A sudden stop of the refrigerator or, conversely, its continuous operation without reaching the desired temperature often indicates critical problems with the “heart” of the unit - the compressor. It is this unit that is responsible for circulating the refrigerant in the system, creating the necessary pressure for the evaporation and condensation of freon. When you hear strange clicks, hums or complete silence of the equipment, suspicions first fall on the motor-compressor, and this is logical, since it is the one that experiences maximum mechanical and thermal stress.
Understanding what exactly can fail inside this complex mechanism helps the owner not to panic ahead of time and correctly diagnose the situation. Often the breakdown seems fatal, but in some cases the problem lies in the starting relay or an open circuit, and not in a jammed piston. Diagnostics allows you to save significant money by distinguishing a simple repair from the need to replace an expensive unit.
In this article we will analyze the internal structure in detail, look at typical scenarios for the destruction of parts and answer the question of what exactly breaks in the refrigerator compressor most often. Knowing these nuances will help you more accurately describe the symptoms to a technician or decide on independent intervention if you have the appropriate skills and tools.
The principle of operation and vulnerable spots of the motor
To understand the nature of the breakdowns, it is necessary to briefly consider the design. Most household refrigerators are equipped with hermetically sealed piston compressors, where the electric motor and compression part are located in a single steel housing filled with oil and inert gas. Rotor The engine rotates, driving the crankshaft, which pushes the pistons through connecting rods. This circuit, simple at first glance, contains several critical points of failure.
The main vulnerability lies in the inability to access internal components without breaking the seal of the housing (opening it). That is why many malfunctions are diagnosed indirectly, by external signs. Crank mechanism is subject to wear, and the electric motor windings are subject to overheating. Any imbalance between these elements leads to a stop.
It is important to note that modern inverter models have more complex electronic components, but the mechanical part remains similar to the classic versions. However, control boards in them often fail, rather than the mechanical gas compression unit itself. In classic linear models, mechanical wear is more common due to constant on and off cycles.
⚠️ Attention: Opening the sealed compressor housing at home is strictly prohibited without special equipment for vacuuming and filling. This is life-threatening and requires professional re-soldering of the tubes.
Electrical faults of the motor windings
One of the most common causes of failure is damage to the electrical part. The compressor motor has two main windings: working and starting. During long-term operation or voltage surges in the network, an insulation breakdown may occur. Interturn short circuit leads to a sharp increase in current and the protective relay is activated, after which the unit hums, but cannot start.
Often a circuit break occurs. This can happen both inside the case due to a wire burnout, and outside - at the connection point of the terminals. If, when testing with a multimeter, the device shows infinite resistance, it means the circuit is broken. In some cases, a break occurs in the thermal protection built into the motor housing, which burns out due to overheating.
A short circuit to the housing is another dangerous type of malfunction. In this case, the current goes to the metal casing, which can lead to an electric shock when touching the refrigerator. Dielectric strength insulation decreases over time due to oil aging and high temperatures. You can check this by measuring the resistance between the contacts and the body: it should be infinite.
How to check the windings with a multimeter?
To check, you need to remove the starting relay. There are usually three terminals on the compressor contacts. The resistance between the working and starting windings should be the sum of the resistances of each of them relative to the common wire. If somewhere there is zero or infinity, the winding is faulty.
Mechanical wear and jamming of the piston group
The mechanical part of the compressor experiences enormous loads. Over time, the rubbing parts wear out Pistons and the cylinders may lose their geometry, which leads to a drop in compression. In this case, the motor is running, the shaft is spinning, but there is no pressure in the system - the refrigerator stops freezing, although the compressor is hot and humming.
The most unpleasant scenario is jamming. This occurs when the parts are so deformed that the shaft cannot make a single revolution. When you try to start, a characteristic hum is heard, the thermal relay is activated, and after a while a click is heard. Repeated attempts to turn on only aggravate the situation, heating the windings to critical temperatures.
The cause of jamming is often the loss of properties of the compressor oil or moisture entering the system. Water, reacting with oil and refrigerant, forms an acid that corrodes internal surfaces. It is also possible for the crankshaft bearings to wear out, which creates runout and eventual misalignment of parts.
There is a method of “reanimating” a jammed compressor by applying increased voltage, but it helps only temporarily and only if there is no physical destruction of the parts. In most cases, when jamming, a complete replacement of the unit is required unit replacement.
☑️ Signs of mechanical failure
Problems with start-up protection equipment
Often, what is mistaken for a breakdown of the compressor itself is actually a malfunction of external controls. The starting relay is responsible for supplying a pulse to the starting winding, and the thermal relay protects the motor from current overloads. If these components fail, the compressor simply does not receive the command to start.
The starting relay (especially the posistor type in modern models) may burn out or lose its contact group. In older models with electromagnetic relays, contacts often burn out or the mechanism jams. You can check it visually (carbon deposits, melting) or by replacing it with a known good one.
Thermal relay (thermal breaker) opens the circuit when the temperature or current is exceeded. If it is “tired,” it may open the circuit too early, preventing the engine from developing the required speed. This is a common reason for the refrigerator to cycle on and off at intervals of several minutes.
| Symptom | Probable cause | Action |
|---|---|---|
| Click, silence, repeat after a while | Faulty starting relay | Replacing the relay |
| Beeps for 5-10 seconds and turns off | The compressor is jammed or the winding is burned out | Diagnostics with a multimeter |
| Silent, no light in the chamber | Open circuit, no power | Checking the socket and cable |
| Works without stopping | Freon leakage or piston wear | Search for leaks, measure pressure |
The influence of voltage quality and external factors
Do not forget that a compressor is an electric motor that is sensitive to the quality of the power supply. Power surges, frequent power outages and low voltage are the killers of household appliances. At low voltage, the motor tries to start, consumes a huge starting current, but cannot turn the shaft, which leads to overheating and burning of the insulation.
Overheating of the compressor itself can also be caused by external factors. If the refrigerator is close to the wall, the rear grille (condenser) is not blown with air. Heat transfer it is broken, the condensation pressure increases, the load on the compressor increases, and it wears out. Regular overheating shortens the life of the oil and accelerates wear of parts.
Case corrosion is another enemy, especially in conditions of high humidity. Rust can eat through a steel flask, breaking the seal. Refrigerant and oil will escape through microcracks, and air and moisture will get inside, which is guaranteed to damage the equipment.
⚠️ Attention: Installing the refrigerator in a niche without ventilation gaps provided by the manufacturer (usually 5-10 cm on the sides and back) leads to chronic overheating of the compressor and a reduction in its service life by 2-3 times.
Specifics of inverter compressors
Modern models are increasingly using inverter compressors that do not turn off completely, but smoothly change speed. They do not have a classic starting relay and heavy starting currents, which theoretically should increase the service life. However, they have their own Achilles heel - electronics.
Inside such a compressor or in a separate control unit there is an inverter board that converts direct current into alternating current with a variable frequency. It is this board that most often fails during power surges. The mechanical unit itself in inverters breaks down less often, but its replacement is much more expensive due to the complexity of the design and the need to reconfigure the control system.
Diagnostics of inverters requires special equipment. Testing the windings with a multimeter is often not enough here, since the resistance can be very low (less than 10 ohms), and a regular tester will show a short circuit where there is none. It is necessary to check the signal shape and the operation of the control module.
Diagnostics and restoration methods
Before drawing conclusions, it is necessary to carry out competent diagnosis. The first step is to check the presence of power and the integrity of the cord. Then, if there is access, the start relay is checked. If the relay is visually and contactally in good working order, the windings of the compressor itself are checked.
To check, the compressor is “turned on” directly, bypassing the relay, but only for a short time (2-3 seconds) to hear whether it starts. If the shaft does not rotate and a humming sound is heard, it is probably jammed. If the engine starts with a characteristic sound of air intake, it means that the mechanics are intact, and the problem may be in the freon circulation system (clogging, leakage).
Restoring performance in the event of an electrical breakdown or mechanical jamming at home is impossible. The compressor needs to be replaced with a new one. In this case, the filter drier must be changed and the system is evacuated before filling with freon.
Is it possible to change the compressor yourself?
Theoretically, yes, if you have the skill of soldering copper tubes, a vacuum pump and a pressure gauge station. However, without experience, there is a high risk of poor-quality soldering (oxides inside) or incorrect dosage of oil and freon, which will kill the new compressor in a couple of months.
Why does the compressor hum loudly when starting up?
A humming noise when starting up usually means that the electric motor is trying to turn the shaft, but encounters resistance. This may be a sign of an incipient jamming, low voltage in the network, or a malfunction of the starting relay, which does not give the desired impulse. If the hum is replaced by a click and silence, the thermal protection is triggered.
Can the compressor work without stopping and not break down?
Yes, in maximum cooling mode (for example, when loading warm products) or with a strong freon leak, the compressor can work continuously. However, long-term operation without rest cycles (especially in older models) leads to overheating of the oil and accelerated wear of rubbing parts.
What to do if the compressor burns out?
If diagnostics confirmed combustion of the windings or mechanical jamming, the only way out is to replace the unit. Repair (“rewinding” or “wedging”) in a workshop is possible, but it is not economically feasible and gives short-term results. It is safer to install a new original or high-quality analogue.
How to extend the life of a compressor?
To extend the service life, ensure good ventilation of the back wall, do not place the refrigerator close to the wall. Defrost the chamber regularly (if it is not No Frost) to prevent the formation of an ice coat that increases the load. Avoid frequent power surges by using a stabilizer or surge protector.