Sudden silence in the kitchen or, conversely, an unusually loud hum can be the first alarming signals that the heart of your refrigerator - compressor - is working intermittently. It is this unit that is responsible for circulating the refrigerant, creating the necessary pressure to cool the chambers. When it fails, the products begin to quickly deteriorate, and room temperature is established inside the unit, which requires immediate intervention.
Independent diagnosis allows you to save time waiting for the technician and understand the scale of the problem even before his arrival. However, in this article we will analyze the key signs of malfunction, testing methods and situations when repairs no longer make economic sense.
Main signs of motor-compressor failure
The first and most obvious symptom is a change in the temperature regime inside the chambers. If you notice that food in the refrigerator compartment begins to thaw, and ice forms in the freezer or, conversely, everything is completely defrosted, you should listen to the operation of the unit. Often in such cases compressor either works continuously, without turning off for a minute, trying to gain temperature, or is completely silent.
Pay attention to the engine operating cycles. A working refrigerator works intermittently: it turns on, cools, turns off. If the engine hums 24 hours a day without a rest break, this indicates its loss. It may be mechanically functional, but is not able to create sufficient pressure due to the depletion of the piston group or freon leakage, which is often confused with a breakdown of the motor itself. performance. It may be mechanically sound, but it is not able to create sufficient pressure due to the piston group being worn out or freon leaking, which is often confused with a breakdown of the motor itself.
Appearance and sound are also important indicators. The appearance of extraneous knocking, clanging or metallic grinding noises during startup indicates mechanical destruction of the internal components. In normal condition, a working unit emits only a smooth, low-frequency hum, which should not cause uncomfortable noise.
⚠️ Attention: If you smell burning or see sparking in the motor area, immediately disconnect the device from the power supply. Operation of such a device can lead to a short circuit or fire of the wiring.
Visual and acoustic diagnostics of the condition
Before grabbing the tools, carry out a thorough visual inspection of the rear of the refrigerator. In this area there is a condenser (radiator grille) and itself motor-compressor. In operating condition, the condenser should be warm or hot evenly over its entire area. If the grille is cold and the motor is running, this may indicate a lack of freon circulation or a complete inoperability of the discharge mechanism.
Acoustic analysis also provides a lot of information. Listen to the startup sound. If you hear a loud click, followed by a hum that lasts a few seconds, and then another click and silence, this is a classic sign that the engine is trying to start but can't turn over. Often the culprit here is the starting relay, but sometimes the compressor itself jams. piston mechanism compressor.
Check the integrity of the tubes and connections. The presence of oily stains in the lower part of the unit, especially near the compressor, indicates depressurization of the system. The oil leaks out along with the gas, and without freon, the compressor will run idle or go into protection. Also inspect the wires for melting or oxidation of the contacts, which can cause power failures.
Why is the compressor hot, but the refrigerator does not freeze?
This can occur when the capillary tube is clogged or the valve is faulty. In such cases, the discharge pressure increases to critical values, the motor overheats and goes into thermal protection without cooling the chambers.
Checking the electrical circuit and start relay
Often the situation when the refrigerator does not turn on is mistakenly taken for the death of the compressor, although the problem lies in its control circuit. The key element here is the start-up relay. It is this that supplies the impulse to start the windings and turns off the motor when overloaded. If the relay is faulty, no voltage is supplied to the motor windings, and it is silent, even if it is working properly.
To check, you need to remove the casing from the back of the unit and remove the relay from the compressor. Visually assess the condition of the contacts: the presence of carbon deposits, black spots or melted plastic indicates the need to replace the element. You can also shake the relay near your ear: if a rattling sound is heard inside, it means that the core or contacts have broken, and the part requires replacement.
If everything is in order with the relay, it is worth checking the integrity of the windings of the motor itself using a multimeter. Switch the device to resistance measurement mode (Ohms). Normal readings for different pairs of contacts (working, starting winding and housing) should be in the range from 10 to 30 Ohms. A short circuit to the housing (resistance equal to 0 or infinity) indicates a breakdown of the insulation and malfunction motor.
Testing pressure and discharge performance
The most accurate test method is to measure the pressure at the outlet of the compressor. A pressure gauge station is required for this procedure. The discharge tube is cut off and a hose with a pressure gauge is connected to it. When a working unit is turned on, the arrow of the device should rise quickly, showing pressure up to 6-8 atmospheres and above, after which the compressor usually goes into protection or it must be manually turned off.
If the pressure does not rise above 1-2 atmospheres or the arrow stands still, this indicates that compressor it is not pumping. The cause may be wear of the piston group, broken valves or burnout of the gasket. In such cases, even a running motor is useless for the cooling system, since it does not create the necessary pressure drop for the refrigerant to boil.
It is also worth checking the current consumption. Using a current clamp, measure the current in the compressor power circuit during operation. If the actual current significantly exceeds the rated current (indicated on the tag), this indicates an interturn short circuit in the windings or mechanical jamming. Excess current often leads to the thermal relay tripping and stopping the engine.
☑️ Pressure diagnostics
Comparative table of symptoms and probable causes
To systematize the data obtained and understand where exactly the problem lies, it is convenient to use a summary table. It will help to separate the symptoms of a compressor breakdown from other malfunctions of the refrigeration system, such as a freon leak or a blockage.
| Symptom | Probable cause | Action |
|---|---|---|
| Beeps for 5-10 seconds, clicks and silent | The compressor is jammed or the relay is burned out | Replacing the relay, checking the windings |
| Works constantly, without turning off | Loss of performance, freon leakage | Metering pressure, leak search |
| Loud knocking and vibration | Destruction of the suspension or piston | Replacing the compressor |
| Warm condenser, cold motor | The circuit does not turn on power supply | Checking the thermostat and relay |
| Strong heating of the motor housing | Interturn short circuit | Measuring current, replacing the motor |
Analyzing the table, You may notice that many symptoms overlap. For example, continuous operation can be caused by either a weak compressor or a simple gas leak. Therefore, comprehensive diagnostics, including electrical measurements and pressure testing, is the only correct way.
Even the slightest deviations in the operation of the equipment should not be ignored. Early detection of problems with pressure or electrics can save the compressor from final failure if the cause was, for example, a thermostat malfunction that caused the motor to wear out.
Economic feasibility of repair or replacement
When the diagnosis is “faulty” compressor" is confirmed, the owner is faced with the question of repair. The cost of a new original motor, especially for modern models with inverter control, can be up to 70% of the price of a new refrigerator. In addition, replacement requires evacuation of the system, refilling with freon and the presence of special equipment, which, combined with the work of a technician, makes repairs an expensive pleasure.
Consider the option of installing a universal compressor. They are cheaper than the originals and fit many models, but their service life and noise level may be inferior to their factory counterparts. If your refrigerator is more than 10 years old, it is often more rational to purchase new equipment, since after replacing the motor, failures of other components, such as the evaporator or electronic module, may follow.
However, if the refrigerator is of a premium class or has a unique No Frost system, which is difficult to find on sale separately, replacing the compressor may be justified. In any case, the decision should be based on a comparison of the cost of restoration and the residual life of the device.
⚠️ Attention: When replacing a compressor, it is necessary to replace the filter-drier. The old filter is already saturated with moisture and will not be able to efficiently clean the refrigerant, which will lead to rapid failure of the new motor.
Prevention and extension of service life
In order compressor your refrigerator to serve as long as possible, it is important to provide it with the correct operating conditions. First of all, this concerns heat dissipation. Do not move the refrigerator close to the wall, leave a gap of at least 10 cm for free air circulation around the condenser. Overheating is the main enemy of the engine, leading to thickening of the oil and increased wear.
Regularly clean the rear grille of dust and pet hair. The dust “carpet” acts as a heat insulator, preventing heat from being effectively removed, which forces the compressor to work longer and with greater load. It is enough to carry out such cleaning once every six months to significantly reduce the load on the unit.
Also avoid frequently opening doors and placing hot foods inside. Sudden temperature changes force the automation to turn on the motor at full power, which reduces its resource. Uniform distribution of products inside the chambers also contributes to proper air circulation and a reduction in the frequency of switching on.
Is it possible to start a refrigerator with a faulty compressor?
No, operation It is impossible to repair a refrigerator with a faulty compressor, since it is the compressor that creates the pressure for the circulation of the refrigerant. Without a working motor, there will be no cooling, and attempts to turn on the unit can lead to burning of the wiring or a fire.
How long does a compressor last in a refrigerator on average?
The average service life of a modern compressor is from 10 to 15 years, subject to operating conditions. Inverter models can work longer due to a smooth start and the absence of constant overloads at start.
Why does the compressor get very hot during operation?
Heating up to 70-90 degrees is the norm for compressor operation. However, if it heats up to such an extent that it is impossible to touch it, or the thermal protection is triggered, this indicates problems with cooling, a freon leak or an interturn short circuit.