Possibly according to several schemes. In private homes, a simple and economical heating system is most often used - a single-pipe with forced circulation. It ensures reliable operation of the entire heating circuit, while being easy to install and safe.
Natural circulation of the coolant occurs according to physical laws: heated water or antifreeze rises to the top point of the system and, gradually cooling, falls down, returning to the boiler. For successful circulation, it is necessary to strictly maintain the angle of inclination of the forward and return pipes. With a short system length in a one-story house, this is not difficult 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 can cause air pockets to form, circulation to be disrupted and, as a consequence, overheating of the coolant in the boiler. This situation is dangerous and can 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 required pressure and water circulation rate in the system. In this case, the heated coolant is promptly discharged to the heating devices, the boiler operates normally, and the microclimate in the house remains stable.
Diagram: heating system elements
Advantages of the forced system:
- the system operates stably in buildings of any length and number of floors;
- you can use pipes of smaller diameter than with natural circulation, which saves the cost of purchasing them;
- 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 service life of fittings, pipes and radiators;
- It is possible to regulate the heating for each room.
Disadvantages of a forced circulation system:
- it requires calculation and installation of the pump, connecting it to the electrical network, which makes the system energy-dependent;
- The pump makes noise when running.
Forced circulation system elements
Forced circulation is a process that requires the installation of not only a pump, but also other required elements.
- These include:
- expansion tank to compensate for the volume of coolant when 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;
- system fill and drain taps;
- coarse filter.
In addition, when used as a heater, without automatic fuel loading function, It is recommended to include a heat accumulator in the system - a storage tank of the required volume. This will equalize the temperature of the coolant and avoid its daily fluctuations.
Types of wiring of a single-pipe system
In a one-pipe system no separation between forward and return pipes. 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 adjusting the temperature regime and correctly calculating the power of the radiators.
A simplified version of the single-pipe system is only suitable for a small one-story house. In this case, the pipe passes through all radiators directly, without temperature-regulating valves. As a result, the first batteries along the coolant path turn out to be much hotter than the last ones.
This type of wiring is not suitable for extended systems., because the cooling of the coolant will be significant. For them, they use a single-pipe “Leningradka” 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 wiring of a single-pipe system in multi-story buildings is divided into horizontal and vertical.
Horizontal layout
With horizontal wiring, a straight pipe rises to the top floor along the main riser. A horizontal pipe departs from it on each floor, passing sequentially through all the batteries on a given floor.
They are combined into a return riser and returned to the boiler or boiler. Taps for temperature control are located on each floor, and Mayevsky taps are on each radiator. Horizontal wiring can be done either through flow or using the Leningradka system. 
Vertical layout
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-through system.
The choice of wiring system for a private house depends mainly on its layout. With a large area of each floor and a small number of floors in the house, it is better to choose vertical wiring, this way 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 regulate. In addition, with a horizontal type of wiring, you will not have to make extra holes in the ceilings.
Video: single-pipe heating system
Heating system installation
A single-pipe system is easy to install if the calculations are done correctly and pay close attention to connecting all its elements. It usually begins with the installation of a heating unit.
Boiler
- The installation requirements for the boiler depend on its type. Heating boilers 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 the electrical network, and its heat exchanger is connected to the heating system. For this purpose, the boiler is equipped with two pipes intended for coolant input and output. The inlet pipe is usually located at the bottom of the rear or side wall of the boiler; cooled coolant flows through it. The outlet is 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, you can only use pipes that can withstand high temperatures: polypropylene, cross-linked polyethylene 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; a larger diameter is chosen for risers and main pipes, and a smaller diameter is chosen for connections to radiators.
The connection of pipes depends on their material. Steel and copper pipes are connected by welding and using metal threaded fittings. Polypropylene is welded using a special device, as shown in the photo. 
- According to the type of installation, pipes are divided into:
- open, freely available;
- hidden, placed under the finished floor or wall finishing.
The choice of installation type is influenced only by the design intent, but you must remember: open installation in the event of a leak allows you to quickly detect and eliminate it.
It is better to carry out welding work on metal pipes before laying the finished floor and finishing the walls, otherwise they will inevitably be damaged by scale.
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 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 using 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 released through the safety valve.
A closed expansion tank can be installed directly in the boiler room, in a direct or return pipe. The diagram and options for placing the tank are shown in the figure.
- The group includes several elements that prevent an emergency situation, overheating and boiling of the coolant:
- pressure gauge 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 boiler models 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 located above the coolant outlet from the boiler. 
Radiators and their connection diagrams
Selection of radiators and number of sections produced on the basis thermal calculation. In general, per 1 sq. meter of room 0.1 kW required radiator thermal power. You can clarify this indicator in the passport for heating devices.
Their heat transfer depends on the type of connection of pipes to radiators.. Connection types suitable for a single-pipe forced circulation system are shown in the figure. 
As can be seen from the diagram, the highest efficiency of radiators is achieved with cross connections. In order to make the heating in each room adjustable, it is necessary to connect the batteries according to a circuit with a bypass and a valve. It is also necessary to install a Mayevsky valve on each radiator to bleed air from the system.
Circulation pump
Calculation and installation of the pump is a critical stage. It is placed immediately before the return pipe enters 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 placed level.
Before the pump, a coarse filter is cut into the pipe to remove impurities, sand and rust from the system. The sediment collector should be directed 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 a backup power source is connected or until the boiler cools down. Otherwise, circulation will be impossible and the water in the heat exchanger will boil.
In addition, the bypass will allow 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 when installing heating systems
The heating system must also have taps for filling and draining coolant. When starting up for the first time, pour water through the tap, bleed air through the air vents, and then unscrew the screw on the circulation pump until water appears. After this, you can start firing the boiler and, after heating it, adjust the temperature.
Despite the increased reliability of natural circulation systems, in regions with more or less stable power supplies they are rapidly losing ground to forced circulation heating. The thing is that installing a pump in one fell swoop solves important problems:
Quite a long list of benefits. There are only two significant disadvantages:
- no electricity - no heating;
- During operation, the pump consumes electricity and is audible.
If we talk about the dependence of the system on the availability of electricity, then it can be reduced. It must be installed with several batteries connected in parallel to it. This scheme gives several hours of system operation (depending on the energy consumption of the boiler and pump, as well as on the parameters of the UPS and batteries). Diesel will provide more time.
As for the noise that the pump makes during operation. Most stakes have virtually silent units. For example, in gas boilers the burner makes much more noise than the pump. And it consumes less electricity than a table light: 60-120 W/hour - depending on the power of the unit.
Types of forced circulation systems
The system can be any: one-pipe or two-pipe, with horizontal or vertical wiring, top or bottom supply. A feature of systems with forced circulation is that the pump is installed at the inlet/outlet of the boiler before the first branch. Previously, it was necessary to install it on the return line - there the coolant temperature is lower. And since the seals were rubber, they lasted longer at gentle temperatures. Today there is no such need - the materials of the sealing rings can withstand temperatures up to 110 o C without consequences.
Then we proceed to calculate the number of radiators: at least one for each window, plus one radiator for the bathroom/toilet. In the northern regions, radiators installed in the corridor/vestibule, which act as thermal curtains, have performed well to conserve heat.
When calculating the number of radiators, we proceed from the rule: one radiator for each window
Once you have decided on the number of radiators, you need to calculate the number of sections in each. In general, they are calculated based on the area of the room: there are standards. Knowing the area of the room, divide it by the norm and get the number of sections. But this is again an average approach. Here you also need to take into account the type of wiring and the location of the radiator in the heating circuit. For example, single-pipe wiring. It is characterized by the fact that radiators located closer to the boiler receive hotter coolant and heat up to higher temperatures. The farther the radiator is located, the colder the coolant washes it. Therefore, to compensate and equalize the position in distant radiators, the number of sections is increased or they are installed with a larger area (height and power).
They do the same with a two-pipe installation, although the difference there is not so obvious: a coolant with the same temperature is supplied to the input of each radiator, it’s just that those located closer to the boiler have a higher flow rate through the radiator than those further away. To equalize the flow, thermostatic valves are installed on each radiator.
A forced circulation system can be open or closed. The difference is in the type of expansion tank used. If it is open, then the system is open. If it is membrane type, the system is closed. The volume of the tank is calculated based on the volume of the system: for 10 liters of coolant, take 1 liter of tank volume. When planning heating with forced circulation with your own hands, try to place the expansion tank next to the circulation pump. It is equally important during installation of the system to prevent air from entering the pump housing, as well as to remove all air pockets from the system before starting it up. To do this, an automatic drain valve is installed at the highest point of the system, and Mayevsky taps are installed on each radiator.
To bleed air from the system, install a Mayevsky valve on the radiators
When installing the system yourself, after the radiators are assembled and the pipes are connected, the entire system must be flushed. And only then connect the pump and boiler. In systems with solid fuel boilers, a safety group is required, which includes a pressure gauge, an air outlet valve and a blast valve, which is set to the operating pressure in the system and, if it is exceeded, is activated automatically.
A filter must be installed at the feed line inlet to the boiler to protect the circuit and equipment from the ingress of abrasive or contaminant particles.
The selection of a pump and expansion tank is irrelevant if you plan to install. Most models have a built-in expansion tank and pump. Then all that remains is to navigate by the volume of the system with which this modification can work. Based on this, select the diameters of the pipes and the area/power of the batteries.
One of the main advantages of gravity heating schemes is reliability. Despite this, today they are increasingly being replaced by schemes with forced movement of coolant. Many people ask why this happens? At first glance, the whole point is the disadvantages of gravity heating, which can be solved by simply installing a pump. If you look deeper, it turns out that for the most part, modern boiler systems are already equipped at the factory with equipment that makes it possible to easily create a heating system with all the advantages of forced circulation of coolant in the circuits.
Advantages and disadvantages
First of all, let's consider all the pros and cons of this heating system (HS).
- Heating with a pump can cope perfectly with the coolant, which moves along a circuit made of fairly thin pipes. There is a reduction in the estimated cost due to the smaller cross-section of the pipeline.
- The boiler system will heat up a smaller volume of water in the pipes faster. In such COs, inertia is reduced.
- With a heating system with forced circulation, there is no need to observe the slope of the circuit.
- With such a system, you can use a lower wiring diagram, which makes it more aesthetically pleasing.
- It is possible to significantly increase the length of the circuit, and not be limited to 30 meters, as with the natural movement of the coolant.
- You can use multi-circuit schemes, “warm floors”, etc.
- In forced systems, you can install an expansion tank in any place convenient for you.
And these are just the main advantages of this method of moving coolant. There are much fewer disadvantages, but we have no right not to consider them:
- Noise from the pump. If you organize a boiler room, then this drawback immediately becomes insignificant.
- Electricity costs for operating pumping equipment. The average electricity consumption of modern devices (depending on the model and performance) is 50 – 120 W/h. Therefore the costs are minimal.
- Dependence on electricity supply. In areas with unstable power supply, it is recommended to create combined heating.
In addition, if you use IPB, then this drawback can be ignored.
Types, varieties, schemes
There are two types of CO: single-pipe and double-pipe. A single-pipe forced circulation heating system can be horizontal or vertical.
When horizontal, the coolant from the boiler installation moves through the main pipeline, to which the radiators are connected in series.
This figure shows a modernized, closed-loop heating system with forced circulation, with jumpers (bypasses) between the input and output of each battery. The circuit is equipped with a safety group, which includes: a pressure gauge, a blast valve, and an automatic air vent.
Vertical single-pipe CO works as follows: the coolant heated in the boiler unit rises along a vertical riser. With lower wiring, the coolant passes through series-connected radiators and, already cooled, is again lowered along a vertical riser into the boiler installation.
With top distribution, heated water rises through a vertical pipeline, moves through the distribution pipeline, and then descends and passes through all connected heating devices.
A two-pipe forced circulation heating system can be routed horizontally and vertically with various wiring options. There are three types of horizontal CO:
Important! A dead-end circuit can be implemented in both horizontal and vertical systems.
Equipment selection
In order to turn any gravity heating system into a circuit with forced movement of coolant, you need to choose the right equipment. Its effectiveness and efficiency will depend on this.
The pump is the central figure in ensuring the circulation of water throughout the circuit. As a rule, centrifugal-type devices with straight impeller blades are used for household heating systems. Pumps differ in the operating pressure that can be created in the system, productivity, power consumption, pressure height and diameter of the connecting pipes.
The required performance of the circulation pump can be calculated using the formula (Q/c*Dt)/ P, where Q is the heat loss of the house;
C – how much heat water can carry (tautical value, equal to 1.16);
DT – temperature delta;
P – density of water at nominal t°C (tabular value).
- For residential buildings with an area of up to 250 m2, it is recommended to use a circulation pump with the following characteristics: productivity 3 - 4 m3 / h; pressure 0.4 - 0.5 atmospheres.
- Up to 350 m 2 – 4 – 5 m 3 / h; pressure 0.6 atmospheres.
- Up to 800 m 2 – 11 – 12 m 3 / h; pressure 0.9 atmospheres.
Important! Please understand that the above figures are approximate. The correct calculation depends on many factors (type and degree of insulation of the house, material of pipes and fittings, system configuration, etc.) For a more accurate selection of the circulation pump, contact a specialist.
Pump, a self-sufficient element of circulating CO. But for reliable operation of this device, proper harnessing is required, which includes:
- Ball valves on both sides of the pump.
- Sump.
The expansion tank is another one of the most important elements of CO with forced circulation. Depending on its design, there are schemes of open heating systems with forced circulation and closed ones.
In open COs, atmospheric devices are used that serve to compensate for the thermal expansion of the coolant. If the pressure in the system exceeds, part of the coolant is discharged. To replenish water in the CO, a float valve is used, which is connected directly to the water supply.
Modern heating systems use membrane expansion tanks. Because of the tightness of the latter, the circuits in which they are used? are called closed. The operation of a sealed expansion tank in closed heating systems with forced circulation is very simple: a rubber membrane is installed in the body of this device. On one side of the membrane there is a coolant, on the other there is air pumped into the tank under a certain pressure.
When the pressure in the CO is exceeded, the membrane bends towards the air, and when it falls, it bends towards the coolant. Thanks to this simple technology, pressure surges in heating systems are leveled out. 
Tip: the capacity of the expansion tank depends on many factors. Based on experience, expansion tanks with a capacity of 10% of the amount of coolant are used in household CO systems.
Stages of planning a heating system with forced movement of coolant
Let's consider the stages of creating a heating system for a one-story house with forced circulation. The first thing to do is a hydrodynamic calculation, which includes the following steps:
- Determination of the power of the boiler installation.
- Selection of scheme: one-pipe, two-pipe.
- Calculation of resistances on each section of the highway.
- Calculation of the number of batteries and sections.
- Selecting their connection diagram.
- Calculation of the diameter of the main pipeline and branches.
- Equipment selection, installation, pressure testing, CO balancing.
Advice! Creating an economical and reliable heating system requires knowledge and competent calculations. We strongly recommend seeking advice from specialists.
Heating systems with forced circulation of coolant are becoming increasingly popular. And this is not surprising. The forced circuit has many advantages; it is suitable for heating large houses; it does not have the disadvantages of heating based on the principle of self-circulation.
The only disadvantage of the solution is the dependence on the availability of electricity, but this problem can be solved by installing a UPS or connecting a generator.
Types of pumped circulation systems
Autonomous water heating with mechanical circulation has good thermal characteristics. Heating systems have the following positive aspects:- Forced circulation of coolant in the heating system ensures uniform heating of all heating units at any point, regardless of the distance from the boiler. The maximum temperature difference, with properly selected circulation equipment, is no more than 1°C.
- There are no strict installation requirements - there is no need to observe the slope of the pipeline in a heating system with pump circulation. Turns and other obstacles do not have a significant effect on the intensity of warming up.
- Possibility of using different circuits with almost the same efficiency and heat transfer.
The heating scheme for a one-story or two-story house, with forced circulation, is carried out in several ways. When choosing a suitable solution, you should pay attention to the complexity of calculations and installation work, the consumption of building materials and the appearance of the structure, and possible difficulties during operation.
Single-pipe heating system with pump
The advantages of a single-pipe heating system for a private house, with forced circulation, include the following:- Beautiful appearance.
- Economical consumption of materials.
- Easy to install.
- The need for careful calculations of the cross-sectional diameter of the pipeline, the power of the circulation boiler and other components of the single-pipe system.
- Reduced efficiency when heating large areas.
- Uneven heating of radiators located on different floors of the building.
Radiator piping in a one-pipe system occurs as follows:
It is worth choosing a single-pipe scheme if it is necessary to heat buildings with an area of up to 150 m². In other cases, you should choose a different wiring option.
Two-pipe system with forced circulation
The branched scheme of a two-pipe system effectively copes with heating buildings with several floors and a large heated area. The principle of operation is that two different pipes are used to supply and remove coolant. The system is used for the following buildings:
The two-pipe system is popular due to its high thermal efficiency and uniform heating of rooms. Suitable for rooms of any configuration and heated area.
Open system with pump circulation
An open heating system for one-story and two-story houses with forced circulation is used when modifying existing wiring with self-circulation of the coolant. The principle of operation is that the circuit provides for the installation of an open type expansion tank. The open solution is only suitable for energy-independent boilers. Most modern models produced by manufacturers are sensitive to system parameters and refuse to work if the pressure is insufficient. Some boilers are equipped with a built-in membrane tank and are therefore not suitable for open heating circuits.
As a disadvantage of the solution, it should be noted that poor pressure in the system with an open expansion tank is observed in every second case. This connection method is not suitable for rooms with several floors and a large heated area.
Closed system with forced circulation
Closed one-pipe and two-pipe heating systems differ in that the circuit provides for the presence of an expansion membrane tank. The advantage of a closed solution is the high pressure generated by the circulation pump. As a result, there is no airing of the system. The internal circuit of radiators and heating pipes is less susceptible to corrosion. The diagram of a closed heating system with forced circulation includes the following components:
- – installed immediately behind the boiler. In a closed-type system, there is no need to install a tank at the top point of the water circuit.
- Wiring - pipes are connected to heating radiators using any of the methods listed above.
- Circulation pump - installed on the return pipeline, directly in front of the boiler.
Bottom wiring system
The coolant is supplied through a pipeline running at floor level. There are two connection options:- Single-pipe heating system with bottom wiring. The principle of operation of the circuit is as follows - the coolant enters the radiator and is discharged using the supply pipeline. There is no return. The last battery is connected to the boiler return and supply pipeline. Distribution is carried out by pipes lying at floor level.
- Two-pipe heating system with bottom wiring - suitable for radiators with bottom connection. The supply and return lines run along the floor. A radiator is connected to each pipe. The advantage of a two-pipe solution is the ability to hide pipes in the floor or decorative box. The disadvantages include the high consumption of materials required for connection.
Top wiring system
A single-pipe system with a top connection is more efficient than a bottom connection. The essence of the scheme is as follows: a supply pipeline is laid under the ceiling or along the floor of the attic. Parallel vertical risers extend downwards, from which pipes diverge for connecting radiators connected in series. The return line is installed only on the last radiator.A two-pipe heating system with overhead wiring is less convenient to install and operate, as it requires simultaneous laying of the supply and return pipelines. The scheme works as follows. The coolant is supplied to the acceleration pipe, which is the highest point of the heating system. From there, the heated liquid is distributed throughout the rooms. The pipe is mounted under the ceiling. The return line is at floor level. A circulation pump is installed directly in front of the boiler.
How to properly install heating in a private house - diagram with a pump
In order for a system with forced coolant circulation to be operational, several important requirements must be met:- Calculate the diameter of the pipeline.
- Select the most suitable heating pipes.
- Calculate the parameters of the required pressure.
- Ensure the operation of the circuit during a power outage and protect it from emergency situations.
How to calculate the diameter of pipes for forced circulation
It would seem, why carry out unnecessary calculations. It is enough to install a large diameter pipe and this will automatically solve all problems. But the basic rules of hydraulics when calculating a system state that the larger the diameter of the pipeline, the lower the pressure inside the circuit will be. Consequently, the flow rate will decrease and heat transfer will decrease. As a result, the problem will not only not be solved, but will also create new difficulties. Therefore, the calculation of pipe diameter should be approached with all seriousness.The abbreviations in the formula mean:
- V – water flow speed.
- ∆dt – temperature difference between the supply and return coolant (the coefficient is conventionally assumed to be 20°C).
- Q is the thermal energy given off by the system.
The water flow rate is indicated in the technical documentation for the pumping equipment.
What pipes are used for forced circulation systems
In systems with forced pressure, pipelines made of different materials are used. The most popular types of pipes are:- Steel pipes are one of the cheapest materials. They are popular due to their long service life. Installation is carried out by welding. Over time, hydraulic resistance increases due to overgrowth of the internal circuit.
- Polypropylene – has a long service life, high noise insulation and low weight. Disadvantages include susceptibility to linear expansion. When the coolant is heated above 70°C, the circuit of propylene pipes begins to sag. To avoid sagging, the installation of special fasteners is required. During installation, the susceptibility of the material to mechanical stress is taken into account.
- Metal-plastic – withstands operating pressure up to 10 atm, and heating of the coolant up to 95°C (short-term increase to 110°C). It is easy to assemble a heating system with your own hands from metal-plastic pipes. Installation is carried out using the collet method, which slightly reduces the internal diameter. When choosing a material, add 10% to the recommended cross-section.
- Copper has better thermal conductivity than any other material used for heating. Piping the system with copper pipes is allowed only if there is no direct contact with aluminum parts. Copper will last at least 100 years and can withstand overloads well. The disadvantage of copper is the high cost of material and installation work.
What pressure should be in the system
It should be noted that there are no standards regulating the minimum pressure in autonomous heating systems. It is worth focusing on the performance of circulation and water heating equipment, as well as the features of the water circuit. According to physical laws, even a liquid that is at rest and not subject to heating exerts a pressure on the walls of the pipeline corresponding to 0.1 bar for every meter of pipe rise. When heated, the parameters increase. Circulation equipment creates additional pressure, increasing the pressure inside the circuit.
The operating pressure in a system with a membrane expansion tank is considered normal and does not exceed 1.5-2.5 atm. When making calculations, it is generally accepted that the maximum load on the pipe walls should not exceed the minimum value of the weakest element in the system.
Circulation equipment of sufficient capacity is selected according to the pressure of the water column. The permissible length of the contour branch is calculated in the ratio of 10 linear meters. = 0.6 m in. Art.
Where to install the expansion tank on the system
An expansion tank in a system with forced water circulation is needed to compensate for pressure drops resulting from an increase in volume (during heating) and a decrease (during cooling) of the coolant.The location of the container is determined depending on its design and type of wiring: 
The volume of the expansion tank is calculated based on the power of the hot water boiler, taking into account the ratio 1 kW = 15 liters. The expansion coefficient (tank capacity) will be about 4.5% of the result obtained.
Methods and methods for removing air from the system
There are many reasons for air accumulation in pipes and radiators of a heating system. The most common are the following:- Carrying out repair work.
- Using an open expansion tank.
- Leaking pipes.
- Poorly sealed pipeline joints.
- Incorrect filling of the closed system with coolant.
What to do with a pump circulation system during a power outage
When there is a power outage, the system stops completely. Stopping circulation leads to instant boiling of the coolant and an increase in pressure in the water circuit. For this reason, you should consider how the system will operate after a power outage.There are several ways to solve this issue: 
What are the pros and cons of a forced circulation heating scheme?
The advantages that are the main arguments in favor of connecting heating systems with forced circulation:- Possibility of installation in high-rise buildings, which is impossible when using self-circulation systems.
- It is allowed to pour non-freezing liquid into the system. At the same time, heat transfer rates and uniform heating of the premises do not decrease.
- Minor errors in calculations and during installation work do not affect the performance of the heating.
- You can use any radiator connection diagrams, wiring with bottom and top filling, etc.
If the area of the house is large enough or it is necessary to provide heating for a two-story building, it is better to abandon a heating system with natural circulation. Due to the slow movement of the coolant through the pipes, it will be extremely difficult to warm the air in the room quickly enough.
This problem does not exist if a heating system with forced circulation is initially selected, which is especially important for houses in which people live permanently. By installing a special pump, you can significantly increase the heating efficiency of a building of any size. The main thing is that the selected heating scheme meets certain requirements.
How does heating work without a pump?
To understand how a forced circulation system works, it is worth understanding how buildings are heated using natural coolant circulation. As the latter, various special compounds and water can be used. For a one-story house, water heating is most often chosen.
The movement of water through pipelines is carried out according to the laws of physics. Having heated up in the boiler to a given temperature, it begins to rise up the riser. Due to this, all pipes and radiators of the system are gradually heated. The newly incoming hot water gradually displaces the cold water down to the boiler.
After the cooled coolant heats up again in the boiler, it will begin to rise up the riser to displace the cooled down. This cycle will be repeated as long as the boiler operates. Obviously, the larger the diameter of the pipe, the more coolant will pass through its cross section per unit time.
That is why, with natural circulation, the diameter of the pipeline and the dimensions of the mounted radiators are of great importance. If the area of the latter is insufficient, it will be difficult to warm the room to a comfortable level.
Forced circulation
The heating circuit with forced circulation is characterized by the presence of a pump. Thanks to it, the coolant moves through the pipes at a given speed, and not just under the influence of the laws of physics.
The pump creates pressure sufficient to move the coolant, but at the same time ensuring uniform distribution of water heated to different temperatures.
What does the heating system consist of?
The forced circulation heating system consists of:
- boiler (solid fuel, gas or electric);
- membrane type expansion tank;
- circulation pump, the power of which is selected individually;
- heating radiators (batteries);
- pipes;
- fittings - adapters used to connect pipes;
- valves (ball and plug);
- check valves;
- air vents;
- filters that ensure the operation of the heating boiler and pump;
- fasteners.
When choosing the equipment necessary for the operation of the system, be sure to take into account:
- power of the purchased boiler and radiators;
- pipeline size;
- coolant movement speed.
The single-pipe scheme involves combining the supply and return pipelines. The coolant is supplied through a special pipeline with shut-off valves. A separate pipe with a valve is provided for draining water into the sewer.
After heating in the boiler, the coolant, passing through the risers and radiators and giving them the required amount of heat, enters the pump. The latter ensures the injection of flow moving to the boiler.
Tank
A membrane-type tank, which includes a single-pipe system, helps prevent emergency situations.
Such a tank can be not only closed, but also open. It is installed on the top (technical) floor of the building.
If the tank is closed, then the heating system is closed. If it is open, then the system is called open.
A one-pipe system necessarily includes a safety group consisting of:
- air vent;
- safety valve;
- pressure gauge and thermometer, often combined in one housing.
Such a group will allow you to quickly reduce excess pressure in the system, thereby preventing pipeline rupture and equipment breakdown.
It is permissible to install devices from the safety group separately from each other. For example, the safety valve is inserted slightly above the boiler. However, this is not always justified in terms of the cost of installing a heating system.
Radiators
Radiators with this scheme can be connected in different ways: diagonally, parallel, etc. It is advisable to provide thermostats and Mayevsky taps on each battery. On sale you can find radiator models with pre-installed taps.
Wiring
The pipe layout in the system can be horizontal or vertical. Both types of wiring allow connection to a boiler and underfloor heating system.
To do this, you just need to provide a special distribution manifold to ensure that the heated coolant flows simultaneously into the radiators, boiler and underfloor heating circuit.
Two-pipe scheme
The advantage of a single-pipe scheme is its availability. In this case, fewer pipes are required than with a two-pipe system, and therefore its installation is much cheaper.
However, the efficiency of the latter is much higher, due to the fact that in a two-pipe system the supply and return pipelines are separated.
This system allows you to repair a radiator in one room without turning off the heating in the entire building, and is suitable for buildings of any number of floors.
Is forced better?
If a heating system is to be installed in a one-story building, preference may be given to a system with natural circulation. Especially if the building is located in an area with typical power supply problems.
When choosing a scheme for a two-story house, it is better to pay attention to a system with forced circulation. Especially if the building area is large.
Save on pipes
If you prefer a forced circulation scheme, you don’t have to worry about the diameter of the pipe being installed. Due to the same coolant speed, it will certainly be possible to ensure uniform heating of the entire system.
That is why cheaper pipes are purchased for such a system. Considering that their diameter is somewhat smaller, the pipes can be made almost invisible in the interior.
Avoiding bulky radiators
With natural coolant circulation, bulky radiators are traditionally installed, taking up a lot of space. Due to their large area, such batteries allow for more efficient heating of rooms. In a heating system with forced circulation, preference may be given to even a small radiator model.
Safety and ease of use
Uniform heating of the heating system helps reduce the risk of damage to its elements due to significant temperature fluctuations. As a result, the negative impact on the material of all elements of the heating system is reduced and their service life increases.
Thanks to the presence of Mayevsky taps and special automatic air vents in the forced coolant supply system, there is no fear of airing. The degree of water heating can be adjusted not only by the parameters of the heating boiler, but also by the characteristics of the pump.
With natural circulation, radiators become colder the further they are from the boiler. This contributes to uneven heating of the rooms.
Easy to install
The pipes do not have to be laid at a certain angle, which makes it possible to carry out the work on your own. If this rule is violated, in the case of natural circulation it will not be possible to ensure the passage of coolant through the system, and therefore heating a two-story house will be difficult or impossible.
About the disadvantages
Considering that the system contains a circulation pump, a mandatory connection to the electrical network is required. In areas with frequent power outages, this fact can create serious problems. If desired, you can get rid of this problem by providing an uninterruptible power supply.
Also, do not forget about the possible increase in the cost of paying electricity bills. To do this, it is worth making the appropriate calculations before purchasing equipment. Sometimes, due to the fact that pipes with a smaller diameter are installed, coolant consumption is reduced.
This, in turn, leads to a reduction in the power consumed by the boiler. As a result, the cost of operating the pump can be fully compensated by reducing the cost of operating the boiler.
Operation of the pump is accompanied by slight noise. If the equipment is installed in a separate room, such a drawback does not deserve attention. However, for a small house or one-room apartment this can be a serious problem.
If a heating system with forced circulation is installed to heat a two-story building, there is no doubt: such a house will always be warm, quiet and comfortable.