Damage to the copper circuit is one of the most critical breakdowns that the owner of household appliances may encounter. If you notice an oily spot under the unit or hear a characteristic hiss of escaping gas, it means that the tightness of the system is broken. In such a situation, the user is faced with the question: call a technician or try to fix the leak himself by soldering the damaged area.
Independent soldering requires not only theoretical knowledge, but also the presence of specific equipment. Copper pipe The refrigerator has thin walls that are easy to burn if handled ineptly with an open flame. In addition, the system is under pressure, and even a microscopic hole leads to the rapid release of refrigerant and moisture entering the circuit.
In this article we will analyze in detail the technology for connecting copper pipes, choosing the right materials and the sequence of actions for reliable repairs. You will learn why ordinary rosin is not suitable for this process and how to properly prepare surfaces. Atlant refrigerators, Indesit and other brands have a similar line design, so these recommendations are universal for most models.
Required tools and materials for soldering
Quality connection directly depends on the equipment used. To operate, you will need a gas burner capable of producing a narrow and adjustable flame. Ordinary construction hair dryers will not help here, since the melting point of copper solder is much higher than that of tin. The ideal option would be a portable burner with a cylinder running on propane or a mixture of MAPP gas.
Particular attention should be paid to the choice of solder. For refrigeration circuits where refrigerant and oil circulate, lead-tin alloys with low melting points should not be used. You will need hard solder (for example, PSr15, PSr45 or imported analogues containing silver). It is silver that provides the necessary strength and resistance to vibration of the compressor.
⚠️ Attention: The use of acid-containing fluxes is strictly prohibited! Residual acid will eventually corrode the copper from the inside, causing repeated leakage and contamination of the system. Use only acid-free fluxes or pure borax.
You should also have a pipe cutter, a rimmer (for chamfering) and a roller in your arsenal. If the damage is in a straight section, you will need a piece of copper pipe of the same diameter to insert inside the joint. To clean the surfaces, use fine sandpaper or a special brush.
Preparation of the workplace and safety precautions
Soldering of the refrigerator is associated with open flames and flammable gases, so space preparation is key. Work should be carried out in a well-ventilated area, away from flammable materials. Make sure that you have free access from all sides to the unit, and the floor is protected from sparks with non-flammable material.
Before starting any actions, you must completely defrost the refrigerator and allow it to dry. Moisture on the tubes will evaporate when heated, but it is better to eliminate its presence in advance. It is also critical to release all residual coolant if it has not already escaped through the damage site. You cannot work with a circuit filled with freon.
Do not forget about personal protective equipment. Heat-resistant gloves and safety glasses will protect your hands and eyes from accidental splashes of molten metal or flying particles. Copper shavingsremaining after stripping can get into your eyes, so you should not neglect glasses.
Technology for soldering copper pipes: step-by-step instructions
The process of connecting pipes requires strict consistency. First, you need to carefully cut off the damaged area with a pipe cutter, being careful not to deform the edge. Then, using a rimmer or a file, the chamfer is removed and the inner and outer surfaces of the joined elements are cleaned to a metallic shine.
If you use the insertion method (when one pipe is inserted into another), the gap between the walls should be minimal. A thin layer of flux is applied to the cleaned surfaces. Next, the parts are assembled into a single unit, and heating begins. The burner flame is directed to the joint, heating both parts evenly. Do not hold the flame at one point for too long so as not to burn through the wall.
When the copper heats up to the desired temperature (about 700 degrees), the solder will begin to melt from contact with the hot pipe, and not with the burner flame. A drop of solder should flow into the gap under the action of capillary forces. After filling the seam, stop heating and allow the joint to cool naturally, without blowing on it or cooling it with water.
☑️ Soldering algorithm
The cooled seam must be cleaned of flux residues with a damp rag to prevent future corrosion. Visually, the connection should be smooth, without sagging or cracks. If the solder lays flat and surrounds the pipe in a circle, the stage can be considered successful.
Table: Selection of solder and melting temperature
Different alloys are used for different types of metals and operating conditions. In refrigeration technology, the most common solders are copper-phosphorus and silver. Below are the characteristics of the main materials that you may find on sale.
| Solder brand | Melting point | Composition | Application |
|---|---|---|---|
| PSr15 | 640-815 °C | Silver, copper, zinc | Copper, brass, bronze |
| MF-1 | 650-750 °C | Copper, phosphorus | Copper-copper compound |
| Castolin 187 | 650-800 °C | Copper, silver, phosphorus | High-strength seams |
| POS-61 | 183-190 °C | Tin, lead | Not suitable for freon! |
As can be seen from the table, Low-temperature tin-lead solders (PLS) have a melting point that is not comparable to the operating temperatures in a refrigerator condenser. Their use is a gross mistake that will lead to destruction of the seam when the compressor is first started.
⚠️ Attention: The characteristics of solders may vary depending on the manufacturer. Always check the data on the packaging with the requirements for high-pressure refrigeration systems.
Typical mistakes and how to avoid them
Beginners often make mistakes that ruin all their efforts. One of the most common is overheating of the soldering area. If you keep the torch on for too long, the copper oxidizes, becomes brittle, and the flux burns out, no longer protecting the metal. The result is a porous and unreliable seam.
The second mistake is insufficient cleaning of surfaces. The oxide film on the copper prevents the solder from spreading evenly. The metal simply rolls into balls without creating a monolithic connection. Cleaning must be done carefully, until a bright shine appears.
The need for nitrogen purging is also often ignored. When soldering, scale forms inside the pipe, which can clog the capillary tube or filter drier during system operation. Professionals always flush the circuit with nitrogen during soldering to displace oxygen.
What is an oxide film and why does it interfere?
An oxide film is a thin layer of oxidized metal on the surface of copper that forms upon contact with air. It prevents the diffusion of solder into the base metal, which is why the connection is mechanical, not chemical, and is easily destroyed under pressure.
Checking tightness and vacuuming
After you have soldered the tube, you cannot immediately start the refrigerator. It is necessary to check the system for leaks. To do this, the circuit is connected to a nitrogen cylinder and excess pressure is created (usually 10-15 atmospheres). The soldering areas are generously lubricated with soapy water and watch for the appearance of bubbles.
If there are no bubbles, release the pressure and begin vacuuming. This is the process of removing air and moisture from the system using a vacuum pump. Residual moisture in the circuit will freeze in the capillary tube and block the circulation of freon, so this step is required. The pumping time depends on the power of the pump and the volume of the system, usually 15-30 minutes.
Without a vacuum pump and a pressure gauge station, high-quality repair of the refrigerator is impossible - filling “by eye” without pumping out air is guaranteed to lead to breakdown of the compressor in the near future.Only after successful evacuation is the refrigerant charged strictly according to the weight indicated on the technical sticker of the refrigerator. Using the wrong type of freon or violating the dosage is unacceptable.
Frequently asked questions (FAQ)
Is it possible to seal a pipe with ordinary tin solder?
No, you can’t. Conventional solder (POS) has a low melting point and insufficient strength. Under conditions of compressor vibration and high pressure, such a seam will quickly collapse, which will lead to repeated leakage.
How to replace nitrogen during soldering, if it is not available?
Ideally, nothing. Nitrogen prevents copper from oxidizing from the inside. In extreme cases, some craftsmen try to minimize oxidation by quickly completing the work, but this increases the risk of the formation of an oxide film and blockage of the system.
Why does the refrigerator not freeze after soldering?
There may be several reasons: insufficient vacuuming (moisture remains), the capillary tube is scaled, an incorrect dose of freon or the presence of a microcrack in the the seam through which the gas escaped.
Is it necessary to change the filter-drier after soldering?
Yes, this is a mandatory requirement. The filter drier is a disposable element. After the circuit is depressurized, it becomes saturated with moisture from the air and loses its properties. Installing a new filter is mandatory for any circuit repair.