Situation, when the refrigerator stops freezingice builds up inside or, conversely, becomes warm, it often confuses the owner. The most common and frightening cause of breakdown is failure the compressor, which is the heart of the entire refrigeration system. Many people immediately call a specialist, fearing the complexity of the work, but if they have minimal skills and tools, replacing the unit is possible at home.
However, it is worth immediately noting that the process requires not only mechanical actions, but also strict adherence to safety precautions, since the work is carried out with electricity under voltage and chemicals under pressure. Replacing the compressor —this is not just unscrewing the bolts, it is a complex operation, including evacuation of the system and charging with freon. If you are ready for painstaking work, then restoring the equipment yourself will save you a significant amount of money.
Before proceeding with dismantling, you need to make sure the diagnosis is correct. Sometimes symptoms indicating a motor breakdown can be caused by a freon leak or a faulty start relay. Attentive diagnostics at the initial stage will save you from buying unnecessary expensive spare parts and unnecessary work.
It is important to understand that modern models of refrigerators, such as Bosch, Liebherr or Atlantmay have structural features that require a specific approach. However, the basic principle of operation of the refrigeration circuit remains the same for most household devices, which makes it possible to develop a universal algorithm of actions for successful repair.
Diagnostics of a compressor malfunction
The first step should always be a thorough check. If you hear the engine hum but won't start, or it turns on for a couple of seconds and clicks when it turns off, these are classic signs of a problem. However, do not rush to conclusions, since often the culprit is starting relay or the winding of the motor itself. Checking the resistance of the windings with a multimeter is a mandatory procedure that must be carried out before removing the casing.
Visual inspection can also provide a lot of information. Pay attention to the condition of the tubes and the motor housing itself. The presence of traces of oil, swelling or deformation of the housing indicates a serious problem. If the compressor is too hot to touch, this may indicate a turn-to-turn short. In such cases compressor repair is no longer possible, only a complete replacement is required.
⚠️ Attention: If, when testing the windings, the multimeter shows a resistance close to zero or, conversely, infinity, the engine is considered faulty. Also a critical indicator is a breakdown to the housing, when the device shows the connection between the winding contacts and the copper tube.
Sometimes the problem lies not in the electrics, but in the mechanics. Jamming of the piston group leads to the fact that the shaft cannot turn, and the motor hums while being blocked. An attempt to wedge such a unit is often successful only for a short time, after which the breakdown recurs. Therefore replacing the compressor in case of mechanical jamming, this is the only correct solution for long-term operation of the equipment.
Necessary tools and materials
To perform the work efficiently, you will need a specialized set of tools, without which replacing the unit is impossible. The main tool is a torch running on a propane-butane mixture, which allows you to heat copper tubes to the melting point of the solder. In addition, you need wire cutters, pliers, a set of screwdrivers and, of course, a multimeter for checking electrical circuits.
Particular attention should be paid to materials for soldering. You will need copper-phosphorus solder, which provides a reliable connection to copper tubing without the use of additional fluxes. The use of tin-lead solders is allowed only in extreme cases and requires the use of flux, which is undesirable inside the refrigeration circuit due to the risk of system contamination.
Also you will need technical liquids and gases. Nitrogen necessary for purging the system and creating excess pressure during soldering to prevent oxidation of copper from the inside. To remove moisture and air after assembling the circuit, it is required vacuum pump, without which normal operation of the refrigerator is impossible. Refilling is carried out with refrigerant, the brand of which is indicated on the nameplate of the old compressor.
Do not forget to prepare a new compressor, which must strictly correspond to the model of your refrigerator in terms of power, refrigerant and overall dimensions. An attempt to install a unit with other characteristics may lead to rapid failure of the entire system or ineffective operation.
Removing the old compressor
You should begin work by completely disconnecting the refrigerator from the power supply. This is a basic safety rule and, if ignored, may result in electric shock. After this, you need to gain access to the motor by removing the rear protective panel and removing the condensate tray if it interferes with access to the pipes.
The next step is to remove the refrigerant. In a factory setting, this is done through a special valve, but at home, craftsmen often carefully cut through the filling tube, allowing the gas to escape. This should be done in a well-ventilated area, since freon vapor is heavier than air and can displace oxygen. After releasing the pressure, you can begin to disconnect the electrical contacts.
To solder the tubes, use a torch. Heat the joint evenly, moving the flame in a circle. When the solder melts and flows, the tube can be carefully pulled out. It is important not to overheat the tube itself. compressor tube so as not to damage the internal insulation of the windings. After disconnecting all three tubes (suction, discharge and filling), the compressor can be unscrewed from the refrigerator frame.
☑️ Dismantling the compressor
When removing the old unit, be careful, as compressor oil may remain in the tubes. Place a container or. place a rag so as not to stain the floor and internal parts of the refrigerator. The old compressor should be disposed of according to the rules, since it contains technical fluids.
Preparation and installation of a new unit
The new compressor is often supplied with plugs on the pipes, they should be removed at the very last moment, immediately before soldering, so that air and moisture do not get inside. Moisture in the system is the main enemy, which can lead to the formation of an ice plug in the capillary tube and failure of the refrigerator.
Install the new motor on the frame using standard mounting holes and shock absorbers. If new shock absorbers are not included, you can use old ones, having first checked them for integrity.
Before soldering the tubes, it is necessary to clean their ends from oxides and contaminants. Use fine sandpaper or a special pipe stripping blade. Surface cleanliness is the key to high-quality soldering. Insert the tubes into the compressor pipes until they stop, leaving a small gap for the metal to expand when heated.
⚠️ Attention: When soldering, be sure to supply nitrogen inside the tubes. If you solder without nitrogen, scale will form inside, which will eventually clog the filter drier and capillary tube, which will lead to repeated failure.
After installing the compressor, it is necessary to replace the filter drier. This is a mandatory requirement for any opening of the refrigeration circuit. The filter removes moisture and acidic residues that are removed. may have formed in the system. It is strictly forbidden to reuse the old filter.
Soldering of pipelines and circuit assembly
The soldering process requires accuracy and experience. Heat the joint with a torch while holding the solder in the contact area. When the metal reaches the desired temperature, the solder itself will flow into the gap between the tube and the nozzle due to the capillary effect. Do not apply too much solder so as not to create a blockage inside the tube.
After soldering all connections, allow the system to cool naturally. Do not cool the soldering area with water or a damp cloth, as a sudden temperature change can cause cracks in the metal or break the seal of the seam. Visually inspect all seams for cavities and unsoldered areas.
| Type of connection | Melting point | Necessity of flux | Seam strength |
|---|---|---|---|
| Copper-Copper | 650-750 °C | Not required | High |
| Copper-Steel | 750-850 °C | Required | Medium |
| Aluminium | Low | Special. flux | Low |
| Tin (soft) | 200-300 °C | Required | Low |
Pay special attention to the connection of the copper and steel tube (if available in design of your refrigerator). Steel takes longer to heat up and requires a higher temperature, but it is also easy to burn through. Use special adapters or careful preparation of the edges.
Why is soldering speed important?
Heating for too long can lead to burning of the oil inside the tubes and the formation of carbon deposits that will clog the system. Heating too quickly will not allow the solder to distribute evenly.
Evacuating and charging with refrigerant
After assembling the circuit, it is necessary to remove air and moisture from it. To do this, a vacuum pump is connected to the filling fitting. The vacuum process should last at least 30-40 minutes. The system pressure should drop to a deep vacuum (about 0.98 bar). This is a critical step, as the remaining moisture will freeze in the capillary tube and block the circulation of freon.
Once the vacuum is reached, close the valve on the pump and turn it off. Wait 15-20 minutes while watching the pressure gauge. If the arrow does not deviate, then the system is sealed. If the pressure rises, it means there is a leak somewhere that needs to be found and repaired before refilling.
Refrigerant refilling is carried out strictly according to the weight indicated on the refrigerator nameplate. Use digital scales for accuracy. An excess or lack of freon is equally harmful to the operation of the compressor and the quality of freezing. Refilling is carried out with the compressor running through the suction tube.
⚠️ Attention: The type of refrigerant must strictly correspond to the marking. Replacing R134a to R600a or vice versa without completely reworking the system and changing the oil is prohibited, since they use different types of oils and have different operating pressures.
After refueling, the filling tube is sealed. Make sure there are no leaks at the sealing area by testing the connection with soapy water. The appearance of bubbles will indicate a soldering defect.
Checking operation and first starts
After completing all work, turn on the refrigerator. During the first minutes of operation, listen to the engine start. It should work smoothly, without strong vibration or extraneous knocks. After 10-15 minutes, the condenser grille at the back of the refrigerator should begin to heat up evenly.
Do not load the refrigerator with food at once. Let it run idle for several hours to make sure the temperature is stable and there are no cyclic on-off cycles (clocking), which may indicate problems with the thermostat or the amount of freon.
Check the operation of the freezer. The ice should grow evenly. If one part of the evaporator is frosted and the other is dry, this may indicate a blockage in the system or improper charging. In this case, repeated intervention may be required.
Check the condition of the compressor regularly during the first week of operation. It should not overheat beyond measure. A warm case is normal, but if you can’t touch it, then there is a problem with heat transfer or the amount of refrigerant.
Is it possible to replace a compressor without a vacuum pump?
Theoretically, some craftsmen use the method of displacing air with freon itself, but this is highly not recommended. Remaining moisture and air will lead to oil oxidation, acid formation and rapid failure of the new compressor. A vacuum pump is a must-have equipment for high-quality repairs.
How much does it cost to replace a compressor yourself?
The cost consists of the price of a new compressor (from 3,000 to 8,000 rubles depending on the model), a filter-drier, solder and a cylinder of freon. The savings compared to calling a technician can be up to 50-60% of the market cost of the service.
Is it necessary to flush the system when replacing a compressor?
Nitrogen flushing is required if the old compressor has burned out and released black oil into the system. If the replacement is planned or due to a leak, it is enough to simply purge the circuit with nitrogen under pressure before installing new components.
Why may a new compressor not start?
The reasons may be different: a faulty starting relay (often included in the kit, but sometimes defective), lack of electricity at the terminals, jamming due to water hammer (hit liquid freon into the cylinder) or a factory defect of the unit itself.