The situation when a loved one stops freezing, and a puddle forms on the floor or a hissing is heard, often poses The owner is faced with a choice: call an expensive technician or try to fix the problem yourself. Self-repair refrigerator If it stops freezing, and a puddle forms on the floor or a hissing sound is heard, it often leaves the owner with a choice: call an expensive technician or try to fix the problem yourself. DIY repair refrigeration circuit is not an easy task, requiring accuracy, theoretical knowledge and special tools, but quite feasible for a person with “golden hands.”
Before handling the burner, you must clearly understand that sealing is only part of the process of restoring the tightness of the system. If you decide to take this step, it means that a refrigerant leak has already been detected or localized. Freonhaving evaporated through a microcrack, it ceases to perform its function, and the compressor circulates air in vain. In this article, we will look at all the nuances of how to properly solder tubes, an evaporator or a condenser so that the equipment works again.
It is important to immediately note: if the damage is in the foamed part of the case or you are not confident in your abilities, it is better not to take risks. However, if the problem is in visible metal tubes, shut-off valves or accessible seams, then competent soldering can extend the life of the unit for many years.
Diagnostics and search for freon leaks
The first and most important step before starting soldering work is to accurately determine the location of the leak. It is pointless to try to solder all visible joints at random, hoping for luck. Circuit tightness It is most often broken in places of corrosion, mechanical damage or poor-quality factory welding. To search for a defect, visually inspect all accessible tubes: the rear grille, shut-off valves, where the tubes enter the body.
If a crack could not be visually found, a more thorough check will be required. Often, technicians use a soap solution, which is applied to suspicious areas while the compressor is running (if there is still pressure in the system) or when nitrogen is supplied. The appearance of bubbles will indicate the source of the problem. In professional settings, they use leak detectorsthat react to refrigerant vapors, but for home repairs, care and simple means are enough.
⚠️ Attention: Never look for a leak using an open flame (lighter or candle). Many refrigerants, when in contact with a flame, form toxic compounds that are hazardous to breathing, and in a confined space this can lead to poisoning.
Particular attention should be paid to aluminum evaporators in older models, for example, Indesit or Stinol. Aluminum is prone to electrochemical corrosion, and microscopic fistulas can appear in droves. In such cases, spot soldering may not have a long-term effect, and the entire evaporator will need to be replaced or an external “crying” evaporator installed.
Required tools and materials for soldering
The quality of the work performed directly depends on the equipment used. In order to solder a refrigerator at home, one soldering iron for radio components will not be enough. You will need a gas torch that can produce the melting point of copper and steel. The optimal choice would be a portable burner for household propane-butane or, better yet, for acetylene, if it is possible to purchase it in small cylinders.
The second critical component is solder. Ideal for copper tubes silver solder (with silver content from 5% to 40%) or copper-phosphorus alloys. They have high fluidity and strength. To solder steel elements (for example, a compressor discharge tube) or aluminum, you need special fluxes and solders with a low melting point, but high adhesion to a specific metal.
Also in your arsenal you should have:
- 🔥 Gas burner with piezo ignition or a separate fire source.
- 🧪 Flux (borax, flux paste for low-temperature soldering or special compounds for aluminum).
- 🧽 Abrasive materials (sandpaper, needle file) for cleaning edges.
- 🔩 Pipe cutter and roller (if you need to replace a section of the tube).
- 🧯 A fire extinguisher or container of water in case the insulation catches fire.
Do not forget about personal protective equipment. Soldering a refrigerator involves high temperatures and chemical fumes. Respirator and safety glasses are a must-have item for a craftsman. Working in a ventilated area or in the open air will significantly reduce health risks.
☑️ Ready for soldering
Surface preparation and copper soldering technology
The success of soldering depends 90% on the quality of surface preparation. The copper tubing you are going to connect or seal must be perfectly clean. Oxides, dirt, and old paint or insulation residue will prevent the solder from flowing and forming a reliable connection. Use fine sandpaper or a special brush to clean the metal to a shine.
The process of soldering copper refrigerator tubes usually occurs using technology hard soldering. First, the connection area is heated. The burner flame should be directed towards the joint, uniformly heating both parts to be joined. It is important not to overheat one point, so as not to burn through the thin wall of the tube. Movements of the torch should be smooth and progressive.
⚠️ Attention: When soldering near plastic elements or insulation, be sure to use a damp cloth or a special heat shield so as not to melt adjacent parts of the refrigerator.
When the metal reaches the desired temperature (cherry-red tint for copper), a solder rod is brought to the joint. Under the influence of heat and capillary effect, the solder itself will flow into the gap between the pipes, forming a sealed seam. There is no need to melt the solder directly with a torch flame - it should melt from the hot metal. This is the key point for creating a strong connection.
After the seam has cooled (naturally, without forced cooling with water), it should be inspected. A high-quality seam should be smooth, without cavities or sagging. If you use flux, after soldering, be sure to remove its remains with a damp rag, since many active fluxes can cause corrosion over time.
Features of soldering aluminum and steel
Soldering aluminum, from which evaporators are often made, is fundamentally different from working with copper. Aluminum instantly oxidizes in air, forming a refractory film that interferes with the bonding of metals. To work with it, special high-temperature solders (for example, zinc-based) and aggressive fluxes that destroy the oxide film are required.
The technique of soldering aluminum requires fast and confident movement. The soldering area is heated, flux is applied, and then by rubbing the solder rod against the surface (while it is hot), the metal “sticks” is achieved. This is similar to tinning, but at higher temperatures. Beginners are advised to practice on scrap pipes before soldering an expensive evaporator.
Steel elements, such as a compressor discharge tube, are more difficult to solder due to the high melting point of steel. A copper-steel connection is often used here. Since it is difficult to directly fuse these metals, they use special adapter bushings or solders with a high silver content, which work well with both metals.
Is it possible to solder aluminum with tin?
Yes, you can, but only with the use of special active fluxes for aluminum (for example, F-59A or F-64). Ordinary rosin flux is powerless here. However, such a connection will be less strong and durable than soldering with high-temperature solders, and is more suitable as a temporary solution.
If you are faced with the need to connect a copper and steel tube, make sure that the steel part is heated up more, as it conducts heat worse. The solder will flow towards the hotter metal. Proper warming up is the key to success in this operation.
Replacing the filter-drier and vacuuming
Any intervention in the sealed circuit of the refrigerator, including soldering, requires mandatory replacement filter-drier. This element is responsible for removing moisture and oil breakdown products from the system. If you soldered the hole, but left the old filter, the moisture that got into the system during the repair will clog the capillary tube with ice in a short time, and the refrigerator will stop freezing again.
The filter-drier is a copper cylinder that is soldered into the circuit break (usually before capillary tube). You need to solder it quickly so that it does not have time to pick up moisture from the air. The direction of refrigerant flow is indicated by an arrow on the filter housing, which is critically important during installation.
After soldering all connections and replacing the filter, it is necessary to evacuate the system. This is the process of removing air and moisture vapor from the circuit using a vacuum pump. Without this step, you cannot start the refrigerator: the remaining air will create excess pressure, and the moisture will freeze in the capillary.
| Stage | Action | Purpose |
|---|---|---|
| 1 | Connecting the pump | Creating a vacuum in the circuit |
| 2 | Evacuation | Removing air and moisture (15-30 min) |
| 3 | Refilling | Inputting the estimated amount of freon |
| 4 | Sealing | Sealing the process pipe |
Filling with refrigerant and checking for leaks
The final step of the repair is filling the refrigerator with freon. The type of refrigerant (R134a, R600a, R12) and its quantity are indicated on the manufacturer's label located inside the chamber or on the rear wall. An error in the choice of gas or its quantity will lead to incorrect operation of the compressor or even its failure. For example, isobutane (R600a) is explosive, and working with it requires special care and the absence of sparks.
Refilling is carried out through the process pipe, using a pressure gauge station to control pressure. The system pressure depends on the ambient temperature and the type of freon, so check the saturation tables. After refueling and starting the compressor, you must once again check all soldered joints for leaks with a soap solution.
If bubbles do not appear and the refrigerator begins to get cold, the process pipe is pinched and sealed. At this point the repair can be considered complete. However, remember that the first start after repair must be supervised: monitor the temperature of the compressor and the absence of extraneous noise.
⚠️ Attention: Do not allow the compressor to operate in a vacuum (without freon) for more than 1-2 minutes. In some models, the motor-compressor is cooled by the refrigerant passing through it, and running “dry” can lead to overheating of the windings and breakdown.
Which solder is best suited for copper tubes?
For copper tubes of the refrigerator, copper-phosphorus solders (for example, PMF-7, PMF-9) or silver solders are best suited (with silver content 5-15%). They do not require flux when soldering copper to copper, have high fluidity and create a strong, corrosion-resistant connection that can withstand compressor vibrations.
Is it possible to solder an aluminum evaporator with ordinary tin?
Using ordinary tin-lead solder (POS-60) aluminum is extremely difficult to make without a special flux. Even if it is possible to apply solder, the connection will be brittle and short-lived due to the difference in the expansion coefficients of the metals. It is better to use special aluminum solders (for example, Castolin 192FB) or replace the entire evaporator.
Is it necessary to change the oil in the compressor after soldering?
In most cases, if the leak was small and the compressor did not operate for a long time in an open circuit, an oil change is not required. However, if the system was open for a long time or moisture/dirt got into it, it is better to replace the oil with one of a similar viscosity and chemical composition (mineral or polyester), as it could lose its properties.
Why does the refrigerator not freeze after soldering?
There may be several reasons: insufficient vacuuming (moisture remains, clogging capillary), incorrect amount of freon, blockage in the filter-drier or poor-quality soldering (solder got inside the seam and blocked the passage). A repeated leak in another place is also possible.