Sudden cessation of operation of the refrigeration chamber or, conversely, its continuous hum often becomes an unpleasant surprise for owner Compressor is the heart of the entire cooling system, and it is its failure that most often leads to food spoilage. You can understand that the problem lies in this particular unit long before the unit stops completely, if you carefully listen to the sounds and monitor the temperature.
Modern models of household appliances, be it Indesit, LG or Atlant, are equipped with complex electronics, but the physics of the motor operation process remains unchanged. Engine creates refrigerant pressure, forcing it to circulate through the system. If this cycle is disrupted, you will notice telltale signs ranging from complete silence to an unnaturally loud humming sound. It is important not to miss the moment when the unit can still be saved or safely turned off in order to prevent a wiring fire.
In this article we will analyze all the symptoms of a malfunction, starting from visual inspection and ending with complex instrumental diagnostics. You will learn to distinguish a banal network overload from a real one inter-turn short circuit in the windings. Understanding these processes will help you avoid unnecessary expenses on calling a technician to diagnose basic things or, conversely, quickly respond to a serious breakdown.
Primary diagnostics: sounds and behavior of the motor
The first thing you should pay attention to when you suspect a malfunction is acoustic background. A working refrigerator works cyclically: it turns on, cools the chamber and turns off. If you notice that motor it buzzes constantly without going to rest, or, conversely, makes only a short click and goes silent, this is a sure sign of a problem. Normally, the operating cycle is about 15-20 minutes of operation and 30-40 minutes of inactivity, depending on the thermostat settings.
Often owners are faced with a situation where the unit makes a loud metallic clang or knock when trying to start. This may indicate that the piston group is jammed or the valve has come off. In such cases start relay tries to start the shaft, but encounters mechanical resistance, which causes a characteristic sound. Ignoring these symptoms can lead to the final failure of the unit.
There are a number of sound markers that indicate specific problems inside the housing:
- 🔊 Quiet hum without starting: the motor tries to work, but cannot turn the shaft, often accompanied by heating of the housing.
- 🔊 A sharp click and silence: thermal protection is triggered or the starting relay is faulty, current does not flow to the windings.
- 🔊 Whistling or hissing: possible gasket breakdown or freon leak, which forces the compressor to work on wear.
- 🔊 Vibration of the housing: loose mounting shock absorbers or internal imbalance of the rotor.
⚠️ Attention: If you hear a crackling sound or see sparking in the area where the wires are connected to compressor, immediately turn off the power to the refrigerator. Continued use may lead to a short circuit in the apartment's electrical network.
Temperature signs and condition of products
An indirect, but very important indicator of health refrigeration system is the temperature inside the chambers. If the compressor is partially burnt out or loses performance, it will no longer create the necessary pressure to circulate the refrigerant. As a result, the food in the main chamber will begin to thaw, and the “snow coat” may disappear in the freezer or, conversely, an ice crust may form unevenly.
Particular attention should be paid to the temperature of the motor housing itself. During operation electric motor it heats up, this is normal, but it should not be hot. If, when touching (only carefully!), the hand cannot withstand more than 2-3 seconds, it means that the unit is operating in emergency mode. This often happens during an interturn short circuit, when the current increases and the useful power decreases.
Temperature symptoms indicating a breakdown:
- ❄️ Lack of cold: in both chambers the temperature is equal to room temperature, although the light is on and the fan (if any) is running.
- ❄️ Freezing: products in the main chamber are covered with ice due to the continuous operation of the compressor, which cannot reach the cut-off temperature.
- ❄️ Heating tubes: the side walls or condenser tubes at the back remain cold, although the motor hums.
It is important to note that in some models, for example, Samsung No Frost, compressor failure can be simulated by a breakdown of the blower fan. Therefore, before you sin on the motor, make sure that cold air enters the chamber at all. Evaporator may be covered with ice, but without air circulation the products will not cool.
Visual inspection and check of the electrical part
For deeper diagnostics you will need Remove the rear protective panel at the bottom of the refrigerator. Here the compressoritself is located, a start-up relay and a capacitor. First of all, inspect the wires: there should be no traces of melting, black spots or soot on them. Often the cause of failure lies precisely in burnt relay contacts, and not in the motor itself.
Pay attention to the appearance of the motor housing. There should be no oily stains on it. Oil is used to lubricate rubbing parts, and if you see traces of it around the rod or on the tubes, it means that the seals are not sealed properly. In this case, the unit must only be replaced, since sealed circuit is broken.
The table below will help systematize the visual signs of a malfunction:
| Element | Normal condition | Symptom of malfunction | Action |
|---|---|---|---|
| Motor housing | Clean, dry, no rust | Oil smudges, blistering paint | Replacement of the compressor |
| Start relay | Complete plastic, no burning smell | Melting, cracks, burning smell | Replacement of the relay |
| Wiring | Elastic insulation, colored | Blackening, brittleness of insulation | Replacement of wires |
| Tubes | Uniform heating/cooling | Frost only at the entrance, the rest is warm | Checking for leaks |
⚠️ Attention: Before any visual inspection, be sure to unplug the refrigerator! Even after switching off, a residual charge may remain in the capacitors, and accidental contact with exposed live contacts is deadly.
☑️ Safe inspection
Instrumental check: multimeter and tests
To finally make sure, that compressor burnt out, and not just a relay or wiring, it is necessary to “ring” the motor windings with a multimeter. To do this, you need to remove the starting and protective relay from the motor contacts. On the compressor body you will see three contacts forming a triangle: common, starting and working.
Switch the multimeter to resistance measurement mode (Ohms) to the limit of 200 Ohms or 2 kOhms. First check the resistance between each pair of contacts. The values must be in a certain range (usually from 10 to 30 Ohms for the working winding and slightly higher for the starting winding). If the device shows one (infinity), it means winding breakand the motor is dead.
It is also critical to check the breakdown on the housing. Place one multimeter probe on any contact, and the other on a cleaned area on the compressor housing (where there is no paint). The device should show infinity. If you see any resistance values, it means that there has been a current leakage to the housing, which is a direct sign of an interturn short circuit.
Main results of measurements:
- 📉 Resistance is normal: the values correspond to the technical data sheet, there is no breakdown to the housing - look for the problem in the relay or thermostat.
- 📉 Open circuit: the device shows “1” or “OL” on all pairs of contacts - the winding is burned out.
- 📉 Short circuit: resistance is close to zero - the turns are closed, the motor faulty.
- 📉 Fault to the housing: there is resistance between the contact and the housing - operation is prohibited.
Nuances of measuring inverter compressors
In inverter models (for example, LG Linear Compressor), the resistance of the windings can be very low or non-linear due to the built-in electronics. It is often useless to test them with a conventional multimeter - special test equipment is required.
Specifics of diagnostics of inverter models
Modern refrigerators are increasingly equipped inverter compressorsthat operate on the principle of smoothly changing the shaft rotation speed. Diagnostics of such components differs from testing classic linear motors. They do not emit characteristic clicks when starting, since they do not have a starting relay in the usual sense.
If the inverter refrigerator does not turn on or makes strange sounds, the problem may lie not in the motor itself, but in the control board (inverter). These boards are sensitive to power surges. Before concluding that the compressor burned outit is necessary to check the voltage at the output of the inverter module.
Frequent symptoms of problems with the inverter:
- 🔌 Error on the display: many brands (LG, Samsung, Bosch) display error code indicating a failure in communication with the compressor.
- 🔌 Start attempts: the motor jerks, begins to accelerate and immediately stops.
- 🔌 No response: complete silence, although there is light in the chamber lights up.
⚠️ Attention: Inverter compressors often have a long warranty (up to 10-20 years) from the manufacturer. However, the warranty usually only covers the assembly itself, not the labor to replace it. Always check the documents before calling a paid technician.
It is worth noting that in inverter systems the voltage on the windings can reach 200-300 Volts DCwhich makes self-diagnosis under voltage extremely life-threatening. If you do not have the skills to work with high voltage, it is better to limit yourself to an external inspection.
Is it possible to restore a burnt out compressor?
Question about repair compressor often confronts owners of expensive equipment. Theoretically, it is possible to rewind the windings or replace the valve group, but in practice this is not economically feasible. The factory sealing of the case is broken, and it is impossible to assemble it efficiently at home without special equipment.
The only case when repairs make sense is to replace the starting relay or capacitor if diagnostics have shown them to be faulty. These items are inexpensive and easy to replace. If the problem is in the motor itself (wedge, breakdown, break), then replacement of the compressor is the only correct solution.
The replacement process includes:
- 🛠️ Draining the refrigerant: requires special equipment and compliance with environmental standards.
- 🛠️ Removing the old motor: sawing off the tubes and disconnecting the wires.
- 🛠️ Installing a new one unit: soldering the tubes, installing a filter drier.
- 🛠️ Evacuation and refueling: creating a vacuum in the system and pumping in the exact amount of freon.
The service life of a new compressor, if installed correctly and operating conditions are observed (level installation, ventilation, no power surges) is 10-15 years. Using a voltage stabilizer can significantly extend the life of electronics and motor your refrigerator.
Why does the compressor burn out immediately after replacement?
This often happens due to savings on service procedures. If the technician did not replace the filter drier, did not properly evacuate the system (moisture remained) or used the wrong oil, the new compressor may fail within a month. Moisture in the system causes an acid reaction that destroys the windings.
Does a working refrigerator hum?
Yes, a working refrigerator produces a background hum, which should not be louder than 40 dB (whisper). However, this sound should be smooth and intermittent. A constant monotonous hum, which changes only in volume, but does not stop for hours, is a sign of a malfunction of the thermostat or loss of tightness of the circuit.
Is it possible to turn on the refrigerator if it has just been defrosted?
After defrosting, you must wait at least 2-4 hours before turning it on. The oil in the compressor should drain into the crankcase, and the moisture from the evaporator should completely evaporate. Turning on a “hot” unit creates an excessive load on the motor, which can lead to its rapid failure.