Replacement compressor is one of the most difficult and responsible operations in servicing a household appliance refrigeration equipment. This process requires not only theoretical knowledge of the principles of operation of the freon system, but also the presence of specialized tools, as well as skills in working with open fire and high pressure. Sealed unitinstalled on the back panel of your refrigerator, serves as the heart of the entire system, ensuring the circulation of refrigerant throughout the circuit.
If you have made a firm decision to do this work yourself, you must be aware of all the risks. Improper soldering can lead to gas leaks, fires, or complete failure of expensive equipment. Unlike replacing a light bulb or seal, this requires mandatory vacuumization of the system before refueling, which cannot be done without professional equipment.
In this article we will analyze the technological process in detail, paying special attention to the nuances of soldering copper connections, since it is the quality of the seam that determines the durability of the repair. We will look at the preparation of materials, the choice of solder and the sequence of actions that must be performed to successfully replace the motor.
Preparation of the workplace and the necessary tools
Before you begin dismantling the old unit, you need to prepare the workspace. You will need a free area with good lighting and ventilation, since the soldering process involves the release of gases and the use of an open flame. It is important to ensure the stability of the refrigerator so that it does not tip over during manipulations with the tubes.
The main tool for performing the work will be gas burner. For domestic needs, propane-butane mixtures or more refractory acetylene are most often used if work with thick-walled pipes is required. You will also need a set of pipe cutters, a flaring tool (if you have to remake the ends of the pipes) and a set of wrenches.
Particular attention should be paid to personal protective equipment. It is necessary to wear heat-resistant gloves and safety glasses, as splashes of molten solder can cause serious burns. Ventilation of the room must be forced to avoid the concentration of flux vapors and combustion products.
⚠️ Attention: It is strictly forbidden to carry out soldering in closed residential areas without a working hood or in a draft that can blow away the burner flame or spread sparks.
To collect residual refrigerant and oil Capacity will be required from the system. You can’t just dump freon into the atmosphere—it’s harmful to the environment. In addition, you will need rags, rags for wiping pipes and a container for disposing of used compressor oil.
Removing the old compressor and preparing pipes
The first stage of work is to disconnect the refrigerator from the power supply and gain access to the engine compartment. Typically the compressor is located at the lower rear of the housing. It is necessary to remove the protective casing, if any, and disconnect the electrical wires from the starting relay and motor terminals.
Next follows the procedure of biting off the process tube to relieve pressure. This must be done carefully, using side cutters or pipe cutters, as excess pressure may remain in the system. After the gas has escaped, you can begin to disconnect the suction and discharge tubes.
The tubes are cut at a distance of 10-15 cm from the compressor housing. This is done in order to have a supply of copper for subsequent soldering and to avoid overheating of the motor housing during dismantling. The old compressor is removed from the shock-absorbing pins or rubber feet and put aside.
Now you need to prepare the ends of the copper tubes coming from the condenser and evaporator. Their ends are cleaned of oxides and old solder. To do this, you can use fine sandpaper or a special copper cleaner. The surface should be shiny and smooth.
- 🔥 Use a pipe cutter to obtain a perfectly smooth cut without burrs.
- 🧹 Thoroughly clean the inner and outer surfaces of the pipes before soldering.
- 🛢️ Make sure there are no old oil or oil residues inside the pipes contamination.
If the ends of the pipes are too short or deformed, they can be carefully flared with a special tool to ensure a reliable connection to the new unit. It is important not to overthin the pipe walls during processing.
The choice of solder and technology for soldering copper connections
The quality of soldering directly depends on the correct choice of consumables. For refrigeration systems operating under pressure, conventional tin-lead solder is not suitable. It is necessary to use silver solders (with a silver content from 5% to 45%) or phosphorus-copper alloys.
Phosphorus-copper solders have good fluidity and do not require the use of flux when soldering copper to copper, which simplifies the process and reduces the risk of acid formation inside systems. However, if you are joining copper to brass or steel, the use of flux becomes mandatory.
The melting point of silver solders is higher than that of tin, so the torch must provide sufficient heat. The flame must be directed and concentrated in order to heat the connection evenly, without burning out the thin walls of the tubes.
The soldering process is as follows: first the joint is heated, then a solder rod is introduced into the contact area. Under the influence of high temperature, the metal melts and is drawn into the gap between the pipes due to the capillary effect.
It is important not to overheat the soldering area, as copper may lose its properties or burn out. As soon as the solder has spread, heating must be stopped immediately and the connection allowed to cool naturally, without blowing on it or cooling it with water.
Installing a new compressor and soldering connections
The new compressor is installed in its original place and fixed with fasteners. Before starting soldering, make sure that the protective plugs on the pipes of the new motor are removed immediately before the connection to minimize the ingress of moisture and dust inside.
First, the discharge tube (output to the condenser) is soldered, then the suction tube (from the evaporator). The process tube remains open for now or is temporarily closed if a break in operation is planned. When heating the compressor housing during soldering, you need to act quickly and carefully so as not to damage the internal winding or valves.
If the diameters of the tubes of the new compressor differ from the old ones, adapters or copper tube inserts are used. In this case, the number of soldered joints increases, which increases the requirements for the tightness of the seams.
After all connections have been made, it is necessary to allow the system to cool completely. Visually inspect the seams: they should be smooth, without cracks, cavities or sagging. The color of the copper in the weld area may change, which is a normal thermal effect.
⚠️ Attention: Do not allow the open flame of the burner to come into contact with the electrical part of the compressor or the plastic housing of the start relay.
To control the quality of soldering, you can use a soap solution by applying it to the seams and introducing a little nitrogen or dry air into the system under low pressure. The appearance of bubbles will indicate the presence of fistulas that need to be soldered again.
Evacuation of the system and charging with refrigerant
After successful soldering, the most critical stage begins - removing air and moisture from the circuit. There should be nothing left in the system except clean refrigerant. For this purpose, vacuum pumpis used, which is connected to the process pipe.
The vacuum process lasts from 30 minutes to several hours, depending on the power of the pump and the volume of the system. The residual pressure should reach minimum values (about 50-100 microns), which indicates the removal of moisture. Moisture in the system is fatal to the compressor and capillary tube.
After vacuuming, the refrigerator is charged with freon. The amount of refrigerant is strictly regulated by the manufacturer and is indicated on the nameplate (usually on the back of the refrigerator or inside the chamber). Refilling is carried out on scales for accurate dosing or according to the pressure in the system, if a pressure gauge station is used.
The type of refrigerant must strictly correspond to the marking. Replacing R134a to R600a or vice versa without reworking the system and changing the oil is unacceptable, since they have different operating pressures and chemical properties.
| Refrigerant type | Working pressure (bar) | Oil type | Features |
|---|---|---|---|
| R134a | High | Synthetic (POE) | Hygroscopic, afraid of moisture |
| R600a (Isobutane) | Low | Mineral | Explosive, requires caution |
| R12 (Obsolete) | Average | Mineral | Prohibited for use |
| R404a | High | Synthetic | Used in freezers |
After refueling the compressor starts and the system enters operating mode. It is necessary to monitor the temperature of the condenser and evaporator, as well as the current consumption of the motor, to ensure correct operation.
Typical errors and safety measures during repairs
The most common mistake of beginners is neglecting evacuation. An attempt to simply “push” the system with freon does not remove moisture, which will freeze in the capillary tube and cause an ice plug that blocks circulation.
The second mistake is overheating of the pipes during soldering. If the copper turns dark purple or black, it is over-burnt. This leads to the formation of a thick layer of oxides inside, which will eventually come off and clog the filter drier.
The third problem is using the wrong oil. Compressors for R134a use synthetic polyester oil, which actively absorbs moisture from the air. You can’t keep such oil open.
Why can’t you use ordinary solder for pipes?
Ordinary solder has a low melting point and insufficient mechanical strength. Under the influence of compressor vibration and high pressure, such a seam will quickly collapse, which will lead to gas leakage.
It is also important not to forget about fire safety. Refrigerant R600a is explosive. Before soldering in a system running on isobutane, it is necessary to thoroughly flush the circuit with nitrogen to displace any remaining gas.
- 🚫 Do not leave open gas cylinders near a fire source.
- 🚫 Do not solder if the room smells of gas.
- 🚫 Do not use an open flame to check leaks.
Compliance with these rules will minimize risks and perform repairs efficiently. Remember that saving on tools or materials in this case can lead to much higher costs in the future.
☑️ Check before starting
Diagnostics and test run after soldering
After completion of all soldering and filling work, the testing stage follows. The refrigerator is connected to the network, and the technician must control the process of entering the mode. The initial startup may be accompanied by unusual sounds, but they should not be loud or knocking.
It is important to check the heating of the condenser grid (usually from the back or sides). It should heat evenly over the entire area. If only the upper part is heated, there may be little freon in the system or the capillary is clogged.
The temperature of the suction tube (at the inlet to the compressor) is also monitored. It should be cool, but not covered with frost or dew. Freezing indicates an excess of refrigerant or problems with thermoregulation.
The current consumption of the motor is measured with current clamps and compared with the nominal value on the nameplate. Excess current may indicate a malfunction of the compressor itself or mechanical jamming.
If all parameters are normal, the process tube is cut and sealed “tight”. The cut area is also soldered with solder to ensure tightness. At this point, the replacement work can be considered completed.
Frequently asked questions (FAQ)
Is it possible to seal a compressor without a vacuum pump?
Theoretically, you can try to squeeze out the air with freon, but in practice this leads to rapid failure of the equipment. Moisture will remain in the system, which will cause corrosion and ice plugs. A vacuum pump is a must-have equipment for high-quality repairs.
Which solder is best to use for a refrigerator?
The optimal choice is silver solder (for example, PSR-15 or PSR-25) or phosphorus-copper. They provide high seam strength and vibration resistance. Tin solders cannot be used.
Is it necessary to change the filter drier when replacing the compressor?
Yes, this is a mandatory requirement. The old filter is already saturated with moisture and dirt. Installing a new filter drier ensures that the refrigerant is cleaned and the new compressor is protected from breakdown.
How long does it take to evacuate the system?
The minimum time is 30 minutes for domestic refrigerators. However, to completely remove moisture from the oil and pipe walls, it is recommended to vacuum for 1-2 hours, especially if the system has been open for a long time.
Is it dangerous to change the compressor yourself?
Yes, it is dangerous. Risks include fire (open flame + gas), explosion (when working with R600a), burns and electric shock. In addition, there is a risk of permanently damaging the refrigerator. Without experience, it is better to turn to professionals.