Purchasing refrigeration equipment, especially used, is always fraught with risks, because the external integrity of the case often does not guarantee the serviceability of the internal mechanisms. A visual inspection may only reveal scratches or dents, but will not show the condition of the most important thing - the cooling system. That is why the question of how to check whether a refrigerator is working becomes critical for a buyer who wants to avoid costly repairs in the future.
A faulty unit may consume an excessive amount of electricity, not reach the set temperature, or make scary sounds that cannot be noticed when briefly turned on in the store. Diagnostics must be carried out comprehensively, affecting the operation of the compressor, the tightness of the circuit and functionality automation. Ignoring these steps may lead to the fact that a new (for you) device will require replacing the compressor in just a few weeks.
In this article we will analyze in detail the algorithm of actions that will allow you to independently and without special equipment assess the technical condition of the equipment. You will learn to distinguish the normal hum of a running engine from signs of a breakdown, and also learn what nuances unscrupulous sellers may hide. A competent approach to inspection will save your money and nerves.
Initial visual inspection and assessment of the condition of the case
Any inspection begins with a thorough external examination, which can tell a lot about the past operation of the device. Carefully examine the back wall of the unit: the presence of rust, especially in the places where the tubes are attached or around the condenser, may indicate a long stay in a humid environment or leakage of freon and oil. Corrosion metal is often a harbinger of through holes in the evaporator tubes, which makes further operation impossible without complex repairs.
Pay special attention to the condition of the rubber seals around the perimeter of the door. They must be elastic, without cracks, tears or creases. If the rubber is petrified or deformed, the seal of the chamber is broken, and the refrigerator will work for wear, constantly trying to compensate for the leakage of cold. Also check the door hinges: they should hold the door tightly, not allowing it to open spontaneously under its own weight.
⚠️ Attention: If you find oily stains or sticky marks on the rear grille or near the compressor, this is an almost guaranteed sign of a refrigerant leak along with oil. It is not recommended to buy such a device, since searching for a micro-hole in a foamed case may not be economically feasible.
Inspect the interior of the cameras for foreign odors. The smell of mold, rot or chemicals can penetrate into plastic and rubber seals, and it can be extremely difficult to remove. The presence of chipped enamel inside the chamber, especially in the freezer compartment, leads to accelerated corrosion of the metal and disruption of the tightness of the internal circuit. Plastic should not have a yellow tint, unless this is a design feature of a particular retro model.
Diagnostics of compressor operation and level noise
After connecting the device to the network, you need to listen to the sounds it makes. A working one compressor starts with a characteristic click of the relay and begins to hum smoothly, with an increasing, but not annoying sound. A slight gurgling or hissing is allowed - this is the sound of refrigerant moving through the tubes, which is an absolutely normal physical process for modern models using gas R600a or R134a.
Alarm should be caused by metallic knocking, grinding, loud clanging or intermittent humming that is sharp breaks off. If the engine hums too loudly, as if it is working “to break,” this may indicate wear on the bearings or problems with the shock absorbers. Also pay attention to the cyclical operation: the motor should run for a certain time, then turn off for a pause, and then start again.
It is important to check the temperature of the compressor itself after 15-20 minutes of operation. It should be warm or hot (up to 70-80 degrees), but not hot to the point where it is impossible to touch it. Excessive heating may indicate an interturn short circuit of the windings or jamming of the piston group. If the device turns on, works for a few seconds and turns off with a click, and then tries to start again, there is a problem with the starting relay or the motor itself.
Checking the tightness and cooling function
The most important criterion for performance is the ability to freeze. However, you should not expect instant results; Complete freezing of food may take several hours. For a quick check, empty the chambers and turn on the refrigerator at maximum power. After 30-40 minutes, touch the inner walls of the freezer: they should be noticeably cold, perhaps even with light frost in some models like Direct Cool.
Checking the door tightness is carried out by a simple and effective method using a sheet of paper. Press the leaf with the door around the entire perimeter and try to pull it out. If the paper comes out easily, without resistance, it means that the seal does not fit tightly and the cold escapes. This procedure must be repeated in several places along the height of the door, since the distortion can be local.
Elastic, tightly holds a sheet of paper
| Check parameter | Normal condition | Symptoms of malfunction |
|---|---|---|
| Condenser temperature (grid at the back) | Warm or hot (evenly) | Cold or hot only at the beginning/end |
| Compressor operation | Even humming, cyclicity | Continuous operation without shutting down or frequent clicks |
| Door seal | Hard, porous, sheet falls out | |
| Frost in the chamber | Uniform layer (for drip / No Frost otherwise) | “Snow coat” only in one corner or at the entrance |
Particular attention should be paid to models with the system No Frost. They should not form ice on food or walls if they are working properly. If you see a "snow coat" only in one corner or at the entrance to the chamber, this may indicate poor air circulation or defrosting problems. In such systems, the defrost sensor or evaporator heating element often fails, which leads to ice fouling in the air ducts.
Analysis of the operation of the defrosting and defrosting system
Modern refrigerators require minimal user intervention in the defrosting process, but it is necessary to check this function. In devices with drip system moisture should collect in the groove on the back wall and flow into the evaporator. If you see water pouring onto shelves or products, it means that the drainage hole is clogged or displaced.
For systems No Frost the absence of ice plugs is critical. If you can look behind the back panel of the freezer when purchasing (which is rarely possible with a used version, but good to know), there should be no blocks of ice blocking the fan. A running fan should produce a quiet, uniform air noise. A whistling or crackling sound from the fan indicates that its blades are touching ice or the bearing is worn out.
⚠️ Attention: If you buy a refrigerator in winter from frost, it is strictly forbidden to plug it into the network immediately. Bring the unit into the room and let it stand turned off for at least 4-6 hours (or better yet, a day). Condensation formed inside parts due to temperature changes can cause a short circuit or damage to the compressor when starting.
Also check the water collection tray above the compressor (if provided by the design). It should be dry or contain a minimal amount of water only during active defrosting. Constant overflow of the tray indicates problems with the drainage system or too high humidity in the room where the equipment is located.
Electronics, controls and additional functions
In refrigerators with electronic controls, it is necessary to check the operation of the display and buttons. All indicator segments should light brightly, without gaps. Pressing the buttons should be accompanied by a sound signal (if it is not disabled) and an immediate response from the system. If the sensor is “stupid” or reacts every once in a while, this may be a sign of oxidation of the cables or a malfunction of the control board.
Check the operation of the temperature indicator lights. Try changing the settings to the minimum and maximum temperatures to make sure the system is responsive to user commands. In some models, if there is a malfunction of thermostat or temperature sensors, error codes may light up on the display (for example, F1, E2, etc.). It is better to find the decoding of such codes in advance on the Internet for a specific brand Liebherr, Bosch or Indesit.
Error codes on the display
Common codes may mean: F1 - temperature sensor malfunction, F2 - problem with the control board, F3 - No Frost system malfunction. The exact value depends on the manufacturer.
Remember to check the integrity of the power cord and plug. There should be no kinks, insulation cracks or traces of melting on the wires. The plug should sit tightly in the socket and not dangle. If possible, check the voltage in the network: voltage surges can negatively affect the operation of electronics, so the presence of a stabilizer or at least a surge protector will be a plus.
Final assessment and decision making
Summarizing the test, it is important to weigh the pros and cons. Even if the refrigerator freezes, but makes a suspicious noise or has traces of rust, this is a reason to bargain or refuse to purchase. Repairing a compressor or replacing a foamed evaporator often costs the same as the used unit itself. The critical failure factor is always a violation of the tightness of the system, as this requires qualified intervention and the use of special tools.
If you check the equipment in a store, do not hesitate to ask the seller to turn on the device in advance so that it is in working mode when you arrive. An honest seller will always meet halfway, understanding that it is important for the buyer to be convinced of the quality of the product. In case of a second hand purchase, ask for a warranty card or at least a receipt stating that the seller did not hide defects known to him.
☑️ Checklist for checking the refrigerator
Remember that the correct selection and careful testing are the key to long service life of the equipment. Do not waste time on diagnostics, as this time can result in months of waiting for repairs and spoiled products. A properly selected refrigerator will serve faithfully for many years, keeping your food fresh.
How long does it take for a freezer to start freezing after turning on?
Usually the first signs of cooling appear after 20-40 minutes of operation. However, to reach full freezing mode and stabilize the temperature, it takes from 2 to 6 hours, depending on the volume of the chambers, the ambient temperature in the room and the type of refrigerant. It is recommended to fully load food no earlier than 12 hours later.
Is it possible to check the refrigerator without connecting to the network?
It is impossible to fully check the operation of the compressor and cooling system without electricity. However, you can conduct a thorough visual inspection, check the tightness of the seals using a sheet of paper, assess the condition of the hinges, check for the absence of foreign odors and mechanical damage to the case and internal shelves.
What does it mean if the refrigerator does not turn off?
Continuous operation of the compressor without shutting off may indicate several problems: freon leakage, thermostat malfunction (it “doesn’t see” that the temperature has been reached), the door is not sealed properly, or it is operating in super-freezing mode. This is also possible if the refrigerator is located next to the radiator or in the sun, and the heat gain is too high.
Do you need to defrost the refrigerator before checking?
If you buy a used refrigerator with a large layer of ice (“fur coat”), it is advisable to defrost it before turning it on in order to assess the real condition of the evaporator and the absence of hidden leaks. However, if the layer of ice is small, you can turn on the device and observe the defrosting process (if it is a drip system or No Frost), which is also part of the diagnosis.