A sudden stop in the operation of refrigeration equipment often becomes an unpleasant surprise, especially when perishable products remain in the chambers. Owners immediately begin to guess about the reasons: the electricity went out, a light bulb burned out, or a more serious breakdown occurred. The most expensive and critical malfunction is the failure of the compressor, which in everyday life is often called a motor.
Understanding this how to understand that the motor has burned outwill help you avoid unnecessary costs for unnecessary repairs or, conversely, stop the operation of a dangerous device in time. The compressor is the heart of the system, and stopping it means that the refrigerant circulation completely stops. If you notice that the unit has stopped cooling and room temperature has set inside, do not rush to call a technician right away.
Initial self-diagnosis will allow you to more accurately describe the problem to a specialist or even eliminate a minor malfunction, for example, replace the starting relay, without purchasing a new unit. In this article we will analyze in detail all the symptoms, sounds and testing methods that will indicate a fatal engine breakdown.
Primary external signs of a compressor malfunction
The first thing you should pay attention to if you suspect a breakdown is the behavior of the refrigerator itself as a whole. If you open the door and find that food has flowed out and it’s warm inside, this is a clear signal that the system is malfunctioning. However, heat inside the chamber does not always mean the death of the motor; sometimes the problem lies in a freon leak or a clogged capillary tube.
Pay attention to the back wall of the unit, where the condenser is usually located (black grille). It should be warm or hot when in use. If the grille is cold, and the motor is silent or makes strange sounds, the likelihood that the compressor has burned outincreases significantly. It is also worth checking whether the indicator light inside the chamber is on to rule out problems with the electrical network in the apartment.
⚠️ Attention: If you smell a burning or burning plastic smell coming from the back of the refrigerator, immediately unplug the appliance. Continued operation may result in wiring fires or insulation melting.
A visual inspection of the bottom of the refrigerator, where the motor is located, can also provide important clues. If you see blackening, traces of soot or melted plastic on the body of the compressor itself, then the diagnosis is obvious without additional checks. In such cases starting relay often also has traces of thermal effects.
Acoustic diagnostics: sounds of a running and faulty motor
The sound of a refrigerator operating is one of the most informative indicators of its health. A working unit operates relatively quietly, emitting a uniform low-frequency hum. Any changes in the acoustic profile should alert the owner. If the motor hums louder than usual, this may indicate overload or wear of the bearings, which often precedes complete failure.
Particular attention should be paid to the nature of the start-up. Normally, the engine turns on, runs for a certain time and turns off. If you hear a short beep followed by a click, and this repeats cyclically, this is a sign that the motor cannot start. This symptom often indicates jamming of the piston group or interturn short circuit of the windings.
- 🔊 A uniform hum is a sign of normal operation of the compressor.
- 🔨 A metallic knock or clanging indicates a mechanical destruction of the internal parts of the motor.
- ⚡ A loud click and silence - a possible malfunction of the starting relay or a break in the winding.
- 📉 A fading hum followed by silence - the motor is trying to start, but it does not have enough power.
Sometimes you can hear a quiet hissing or gurgling sound immediately after stopping the engine. This is normal and is due to the movement of refrigerant in the system. However, if the hissing is accompanied by a whistle and continues for a long time, there may be a freon leak, due to which the motor idles and overheats, which ultimately leads to its combustion.
Temperature conditions and operation of the No Frost system
Analysis of temperature indicators inside the chambers allows us to indirectly judge the condition of the compressor. If the refrigerator is plugged in, the light is on, the motor is silent or hums in vain, and the temperature in the main chamber and freezer does not drop below 15-20 degrees, then the cooling cycle does not occur. In systems No Frost a sign of the compressor stopping is also the cessation of fan operation, since it is often powered through the compressor circuit.
It is important to distinguish between situations when the motor simply does not turn on due to a broken thermostat, and when it has burned out. If you turn the thermostat knob to maximum or close the thermostat contacts, a working refrigerator should start. If, upon forced activation, there is no reaction, or the motor makes convulsive sounds and turns off, the problem lies in the unit itself or its starting equipment.
In models with two compressors, the situation may be local. If one chamber freezes perfectly, and the second has turned into a heating cabinet, then only one of the motors has burned out. This simplifies diagnostics, as it allows you to compare the operation of a working unit with a faulty one.
⚠️ Attention: Do not leave food in a non-working refrigerator for more than 4-6 hours during the warm season. Even if you wait for a technician to replace the motor, the food may go bad.
Checking the evaporator also provides important information. In refrigerators with a drip system or No Frost, when the compressor is running and freon is present, the evaporator should be evenly covered with frost. If the motor hums, but the evaporator is cold only at the inlet or does not cool at all, the compressor may have lost performance due to wear on the valves, which is technically also considered a malfunction requiring replacement.
Visual inspection and check of the start relay
Before making a final conclusion that the compressor burned out, it is necessary to exclude faults that are simpler and cheaper to repair. Often the culprit behind silence or malfunction is the start relay. This is a small device that fits onto the contact group of the motor. It supplies the initial impulse to start and turns off the starting winding.
To carry out the inspection, you need to disconnect the refrigerator from the power supply, move it away from the wall and remove the rear protective panel at the bottom. You will see a black barrel-shaped element - this is the compressor. A relay (plastic box) is attached to its side or top. Carefully remove it by disconnecting the wires (after photographing the connection diagram).
☑️ Diagnostics of the starting relay
Shake the relay near your ear. If it rattles inside, like in a maracas, it means the ceramic insert has broken or the contacts have crumbled. Such a relay will not be able to start the motor, and it will constantly click. If the relay is intact, but carbon deposits are visible on its contacts, the plastic has melted or there is a burning smell, it also needs to be replaced. Only after installing a known-good relay can you judge the condition of the motor itself.
Also inspect the wires going to the compressor. They should not be melted or have signs of rodent bites. Oxidized contacts in the connector can also prevent starting. Cleaning the contacts sometimes brings the refrigerator back to life without replacing expensive components.
How to properly remove a relay
The relay can be mounted on spring brackets or simply sit tightly on the contacts. Don't pull the wires! Carefully pry up the housing with a flathead screwdriver or remove the retaining bracket. If the relay is magnetic (heavy), handle it carefully, do not drop it.
Instrumental check of the windings with a multimeter
The most accurate way to understand that the motor has burned out is to measure the resistance of the windings using a multimeter. This method allows you to determine the presence of an open or short circuit inside the motor. To carry out the test, you will need to remove the relay and gain access to the three contacts on the compressor.
Switch the multimeter to resistance measurement mode (Ohms). First, check the continuity of the circuit between each contact and the compressor housing (where there is no paint or a specially cleaned area). The device should show infinity (one in the most significant digit). If the multimeter shows any value, it means something has happened breakdown to the housing, and such a motor cannot be operated - it is mortally dangerous.
Then we measure the resistance between pairs of contacts. Usually there are three of them: a starting winding, a working winding and a common wire. The sum of the resistances of the starting and operating windings should be equal to the resistance between the extreme contacts. Normal values vary depending on the model, but are usually:
| Pair of contacts | Normal resistance (Ohm) | Fault symptom |
|---|---|---|
| Working winding | 10 - 30 Ohm | Open (infinity) or short circuit (close to 0) |
| Starting winding | 20 - 50 Ohm | Open or short circuit |
| Between the extreme | The sum of the two is higher | Sum discrepancy |
| Any contact - Body | Infinity (∞) | Any value (Breakdown) |
If the measurements showed a break (the device beeps or shows 1) or a short circuit (shows 0 or very little), then the motor must be replaced. Such windings cannot be restored at home. It is also worth noting that in some modern inverter models the resistance may be measured incorrectly by a conventional tester due to the presence of electronics inside, but classic linear compressors are checked this way.
Causes of compressor failure
Understanding the causes of failure helps prevent the situation from reoccurring with new equipment. Most often, motors burn out due to power surges in the network. Even a short surge can damage the winding insulation or damage the starting electronics. Using a voltage stabilizer is the best protection for expensive equipment.
Another common reason is natural wear and tear. The compressor service life is on average 10-15 years. After this period, the oil in the system loses its properties, the rubbing parts wear out, and the engine seizes. An attempt to start such a unit leads to burnout of the windings.
- ⚡ Voltage surges in the electrical network are the main cause of electrical breakdown.
- 📉 Lack of refrigerant leads to the motor running without load and overheating.
- 🌡️ Violation heat exchange - if the refrigerator is close to the wall or in a niche, the motor overheats.
- 🛠️ Poor quality previous repairs - moisture or air getting into the system when replacing freon.
It is also worth mentioning the problem of refilling. If moisture gets into the system during repairs, it turns into ice in the capillary tube, creating a plug. The compressor tries to push through this plug, works with overload and burns out. Therefore critically important only contact certified technicians who use a vacuum pump to remove moisture from the system.
⚠️ Attention: Refrigerator specifications and refrigerant requirements may change. Always check the technical documentation of your model before carrying out any work related to electrical or refrigerant.
Frequently asked questions (FAQ)
Is it possible to restore a burnt out compressor?
In 99% of cases, it is impossible to restore a burnt out motor. Windings are not rewinded at home, and factory rewinding is not economically feasible. A complete replacement of the unit with a new one or a contract one is required.
How much does it cost to replace a compressor?
The cost consists of the price of the unit itself and the work of the technician to replace, evacuate the system and refill with freon. The price may vary depending on the model of the refrigerator and the type of refrigerant.
Is the new compressor buzzing louder than the old one?
Modern compressors, as a rule, operate quieter than their old Soviet counterparts. However, immediately after installation, louder operation may be observed in the first hours until the system comes into operation. If the hum does not subside for a day, this is a reason to check.
Why does a new compressor burn out after a month?
Most often, the reason lies not in the motor itself, but in poorly performed repairs: the system was poorly cleaned of old oil, moisture was not removed, the wrong refrigerant was used, or the filter drier was not replaced.
Is it possible to use a refrigerator if it does not freeze well?
You cannot operate equipment with a faulty compressor or a leak. This will lead to spoilage of food, excessive consumption of electricity and the final failure of the motor, which could have been saved at an early stage.