Boiler with forced circulation. Scheme and features of the operation of a closed-type heating system with forced circulation, video. The difference between single-circuit heating and double-circuit heating

Designing a private house involves calculating the scheme heating system, which is open and closed (assuming the installation of an expansion tank). The second option is considered the most preferable among the owners of cottages, as it makes it possible to significantly save on the consumption of resources. The main advantage of such a system is that the coolant does not come into contact with air, which means it does not corrode the equipment.

The main element of a closed-type heating system is a boiler, to which a pipeline is connected. A tank and a circulation pump are also installed. Typically, this method of heating implies that the carrier moves through the pipes forcibly. This is a volatile method, as the devices are powered by electricity. When the light is turned off, care must be taken to continue activities in the normal mode. To do this, install a special adapter - a bypass, which blocks the pump and converts it into a closed heating system with natural circulation.

If we are talking about a single-pipe heating option, it is important to ensure an even distribution of the carrier over the radiators in a private house. A pipe is launched from the boiler through all rooms, to which batteries are mounted. Without the pump running, only the elements in the immediate vicinity of the heater will be hot. Cold air will remain in the rest of the rooms. This problem is solved closed system heating with forced circulation. Thanks to the scheme, pressure is created at which the carrier receives a certain speed, sufficient to provide all the radiators.

In the two-pipe version, the approach is also rational, especially for maintenance large areas. This type of heating involves the connection of two parallel lines. One at a time, the hot liquid diverges through the pressurized batteries in case it acts forcibly. Through another pipe, the cooled carrier returns to the boiler, bypassing expansion tank.

There is a horizontal and vertical wiring of the highway. The first type involves combining all batteries into a single line connected to a common riser. Most often, this method is used in multi-apartment buildings. The second option is considered more effective, usually mounted in a private house. The supply pipes are located at the top, which ensures good heat dissipation in closed systems.

The size of the tank depends on the volume of the carrier. The parameter should be 10% of all heating equipment. Automatic boilers allow you to control processes, regulate pressure and temperature. Overheating sensor activates safety valve at the moment of boiling liquid, protecting equipment from breakdowns. Frost protection equipment works in the same way.

Principle of operation

To understand what a closed heating system is, it is necessary to understand the intricacies of its functioning. The liquid coolant is heated to a predetermined temperature and begins to move through the radiators and pipes, transferring energy to the room and heating. The microclimate in a private house depends on the volume and condition of the liquid. The hotter it is and the greater its quantity, the more comfortable it is to be in the rooms.

When the valve is opened, the excess volume of water is discharged into the expansion tank of the heating system, which is equipped with two chambers separated by a partition. The first compartment is used to store a reserve of liquid, the second contains pressurized nitrogen. Such a scheme helps to maintain the pressure at the same level. Forcibly, the carrier is returned back by means of a pump, in a cooled form. To drain the water at the lowest point, a pipe with a valve is installed.

No matter how securely the forced circulation heating system is insulated, air can get into it during filling and subsequent water intake. At this time, depressurization of the joints occurs. To remove bubbles, standard taps and Mayevsky taps are used. When installing separators in the pipeline, deaeration and stability of the functioning of all elements are guaranteed.

Advantages and disadvantages

A closed heating system has its positive and negative sides:

1. Installation is much faster than furnishing open type.

2. Diaphragm and non-pressure tanks do not allow liquid to escape.

3. Even with small diameter pipes, efficiency is maintained.

4. The impossibility of ingress of oxygen implies protection against corrosion.

5. Water or antifreeze is used as a carrier in the heating system.

6. The expansion tank can be installed next to the boiler.

7. High heat dissipation rate ensures stable heating.

The following factors were noted as disadvantages:

  • The use of a pump implies dependence on electricity.
  • The closed type requires a large volume tank.
  • Without automation, it is quite difficult to regulate temperature and pressure.
  • If you plan to use it forcibly, a pump must be installed.

The main nuances of setting up and launching

The scheme for connecting the heating system consists in installing the boiler in a ventilated room. At the outlet, a safety assembly with a pressure gauge, an air vent and a pressure relief valve is mounted. Next, a circulation pump is connected with a capacity of approximately 40 liters per minute for a house with an area of ​​200 m 2. The podium for equipment is lined with non-combustible material containing asbestos. An expansion tank is mounted nearby. In accordance with the wiring diagram, through holes are made for pipes and shut-off equipment is installed.

The next step is to fill the system. Before the procedure, it is necessary to ensure that the quality of the coolant meets the requirements. It is better to expose the water pre-treatment, antifreeze is prepared in advance. It is important not to forget to flush the pipeline, remove scale and dirt from the radiators.

To download the media for heating a private house, it is necessary to check the condition of the drain valves and Mayevsky taps, they must be closed all the way. Water is supplied under slight pressure to expel air evenly. In the process, oxygen is removed from the radiators. As soon as the flow of the carrier ends, you need to start increasing the pressure, watching the pressure gauge. At a mark of 2 atmospheres, the air is bled off by means of the Mayevsky cranes, then the injection is started again. You need to pump the liquid until it overflows from the overflow.

In the absence of a centralized supply, it is necessary to fill the equipment with a boiler and a pump in this way: connect the discharge hose to the drain pipe to get a straight line from the well to the valve. All taps open to let air out, allowing you to pump required amount liquids.

If the pump is not provided, the hose is raised to a height of 20 meters, through which the heating circuit will have to be filled. This method helps to create water pressure at 1.5 atmospheres. The threaded connection on which the expansion tank is attached is removed to prepare the funnel for the pipeline. After a complete download, it is returned to its place. In the process, it is necessary to monitor the pressure gauge.

At the end of the work, the equipment is turned on to understand whether the filling has been done correctly and the pressure has been selected. If a mistake was made, the radiators will remain cold, water will flow from the tank, characteristic sounds will be heard in the batteries: gurgling, tapping.

The heating system in a private house of a closed type involves natural or forced circulation, vertical wiring of the main. To achieve optimal temperature regime indoors, it is important to correctly set up and start the equipment, prepare the carrier, and properly pump it. Thanks to a job well done, the radiators will warm up instantly, and the system will function without interruption.

The construction of a private house, and especially if it is carried out independently, is a long series of solutions to a wide variety of problems. And one of the most important is the provision in the future building the most optimal living conditions at any time of the year (unless, of course, the house is planned only as a summer cottage).

And already in this area of ​​​​creating the necessary microclimate in the premises, the most difficult task will be the correct calculation and installation of a reliable heating system. Despite the appearance modern systems electric heating at home, the leader in terms of popularity and demand remains water heating- it is more familiar, time-tested, the technologies for its installation and debugging have been worked out to the smallest detail. The owner of the house, who chose water heating, has to decide on a specific type - a closing or open heating system, with its “hardware filling” and with a piping system around the house. Then there are the stages of careful design and installation.

Among the numerous publications on this issue posted on the Internet, you can find quite a few that claim that an open heating system is extremely simple to use and can be installed in just one day. If the reader comes across such "art" - you can interrupt reading without any regret and close the page - the author obviously does not have not the slightest ideaabout heating in general, not about open system- in particular. Any system must be properly designed to m m numerous nuances, well balanced, securely mounted - and these tasks cannot be called absolutely simple and fast in execution.

What is an open heating system

First of all, it is necessary to immediately make one important remark. Very often, when describing an open heating system, the authors “mix all the facts together”, presenting it necessarily as heating with natural circulation of the coolant. Nothing like this! An open system can be with both natural and forced circulation of fluid, and with proper execution by the host in It is always possible to easily and quickly switch from one mode to another.

The main feature of an open system is the absence of any artificially created excess pressure in its circuit, since it is directly connected with the atmosphere. An expansion tank is mandatory installed in the system, the free volume of which is designed to compensate for the expansion of the liquid heat carrier when the temperature rises. Such a tank is always located at the highest point of the entire piping of the heating circuit. Thus, it still has the function air vent- all accumulations of gases in the pipes should come out right here. It also serves as a kind of water seal - a layer of liquid heat carrier, which must always be in the expansion tank, prevents air from entering the system from the outside.

It is worth considering such a system in more detail:

1 - source of thermal energy, boiler, operating on a certain type of fuel (solid, liquid,) or using electrical energy for heating.

2 - ascending from boiler riser, which rises to the highest point of the system and very often it is in this place that it ends with an expansion tank. There may, however, be other options for the location - this will be discussed later. The main thing is that the pipe of the largest diameter in the system is always used for this riser - this helps to ensure the desired pressure difference in the supply return pipes.

The calculation is carried out for each room separately.
Sequentially enter the requested values ​​or check desired options in the suggested lists

Specify the area of ​​the room, m²

100 watts per sq. m

Number of external walls

one two three four

External walls looking at:

North, Northeast, East South, Southwest, West

What is the degree of insulation of the outer walls?

External walls are not insulated Average degree of insulation External walls are well insulated

Level negative temperatures air in the region during the coldest week of the year

35 °С and below from - 25 °С to - 35 °С up to - 20 °С up to - 15 °С not lower than - 10 °С

Ceiling height in the room

Up to 2.7 m 2.8 ÷ 3.0 m 3.1 ÷ 3.5 m 3.6 ÷ 4.0 m over 4.1 m

"Neighbourhood" vertically:

For the second floor - a cold attic or an unheated and not insulated room from above For the second floor - an insulated attic or other room from above For the second floor - a heated room from above First floor with insulated floor First floor with cold floor

Type installed windows

Ordinary wooden frames with double glazing Windows with single-chamber (2 panes) double-glazed windows Windows with double-chamber (3 panes) double-glazed windows or with argon filling

Number of windows in the room

Window height, m

Window width, m

Doors facing the street or balcony:

Which boilers can be used in an open system:

  • If gas pipelines are laid in the settlement, then there is nothing special to think about - today such heating remains the most profitable in terms of the cost of the energy carrier.

There is, however, a significant “minus” - mandatory conciliatory procedures, drawing up the relevant project and its implementation with the involvement of specialists (gas farm workers almost everywhere are “monopolists” for such work and do not entrust them to anyone). All this will cost a fairly “heavy” amount. However, this is a one-time investment that should pay off after some time.

  • Remain popular solid fuel boilers, and in some regions where there is no problem with logging or buying coal, they remain the most popular among homeowners.

Now these are no longer the old cast-iron "giants" that absorb a lot of fuel and have an extremely low efficiency. Modern solid fuel boiler - usually a unit long burning that does not require constant monitoring. - in a special article of our portal. By the way, there you can also find a lot of tips on how to heat using the afterburning function of pyrolysis gases.

  • Electric boilers in open systems are rarely used. To be honest, such a system still loses in efficiency to a closed-type system. What is acceptable when using inexpensive energy sources - gas or firewood (coal), will result in a "good penny" when using electric heating. With some degree of conventionality, induction heating can be used, but again, it is better then to immediately mount a closed system, which is much easier to fine-tune.

Among all electric boilers, induction is the most economical

But the electrode boiler in an open system cannot be used in principle - it requires a special and stable chemical composition of the coolant. In a leaky circuit, it is simply impossible to meet this condition.

  • Optimal in terms of functionality, although a rather expensive solution, would be the acquisition of a multifunctional, combined boiler that can operate in different modes. For example, there are models “wood + gas”, “gas + electricity”, “ firewood+ coal + gas", or even " firewood+ coal + diesel + gas.

the best but expensive solution- combined boiler, working on different types fuel

Expansion tank

As already mentioned, this element can be purchased ready-made - they are on sale, or you can make it yourself from sheet metal, or from an existing metal container. Better to use metal corroded- then the heating will last a long time.

In the manufacture of the simplest tank, it is necessary to provide a hinged or removable cover - it will allow you to control the water level in the system, but in the closed state it still minimizes the evaporation of the liquid.

A pipe must be installed at the top of the tank, through which, in case of excess liquid, it will flow down.

It is considered sufficient if the volume of the expansion tank is up to approximately 10% of the total volume of the heating system.

By the way, an open type directly above the boiler at the highest point is by no means some kind of dogma. Such a scheme is good, however, it is far from always feasible simply for reasons of inconsistency with the real location. technical premises building.

The figure shows several different options for placing the expansion tank, from which you can choose the most suitable for the existing conditions.

It is noteworthy that if an expansion tank is installed on the return pipe, mandatory installation will still be required. air outlet valve at the highest point of the system (this is not shown in the diagram), and this is unnecessary additional complexity.

Heating radiators

If the boiler is the main element in terms of obtaining thermal energy, then radiators are the main ones in terms of its “distribution” throughout the premises. And this means that it is very important to determine exactly in which room, which and how many they need to be installed.

First, you need to decide on the type. They differ both structurally and in the material of manufacture, and in total - in their performance characteristics.

  • Traditional cast iron batteries great for open heating systems. Yes, they are quite inert in heating and cooling, but this is even not bad in combination with similar properties of an open circuit - this “complex” still does not lend itself to very fine tuning, but the savings on such inertia can be achieved quite impressive.

Such batteries are often reproached for being excessively massive and for being unaesthetic. appearance. Well, firstly, one can argue about the type - modern cast iron radiators very cute, and some are just decoration of the premises. And secondly, about massiveness - this is rather a virtue, if, of course, the issue of their reliable fastening is correctly resolved.

  • Steel radiators are inexpensive, light enough, durable (if they have a high-quality anti-corrosion coating).

Steel radiators for home autonomous heating- not the best option

Seemingly - a good option, but here for autonomous system heating, especially open, it is better not to use them. The fact is that they give off heat very quickly and cool down - the boiler with such radiators will turn on very often.

  • Aluminum radiators - today they are among the leaders among the "brothers". They are lightweight, durable, very easy and quick to install. They have excellent heat dissipation and the desired heat capacity. Well fit into any interior.

Aluminum radiators - good heat dissipation, but not too high corrosion resistance

They have a drawback, and a considerable one - this metal is very unstable to oxygen corrosion. This means that either aluminum radiators with a special anti-corrosion coating(these are on sale, but they are certainly more expensive), or the coolant must be of a certain quality. Unfortunately, it is almost impossible to observe the second point in an open heating system.

  • Bimetal radiators - the most modern option that combines everything best qualities. There are practically no shortcomings, except for one - high price. Such radiators are well suited for heating with high pressure in the circuit, as electronic or electromechanical thermostats are easily installed on them, maintaining the exact level of temperature in the room.

Bimetallic radiators - good for everyone, but somewhat expensive

Alas, with an open heating system, such an opportunity remains unclaimed, and you need to think very carefully whether it is worth overpaying for such batteries.

The second question is how to determine the required number of sections in the heating battery. It all depends on the size of the room, its features, and on the specific power of each section of the radiator.

So, for average rooms (residential, with a ceiling height of 2.5 ÷3m) usually take the normal heating power equal to 41 W / m³ of the volume of the room. Thus, it is easy to calculate the required total power by multiplying the volume (the product of the length, width and height of the room) at 41.

For example, a room is 3.5 × 6 × 2.7 m. The volume is 56.7 m³. The required basic power of radiators is 2325 W or 2.33 kW. However, it was not in vain that it was mentioned that this power is basic. It is designed for a room inside a building with one outer wall and one window to the street. If the actual conditions are different, then some corrections are required in this value - see table.

Suppose that in the example we are considering, the room is corner, with one window, with access to the north, and the radiators are removed in a niche. This means that it is necessary to add to the obtained value: 20% for corner arrangement, 10% - for the north and 5% - for the location of the battery under the window. The total correction is 35%, and the total power is 3.15 kW.

Now you need to divide the obtained value by the specific power of one section of the radiator. This figure must be indicated in technical specifications any model of radiators (in the case of steel non-separable radiators, the power of the whole block is indicated).

Let's say, in our case, it is planned to install bimetallic radiators " Rifar"With a section power density of 204 watts. A simple division gives 15, 44, or rounded 16 sections for normal heating of a given, fairly large and cold room.

We suggest using the capabilities of our special calculator, which will help you quickly and accurately calculate the required number of radiator sections for a room.

Possibly in several ways. In private houses, a simple and economical heating system is most often used - one-pipe with forced circulation. She provides reliable performance the entire heating circuit, while being easy to install and safe.

The natural circulation of the coolant occurs according to physical laws: heated water or antifreeze rises into top point system and, gradually cooling down, goes down, returning to the boiler. For successful circulation, it is necessary to strictly maintain the angle of inclination of the direct and return pipes. With a small system length one-story house this is easy to do, and the height difference will be small.

For large houses, as well as multi-storey buildings. such a system is most often unsuitable - it is possible to form air locks, violation of circulation and, as a result, overheating of the coolant in the boiler. This situation is dangerous and may cause damage to system components.

Therefore, a circulation pump is installed in the return pipe, immediately before entering the boiler heat exchanger, which creates the necessary pressure and water circulation rate in the system. At the same time, the heated coolant is diverted to the heating devices in a timely manner, the boiler operates normally, and the microclimate in the house remains stable.

Scheme: elements of the heating system

Advantages of the forced system:

  • the system works stably in buildings of any length and number of storeys;
  • pipes of a smaller diameter can be used than with natural circulation which saves the cost of their acquisition;
  • it is allowed to place pipes without a slope and lay them hidden in the floor;
  • can be connected to a forced heating system;
  • stable temperature conditions extend the life of fittings, pipes and radiators;
  • It is possible to regulate the heating for each room.

Disadvantages of a forced circulation system:

  • calculation and installation of the pump is required, its connection to the mains, which makes the system volatile;
  • The pump makes noise during operation.
The disadvantages are successfully solved by the correct placement of equipment: the pump is placed in separate room boiler room next to the heating boiler and install a backup power source - battery or a generator.

Elements of the system with forced circulation

Forced circulation is a process that requires the installation of not only a pump, but also other mandatory elements.

    These include:
  • expansion tank to compensate for the volume of the coolant when the temperature changes;
  • safety group including pressure gauge, thermometer, safety valve;
  • radiators connected according to one of the wiring diagrams;
  • Mayevsky taps or air separator;
  • check valve;
  • taps for filling and draining the system;
  • coarse filter.

In addition, when used as a heater, without the automatic fuel loading function, it is recommended to include a heat accumulator in the system - storage tank required volume. This will equalize the temperature of the coolant and avoid its daily fluctuations.

Types of single-pipe system wiring

In a one-pipe system no separation between direct and return pipe. The radiators are connected in series, and the coolant, passing through them, gradually cools down and returns to the boiler. This feature makes the system economical and simple, but requires setting the temperature regime and correctly calculating the power of the radiators.

A simplified version of a one-pipe system is only suitable for a small one-story house. In this case, the pipe passes through all the radiators directly, without temperature control valves. As a result, the first batteries along the coolant turn out to be much hotter than the last ones.

For extended systems, this wiring is not suitable., because the cooling of the coolant will be significant. For them, they use the Leningradka single-pipe system, in which the common pipe has adjustable outlets for each radiator. As a result, the coolant in the main pipe is more evenly distributed throughout all rooms. The layout of a single-pipe system in multi-storey buildings is divided into horizontal and vertical.

Horizontal wiring

With horizontal wiring, a straight pipe rises to the top floor along the main riser. From it on each floor departs horizontal pipe passing sequentially through all batteries on a given floor.

They are combined into a riser of the return line and fed back to the boiler or boiler. Temperature control taps are located on each floor, and Mayevsky taps are on each radiator. Horizontal wiring can be performed both by flow and by the Leningradka system.

Vertical wiring

With this type of wiring, the hot coolant rises to the topmost floor or attic, and from there it passes through vertical risers through all floors to the lowest. There, the risers are combined into a return line. A significant drawback of this system is uneven heating on different floors, which cannot be adjusted with a flow system.

The choice of wiring system for a private house depends mainly on its layout.. With a large area of ​​\u200b\u200beach floor and a small number of storeys of the house, it is better to choose vertical wiring, so you can achieve a more even temperature in each room. If the area is small, it is better to choose horizontal wiring, as it is easier to adjust. In addition, at horizontal type wiring does not have to make extra holes in the ceilings.

Video: one-pipe heating system

Heating system installation

A single pipe system is easy to install if the calculations are done correctly and carefully consider the connection of all its elements. It begins, as a rule, with the installation of a heating unit.

Boiler

    The boiler installation requirements depend on its type. Boilers for heating are:
  • gas;
  • diesel;
  • combined.

Gas boilers can be installed in any room equipped with an exhaust hood. All other types of boilers are installed in a separate boiler room. This is due to the peculiarities of their operation. The boiler installation diagram is shown in the figure.

After installation, the boiler is connected to the chimney and electrical network, and its heat exchanger - to the heating system. To do this, the boiler has two branch pipes designed for the input and output of the coolant. The inlet pipe is usually located at the bottom of the rear or side wall of the boiler, through which the cooled coolant enters. Output - in the upper part, on the walls or surface of the boiler. Through it, the heated coolant enters the pipes of the heating system.

Pipes
The elements of the system are connected using pipes. For heating systems, only pipes that can withstand high temperatures can be used: polypropylene, XLPE or metal.

The diameter of the pipes is determined by calculation. In private houses, pipes with a diameter of 15 to 50 mm are usually used, for risers and main pipes choose a diameter larger, for an eyeliner to radiators - less.

The connection of pipes depends on their material. Steel and copper pipes connected by welding and using metal threaded fittings. Polypropylene is welded with special device as shown in the photo.

    According to the type of installation, pipes are divided into:
  • open, placed in the public domain;
  • hidden, placed under the finishing floor or wall decoration.

The choice of the type of installation is influenced only by the design intent, but it must be remembered: open installation in the event of a leak allows you to quickly detect and eliminate it.

Welding metal pipes it is better to carry out before laying the final floor and finishing the walls, otherwise their damage by scale is inevitable.

Expansion tank

    There are two types:
  • open;
  • closed, or membrane.

Tanks of the first type are rarely used, since in an open system the coolant is constantly saturated with air, which contributes to the corrosion of radiators, pipes, and the boiler heat exchanger.

Membrane expansion tanks are a metal container separated by a plastic partition. The lower part of the tank is connected to the heating system, the upper part is equipped with a safety valve and filled with air. The volume of the expansion tank is determined by calculation.

When heated, the coolant expands, and part of it goes into the expansion tank. In this case, the membrane rises, and the air in the upper part is compressed. When the tank is completely filled, the air pressure increases, and it is vented through the safety valve.

The expansion tank of the closed type can be mounted directly in the boiler room, in a straight or return pipe. The scheme and options for placing the tank are shown in the figure.

    The group includes several elements at once, preventing emergency, overheating and boiling of the coolant:
  • manometer for pressure control;
  • thermometer;
  • air vent;
  • safety valve.

As a rule, they are installed as a single block, as in the photo, but installation separately is possible. Pressure gauge and thermometer can be combined in one housing

Some models of boilers are initially equipped with an emergency group. If it is installed separately, then it is placed in such a way that the safety valve is above the outlet of the coolant from the boiler.

Radiators and their connection diagrams
The choice of radiators and the number of sections produced on the basis thermal calculation. In general, for 1 sq. meter of the room 0.1 kW required heat output of the radiator. You can specify this indicator in the passport for heating appliances.

Their heat transfer depends on the type of connection of pipes to radiators.. Connection types suitable for a one-pipe system with forced circulation are shown in the figure.

As can be seen from the diagram, the greatest efficiency of radiators is achieved with a cross connection. In order to make the heating in each room adjustable, it is necessary to connect the batteries according to the scheme with a bypass and a valve. Also, on each radiator, it is necessary to install a Mayevsky valve to bleed air from the system.

Circulation pump
Calculation and installation of the pump is a crucial stage. It is placed directly in front of the return pipe entering the boiler, taking into account the direction of flow - it is indicated by an arrow on the body. The pump rotor must be strictly horizontal, so the pump is leveled.

Before the pump, a coarse filter is inserted into the pipe to remove impurities, sand and rust from the system. The sediment collector must point downwards.

A bypass is installed to bypass the pump, it is necessary for the system to operate in the event of a sudden power outage until the backup power source is connected or until the boiler cools down. Otherwise circulation will not be possible and the water in the heat exchanger will boil.

In addition, the bypass allows you to remove the pump for replacement or maintenance without draining the coolant. To do this, it is equipped with shut-off valves on both sides.

Video: pump installation

Video: errors during the installation of heating systems

The heating system must also have taps for filling and draining the coolant. At the first start, water is poured through the tap, air is bled through the air vents, after which the screw on the circulation pump is unscrewed until water appears. After that, you can start heating the boiler and, after heating it, adjust the temperature regime.

Many, tired of the bustle of the city, dream of a dacha or a cottage. But to be there all year round, you need to install heating at home.

Types of heating system

There are two that differ in the way coolants circulate. The principle of a simple system is the spontaneous movement of fluid through the pipeline. In this case, no additional device is needed, but the required slope of the pipes and their diameter should be taken into account. Natural circulation occurs when the coolant, heating up in the boiler, expands, moves under pressure along heating pipes and gradually cools in the radiator. Such a system is used in buildings with a small area and for boilers with low power. The efficiency of natural circulation through pipes is very low.

When a forced circulation heating system is used, a pump is used to ensure the movement of heat carriers in the pipeline, which must be installed in the "return" pipe. When installing the pump in the return pipe, it is protected from contact with the hot coolant, which significantly extends its service life. It is better to choose a pump with high power, since the higher the fluid velocity in the system, the higher the room temperature.

The pump requires a constant supply of electricity, but if a failure occurs, it does not matter, the device can be powered by a gasoline generator.

Benefits of a circulation plant

The heating system of the house is simplified, since there is no need to install an upper wiring, it is not necessary to ensure the slope of the pipeline.

Saves money on the installation of risers large diameter, as they are not required.

You can use a system with a collector type of wiring, when it is used, the radiators are evenly heated.

It is possible to increase the length of the pipes.

This allows you to arrange additional system"warm floors".

The operating mode is adjusted.

Possibility of connecting metal-plastic pipes to the boiler.

disadvantages

The disadvantages of this system, although not significant, but they still exist:

Pump operation requires supply electric current, which leads to cost overruns, but if there is no energy, then the pump stops working.

There is noise during operation, albeit slight.

Requires large material costs for the installation of additional elements and installation.

The circulation pump is installed on the "return" in front of the boiler. An expansion tank is also mounted nearby, which is mandatory in a closed-type system.

Open and closed heating circuits

As a rule, in open distributions of the coolant, the heating circuit has an expansion tank, where water is added as it evaporates. An open wiring system requires constant monitoring, since if the water boils, the entire heating system may fail.

The most common is dual-circuit heating. It is a two-pipe system with forced circulation. In order for it to work correctly, special equipment is additionally installed.

Pump selection

In order for forced circulation heating to function correctly and for a long time, two basic rules must be considered when choosing a pump. It must meet the following requirements:

Possess energy-saving qualities;

Its use should be simple and reliable.

Which pump is better

The power and pressure of the device are selected depending on the area to be heated, but it is very difficult to say which pump is best used, in which case you will have to calculate the heating. Only a professional can do this correctly, since it is necessary to provide for certain factors.

When calculating, it is necessary to take into account the diameter of the pipes used, the material, the required number of radiators, all shutoff valves, and the fuel used for heating.

From the foregoing, we can conclude that it is very difficult to calculate heating.

It also happens that when private heating systems are used, there is no circulation. The reason may be to eliminate which a valve is installed on each radiator to release air. This is the most best method improve circulation in the system. When purchasing Mayevsky cranes, it is important not to forget that designs with automatic air release have appeared on sale, which allows you not to control its formation.

Diaphragm expansion tank

Unlike open tanks, a closed system does not come into contact with the atmosphere. The increase and decrease in the volume of liquid is controlled by a membrane located inside a closed tank. It has the appearance of a hermetically sealed container, which is internally separated by a flexible membrane. The upper half of the tank is filled with air or nitrogen, while the lower half is connected to the heating system. This device is able to control an unexpected increase or decrease in pressure, saving the system from breakdowns. The capacitance value is selected taking into account the thermal expansion of the coolant. Approximately 10% of the volume of heat carriers in the pipeline. But it is important to control pressure, observing technical requirements to the boiler and pump.

Before installation, the membrane tank is pumped up to the required pressure established by the standards. In some cases, tanks go on sale already with a pumped capacity. For this reason, they are pre-screened. For household systems pressure must not exceed 4 bar.

Also, many are wondering where to install the tank. The forced circulation heating system provides for the installation of a tank on the "return", before the pump, it is located closer to the boiler. To avoid an accident in the event of an increase in pressure in the pipes, which will be greater than the expansion tank can withstand, it is necessary to install a safety valve.

Automatic air outlet

The forced circulation heating system also includes an air vent with automatic device. It plays an important role in the system and performs the function of removing air and preventing cavitation during pump operation. How is air expelled? At the highest point in the system, the coolant is able to change speed and direction dramatically, which leads to the release of bubbles. This is where the water trap is installed.

His device looks like a flask with a float, which is necessary to release air. When air accumulates, the float settles and opens the valve. If the pressure rises, then the coolant fills the flask, and the raised float closes the valve. The easiest air vents to use are those with a shut-off valve. It can be easily screwed on and off. When this element fails, a leak occurs, the cause of which can be determined, there are only two of them:

The needle has become clogged with salt, which may be caused by hard water. You can fix this breakdown by cleaning the needle yourself. For access, the cover is unscrewed, and after cleaning it is assembled in place.

out of order sealing ring under the housing cover. The gasket also changes on its own, or you can wind the fum-tape onto the thread.

The forced circulation heating system also provides for the removal of air in other wiring elements. For convenience, corner automatic air vents have recently begun to be used on radiators. It is important to consider when installing this design that the nipple must be directed upwards, otherwise the float will not perform its functions.

System adjustment

The heating system of the house is regulated by several parameters. But before use, it is important to read the instructions for use. It is also necessary to invite a specialist to adjust the start and stop functions.

It must be taken into account that the heating scheme, which has a large number of turns and knees, does not affect the operation of the system for the better. Elbows with a small angle of rotation are recommended to be replaced in order to avoid the least hydraulic resistance. To increase heat transfer, pipes that are not located in a residential area are recommended to be insulated.

Some nuances during installation

In order for the heating of the house to function without problems for a long time, the installation of important components must be approached with all responsibility, since the performance of the entire system depends on the correctly performed work.

To increase the efficiency of the circulation pump, it is installed on the return water supply pipe. This is explained by the fact that the coolant, reaching the "return", is already cooling down, since the heat remains in the radiators. The design of the pump includes cuffs and seals, which are made of rubber, and with constant interaction with high temperature, it can lose its previous properties. And in this regard, the chilled water entering the return pipe does not destroy the rubber parts, which contributes to the preservation of the original functions.

Also, the forced circulation system allows the use of pipes with a minimum diameter, which significantly reduces the cost of material and its installation. Reducing the volume of coolant filling the pipeline significantly affects the volume of the membrane tank and power heating boiler which directly leads to cost savings.

At present, all technological and constructive directions are aimed at reducing the cost of fuel consumption and reducing operating costs.

Many modern solutions water heating of houses require the use of a pumping group. The design and installation of a heating system with forced circulation must be carried out taking into account technical issues arising due to the rapid movement of the coolant.

The high pressure in the heating circuit allows the implementation of many wiring schemes. Agree, this is an important advantage of a heating system with forced circulation. However, the arrangement of such a scheme requires competent design.

We will tell you by what characteristics the main working units of the system are selected, and we will also describe in detail the possible options for wiring the line and how to organize the heating circuit.

Forced Scheme differs from natural by the addition of one or more circulation pumps. Due to the increase in pressure and speed of the coolant, the rules for the formation of nodes and the location of the elements of the circuit change.

This fact must be taken into account in order to ensure high-quality heating with forced circulation.

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General requirements for the pump group

Circulation pumps are selected based on the requirements for the volume of water distilled (cubic meters per hour) and pressure (meter). The calculation of both parameters depends on the cubic capacity of the heated housing and the method of heating, as well as the length of the water circuit and the diameter of its pipes.

The pump should be selected so that its parameters are not “back-to-back” with the requirements of the system. This will allow you to add elements to the circuit if necessary without replacing the pump.

Basically, the pumps are designed for a voltage of 220 volts, but there are also those with support for 12 volts. In case of power surges, it is necessary to install a stabilizer to prevent the device from failing.

In the event of frequent power outages, you need to take care of availability. There is no need to take a powerful UPS - devices with a consumption of more than 150 watts per hour are rarely used to heat private houses.

Conditionally circulation pumps can be divided into two types according to the position of the engine. Dry rotor devices have more high efficiency, but have increased level noise and reduced resource than with a wet rotor.

If the system wiring provides an opportunity for the natural movement of the coolant along the circuit, then the pump must be installed through the “bypass”. In this case, in the event of a breakdown or a power outage, it is possible to switch the heating to the gravitational circulation mode.

Water can also move through an idle pump, but it will create strong resistance to its movement.

The choice in favor of the pump model in relation to a specific heating system is carried out by determining the operating point and matching it with the required coolant flow rates (+)

The problem of stopping the pump is especially relevant when using stove or fireplace heating. In this case, the furnace will continue to heat the heat exchanger and it is possible for water to boil in it and the entire system to fail for a long time.

Compared to natural circulation, the increased hydrodynamic pressure of the flow will be added to the hydrostatic pressure of the liquid column. Therefore, in order to avoid the formation of leaks or, moreover, a breakthrough of the system, it is necessary to adhere to certain rules.

In the case of a transition from gravity to forced circulation, all, even minor leaks in the circuit must be eliminated. With an increase in pressure, the flow rate will increase, which, in addition to a problem in the room, will cause a decrease in the amount of coolant and its excessive aeration (air saturation).

Before the onset of the heating period, it is necessary to carry out hydraulic tests circuit strength with maximum usable or even slightly higher pressure. This will identify problems and eliminate them before the onset of cold weather, when a long shutdown of heating for repairs is undesirable.

Leakage of heating radiators can occur in the most unexpected places and it will take a long time to fix the problem, so it is better to check the integrity of the system in advance

Since the speed of movement of the coolant will be greater than 0.25 m / s, then, according to SNiP 41-01-2003, there is no need to maintain a constant slope of the pipes to remove air from the circuit. Therefore, with forced circulation, the installation of pipes and radiators is slightly simpler than with a gravity circuit.

Heating options with forced circulation

The use of forced circulation allows you to move away from the principle of designing wiring with the obligatory consideration of the hydrostatic pressure drop, which is necessary for operation with a gravity circuit.

This adds variability when modeling the geometry of the water loop and provides the possibility of using solutions such as collector heating or underfloor heating of a large area.

Application of top and bottom wiring

Any heating scheme can be conditionally attributed to the upper or lower wiring. At top wiring hot water rises above the heating appliances, and then, flowing down, heats the radiators. At the bottom - hot water is supplied from below. Each option has its positive aspects.

Top wiring is also used in natural circulation. Therefore, heating circuits of this type allow the use of both types of circulation. This, firstly, provides a choice, and secondly, increases the reliability of the system.

In the event of a power outage or a pump breakdown, the movement of water along the circuit will continue, albeit at a lower speed.

Good pressure allows you to make a choice between the upper and lower wiring, taking into account the convenience of the pipes supplying the coolant to the radiators (+)

When using the bottom wiring, the total length of the pipes is less, which reduces the cost of creating the system. In addition, there is no need to lay risers on the upper floor, which is good from the point of view of the design of the premises. The lower hot water supply pipe is laid either in the basement or at the floor level of the first floor.

Varieties of single-pipe connection schemes

A single pipe scheme uses the same pipe to supply hot water to radiators and cold outlet to the heating boiler. With such a wiring, the length of the pipes used is almost halved, the number of fittings and valves is reduced.

However, the radiators are heated sequentially, therefore, when calculating the number of sections, it is necessary to take into account the gradual decrease in the temperature of the supplied coolant.

Serial connection of radiators using one pipe for supplying coolant is often used in modern houses to minimize material costs and simplify installation work

Single-pipe circuits can be implemented in horizontal and vertical versions. With forced circulation, in the case of using vertical risers, hot water can be supplied not only from above, but also from below.

The feasibility of using one or another option depends not only on the convenience of laying pipes, but also on the maximum allowable number of radiators on one riser of a single-pipe circuit.

You can connect heating radiators in two ways:

  • Serial connection- the coolant flows through all radiators. In this case, a minimum number of pipes is required, however, if one of the radiators needs to be turned off, the entire branch of the system will have to be stopped.
  • Connection via bypass- the coolant can flow bypassing the radiator through the installed outlet. With the help of a system of taps, it is possible to redirect the flow past the radiator, which will allow it to be repaired or dismantled without stopping the heating.

A single-pipe scheme is often used for heating, however, if there are a large number of radiators, another option is used to evenly heat them.

Single-pipe schemes have many implementation options for forced circulation, so choose suitable solution for a specific geometry of the premises is quite easy (+)

Ways to use the two-pipe option

The heating circuit diagram using a second pipe to drain the cooled water to the boiler is called. The footage of pipes is increasing, as is the number of connections and devices.

However, the system has an important plus - a coolant of the same temperature is supplied to each radiator. This makes the two-pipe option very attractive.

With water heating with forced circulation, both horizontal and vertical wiring is used. Moreover, when vertical version it is possible to use top and bottom hot water supply.

A two-pipe scheme for supplying and discharging water in conjunction with a diagonal radiator connection provides maximum heat transfer to the room

Since the temperature of the water supplied to all radiators is the same, the geometry of the circuits depends only on the following factors:

  • material savings– minimization of pipe footage and the number of connections;
  • ease of contouring heating through walls and ceilings;
  • aesthetic appeal- possibility to enter heating elements in the interior of the premises.

Depending on the movement of hot and chilled water, two-pipe schemes are divided into two types:

  1. Passing. Both pipes move in the same direction. The coolant circulation cycle has the same length for all radiators in this part of the system, so their heating rate is the same.
  2. dead end. In a passing scheme, radiators located closer to the boiler heat up faster. However, for systems with forced circulation, this is not very important due to the significant water velocity in the circuit.

When choosing between a passing and a dead-end option, they are guided by the condition of convenience of conducting a return pipe. AT vertical schemes with the lower wiring, a dead-end system is obtained, and with the upper one, a passing one.

Using a heating distribution manifold

Another popular way to organize heating is now. To some extent, this scheme can be called a subspecies of the two-pipe, although it is also used in the organization of single-pipe heating circuits.

Only the distribution of the hot coolant and the collection of the cooled one takes place not from the main riser, but from special distribution hubs - collectors. Such a system works stably only with the use of forced circulation.

Beam wiring compared to two-pipe requires a collector, a greater total length of pipes, the number of fittings and valves

The distribution unit for a two-pipe system is a complex combination of supply and return manifolds, with the help of which the supply of coolant is balanced in terms of temperature and pressure.

Each branch of the device feeds one heating element or a small group of them. Branches are usually located under the floor, each floor high-rise building served by one centrally mounted collector.

Despite the obvious advantages of this option for organizing heating, the collector system has two significant disadvantages:

  • the greatest length of pipelines, therefore, this option for organizing a water circuit requires considerable financial investments;
  • complexity of changing the contour- pipes with this option are usually located under the floor or in the walls, therefore, in the case of adding heating appliances it will be very difficult to make any adjustments.

All manifolds are mounted, as a rule, in a special cabinet, since the valves are located there and access is required. Placing cranes in one place is very convenient.

In the event of a need to turn on or off the radiators or an emergency situation, it is enough to have access to the cabinet and there is no need to visit all the premises.

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The collector, otherwise the distribution comb, is designed to uniformly supply the coolant to all rings connected to the device


The specified device is selected in such a way that the speed of the coolant within it is not higher than 0.7 m / s


The manifold group includes two elements - a comb for supply and a similar device for return


In the organization of the collector system, both factory-made combs and devices assembled from steel or polypropylene pipes are used.

Distribution manifolds can have a simple structure consisting of two combs and a minimum of shut-off valves. Complex units may also include automatic thermostats, electronic valves, mixers, automatic air outlets, sensors and control units, a water drain valve, a separate circulation pump.

These systems can most accurately regulate the temperature in a home, but require good understanding basics and nuances of the work of water heating.

Heating with underfloor heating

One of the most comfortable ways of heating is the organization of a warm floor. It should be noted that the installation of such an option for heating living rooms, showers, kitchens and other premises is quite complicated.

A water-heated floor of a large area is possible only with the organization of forced circulation, since it is necessary to create pressure in long system narrow tubes.

Pressure is needed to overcome the resistance of narrow pipes with many bends. In addition, it is necessary to achieve a pressure that allows you to remove air from the underfloor heating pipes, which are located horizontally.

There are a large number of tube laying combinations:

  • for small rooms apply schemes with one inlet for hot water and an outlet for chilled water;
  • for large rooms organize more complex systems underfloor heating using a distribution manifold.

Often, separate circulation pumps are installed for fragments of a circuit with a warm floor.

The use of a collector is justified for large areas of underfloor heating, when calculations show that one pipe may not be able to cope with heating

Conclusions and useful video on the topic

Detailed description of two-pipe and sufficient complex scheme heating of a two-story house:

Closed system for a three-story house based on a gas boiler:

The use of pumps for hot water space heating greatly facilitates the design of the circuit, making possible options, inaccessible to the gravity model. Correct selection equipment will solve the issue of heating housing, making this process convenient and simple.

Do you have something to add, or do you have questions about the organization of a heating system with forced circulation? Please leave comments on the publication and participate in discussions. The contact form is in the bottom block.

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