Sudden silence in the kitchen or, conversely, an unusually loud hum of a working unit often becomes the first signals that refrigerator compressor has ceased to function correctly. It is this unit that is the heart of the entire cooling system, ensuring the circulation of refrigerant throughout the circuit. When the motor-compressor fails, the temperature in the chambers rises sharply, the food begins to deteriorate, and the owner is faced with the need for urgent intervention.
There is no need to panic in such a situation, since a complete lack of cold does not always mean a fatal breakdown of the engine itself. Often the problem lies in related elements of the electrical circuit, such as a start relay or thermostat, the replacement of which is much cheaper. However, if the diagnosis confirms that the compressor is faulty, then you will be faced with a choice between complex independent repairs using special tools and calling a professional technician.
In this article we will analyze in detail the algorithm of actions in case of suspected breakdown, methods of primary diagnosis and technical nuances of replacing the unit. You will learn how to distinguish a burnt-out motor from problems with electronics, what tools are needed for the job, and whether it is even worth undertaking such repairs yourself, taking into account the risks and cost of components.
How to understand that it is the compressor that is faulty
The first sign of troubles with the main engine of the refrigerator is a change in its operating mode. In good condition, the unit turns on according to a signal from the thermostat, runs for a certain time to reach the temperature and turns off. If motor-compressor it hums, but does not start, or works continuously without turning off for hours, this is a direct signal of a malfunction. In the first case, a stuck start relay is often to blame, in the second - a freon leak or loss of compression properties.
⚠️ Attention: If you hear a loud metallic knock or clanging when you try to start, immediately unplug the refrigerator. Continuing to operate in this mode can lead to permanent destruction of the internal mechanical parts of the compressor.
It is also worth paying attention to the temperature of the condenser (the grille at the back of the refrigerator). When the compressor is running, it should be warm or hot evenly along its entire length. If the engine hums, but the grille remains cold and the chambers are warm, this may indicate a piston group or a winding break. In some cases, the problem is indicated by a burning smell emanating from the rear of the unit, which indicates overheating of the winding insulation. wedge jamming piston group or winding breakage. In some cases, a problem is indicated by a burning smell emanating from the rear of the unit, which indicates overheating of the winding insulation.
For a more accurate diagnosis, it is necessary to exclude other causes of lack of cold, such as a malfunction of the thermostat or a refrigerant leak. If, when turning the thermostat knob or changing the settings in the electronic unit Settings → Temperature the engine does not respond, the likelihood of its breakdown increases. It is also important to check whether voltage is being supplied to the motor terminals, since the problem may lie in the wiring.
Primary diagnostics and checking the electrical circuit
Before proceeding with dismantling the compressor, it is necessary to thoroughly check the electrical circuit supplying the engine. Often owners of refrigerators brand Indesit or Atlant are faced with a situation where the start-protection relay burns out. This small device is responsible for supplying a starting pulse to the motor winding and protecting against overloads. Replacing it is inexpensive and does not require vacuuming the system, so you should start with it.
To check, you will need a multimeter. The first step is to ring the windings of the compressor itself through the contact group. The normal resistance of the working winding is usually 10-30 Ohms, and the starting winding is 20-40 Ohms. If the device shows an open circuit (infinity) or a short circuit (close to zero), then motor burned out and requires replacement. It is also necessary to check the resistance between the housing and the contacts - it must be infinite, otherwise the motor “breaks through” onto the housing, which is life-threatening.
☑️ Electrical diagnostics
Do not forget about checking the thermostat. If it is faulty, it simply does not send a command to turn on the compressor. You can temporarily close the thermostat contacts (after turning off the power!) to check whether the engine will start. If, after closing the contacts, the motor hums and tries to start, then the problem is with the thermostat and not with the compressor. However, if even with a direct connection the engine is silent or produces only a short-term hum, the diagnosis is disappointing.
Necessary tools and preparation for replacement
Replacing a compressor is a technically complex operation that requires specialized equipment. Unlike replacing a heating element or lamp, you cannot get by with a set of screwdrivers and pliers. For high-quality repairs, you will need a pipe cutter, rolling machine, burner (gas or oxyacetylene), nitrogen for purging and, of course, a new compressor, completely similar in characteristics and dimensions to the old one.
Particular attention should be paid to the selection of a new unit. Compressors from different manufacturers, for example Secop (formerly Danfoss), Embraco or LG, may have different capacities and types of refrigerant. Installing an unsuitable motor will lead to rapid failure of the new part or ineffective operation of the refrigerator. Be sure to check the model of the old compressor with compatibility catalogs before purchasing.
You also need to prepare consumables: copper tubes of the appropriate diameter, drying filters (they are always changed!), solder and flux. Don't forget about safety tools: gloves, safety glasses and a fire extinguisher, since the work will be carried out with an open flame and under pressure.
| Tool/Material | Purpose | Importance |
|---|---|---|
| Burner | Soldering copper pipes | Critical |
| Pipe cutter | Cutting copper pipes without chips | High |
| Vacuum pump | Removal of air and moisture | Critically important |
| Gauge station | Pressure control and refueling | Critically important |
Technology for dismantling the old compressor
The replacement process begins with completely disconnecting the refrigerator from the power supply and access to the engine compartment. If there is still refrigerant left in the system, it must be vented. Professionals do this by piercing the fitting or biting off the tube, but at home this must be done with extreme caution, ensuring good ventilation of the room, since the gas can be flammable or toxic.
After releasing the pressure, the capillary tube and discharge pipeline are unsoldered from the compressor. A burner is used for this. It is important to heat the connection evenly so as not to melt the compressor housing itself or adjacent plastic elements. After the solder has melted, the tubes are carefully moved apart.
Why should you not cut the tubes with cutters?
When cutting copper tubes with cutters, sharp burrs are formed and the end is flattened. This creates turbulence in the refrigerant flow and can lead to clogging of the capillary system, which will cause repeated failure in a short time.
Then the bolts securing the compressor to the frame are unscrewed and the wires are removed. The old unit is removed. A new one is installed in its place, which is pre-fixed to vibration-isolating bushings. Incorrect installation of the compressor without rubber dampers will lead to strong vibration and noise during operation.
Soldering, vacuuming and filling the system
The most important stage is soldering new connections. Copper pipes are put on the suction and discharge tubes of the new compressor, which are soldered into the existing circuit. Be sure to replace the filter drier, since the old one is already saturated with moisture and will not be able to protect the system from the formation of ice plugs. Soldering should be done quickly, using nitrogen purge inside the tubes to prevent the formation of an oxide film (scale) inside the circuit.
⚠️ Attention: The formation of oxides inside copper tubes is a common cause of repeated breakdowns. Copper flakes can get into the capillary tube and clog the system, which will require complete disassembly and cleaning.
After assembling the circuit and checking the tightness (pressure testing with nitrogen), it is necessary to carry out a vacuum. This process removes air and moisture vapor from the system. The vacuum pump is connected through the service connection, and the system is pumped out for 15-30 minutes until a deep vacuum is achieved. Without this step, normal operation of the refrigerator is impossible.
The final step is charging with refrigerant. The amount of freon is strictly regulated by the manufacturer and is indicated on a sticker inside or behind the refrigerator. Refilling is done by scale or by pressure depending on the type of refrigerant (R134a, R600a). After refueling, the pipe is sealed and a test run is carried out.
The cost of repairs and the feasibility of replacement
When deciding to replace a compressor, it is necessary to soberly assess the financial side of the issue. The cost of the compressor itself for a household refrigerator varies from 4,000 to 12,000 rubles, depending on the model and manufacturer. However, if you do not have the necessary equipment, renting or purchasing it (burner, pump, station) may cost more than the repair itself.
When contacting a service center, the price consists of the cost of spare parts, technician work and consumables. On average, replacing a compressor costs 6,000–15,000 rubles. For old refrigerators, the age of which exceeds 10-12 years, such repairs may not be economically feasible, since there is a high risk of failure of other components (evaporator, condenser) in the near future.
If the refrigerator is modern, energy-saving or belongs to the premium class (for example, Side-by-Side), then replacing the compressor will extend its life by 5-7 years and will justified. In the case of simple models in the budget segment, it is sometimes easier to consider purchasing a new unit, which will have a guarantee and a higher energy efficiency class.
Frequently asked questions (FAQ)
Is it possible to restore an old compressor, or just replace it?
In a domestic environment, restoring a hermetic compressor is impossible. Theoretically, it is possible to rewind a burnt winding, but depressurization of the housing and subsequent welding in makeshift conditions will not provide reliability. Manufacturing plants do not provide for the repair of these components, only replacement.
Why does the new compressor get hotter than the old one?
Modern compressors often operate at higher temperatures due to increased energy efficiency and the use of new types of refrigerants. If the body temperature does not exceed 80-90 degrees and the refrigerator freezes, this is normal. However, if it is red-hot or smells like burnt insulation, this is a sign of a malfunction.
How long should the compressor operate after replacement?
The first start-up may last longer than usual (up to 2-3 hours of continuous operation) until the system reaches operating mode and reaches temperature. After this, the thermostat will come into operation and the on/off cycles will begin. If the refrigerator does not turn off for more than 6-8 hours, there may be a freon leak or the compressor power is incorrectly selected.
Is it dangerous to repair a compressor yourself?
Yes, it is dangerous. Pressurized refrigerants can cause frostbite or fire (especially isobutane R600a). Working with open flames and electricity also carries risks. Without experience and tools, there is a high probability of permanently damaging the equipment or getting injured.