Open heating system: open circuits and embodiments of type

Due to the ease of installation, low cost and sufficient efficiency outdoor heating system continues to be in demand. Having dealt with the principle of works, and installation rules, you can organize your own home heating.

We'll show you how to create a workable scheme open heating. We show you how to build a system, clearly following the technological requirements and standards when selecting and connecting elements. Taking into account our recommendations you build a smoothly operating an efficient circuit.

Independent craftsmen, we offer to get acquainted with the proven assembly options. Submitted to the consideration of information complemented by useful diagrams, photo collections, video instructions.

The content of the article:

  • Acquisition and operation of the system
  • The requirements for the arrangement and operation
  • Types of open heating circuits
    • Natural circulation in heating
    • Forced pump system
  • Embodiments wiring duct system
    • Specificity of one pipe and two pipe circuits
    • The upper and lower heating medium flow
    • Vertical and horizontal risers
  • gravity type heating arrangement
    • Calculation of the heating system
    • Selection of the main components
    • Steps for mounting an open system
  • Main features of compulsory schemes
    • Selection of the circulating pump
    • Install the pump in the main line
  • Conclusions and useful videos on the topic

Acquisition and operation of the system

AT a water heating system intermediary fluid acts when transferring thermal energy from the boiler plant to the radiators. The circulation of the coolant can be carried over long distances, providing heating of houses and buildings of various sizes. This explains the widespread introduction of the water heating.

The efficiency of the open type heating system is possible without using a pump. The circulation of the coolant based on the principles of thermodynamics. Movement of water through the pipes takes place due to the difference in hot and cold fluid density, as well as due to bias laid pipes.

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A distinctive feature of the system

In an open heating circuits for expanding the volume of the coolant provides a leaky tank - steel or plastic containers with a lid and spigot to drain the surplus into drains

The specifics of the open-loop

Upcoming heating circuit is directly communicated with the atmosphere. After the tank is evacuated of air, but also evaporation occurs, because of which the heat transfer fluid in the system to periodically replenish

Options improvised open tanks

Expansion vessel for the heating system of a private house can be made of plastic cans, old metal cans, and the like available tools

Single-tube method of connecting devices

In schemes connected devices met the standard principles. There are two-pipe and single-pipe options

Two-pipe heating system

The heating circuits with two pipes in one coolant pipe is fed devices, and is given another. The pipe systems coolant flows from one radiator to another and returns to the one main pipe boiler

The circulation pump in the system

Most outdoor heating systems belong to the category of gravity. However, there are embodiments using a circulating pump, which is selected considering load exceeding standards closed circuits

Methods of removing air from the system

The predominant amount of air in the open circuit goes through the tank. Exception - the contours of the lower connecting devices that require installation on each radiator air vent

Recommended types of heating devices

all kinds of instruments used in the construction of heating systems are used in open heating systems. The truth is recommended to install cast iron model due to its ability to retain heat for a long time

A distinctive feature of the system

A distinctive feature of the system

The specifics of the open-loop

The specifics of the open-loop

Options improvised open tanks

Options improvised open tanks

Single-tube method of connecting devices

Single-tube method of connecting devices

Two-pipe heating system

Two-pipe heating system

The circulation pump in the system

The circulation pump in the system

Methods of removing air from the system

Methods of removing air from the system

Recommended types of heating devices

Recommended types of heating devices

An indispensable element of the system - open expansion tank, which receives surplus heated heat medium. Due reservoir fluid is automatically pressure stabilization. Capacity set on all system components.

The whole process of functioning of the "open heating" is divided into two stages:

  1. Innings. Heated coolant travels from the boiler to the radiators.
  2. tank line. Surplus of hot water supplied to expansion tank, cooled and returned to the boiler.

In the single-pipe flow and return systems function performs one line in two-pipe flow and return circuits pipe independent from each other.

Open heating system

warm water density lower than the density of cold, so formed in the system of the hydrostatic head. Under the pressure of the hot water moving to radiators

The most simple and accessible for self-assembly is considered one-pipe system. The construction of an elementary system.

Basic equipment includes a single-pipe heating:

  • boiler;
  • radiators;
  • expansion tank;
  • pipe.

Some refuse installation of radiators and is placed on the perimeter of the house pipe diameter of 8-10 cm. However, experts point out that the efficiency of the system and ease of use with such a solution is reduced.

Acquisition of the heating system

Scheme gravitational one pipe open type nonvolatile system. Costs for the purchase of pipes, fittings and equipment are relatively low. Ability to work with different types of boilers

Harder and more expensive device by Twin-Tube heating option. However, the costs and complexity of structures fully compensated by the elimination of the disadvantages of standard pipe systems.

The coolant temperature equal to almost simultaneously supplied to all the devices, The cooled water is collected return line, and does not flow into the next battery.

Pipe system open type heating

To serve each instrument in two-pipe heating circuit arranged flow and return, so that the temperature system delivers coolant temperature equal at all points, and chilled water collects and guides the boiler return pipes - independent from the supply highway

The requirements for the arrangement and operation

At home heating device, it is important to take into account a number of features of open heating systems:

  1. To ensure proper circulation of boiler installation is at the lowest point line, and the surge tank - at the highest point.
  2. The optimal location for the expansion tank - attic. In the cold period of the year and the supply capacity of the riser within the unheated attic need to insulate.
  3. Laying lines performed with a minimum number of turns and connecting fittings.
  4. In gravitational heating system water circulates slowly (0.1-0.3 m / s), and therefore, the heating should take place gradually. We can not allow the boil - it accelerates the wear on the radiators and pipes.
  5. If the heating system is not used in the winter, the fluid must be drained - this measure will keep intact pipes, radiators and boiler.
  6. coolant level in the expansion tank must be monitored and periodically replenish. Otherwise, the line be air pockets that reduce the efficiency of the radiator.
  7. Water - the best coolant. Antifreeze is toxic, it is not recommended for use in systems having free contact with the atmosphere. Its use is advisable, if you can not pour coolant to unheated period.

Particular attention is paid to the calculation section and the slope of the pipeline. design standards for regulated SNIP 2.04.01-85 number.

The contours of the gravitational movement coolant size pipe section ahead of pumping schemes, but the overall length of the pipeline less almost doubled. Slope the horizontal parts of the system, equal to 2 - 3 mm per meter, satisfied only when installing heating with natural coolant movement.

Scheme open gravity type heating system

Failure inclination at the device system to the natural movement of the coolant pipe leads to airing and insufficient heating of the radiator remote from the boiler. As a result, thermal efficiency decreases

Types of open heating circuits

The open-circuit heating system coolant movement is carried out in two different ways. First Embodiment - natural or gravitational circulation second - forced or artificial inducement from the pump.

Selection scheme depends on the number of storeys and the areas of construction, as well as on the intended mode of heat.

Natural circulation in heating

AT gravitational system It lacks any mechanism to ensure coolant flow. The process is carried out entirely by expansion of hot water. For performance booster circuit provides riser, the height of which - at least 3.5 m.

natural circulation

If we ignore the setting of the vertical riser transit, there is a high probability that the heat transfer fluid coming from the boiler will not develop enough speed

The heat supply system of the natural circulation type best suited for space constructions 60 sq. M. The maximum length of the circuit, capable of providing a warm, considered a pipe 30 m important factor -. The height of the structure and number of storeys of the house, allows you to mount booster riser.

Scheme natural circulation is not suitable for low temperature application mode. Insufficient coolant expansion will not create adequate pressure in the system.

The possibility of a gravity circuit:

  1. Connecting to warm floors. On the water circuit leading to the floor, the circulation pump is mounted. The rest of the system is functioning normally. When disconnecting the electricity the house will continue to be heated.
  2. Work with boiler. The heating device is mounted at the top of the system - a little below the expansion tank.

To ensure the smooth operation of the boiler can be installed on the pump. Then, hot water heating and the production of the circuit automatically goes into the category of compulsory options. Additionally mounted check valve preventing recirculation of coolant.

Forced pump system

In order to increase the coolant velocity and reduction of time for space heating, the pump is built. The flow of water is increased to 0.3-0.7 m / s. The intensity of heat transfer increases and the branch pipe are heated uniformly.

The circulation pump in the system

Pumping schemes constructing both open and closed. In open circuits the surge tank is installed at the highest point of the system. The presence of the pump increases the conduit between the boiler and the batteries, both in height and in length

Important moments of the organization enforcement system:

  1. Scheme with integrated pump volatile. To space heating is not interrupted by a power failure, the pump equipment is placed on the bypass.
  2. The pump is installed in front of the boiler return pipe. Distance from the boiler - 1.5 m.
  3. When installing the pump is taken into account the direction of water movement.

In the return pipe are mounted two shut-off valve and bypasses the knee with a circulating pump. When a current flows in the network valves are closed - the movement of the coolant through the pump. If no voltage is present, the valves should be opened - the system will be reconstructed on the natural circulation.

installation of the pump

On the supply pipeline is necessary to install a check valve. The element is located immediately after the boiler and prevents coolant recirculation pump during operation

Embodiments wiring duct system

From layout heaters and connecting tubes depends efficiency, economy and aesthetics of the heating system. Selection of wiring is determined based on the design features of the house and the area.

Specificity of one pipe and two pipe circuits

The heated water is supplied to the radiators and back to the boiler in various ways. In single-loop coolant system is supplied through one large diameter line. The pipeline runs through all the radiators.

The advantages of a one-pipe system with self-circulation:

  • minimum consumption of materials;
  • easy installation;
  • a limited number of tubes inside the dwelling.

The main drawback of the scheme with a single tube performing the supply and return obligations is uneven heating of the radiator. The intensity of the heat and heat the battery decreases as their distance from the boiler.

Single-pipe circuit

When a long line of wiring and a large number of radiators last battery can be completely ineffective. "Hot" Heating devices should be installed in rooms of the north side, and the children's bedrooms

Two-pipe heating circuit surely recaptures position. Radiators connect the back and feed conduit. Between the panels and the heat source produced local rings.

The main advantages of the system:

  • all furnaces are heated evenly;
  • the ability to adjust the heating of each radiator separately;
  • reliable operation scheme.

Two pipe system requires a lot of investment and effort. Run the installation of the two branches of communications on building constructions will be more difficult.


Pipe system is easily balanced, providing a flow of coolant in the same temperature all the heating devices. rooms Rooms are heated evenly

The upper and lower heating medium flow

Depending on where the placement line, served hot coolant, distinguish the upper and lower eyeliner.

Layout of an open two-pipe heating system

In heating systems with open upper wiring is not necessary to use devices for exhaust air. Surplus it is discharged to the atmosphere through communicating the surge tank surface

When the upper wiring warm water rises through the main duct and through the return piping is transmitted to the radiators. The device is a heating system it is advisable to one- and two-storey cottages and private homes.

Enough practical heating system with the bottom distributing. The feeding tube is placed at the bottom, next to the return line. Movement of the coolant in an upward direction. The water passing through the radiator, on the return pipeline is sent to the heating boiler. The batteries are fitted bleed screw Removal of air from the line.

Open heating system with the lower wiring

In heating systems with the lower wiring is necessary to use devices for discharging air, the simplest of which is a bleed screw

Vertical and horizontal risers

By type of main provisions of the risers are distinguished vertical and horizontal ways of routing the pipeline. In the first embodiment, radiators all floors are connected to a vertically arranged risers.

Vertical layout of the heating system

The vertical wiring arrangement used in homes in two, three or more with the attic floor, within which can be laid and to insulate the conduit

Features of "vertical" system:

  • no air pockets;
  • suitable for heating high-rise buildings;
  • Self-contained connection to the riser;
  • the complexity of the installation of heat meters in residential apartment buildings.

Horizontal cabling provides a connection radiators one floor to a single riser. The advantage of the scheme - for the device using less pipe installation costs are lower.

The horizontal layout of open heating systems

Horizontal risers, usually used in single and two-storey buildings. Construction of the system relevant to the panel-frame houses and residential buildings without piers

gravity type heating arrangement

The drafting of a gravity system is best left to professionals of Heating. The document indicates type of heating, the method of connecting the radiator and coolant circulation, the recommended settings of equipment, the number of radiators and pipe yardage.

Calculation of the heating system

It is necessary to determine the hydraulic characteristics of the system, which further help to choose the optimal duct diameter.

calculation system

In the natural boiler heating system it is recommended to be installed in the basement or the basement. This makes it possible to increase the length of the riser transit

To calculate the circulation pressure (Rts) Must have the following information:

  1. Distance from the center to the boiler heating radiator center (h). The greater the distance between the devices, the more stable circulation.
  2. Pressure cooled (rho) And heated (Pr) water.

Circulating pressure depends only on the difference in temperature of the coolant. The exact figures can be obtained from table data.

circulating pressure

The greater the temperature difference between the coolant, the pressure in the line above. Therefore, it is important to take care of the "incoming" fluid temperature

the width of the pipeline section It affects the type of material. The diameter of the steel pipe should be not less than 50 mm. After branching line section tapers in one dimension. Tank line, on the contrary, is assembled with subsequent expansion.

Particular attention is paid to the volume of the expansion tank. vessel size should not be less than 5% of the total water volume in the system. Failure to lead to drain water from the pipe system or impulse.

Selection of the main components

To open the system better to pick up the boiler, for solid fuel or fuel oil. installation of electric boilers and gas equipment is prohibited. The line is sometimes formed air pockets - it can lead to an emergency situation.

The heater power is determined based on the calculation - 1 kW of heat energy per 10 sq home. Depending on the quality of thermal insulation space to the obtained value is added to 10-30%.

in the heating system boiler

The boiler is located in a separate room equipped with a forced air circulation. The equipment is installed in the fire resistant material or concreted floor

Expansion tank for heating gravity type system must be made of steel. Polymeric materials are used is highly undesirable. For heating small single-storey house is suitable for 8-15 liters tank.

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The design of a simple open tank

The simplest embodiment of an open expansion vessel is a vessel of arbitrary shape with a hole for air purging and replenishing the coolant, and the overflow pipe

Principle homemade device

According to this principle do homemade expansion tanks of any tanks, the volume of which is equal to 4 - 10% of the total volume of coolant

Place for expansion tank

Open expansion tanks installed at the highest point of the system. If located within the unheated attic construction should insulate

Optimum location for the input feed

Feeding the coolant tube can be screwed or welded anywhere. It is important to choose to enter the lowest point in the tank

The design of a simple open tank

The design of a simple open tank

Principle homemade device

Principle homemade device

Place for expansion tank

Place for expansion tank

Optimum location for the input feed

Optimum location for the input feed

To use the pipe conduit arrangement from the following materials:

  1. steel. Characterized by high thermal conductivity and resistance to high pressure. Disadvantage - the complexity of the installation and the need for involvement of the welding equipment.
  2. polypropylene. Main advantages: resistance to temperature changes, strength, integrity and ease of installation. Service life - 25 years.
  3. metal and plastic. The material is not susceptible to corrosion, prevents clogging of the circuit. Disadvantages line: a limited service life (15 years) and high cost.
  4. Brass. Pipes with maximum heat transfer and resistance to high temperatures - up to + 500 ° C. The main disadvantage - the high cost of the material.

In an open heating circuit mounted radiatorsMade of high strength metals.

The most common steel model. They have the optimum ratio of basic parameters: appearance, price and thermal power.

steel radiator

Steel radiators due to the thin wall, light weight and high degree of heat transfer compared with convectors. Equipment quickly warms the room, due to the rapid movement of air

Steps for mounting an open system

The whole process of organizing the gravitational heating system can be divided into several stages:

  1. installation of the boiler. The equipment is fixed on the floor surface or hung on the wall. The choice of method depends on the size of the boiler.
  2. Pipework according to the selected pattern and developed project. It is important to observe the recommended angle pipe loop bias.
  3. installation of radiators Heating and connect them to the system.
  4. Installation of expansion tank and its insulation.
  5. Compound of elements, Check the tightness of joints and start system startup.

After the boiler, in the flow tube, it is desirable to install a temperature sensor for monitoring the efficiency of the heating system.

solid fuel boiler

Installation of the heating system should be carried out in the warm season. Construction of highways and commissioning will take approximately one week

Main features of compulsory schemes

To force the system proved itself and to function properly, it is necessary to choose the right circulation pump and competently "embed" it in the heat pipe.

Selection of the circulating pump

The main parameters of the choice of pumping equipment: the device power and pressure. These characteristics are determined based on the area of ​​heated space.


  • for homes 250 sq suitable pump which capacity 3.5 m³ / hr, and the pressure of - 0.4 atm .;
  • smokers size 250-350 sq mounted device 4.5 m³ / h with a pressure of 0.6 atm .;
  • if the house is an area of ​​350-800 square meters, it is advisable to purchase a pump capacity of 11 m³ / h, which is the pressure of not less than 0.8 atm.

When more meticulous selection of experts consider the length of the heating system, the type and number of radiators, the manufacturing material and the diameter of the tubes, and the type of the boiler.

Install the pump in the main line

Accommodation is made on the pump return pipe to passing through the device is not too hot coolant. On the flow of the possible installation of modern models of this high-temperature materials.

When "sidebar" pump should not disrupt the water flow. It is important that at any point in line with the work of the pump unit hydrostatic pressure remained excessive.

Pump setting circuit

Four valid circuit heating systems with a circulation pump and an open type expansion tank. Hydrostatic pressure is maintained at the desired level

Option 1. The rise of the surge tank. A simple method for the conversion of the natural circulation system of enforcement. To implement the project require a high attic space.

Option 2. Moving to the far tank riser. Laborious process of reconstruction of the old system and the new device - is not justified. There may be more simple and successful way.

Option 3. Pipe expansion tank around the pump nozzle. To change the circulation type must be cut off from the reservoir flow line and then connect it to return pipe - for the circulation pump.

Option 4. The pump is included in the flow pipe. The easiest way to the reconstruction of the system. minus method - pump adverse operating conditions. Not every device withstand high temperatures.

Conclusions and useful videos on the topic

Video # 1. Recommendations for the assembly of the heating system with natural circulation:

Video # 2. To install the circulation pump:

Important aspects of the arrangement of the effective heating range are workable circuit, calculating line parameters, the selection of components and following mounting technology. Handwritten installation is possible in the presence of plumbing skills, and development of a detailed project best left to professionals.

Want to ask a question about the scheme of organization and apparatus open loop supply wiring? Leave, please comment in the box located below. Here you have the opportunity to ask a question or tell an interesting fact on the topic.

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