modes of the boiler change, or when the temperature in the circuit increases or decreases, the pressure gauge shows the same pressure, it is “stuck”. Those. dirt from the heating system got into it through the pipe. The pressure gauge needs to be replaced.

Low pressure due to expansion tank

In closed heating systems, the following situation often occurs: when starting in heating mode, the pressure on the boiler pressure gauge increases sharply. If the circuit is completely filled with water, the pressure increases to 3 bar and the relief valve is activated, releasing part of the water.

The homeowner turns off the burner and waits for the water to cool. At the same time, the pressure drops to a minimum. Next, the owner then tries to turn on the boiler. But the unit does not work, it gives an “emergency” signal. Although sometimes it is possible to activate the work double-circuit boiler unless the pressure drops too much.

The position of the expansion chamber next to the heating boiler is explained by its importance for the thermal system. The condition and serviceability of the expansion tank must be carefully monitored

All that remains is to try to increase the pressure by adding water to the system in “cold” mode (with the burner off) and achieving a pressure gauge reading of 1.2-1.5 bar. But restarting the boiler occurs with the same result: the pressure increases; the relief valve is activated; the water is drained; pressure at minimum; the boiler does not want to work.

There may be several reasons for this malfunction. However, a common source of the problem is. Moreover, it does not matter where it is located - inside the boiler or outside it.

The expanzomat is divided into two parts by a flexible membrane. One contains coolant, the other gas (usually nitrogen) under a pressure of 1.5 bar. The water contained in the thermal circuit, expanding when heated, presses through the membrane onto the gas compartment of the membrane tank. To compensate for the increased pressure in the system, the gas in the expansion chamber is compressed.

After years of using a closed heating circuit, the nipple through which gas was pumped into the expansion tank begins to leak. It happens that the gas is dumped by homeowners themselves who do not understand the purpose of the nipple.

In any scenario, the gas in the expansion chamber becomes less and less. Soon the expansion tank is no longer able to compensate for the pressure of the expanding coolant in the system; its values ​​reach a maximum.

A closed heating system will react to a malfunction of the expansion tank with a sharp rise and fall in dynamic pressure

Let's figure out how to solve the problem of lack of gas in the expansion tank. First we turn off the boiler; if it is electric, from the mains too.

If the expansion tank is built into the boiler, you need to block the access of water to both circuits (or one). Drain the water from the boiler completely. If the expanzomat is located separately from the boiler, you need “its” piece of pipeline from the general network and drain the water from there.

Then take a car pump equipped with a pressure gauge (a pressure gauge is required), attach it to the nipple on the expansion machine and pump it up. Water will flow from the blocked sector of the pipeline (or boiler, if the tank is in it) - pump further.

We monitor the pump pressure gauge. The water has stopped flowing out, and the pressure has reached 1.2-1.5 bar - we stop pumping air.

All that remains is to open the shut-off valves, fill the circuit with water to 1.2-1.5 bar, and then turn on the boiler. The heating system will work. If you discover that the problem with pressure has reappeared after a while, replace the expansion valve nipple, it is leaking heavily.

Note that there may be another problem with the tank, a more complex one - rupture of the membrane. Then pumping with air will not help, you will have to change the expansion chamber.

Conclusions and useful video on the topic

Video #1. How to balance heating radiators in a home heating system. Let us remind you that without valves on each heating radiator it will not be possible to balance the system.

A properly balanced heating system will perform its functions for several years. But one day the characteristics of the coolant will change or critical elements of the thermal circuit will fail. Therefore, it is necessary to constantly monitor coolant indicators using pressure gauges in order to promptly respond to pressure changes.

Please write comments if you have any questions about the topic of the article. We are waiting for your stories about your own experience in normalizing pressure in the heating circuit. We and site visitors are ready to discuss controversial issues in the block located under the text of the article.

Normal pressure in a closed heating system is very important. Firstly, this warm room V winter time, and secondly, the normal operation of all components of the boiler. But the needle is not always in the range we need, and there can be many reasons for this. High and low pressure in the heating system leads to pump blocking and lack of warm batteries. Let's talk in more detail about how many atmospheres our pipes should have and how to fix common problems.

Some general information

Even at this stage, pressure gauges are installed in different places. This is necessary in order to control blood pressure. When the device detects a deviation from the norm, it is necessary to take some action; a little later we will talk about what to do in a specific situation. If no measures are taken, the heating efficiency drops and the service life of the same boiler is reduced. Many people know that the most detrimental effect on closed systems is caused by water hammer, for damping which expansion tanks are provided. So, before everyone heating season It is advisable to check the system for weaknesses. This is done quite simply. You need to create excess pressure and see where it shows up.

Low and high pressure in the system

Often, the pressure drop in the heating system is due to several factors. Firstly, this is a coolant leak, which is the most common reason for a decrease in the number of atmospheres. Leaks are most often located at the joints of parts. If it is not there, then most likely the problem is in the pump. Scale in the heat exchanger is another reason for low pressure in the system. The same applies to physical wear and tear of the heating element. But an increase in pressure occurs due to the formation of an air lock. The cause may also be difficulty in the movement of the carrier through the pipes due to obstruction in the filter or sump. Sometimes, due to automation failures, the system is overcharged, in which case the pressure also increases.

How to correct the situation when there is a difference?

Everything here is extremely simple. First, you need to look at the pressure gauge, which has several characteristic zones. If the arrow is in the green, then everything is fine, but if it is noticed that the pressure in the heating system is dropping, then the indicator will be in the white zone. There is also a red one, it signals an increase. In most cases, you can handle it on your own. First you need to find two valves. One of them is used for injection, the second is for bleeding the media out of the system. Then everything is simple and clear. If there is a shortage of media in the system, it is necessary to open the discharge valve and monitor the pressure gauge installed on the boiler. When the arrow reaches the required value, close the valve. If bleeding is needed, everything is done in the same way with the only difference being that you need to take with you a vessel into which the water from the system will be drained. When the pressure gauge needle shows normal, tighten the valve. Often this is how the pressure drop in the heating system is “treated”. Now let's move on.

What should be the operating pressure in the heating system?

But to answer this question in a nutshell is quite simple. Much depends on what kind of house you live in. For example, for an autonomous or apartment, 0.7-1.5 Atm is often considered normal. But again, these are approximate figures, since one boiler is designed to operate in a wider range, for example, 0.5-2.0 Atm, and the other in a smaller one. This must be looked at in the passport of your boiler. If there is none, stick to the golden mean - 1.5 Atm. The situation is completely different in those houses that are connected to central heating. In this case, it is necessary to be guided by the number of floors. In 9-story buildings, the ideal pressure is 5-7 atm, and in high-rise buildings- 7-10 Atm. As for the pressure under which the carrier is supplied to buildings, most often it is 12 Atm. You can reduce the pressure using pressure regulators, and increase it by installing a circulation pump. The last option is extremely relevant for the upper floors of high-rise buildings.

How does media temperature affect pressure?

After the closed water supply system is installed, a certain amount of coolant is pumped in. As a rule, the pressure in the system should be minimal. This is due to the fact that the water is still cold. When the carrier heats up, it will expand and, as a result, the pressure inside the system will increase slightly. In principle, it makes perfect sense to regulate the number of atmospheres by adjusting the temperature of the water. Currently, expansion tanks are used, they are also hydraulic accumulators, which accumulate energy within themselves and do not allow an increase in pressure. The principle of operation of the system is extremely simple. When the operating pressure in the heating system reaches 2 Atm, the expansion tank comes into operation. The hydraulic accumulator absorbs excess coolant, thereby maintaining the pressure at the required level. But it happens that the expansion tank is full, there is nowhere for the excess water to go, in which case critical excess pressure (more than 3 Atm.) may arise in the system. To save the system from destruction, it turns on to remove excess water.

Static and dynamic pressure

If in simple words To explain the role of static pressure in a closed heating system, it can be expressed something like this: this is the force with which the liquid presses on the radiator and pipeline, depending on the height. So, for every 10 meters there is +1 Atm. But this only applies natural circulation. There is also dynamic pressure, which is characterized by the pressure on the pipeline and radiators while driving. Please note that during installation closed system heating systems with a circulation pump add static and dynamic pressure, while taking into account the characteristics of the equipment. So, cast iron battery designed to operate at 0.6 MPa.

Pipe diameter and degree of wear

It is necessary to remember that the size of the pipe must also be taken into account. Often, residents set the diameter they need, which is almost always slightly larger standard sizes. This leads to the fact that the pressure in the system decreases slightly, which is due to the large amount of coolant that will fit into the system. Do not forget that in corner rooms the pressure in the pipes is always less, since this is the most remote point of the pipeline. The degree of wear of pipes and radiators also influences the pressure in the heating system of the house. As practice shows, the older the batteries, the worse. Of course, not everyone can change them every 5-10 years, and it is not advisable to do this, but it doesn’t hurt to carry out preventive maintenance from time to time. If you are moving to a new place of residence and you know that the heating system there is old, then it is better to change it immediately, so you will avoid many troubles.

About Leak Testing

It is imperative to check the system for leaks. This is done to ensure that the heating operation is efficient and does not have failures. IN multi-storey buildings With central heating most often resort to testing cold water. In this case, if the heating system drops by more than 0.06 MPa in 30 minutes or 0.02 MPa is lost in 120 minutes, it is necessary to look for places where there are gusts. If the indicators do not go beyond the norm, then you can start the system and begin the heating season. Hot water testing is carried out immediately before the heating season. In this case, the media is supplied under pressure, which is the maximum for the equipment.

Conclusion

As you can see, dealing with this issue is quite simple. If you are using heating system, then the operating pressure in the system should be approximately 0.7-1.5 Atm. In other cases, much depends on the number of storeys of the building, as well as the degree of wear of the batteries and radiators. In all cases, care must be taken to install an expansion tank, which will prevent the occurrence of water hammer and, if necessary, reduce the pressure. Remember that it is advisable to clean the pipes from scale and other decay products at least once every 2-3 years before the heating season.

Most household heating systems depend on the pressure and temperature conditions of the coolant.

Heating works by running heated fluid through pipes and radiators, delivering heat throughout the house thanks to pressure differences in the system.

However, the difference can fail, which requires its adjustment to a smaller or larger direction. This procedure is necessary to restore operational efficiency and maintain safety during its operation.

Standards for pressure drop in the heating system of a private and apartment building

Drop standards are governed by regulations GOST and SNiP. The given documentation calculations ensure full operation of the entire system heating equipment, including objects:

• one-story building - 0.1–0.15 MPa or 1–1.5 atmospheres;
• low-rise building ( maximum three floors) — 0.2-0.4 MPa or 2-4 atm.;
• apartment house with an average number of floors ( 5-9 floors) —0.5-0.7 MPa or 5-7 atm.;
• high-rise apartment buildings — up to 10 MPa or 10 atm.

The difference itself must be 0.2-0.25 MPa or 2-2.5 atmospheres.

Why does pressure fluctuate and when does it not occur?

Special the jump is needed so that the coolant does not stagnate in one place, but constantly circulated between the direct pipeline of the boiler room (during supply) and the radiators of the house (during reverse flow). Thanks to the difference in 2.5 atmospheres, the coolant “runs” at a speed that stably maintains a comfortable temperature.

If the pressure is not enough, heating devices do not receive effective heat transfer from the coolant liquid and the room becomes cold.

Calculation method

IN central system heating systems exist two types of pressure:

• crimping: temporary, with increased load, which is created to test the system after repair and installation work or before the heating season;
• working: constant, at which the system should function perfectly throughout the heating period.

For correct calculation pressure difference, you need to take into account the difference between two points of the heating circuit: on the top floor and the bottom. Final indicator with a functioning pressure should not exceed 10%, and when crimping - 20%.

Usually in the city multi-storey building, working pressure is on the supply pipe - 6 atmospheres, and on the return path - 4-4.5 atm.

Reference. The pressure indicator is influenced by many factors, including clogging of the internal channels of the circuits.

For private houses, a critical indicator is the power of the boiler, i.e. the level of pressure that the unit can withstand. Usually, 2-3 atmospheres For one-story house quite enough.

Regulator for pressure regulation

To comply with all measures for the safe operation of the heating system, It is necessary to constantly monitor the temperature and pressure of the coolant.

Pressure controlled using a Bourdon tube pressure gauge. This device has an elastic measuring component, which, under the influence of a compressive load, is deformed in a certain way.

Photo 1. Pressure gauge installed in the heating system. The device allows you to measure pressure readings.

Converting Changes displayed on the rotational movement of the arrow, showing on the dial the exact value in the usual indicators.

Important! After water hammer, pressure gauges need to be checked, since subsequent readings may be overestimated.

Pressure gauges are installed in the most critical areas of the system:

• at the inlet and outlet of the coolant line ( central heating);
• before and after the heating boiler (individual heating);
• before and after the circulation pump (forced circulation);
• near filters, related regulators and valves.

How to adjust indicators

There are several proven methods for this procedure:

1. Correctness of design, incl. hydraulic calculations and installation of pipelines:

• the supply line should be at the top and the return line at the bottom;
• pipes are needed for risers 20-25 mm, and for bottlings - 50-80 mm;
• pipes for risers are also used for supplying heating devices.

1. Change in water temperature. When heated, the coolant expands, thereby increasing the pressure in the heating system. Eg, at 20°C it may jump 0.13 MPa, A at 70°C- on 0.19 MPa. Therefore, reducing the temperature will lead to its corresponding adjustment.
2. Application of circulation pumps to provide heat to apartments upper floors in high-rises.

Photo 2. Circulation pumps installed in a multi-storey building. The devices circulate coolant through the heating system.

1. Introduction of expansion tanks. At individual heating, the “extra” volume of heated coolant will go into the container, and the cooled volume will return to the system, maintaining pressure stability.
2. Using special controls. Such devices are able to prevent airing of the system during sudden pressure surges in the lines. Installation is carried out on the pump bypass line or on a jumper placed between two pipelines - supply and return.

Causes of pressure drop and ways to eliminate them

Among the main reasons for the drop in pressure are the following:

• a leak coolant;
• reduction in radiator volume when eliminating the air masses contained in it;
• reducing device temperature due to damage to boiler equipment;
• malfunction pumping equipment (with forced circulation).

Leaks can be detected visually carefully inspecting the pipes and radiators, and also turning off the pump. If the static (natural) pressure remains at the same level, then the reason will be in the pumping equipment.

If the coolant temperature drops, it is necessary to check the boiler, and if the volume decreases due to air, simply restore it.

Why pressure increases, troubleshooting methods

Pressure rises in the heating system due to the following reasons:

• airing of the system;
• excessive clogging of filters;
• malfunction of the corresponding regulator or its incorrect setting;
• increase in coolant volume due to incorrect functioning of the control automation.

First you need clean the filters and remove air pockets in the system. After check the operation of the automation, by turning off the recharge. Then test the regulator by adjusting its settings.

What are the consequences of increased and decreased indicators?

The consequences of incorrect pressure can be different - from sudden change in temperature indoors (too cold or too hot) until lack of water on the highest floors.