The situation when the refrigerator is turned on, the compressor is humming, but room temperature remains inside is one of the most stressful for the owner. You open the door, and there is defrosted meat and melting ice. This may indicate a serious technical problem that requires immediate attention, or a simple malfunction of the electronics. Ignoring symptoms At an early stage, it often leads to the failure of expensive components, such as a compressor.
Before calling a technician, it is necessary to carry out an initial diagnosis. In some cases, the unit is simply overheated or clogged with food, which interferes with air circulation. However, if you hear a smooth hum of the engine, but there is no cold, most likely the refrigerant circulation cycle is broken or one of the starting elements has burned out. Modern models With the No Frost system, problems with defrosting are often signaled long before the products are completely defrosted.
In this article we We will analyze in detail the mechanical and electrical reasons for the lack of cold. You will learn how to distinguish a banal network overload from a freon leak. We will also discuss why inverter compressors they can behave differently than classic ones, and what to do if the unit turns on and immediately turns off. Remember that correct diagnostics will save you time and money.
Primary diagnostics: checking mode and load
Before sounding the alarm and looking for a service center number, you should exclude external factors. Often the reason for the lack of cold lies in improper operation or settings failure. Check whether the device super freezing modeis installed that could block the normal operation cycle, or whether the temperature settings are lost. In models with electronic control, a failure could occur due to a power surge.
The second important point is the air circulation inside the chambers. If you've just loaded your refrigerator with a lot of warm food or packed the shelves too tightly, cold air simply can't reach the sensors. In systems No Frost air channels may be blocked by bags or boxes.
It is also worth paying attention to the position of the equipment. If the refrigerator is too close to the wall or heating devices, heat exchange is disrupted. The compressor works hard, trying to cool the chambers, but physically does not have time to dump the heat through the condenser. Make sure that the distance to the wall is at least 5-7 cm.
If a visual inspection does not reveal any violations, and the equipment continues to operate without cooling, we move on to more complex reasons. Below is a table that helps classify symptoms for a primary understanding of the problem.
| Symptom | Probable cause | Difficulty of repair |
|---|---|---|
| Hums, but does not freeze | Freon leakage, blockage | High |
| Clicks and does not start | Start relay, compressor | Medium |
| It freezes slightly | Wear seal, thermostat | Low |
| Ice only in the freezer | Fan malfunction | Medium |
Refrigerant problems: leaks and blockages
One of the most common reasons why the refrigerator turns on but does not cool is the banal freon leakage. The refrigerant circulates in a closed circuit, and if a microcrack appears in the tubes or heat exchanger, the gas escapes. Without a sufficient amount of freon, heat exchange does not occur, and the temperature inside the chambers does not drop below room temperature.
Leaks often occur in places where tubes are soldered or in the foamed part of the body due to corrosion. You may notice oily stains under the refrigerator or on the back grill. However, in most cases, the leak is invisible, and the only sign is the lack of cold when the engine is running. Self-filling in this case, it is impossible without special equipment and evacuation of the system.
⚠️ Attention: If you find a leak, do not try to simply add freon. It is necessary to find the place of depressurization, eliminate it and only then refill the system. Otherwise, the gas will come out again after a short time.
The second problem of the circuit is clogging of the capillary tube. Not only gas, but also compressor oil circulates in the system. Over time, especially when using low-quality refrigerant or a leak, the oil oxidizes and turns into a viscous mass that clogs a thin capillary. Freon cannot pass through the plug, and circulation stops.
The blockage can be diagnosed by characteristic signs: the condenser grid on the rear wall will be hot only in the upper part, and the lower part will remain cold. The compressor may also overheat as it tries to push gas through the obstruction. To eliminate this, you need to flush the system with nitrogen or replace the capillary tube.
Why can’t you ignore working without freon?
Operating a compressor without proper cooling with freon leads to overheating of the windings and rapid failure of the motor. The longer you operate the equipment in this mode, the higher the likelihood that repairs will cost the cost of a new refrigerator.
Faults of the compressor and start relay
The compressor is the “heart” of the refrigerator, creating pressure for the movement of the refrigerant. If it runs but there is no cold, it may have lost its performance. This is called turn-to-turn short circuit or wear of the piston group. The motor hums, the shaft rotates, but the necessary pressure is not created in the system. Freon circulates, but too slowly to cool the chambers.
Often the problem lies not in the motor itself, but in starting relay. This small element is responsible for starting the engine. If the relay is faulty, the compressor may try to start, make a clicking sound and immediately stall, or hum without starting. In some cases, the relay gets stuck and the motor runs constantly without being turned off by the thermostat, which leads to freezing or, conversely, a lack of cold due to cycle failure.
You can check the relay visually (for the presence of carbon deposits) or by replacing it with a known good one. This is one of the few parts that you can replace yourself if you have basic skills. However, if the compressor itself burns out, replacing it requires resoldering the tubes, vacuuming and refilling, which only a specialist can do.
It is worth noting that in modern inverter models diagnostics are more complicated. There is no classic start relay, and the start is controlled by an electronic module. If the inverter compressor hums but does not develop power, the control itself is often to blame. inverter unit management.
Failure in the defrost system (for No Frost models)
In refrigerators with the system No Frost lack of cold in the main chamber when the freezer is running (or vice versa) often indicates problems with evaporator defrosting. The defrost heating element, defrost sensor or timer may fail. As a result, a “coat” of ice grows on the evaporator, which blocks the operation of the fan.
The fan circulates air, but the ice plug prevents the cold flow from penetrating into the chamber. You hear the engine running, perhaps even the noise of the fan, but there is no cold. Over time, ice can completely block the impeller, and then a characteristic cracking or hum will appear. Defrosting in this case, it helps temporarily, but after 1-2 weeks the problem returns.
For diagnostics, you need to remove the back panel in the freezer (after defrosting the unit for at least 24 hours). If ice is visible on the evaporator, and the heating element does not heat when the defrost mode is turned on, look for a malfunction in the defrost circuits. Often the heating element itself burns out or the sensor “glitches” and does not give a command to turn on the heating element.
⚠️ Attention: When checking the defrost heating element, be careful. Do not turn on the heating element in air without load - it may burn out instantly. Check the resistance with a multimeter only when the device is cold and unplugged.
If there is no ice coat, but the fan does not spin, the problem may be in the fan motor itself or in icing of its axis. In some models LG or Samsung there is a break in the wires going to the fan due to constant vibration of the door.
Failure of the thermostat or electronic module
Thermostat (temperature regulator) is a sensor that reports the compressor when to turn on and when to turn off. If its contacts are stuck in the “open” position, the compressor simply will not receive a signal to start. Externally, the refrigerator looks off, but if you listen, you will notice that the motor is silent, although the light bulb is on.
In models with electronic control, the role of the thermostat is performed temperature sensors and the main control module. If one of the sensors (in the chamber or on the evaporator) gives incorrect readings, the “brain” of the refrigerator may decide that there is already cold and not turn on the compressor. Or, on the contrary, the module has burned out and does not supply voltage to the motor.
Diagnostics of the electronic module is complex and requires knowledge in radio engineering. Triacs for controlling the compressor or defrost heating element often burn out. Visually, swollen capacitors or traces of burning may be visible on the board. In such cases, it is usually necessary to replace the entire module or professional repair of the board.
☑️ Thermostat diagnostics
It is important to distinguish between a mechanical thermostat and an electronic sensor. The mechanical one can be checked by closing its contacts directly: if the refrigerator is working, the sensor needs to be replaced. You can’t do this with electronic sensors; you need to measure their resistance at different temperatures.
Violation of the seal tightness
It would seem that a simple rubber gasket around the perimeter of the door plays a critical role. If seal has dried out, torn or simply become dirty, warm air from the room constantly enters the chamber. The compressor works without interruption, trying to compensate for the heat influx, but cannot cope with the volume.
As a result, it may be a little cooler inside than in the room, but complete freezing does not occur. The motor wears out, which ultimately leads to its combustion. You can check the tightness using a sheet of paper: clamp it with the door and try to pull it out. If the paper comes out easily without resistance, the seal does not fit.
Often the problem is solved by thoroughly washing the seal and adjusting the door hinges. If the rubber has lost its elasticity, you can try to restore it with a hot hairdryer, stretching it and pressing it against the body. But in most cases it is required replacement of the seal to a new one.
It is also worth checking whether there is a refrigerator. If it is tilted forward, the door may not close completely under its own weight, leaving a microscopic gap.
Frequently asked questions (FAQ)
Why does the refrigerator hum, but does not freeze after defrosting?
If you defrosted the refrigerator and it stopped freezing, you may have turned it on too early. It is necessary to let the equipment stand turned off for at least 4-6 hours (preferably a day) so that the oil in the compressor flows into the crankcase and the moisture in the wiring evaporates. Switching on “hot” can lead to water hammer or short circuit.
Is it possible to fill the refrigerator with freon yourself?
Theoretically, it is possible if you have the equipment (vacuum pump, pressure gauges, scales). But in practice it is difficult. You need to know exactly the brand of refrigerant, its weight in grams and the type of oil. An error in dosage or the presence of air in the system will lead to compressor failure. It is better to entrust this to professionals.
How long should a refrigerator freeze after turning it on?
Usually, raising the temperature to operating values (-18°C in the freezer) takes from 2 to 12 hours, depending on the model, volume and initial temperature of the products. If after 12 hours of operation there is no cold compressor, this is a malfunction.
What to do if the refrigerator makes a strange sound and does not cool?
Strange sounds (gurgling, hissing, whistling) often indicate the movement of the oil and gas mixture in the system due to a leak or blockage. If the sound is accompanied by a lack of cold, the circulation of the refrigerant is most likely impaired. You need to call a technician to find a leak.