Copper pipes for heating: types, specifics of marking + application features

Amir Gumarov
Checked by a specialist: Amir Gumarov
Author: Lydia Korzheva
Last update: October 2019

In the assembly of heating circuits, copper pipes are not used very often. Their cost does not attract owners of private houses and apartment owners too much. However, if the installation is done correctly, then the high cost of the copper pipeline will pay off for many years of operation without repair costs.

We will talk about how to correctly select copper pipes for heating. In our article, we present the features of marking, describe how to connect components. Independent owners will find instructions for assembling heating systems.

Types of Copper Tubes

There are two large groups of copper pipes: thick-walled and thin-walled. Pipes included in the first group have increased strength characteristics. They are produced in a seamless and welded manner.

The pipes of the second group have found application in shipbuilding and automotive, aviation, i.e. where communication systems must be lightweight and more robust. The cross section of copper pipes can be either round, or rectangular, square. In heating systems, profile pipes, as a rule, are not used.

For thick-walled pipes, the cross section is round, the wall thickness varies in the range of 0.8 - 10 mm. Different types of copper are used in their production: M1, Mp3, Mp1 and others. The digital index here indicates the degree of purity of the alloy. This does not affect the characteristics of the pipe itself. Thin-walled pipes have a wall thickness of 0.15 to 0.7 mm.

The state standard allows the measurement of copper pipes both in the metric system and in inches. In the designation of the first indicate the outer diameter, and the second - the inner. The pipes used in the installation of heating systems are marked in inches.

Table with the dimensions of the copper pipes for the heating device
Here, all existing diameters of copper pipes are tabulated. Using these data, you can easily pick up accessories for installing a heating main

To perform internal heat exchangers use copper pipes with a diameter of up to 10 mm. Such a diameter, combined with a highly efficient energy transfer, guarantees the maximum return on the functioning of this device.

Pipes 3/8 inch or more are used in the heating systems themselves. They provide efficient heating with low energy consumption.

Specifics of decoding of markings

The normative document defining the standards of copper pipes used for heating is GOST 617-2006. It stipulates the requirements for the brand of copper, the range of sections, wall thickness.

Copper products have their own marking, decoding which you can find out the characteristics of the pipe:

  1. Preparation method. It is denoted by the letters D and G. The first indicates that the pipe is cold-deformed drawn. They are made from 1.5 to 6 m long. The second - the product is made by pressing. According to regulatory requirements, they are made from 1 to 6 m long.
  2. The geometry of the cross section of the pipe. КР - section in the form of a circle.
  3. Precision manufacturing. Letters N and P. N - normal, P - increased.
  4. condition. M, P, T, L, R, Ch. These indices indicate a soft, semi-solid, hard, soft pipe with increased ductility, semi-solid pipe with increased strength, and hard pipe with increased strength, respectively.
  5. Length. ND - the index indicates that the pipe is non-dimensional, MD - means a measured pipe, KD - multiple measured, BT - in bays.
  6. Special conditions. Y - the length of the pipe in the bays is increased, B - the pipe has increased accuracy with respect to length, K - the pipe has increased accuracy in curvature.

For illustration purposes, an example: suppose a marking in the form of a DKRNM 32 x 3 x 3000 M2 B is present on the pipe.

It can be decrypted as follows: a cold-deformed pipe with a round shape of normal accuracy, made of soft copper, having an outside cross section of 32 mm and a wall thickness of 3 mm. It is a measured length of 3000 mm, made from copper grade M2.

Pipes for heating
For heating, solid pipes are mainly used. Pipes in soft execution are expedient to use for the device of a heat-insulated floor where it is required to perform a large number of turns

In the manufacturing process, copper pipes can be heat treated and then they are called annealed. When this step is excluded from the process, unannealed pipes are obtained at the outlet.

All three types of copper pipes are suitable for arranging private houses, since the pressure in the heating circuits in them never exceeds the values ​​indicated even for soft varieties.

The marking is as follows:

European standard
Being able to decipher the marking of pipes correctly, you will never purchase products intended for the installation of water pipes for a heating device

In the first case, the products gain plasticity, but lose their resistance to deformation. Pipes made without annealing have increased strength characteristics, but it is almost impossible to bend them.

The advantages of copper pipelines

All the advantages of copper pipes stem from the unique properties of this material, the products of which:

  1. Harmless and possess bactericidal qualities.
  2. Long do not age and do not lose their performance.
  3. Resistant to corrosion and ultraviolet. They work in a wide temperature range - from -200 to + 350 ° C.
  4. Immune to chlorine in tap water.
  5. They have high thermal conductivity, which increases the efficiency of the heating system.
  6. On the surface of copper pipes having a small roughness coefficient, no plaque is formed.
  7. Resistant to freezing. The pipeline does not collapse and does not lose its original characteristics, being frozen up to four times.
  8. Able to maintain strength properties under the influence of pressure, reaching 200 - 400 atmospheres.
  9. Resistant to vibration.
  10. They have a wide assortment range.
  11. 100% recyclable.

From the choice in favor of copper pipes for heating, many often stop both the high price of the pipeline itself and consumables.

The heating device from copper pipes is accompanied by the purchase of a variety of fasteners, connectors, fittings. The cost of all this is about 30% of the amount spent on pipes

Copper pipes are lightweight, they can be cut, bent and soldered. The most requested connection method copper pipe - soldering at high temperatures using silver-bronze solder. Faster installation is carried out using fittings.

Features of the choice for heating

Copper has its own individual characteristics, which impose both operational and technical limitations on their use. These points must be considered when installation of a heating system.

Although copper pipes are known for their strength, they calmly withstand pressure surges, temperature drops, and repeated freezing, but they do not withstand mechanical stresses. Therefore, when laying the pipeline, shock protection should be provided.

A heat carrier such as water contains sand and other suspended particles. The result of their exposure to soft copper is erosion. To avoid this phenomenon, it is necessary to include water treatment filters in the system.

The hardness of water also affects the pipe life. The value of this indicator in milligrams below the value of 1.42 and above 3.1 significantly reduces their longevity. This is explained by the fact that chlorine dissolved in water reacts with an oxide film present on the pipe walls. The result is strong protective armor.

If the water hardness indicators do not meet the standards, this protective layer begins to collapse, then, due to the presence of chlorine, it regenerates. If this process is repeated many times, copper resources are depleted.

Connecting pipeline by soldering, overheating that adversely affects strength should be avoided. The flux that remains after soldering must be removed, as it can cause corrosion.

If you want to bend the copper pipe, you need to use a special tool for this. An unsuccessfully bent pipe can be corrected once, and then it remains only to remove the wrinkled area.

The ideal option is to install a heating system from the same pipes. If for some reason this does not work out, you need to use transition fittings - brass or bronze. Adapters made of other materials cannot provide electrochemical compatibility.

Copper pipes can be mounted even at very low temperatures, therefore such a heating system is a rational solution to the problem in regions where cold weather is normal

So that pipes from other materials do not corrode under the influence of copper, a certain sequence of connection of such a combined pipeline with respect to the water flow vector is needed. Copper pipes must be mounted after elements made of other metals.

If planned heating system device with laying pipes inside the wall, you need to use copper pipes in a plastic shell. It will fulfill not only the role of thermal insulation, but also protect the metal from destruction. Copper pipes and stray currents have a detrimental effect.

Copper Pipe Docking

The connection of copper pipes is carried out by different methods. The most popular are 2 approaches to this issue: soldering and assembly using compression or press fittings. In general, one-piece and conditionally detachable connections are made.

In such a pipeline, there are practically no additional parts, except for the elements with which devices are connected to the pipeline. To install the system in this way, special devices are needed. Without proper qualifications, joining or soldering is difficult.

The use of fittings facilitates installation, requires less effort and reduces pipeline assembly time. The connection of this type can be detachable and one-piece.

A detachable connection is obtained using self-locking, threaded and compression fittings. This method complicates the design, the connections must be checked periodically, but even a person without experience can perform the installation.

One-piece crimp connections

To dock copper pipes manufacturers produce special fittings that vary in purpose, installation methods, the material from which they were made.

Based on the purpose, the following fittings exist:

  1. Bends, which are needed for joining pipes of different sections with corner joints.
  2. Crosses, which are also called tees and are used in the installation of branches from the main pipeline.
  3. Couplings used on straight routes for bundling copper pipes of different diameters.
  4. Collet fittings that are used when installing automation in the heating system.

For copper pipes, crimp fittings made of copper, brass, and bronze are most often chosen. Brass fittings are sometimes nickel plated to give them added strength.

Brass elements for connecting copper pipes are cheaper than copper, and are not inferior in strength to stainless steel. All fittings, regardless of manufacturer, are regulated by international standards and are interchangeable.

One-piece - this is a connection by pressing. Since copper is very ductile, installation is carried out using press fittings and crimp sleeves. In terms of tightness and strength, such a connection can be compared with soldering, and it is more durable than compression.

Visually, press fittings are similar to capillary solder connectors. The difference is in the presence of an o-ring made of high quality polymer.

In order to connect the pipes by means of a press fitting, they are cut into pieces of the desired length, the ends are cleaned, calibrated. After, the ends are pushed into the connector and clamps the joint using special pliers

When installing a heating system using copper pipes of small and medium diameters, low-temperature soldering is mainly used. Welding is used when pipes of large cross section are used. The pressing method is in demand when installing underfloor heating.

Compression fittings

For the installation of compression fittings there is no need for either special equipment or the use of open flame. All you need is a wrench, a calibrator mandrel, a cutter. To make these connections, collet or crimp fittings are required.

There are 2 types of compression fittings - some having an index A connect hard and semi-solid pipes, others marked with an index B connect soft and semi-solid pipes. The fitting includes a body, a crimp nut, a copper crimp ring, which flattens when pressure is applied to it.

Thus, the connection becomes airtight and resistant to vibration fatigue. The connection is carried out according to the same scheme as during the installation of press fittings.

The abutting ends of the segments of the copper pipes are cleaned, the geometry of the section is checked with a caliber, a crimp ring is put on, the ends of the pipe are inserted into the fitting until they stop. The nut is first tightened by hand, and when the pipe becomes stationary relative to the connector, take the tool and carry out the pull-up.

Connection diagram for compression fittings
Crimp fittings of type A are sometimes used not only for connecting pipes made of solid copper, but also for products made of soft copper. In the latter case, the support sleeve is inserted inside to avoid deformation of the pipe ends

On durability copper pipe joints with fittings, temperature instability and pressure surges are weakening. After a certain time, the seals wear. To oversee this weak link in the system, the connectors must be positioned so that they have easy access.

Do not thread copper pipes. To connect them with threaded parts, special adapters are produced. Their design provides for a socket connecting the fitting to the pipe by crimping or soldering and threading from the opposite side.

Emergencies in a heating system assembled from copper pipes are extremely rare, but if this happens, then pipes of equal diameter are temporarily connected by shrink couplings. You should be aware that all types of connections do not reduce the strength characteristics of the heating system.

Fittings increase the thickness of the pipe walls, and at the weld point over time, the connection becomes more durable, exceeding the strength of the pipeline itself.

Copper Soldering Fittings

Such fittings are called capillary. The connection with their help provides for the presence of solder. The key is right selection of fitting for copper pipe. Its internal section should be 0.1 - 0.15 mm larger than the outer diameter of the pipe.

The technology is simple:

  • cut the required pipe size;
  • protect;
  • chamfer with a chamfer - outside and inside;
  • clean the pipe, as well as the inside of the fitting, again until a matte sheen
  • Coat the end of the pipe. Designed for placement in the fitting and the fitting itself from the inside with special paste;
  • insert the pipe into the connecting element, rotate;
  • wipe the protruding paste, otherwise it will interact with the metal;
  • heating the compound using a gas burner or building hair dryer;
  • bring the solder to the gap after the flux begins to melt and lighten;
  • end the process when the solder flows over the entire surface and fills the gap evenly.

In order not to spend extra solder, you can wrap a pipe with it even before soldering, and cut off the excess. Upon completion soldering copper pipes the compound was allowed to cool at room temperature.

After installing the entire heating system, rinse it using hot water. This procedure will help to clean the remaining paste from the pipes. Docking places are inspected from the outside of the pipeline. If somewhere there is a flux or solder, it is removed with a damp cloth.

With guidelines for choosing copper pipes for the construction of water supply next articlededicated to their technical specifications and marking specifics.

Conclusions and useful video on the topic

Video # 1. On the pros and cons of copper pipes:

Video # 2. Copper pipe training:

If we compare copper pipes with polymer and steel pipes, then the first are distinguished by higher quality and reliability. Despite the high cost, they find their consumer and their popularity is growing.

The main thing is to choose the right consumables, and if you do it yourself, the heating system from copper pipes will cost much less.

Want to talk about how you bought copper pipes for the construction of the heating circuit? Do you know the technological nuances of assembling copper pipelines that are not covered in the article? Please write comments in the block below, post a photo on the topic of the article, ask questions.

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