Has the refrigerator stopped freezing or is it making an unnatural hum? In most cases, the problem lies in the heart of the unit - the compressor. This is a complex electromechanical device responsible for the circulation of the refrigerant, and it is its breakdown that most often leads to food spoilage. Understanding the nature of the malfunction helps not only save on repairs, but also avoid dangerous situations associated with a short circuit or freon leak.
You should not panic if you hear a strange sound, but you cannot ignore the first signs. compressor malfunctions you cannot. Modern models are equipped with sophisticated electronics that can block the engine from starting at the slightest suspicion of failure. At the same time, old units can continue to work “wear and tear” until they burn out completely. Let's figure out how to independently carry out initial diagnostics.
⚠️ Attention: Before any manipulations with the electrical part of the refrigerator, be sure to disconnect the device from the network. Working with high voltage without proper qualifications is deadly.
In this article we will look in detail at the main types of breakdowns, their symptoms and testing methods. You will find out when you can get by with replacing the start relay, and in which cases you will need to call a technician to replace the unit itself. It is important to distinguish between mechanical and electrical defects, since the approaches to eliminating them are radically different.
Main types of electric motor malfunctions
A compressor is a piston or inverter pump that compresses gaseous refrigerant and pushes it through the system. The most common problem is turn-to-turn short circuit the motor windings. In this case, the insulation of the wires inside the coils is broken, which leads to a sharp jump in current and the activation of protective mechanisms or burnout of the wiring. It is difficult to determine such a breakdown visually; a continuity test with a multimeter is required.
Another common scenario is “jamming” of the mechanical part. The pistons or shaft may get stuck due to wear out, metal shavings, or, conversely, due to lack of lubrication. In such cases, the motor hums, trying to start, but the shaft does not turn. After a few seconds, the thermal relay is activated and a characteristic click is heard, after which the cycle repeats. This condition is called “working in a loop.”
There is also a problem winding break. Unlike a short circuit, here the circuit simply breaks and the current stops flowing to the motor. The compressor is silent, the refrigerator does not make any sounds of the motor running, although the light inside may be on. This often happens after power surges or thunderstorms. Sometimes a break occurs at the soldering point of the wires coming out of the housing.
Is it possible to start a jammed compressor?
There is a “wedging” method by applying voltage directly, bypassing the starting relay for a short time. However, this method is extremely dangerous and requires special skills. In 90% of cases, jamming means physical destruction of the rubbing pairs, and it is better to replace such a unit.
Symptoms: how to understand that the compressor is broken
Diagnostics begins with an analysis of the behavior of the refrigerator. If you notice that the unit works continuouslywithout turning off for days, this is a sure sign of loss of productivity. The compressor tries to reach the set temperature, but due to a decrease in compression or a freon leak (although this is a related problem), it fails. Constant operation leads to overheating of the motor housing.
The second important symptom is lack of cold with the motor running. You hear a hum, feel a vibration, but the cells are warm. This may indicate that the compressor is running dry. The piston group has worn out so much that there is not enough pressure to circulate the refrigerant. This also happens when the valves inside the cylinder head are broken down.
- 🔊 Loud knocking or clanging at startup and during operation indicates broken bearings or destruction of the motor suspension inside the casing.
- 🔥 Strong heating of the housing compressor (to the point where it hurts to touch) indicates an overload or short circuit.
- ❄️ Sparking in the area of the starting relay or the motor itself is a critical sign that requires immediate shutdown of the device.
- 🔌 Knocking out plugs or automatic machines in the panel when the refrigerator is turned on, indicates a short circuit in the windings.
Do not confuse the noise of the compressor with the noise of the fan (in No Frost systems) or the gurgling of the refrigerant. The engine makes a smooth, monotonous hum. Any extraneous sounds, such as metal grinding against metal or intermittent humming, are alarm signals. If the refrigerator Atlant or Indesit began to behave strangely, listen to the nature of the sound.
⚠️ Attention: If you smell burnt insulation or plastic when the compressor is running, immediately unplug the plug from the socket. Continued operation will lead to a fire.
Problems with the starting and thermal relay
Often the culprit for stopping the refrigerator is not the motor itself, but its “retinue” - the starting and thermal relay. These small devices are responsible for starting the engine and protecting against overheating. The starting relay supplies an impulse to the starting winding, helping the rotor move. If it burns out, the compressor will only hum or click quietly, but will not start.
The thermal relay (thermal relay) opens the circuit if the current exceeds the norm or the temperature of the windings becomes critical. Sometimes the relay “sticks” in the open state, and then the motor will not receive power at all. In other cases, on the contrary, it does not open the circuit when overheated, which leads to burning of the windings. Replacing these elements is the simplest and cheapest repair procedure.
To check the relay, you need to remove it and shake it. If a ringing sound is heard inside (as from broken ceramic or a broken contact), the part is faulty. You can also visually assess the condition of the contacts: if they are blackened or melted, the relay requires replacement. It is important to select the relay strictly for the compressor model, since the starting currents for different motors are different.
☑️ Diagnostics of the compressor relay
It is worth noting that in In inverter models, the role of a relay is performed by an electronic control unit, which is located separately. There are no mechanical clicking parts, and diagnostics are made by measuring the output voltage to the compressor. If the control unit generates an error, the corresponding code often lights up on the refrigerator display.
Mechanical damage and wear of components
Mechanical malfunctions of the compressor are often associated with the wear and tear of the rubbing parts. Pistons, rings and cylinder wear out over time, causing gaps. Through these gaps, gas begins to flow from a high-pressure zone to a low-pressure zone, bypassing useful work. The pressure in the system drops, the refrigerator stops freezing, although the motor is running.
Another mechanical problem is destruction motor suspension. Inside the sealed casing, the motor is suspended on springs to dampen vibrations. If one of the springs bursts or jumps off, the motor will begin to bang against the walls of the casing. This causes severe vibration, noise and can lead to rupture of the tubes inside the housing, which is fatal for the compressor.
The ingress of moisture or acid into the system also refers to mechanical and chemical damage. If the system was depressurized (for example, when the evaporator was punctured with a knife), air and moisture could get inside. Moisture reacts with oil and freon to form acid. This acid corrodes the engine windings and varnish coating, causing short circuits and coking of the oil.
| Symptom | Possible cause | Probability of repair |
|---|---|---|
| Buzzing, clicking, not working starts | Stuck or burnt relay | High (replacement of relay/compressor) |
| Works silently, no cold | Winding break or freon leak | Medium (diagnostics needed) |
| Heavily knocking and vibrating | Broken bearings or suspension | Low (replacement of the unit is required) |
| Heats up and turns off | Thermal relay malfunction | High (relay replacement) |
Electrical parameters and diagnostics with a multimeter
For accurate diagnostics, you must use a multimeter. The first step is to check the integrity of the windings. There are three terminals on the compressor housing (usually labeled C, S, R or common, start, slave). There must be resistance between them. Between the working and starting windings, as well as between each of them and the common wire.
Normal resistance values depend on the power of the motor, but usually range from 10 to 30 Ohms for the working winding and 30-60 Ohms for the starting winding. The sum of the resistances of the two windings should be equal to the resistance between the extreme terminals. If the multimeter shows infinity (open) or zero (short circuit), the winding is faulty.
It is also critically important to check breakdown to the housing. One multimeter probe is placed on any terminal, the other on the cleaned metal of the case (where there is no paint). The device should show infinity. If there is any resistance, it means that the insulation is broken, and operating such a compressor is deadly.
In inverter compressors, the resistance of the windings can be very low (2-5 Ohms), and it is difficult to check them with a regular tester, since they are controlled by frequency converters. For them, it is important to check the integrity of the wires to the control board and the presence of power on the unit itself.
⚠️ Attention: Technical characteristics of compressors (winding resistance, starting current) may vary depending on the manufacturer and model. Always check the official technical documentation or markings on the nameplate.
Inverter compressors: features of breakdowns
Modern refrigerators are increasingly equipped with inverter compressors. They do not have a classic starting relay and operate smoothly, changing the shaft speed. This makes them quiet and economical, but diagnosing such units is more difficult. The majority of breakdowns here occur not in the motor itself, but in the electronic control module.
If the inverter compressor does not start, first check the control board. Power surges in the network often damage power transistors or controllers on the board. The motor itself in such cases often remains operational. However, if the board burned out, it could send the wrong signal and damage the motor windings.
Another feature is sensitivity to voltage quality. Inverters require a stable sine wave current. The use of cheap stabilizers or generators with a distorted waveform can lead to failure of the compressor electronics. Repairing such systems requires special equipment and knowledge of electronics.
FAQ: Frequently Asked Questions
Is it possible to repair a burnt out compressor or just change?
In 99% of cases, compressors are non-separable sealed units. It is impossible to rewind the windings or replace the piston group at home. If the diagnostics showed an interturn short circuit, breakage or jamming, the unit must be completely replaced.
Why does a new compressor burn out a short time after installation?
Most often the reason lies in poor preparation of the system. If the technician did not flush the system with nitrogen, did not replace the filter-drier, or allowed moisture to enter during soldering, contaminants or acid remain inside. This leads to rapid failure of the new motor. The correct selection of power and type of refrigerant is also important.
How long does a compressor last in a refrigerator on average?
The service life of a modern compressor ranges from 10 to 15 years or more. However, the resource depends on operating conditions: the stability of the voltage in the network, the frequency of defrosts, the cleanliness of the condenser at the back of the refrigerator and the temperature in the room where the device is located.
Is it dangerous to change the compressor yourself?
Yes, it is dangerous and difficult. The process requires working with an open flame (burner), evacuating the system, and filling the exact amount of freon and oil. In addition, improper soldering may result in gas leakage or fire. Replacement requires licenses to work with refrigerants.