Pipes for heating boilers: which pipes are better for tying the boiler + installation tips

An autonomous source of heat energy used in individual buildings is often a heating boiler operating on one of the types of fuel: coal, gas or electricity. An important role in the organization of heating is played by pipes for heating boilers, with the help of which they are strapped - the assembly of all elements into a single system.

The complexity of installation, the cost of installation and the efficiency of the heating complex largely depend on the type of pipe products. Therefore, the issue of choosing pipes should be taken carefully, agree?

We will tell you what characteristics pipelines of different materials have, indicate the parameters of the heating system that must be taken into account when designing the main, and also give practical tips for installing utilities.

What pipe options can I use?

During the installation of the heating boiler, elements made of metals and polymers can be used. When choosing, you should pay attention to such characteristics as thermal insulation properties, ease of installation and operation, durability, as well as the cost of products.

Based on the sum of these criteria, the following types of pipes are used to complete the strapping.

Quality but expensive copper products

Copper strapping is relatively rare, since such pipes are quite expensive, and also require special skill in laying.

At the same time, structures made of this metal have a number of significant advantages, namely:

• good heat dissipation;
• resistance to corrosion and aggressive substances;
• resistance to freezing;
• high heat resistance.

Copper quickly and well warms up with a minimum amount of thermal energy; therefore, parts made of this material will constantly generate heat during transportation of the coolant.

Copper pipes are able to withstand significantly higher temperatures than plastic pipes (up to + 300 ° C), while they practically do not change in size. Hot fluid can also circulate in steel structures, but in this case the risk of corrosion increases

Pipes made of this metal withstand environmental influences. Over time, they can only be coated with a thin layer of oxide, which does not affect the operational characteristics.

Unlike pipes made of steel or polymers, ductile copper structures do not break when the coolant in them freezes.

Disadvantages copper pipes for heatinginclude the impossibility of their use to create closed structures in gates, as well as the already mentioned high cost.

Low cost steel products

Another common option are products made of steel.

Their benefits include:

1. High strength, allowing easy transfer of mechanical loads.
2. Low linear expansion coefficientthanks to which the length of the parts remains unchanged even with high heating.
3. High thermal conductivityallowing efficient heat transfer.

The disadvantages, first of all, are the tendency to corrosion, which destroys the metal, because of which similar elements need to be painted or coated with an anticorrosive composition.

The disadvantage of steel elements is the difficulty in laying, requiring special equipment and professional skills. The manufacture of structures from such elements must be trusted by specialists

When choosing, it is better to give preference steel pipes stainless steel: they are more expensive, but demonstrate greater resistance to environmental influences and better performance.

Strong and lightweight polypropylene piping

Similar products made from modern types of plastics are widespread due to many positive aspects.

Main advantages:

1. Affordable cost: prices for such products are much lower than for metal counterparts.
2. A light weight. Such elements weigh very little, so that you can save effort and money on their storage, transportation and installation.
3. Easy installation. Plastic pipes are easily assembled into finished structures. Via special soldering iron even a layman can quickly arrange the harness.
4. Coolant circulation rate. In polypropylene pipes, even if they have a complex shape, virtually no clogging occurs. This facilitates the flow of water, the speed of which remains unchanged throughout the entire period of operation (20-50 years).
5. Good resistance to high pressure. This allows the use of plastic elements even under difficult operating conditions.

The main disadvantage Ppr pipes - a high coefficient of thermal expansion coefficient, due to which these products, when heated, slightly increase in length. To counter this phenomenon, it is necessary to take measures by installing compensators.

Polypropylene pipes allow you to create heating circuits of any degree of complexity. However, designs with a large number of elements make installation difficult and adversely affect the efficiency of the heating system

In addition, there are special pipe options, which include aluminum foil-reinforced products marked PN 25 - they can be used in systems with pressures up to 2.5 MPa and a temperature of + 95 ° C, as well as reinforced PN 20 elements that can be used in temperature + 80 ° С and pressure 2 MPa.

One and two pipe heating systems

The choice of pipes is also influenced by the piping scheme (one-, two-pipe), along which the coolant moves.

The presented figure schematically depicts a single-pipe and two-pipe heating systems, each of which has advantages and disadvantages (+)

Consider the differences in the installation of both circuit solutions.

Option # 1 - single pipe system

In this case, the "feed" departs from the boiler - the main line with a large diameter. It simultaneously serves both for transferring hot heat carrier and for collecting already cooled liquid.

The figure shows one of the circuits of a possible boiler piping, including an anti-condensate pump and a deaerator installation (+)

Heating radiators are connected in series to the central artery. Two thin pipes are used for this, one of them accepts the coolant, and the second returns it.

AT single pipe heating system the fluid alternately passes through all radiators, transferring part of the heat energy during its journey.

Two varieties of single pipe designs

According to the design features, two variants of the system can be distinguished: flow-through and with bypasses. The flow-through design does not provide risers, limiting itself to the direct connection of the radiators of the upper floor with their counterparts located below.

When using this scheme, one must not forget about the ban on the use of control valves, since they can impede the access of the coolant going to the devices.

Such a system is easy to implement, but it has several disadvantages. The coolant in the circuit cools quickly enough, in addition, it is impossible to repair or adjust the system without completely shutting it down.

In this figure, you can clearly see the installation features of two popular varieties of single pipe systems (+)

Heating bypass system also involves the connection of radiators with risers, which are responsible for supplying networks with a coolant. At the same time, the batteries are separated from the circuit by shorting links.

The distribution of the coolant over all connected devices is carried out portionwise at almost the same time, so that the heated liquid cools much less than in flow-through circuits.

With a heating circuit with bypasses, it is possible to adjust the temperature and repair the outgoing device without shutting down the system.

Single element selection

The most popular option for performing single-pipe heating schemes are steel products, which have reasonable prices and good technological characteristics. They are especially common in apartment buildings of the old buildings.

When installing pipes, it is required to observe a slope, the value of which should exceed 5 millimeters per 1 linear meter. This installation ensures free transfer of the coolant, which will continue even in the event of a sudden or planned shutdown of the circulation pump.

In addition to steel elements for laying single-pipe systems, you can use products made of plastic. Due to the lower hydraulic resistance of polymer pipes, smaller diameter elements can be used.

Elements of large diameter (<50 mm) are used to direct and return the single pipe system, while structural elements with a diameter of 32 mm are enough to connect heating radiators in an open system.

Option # 2 - Effective Two-Pipe Scheme

This version of the heating circuit provides for two mains: one of them - “supply” - conveys the coolant that is heated in the boiler, and the second - “return” - collects the cooled liquid, which is discharged into the heating unit.

With forced circulation, the heated fluid rises along the main riser, after which it is distributed among the batteries connected in series.With systems with natural circulation, reverse risers are not provided for in the design, and devices are connected using the upper wiring (+)

This modification of the heating system provides for parallel connection of batteries. Since the intensity of the fluid circulation depends on the difference in temperature between the supply and return hoses, the coldest battery will warm up faster, and, therefore, the temperature in all connected devices will equalize.

The advantages of two-pipe systems include:

• high coolant circulation rate;
• the ability to create hidden systems with pipelines hidden in walls or floors;
• air heating efficiency;
• hydrodynamic stability of the system;
• the ability to easily connect the device used to adjust the flow of hot water.

Two-pipe systems can be of different types:

• with lower or upper wiring;
• with passing or deadlock transfer of the heat carrier;
• natural and forced circulation (in the latter case, a circulation pump is used).

A two-pipe system costs significantly more than a single-pipe system, and is also more difficult to lay than the last. At the same time, this option guarantees more comfortable operating conditions.

Among the disadvantages of such a system are factors such as:

• double the number of pipes required for laying the structure, which significantly increases its cost and increases the time required for installation;
• the need to use various types of control and shutoff valves.

Despite the comments made above, it is double pipe system considered the preferred solution, especially when it comes to the network associated with autonomous boilers.

It works with greater efficiency and allows you to quickly achieve a comfortable microclimate. The compatibility of such designs with all types of boilers and various types of heating batteries attracts attention.

Structural elements for two-pipe systems

When choosing parts for the construction of two-pipe structures, it is better to give preference to polypropylene elements, although other options (copper, metal-plastic) that can withstand high temperature and pressure can be used.

Modern materials and technologies provide the ability to mount systems without the use of welding, to install according to the principle of the designer. Since each bend of the pipe increases the hydraulic resistance, bends should be avoided and strive to lay the pipes as evenly as possible

Pipes with a diameter of 50 mm are optimally suited for the supply and collecting lines that are connected to the boilers. From similar parts, risers are also made to which radiators are attached.

Connection to the battery feed and return is made by pipes of various diameters, the choice of which is influenced by the number of sections:

• 1.5- inch pipes are required to connect 25-35-section radiators;
• 10-25-section - 1 inch;
• less than 10 sections — three quarters of an inch.

To prevent heat loss, all pipes and connections must be insulated.

Installation Tips

When tying heating boilers, some rules should be applied. For example, it is recommended to use polypropylene pipes, the marking of which indicates operation class 5, operating pressure 4-6 atmospheres, and nominal pressure (PN) 25 atmospheres or higher.

To prevent the resizing of PPR pipelines during the design, the installation of compensation loops should be considered.

For heating systems, it is preferable to use reinforced pipes, since the layer of foil reduces the rate of thermal elongation by two, and fiberglass by five times

At boiler piping polypropylene fittings can be connected to pipes in a single heating system by screwing threads or by cold / hot welding. The threaded method is much more convenient, however, it will cost a lot more due to the need to use a large number of adapters.

It is impossible to do without threaded fittings if there is a need to connect polypropylene pipes to metal parts or arrange fasteners between elements of different diameters.

When assembling structures from pipes and various fittings, it is desirable to use elements made of the same type of material, ideally, by the same manufacturer. This will ensure uniform product characteristics, which will affect the reliability and durability of the system.

A large assortment of fittings is designed for convenient laying of linear systems and performing nodal connections: tees, couplings, adapters and others.

By cold welding is meant the use of a special adhesive composition, which secures the details of the system. Recently, this method has almost gone out of use, since its result is not reliable enough.

The threaded connection allows the reuse of structural elements: in case of problems, they can be disassembled and then screwed on again. Welding allows you to mount more reliable systems, but they are disposable: at the slightest malfunction of the structure it will need to be replaced.

For welding polypropylene pipes of large diameter (> 63 mm), it is advisable to use the butt method, which is performed using a specialized device. In this case, you can do without the use of fittings (+)

For hot welding a special apparatus is used to solder plastic elements. In this case, both parts of the structure are simultaneously heated on the nozzle to a melting temperature of 260 ° C, after which they are pressed against each other, forming a reliable connection.

When connecting reinforced pipes with foil, the metal layer must be smoothed so that it does not interfere with fasteners, while with glass fiber elements this operation can be safely avoided.

Plastic does not combine well with antifreeze, therefore, in systems made of polymer elements, only heated water is suitable as a coolant.

When performing heating systems, all threaded connections should be sealed with paronite or other high-temperature sealant, since the coolant circulating in them has a high temperature.

Conclusions and useful video on the topic

In the video below you will hear a reasoned opinion of a specialist about the use of various types of pipes for the installation of a heating system.

To complete the boiler piping, various types of pipes can be used, for the optimal choice of which a whole range of factors should be taken into account: features of the boiler and heating system, material capabilities, personal preferences.

If there is some qualification, the installation of plastic elements can be carried out independently, strictly observing the scheme, but for the installation of metal pipes it is better to seek help from specialists.

Looking for quality pipes for boiler piping? Or is there experience in installing and using a particular pipe rolling? Please leave comments on the article, ask questions and participate in discussions. The contact form is located below.