Welding of air conditioner pipes

Welding of air conditioner pipes. How is it performed?

In order for the system to work properly and efficiently, it must be properly mounted. Installation of an air conditioner is a complex, time-consuming job. One of the most difficult stages during installation is the laying of freon copper pipes. A refrigerating agent will subsequently circulate through them, this issue needs to be approached with special attention.

In most cases, the flaring method is used to connect the freon tubes of the air conditioner. It provides a tight and neat connection, in which the tubes can be easily disassembled. However, sometimes the installer has to use soldering or even welding to connect the pipes.

In this article, we will tell you in detail what tools you need to use for soldering copper pipes, how the connection is made using soldering and whether it is possible to weld the air conditioner tube using argon welding.

Accessories and tools

soldering of copper pipes of the air conditioner

To properly perform soldering of copper pipes for your air conditioner, it is important to choose the right consumables.

The first thing you should pay attention to is the tubes themselves. Copper tubes are most often used, because they are quite plastic, at the same time durable, they can withstand operating temperatures up to +100 degrees Celsius, they are not afraid of corrosion and the chemical composition of freon.

Tools and materials for soldering air conditioner pipes:

  1. Pipe cutter. A mandatory tool. We strongly do not recommend using a hacksaw instead of a pipe cutter. Otherwise, you will get an inaccurate cut, and also increase the probability of metal chips getting inside the pipe;

  2. A tool for bending pipes. Pipes can be bent manually, but in the process you will easily damage the metal, creases will appear on it. And this is unacceptable;

  3. Gas burner with flame adjustment;

  4. Solder for soldering copper pipes (soft or hard, it does not matter);

  5. Gas mixture;

  6. Metal brush and sandpaper;

  7. Protective equipment (mask and glasses-a minimum set).

Let’s focus on the solder in more detail. The solder can be silver or copper-phosphorus. If there is also cadmium in the composition, then you are obliged to use protective equipment. Because when heated, such solders emit toxic fumes.

For working with copper pipes, it is better to use silver solder for soldering. Copper-phosphorus solders are more often used when working with aluminum. We will say more about aluminum at the end of the article, when we mention argon welding. But, in general, the article is devoted to soldering COPPER tubes.


A few words about the gas mixture. It is necessary to use only high-quality mixtures, because the reliability and tightness of the connection largely depends on this. Before soldering, check the mixture: the torch should be bright blue throughout its entire length. If the color is more like a pale blue, most likely there is too much oxygen in its composition. This means that the metal will be oxidized faster. If possible, do not use such mixtures in your work.

Next, we will tell you how the soldering of copper pipes for the air conditioning system is carried out, and what nuances need to be taken into account.

How the work is done

welding of air conditioner pipes

The ends of the tubes must be pre-cleaned with sandpaper or a hard metal brush, thereby reducing the wall thickness and preparing the surface for work. Also, the metal needs to be degreased. There should be no traces of dirt or paint on the tubes. Any contamination worsens the quality of the seam.

One tube must be inserted into the other for a length equal to the diameter of these tubes. At the same time, the gap should be minimal! One tube should fit quite tightly into the other. But be careful, copper pipes are easily deformed, with excessive force, creases can form on them. And this is unacceptable.

Next, you need to warm up the solder, after lowering it into the flux. The latter will protect the solder from oxidation. The flux layer should be small! Otherwise, the connection will be of poor quality.

Soldering of the copper pipes of the air conditioner is carried out with the help of a flame from a gas burner. The burner must be run smoothly. During operation, solder is used for soldering. It should penetrate into the gap between the tubes. Heat the burner not only at the junction of the two pipes, but also 5-10 centimeters to the left and right of the joint.

After soldering, it is necessary to clean the traces of flux from the surface of the tube. Use a metal brush or sandpaper to achieve a smooth joint surface.

Please note

Important nuances that you should pay attention to:

  1. Use a burner with adjustable flame intensity. This way you can clearly adjust the heating temperature of the parts. Next, we will also touch on the issue of soldering at low and high temperatures;

  2. Use protective equipment: a mask and glasses. Also open a window. Some solders can emit toxic gas when heated, take care of your health;

  3. Heat the joint slowly and evenly, do not rush. The main task is to achieve a neat sealed seam.

Optimal soldering temperature

Soldering should be performed precisely in a low-temperature mode. This means that the pipes at the junction should not be heated above 427 degrees Celsius. This method is the most effective: local heating is achieved, the metal is almost not oxidized, the seam is neat.

But it is better to forget about high-temperature soldering. When connecting freon pipes, this method is not used. At elevated temperatures, it is not possible to achieve the same exact and tight joint as with low-temperature soldering. This is especially true if you do the work at home and do not have enough experience.

In some cases, soldering with the use of high temperature is quite viable, but you need to observe a lot of nuances. This work is only possible for an experienced master who knows why it is better to use a high-temperature method in one case or another.

A few words about welding

aluminum air conditioner pipes

The argon welding method, and welding in principle, is rarely used when laying freon pipes. Argon welding is good in cases where aluminum tubes are used. But often copper pipes are used for the route.

In this article, we will not touch on the issue of argon welding, since this method is used extremely rarely. If you are at the stage of preparation, it is better to buy copper pipes and use soldering or rolling. It’s easier and faster.


A high-quality connection of pipes for air conditioners guarantees tightness, and therefore the efficiency of the air conditioning system. For connecting pipes, they often use rolling, but sometimes soldering is also used. This method can be used to connect copper tubes.

But the welding of air conditioner pipes is justified only if the pipes are aluminum. In this case, the argon welding method is used. In this article, we did not dwell on this method in detail, since aluminum pipes are extremely rarely used when laying a freon route.

Any other questions? Ask them in the comments below. And if you have already had experience soldering or welding freon tubes, share it. Give some useful tips and recommendations. They will be useful for many readers. Also check out other articles on our website. We wish you good luck!

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