The situation when the upper compartment of the refrigerator ceases to perform its function, and the freezer continues to operate as normal, is one of the most common problems with household appliances. Users often experience that food in the main chamber begins to spoil, milk turns sour, and vegetables wilt, while frozen meat remains rock-hard. This behavior of the unit indicates a violation of the refrigerant circulation or a malfunction in the temperature control system.
The reasons can vary from banal freezing of the evaporator to a serious freon leak or compressor failure. It is important not to ignore the first signs of a malfunction, since operating equipment in emergency mode can lead to complete failure of expensive components. In this article we will analyze in detail the mechanics of the process, typical malfunctions and methods for diagnosing them.
The principle of operation of the No Frost and static cooling system
To understand why a temperature imbalance occurs, you need to understand the structure of your refrigerator. In models with the system No Frost cold is generated in the evaporator located behind the rear wall of the freezer. A special fan forces cooled air through the channels into the main compartment. If this air flow is blocked by an ice plug or the fan itself is faulty, the cold simply does not reach the upper shelves.
In units with a static (drip) type of defrosting, cooling occurs due to natural convection or the operation of one common evaporator. The thermostat and proper refrigerant circulation play a key role here. If there is little freon in the system due to microcracks, it may only be enough for intensive cooling of the freezer, where the main circuit is located, and there is no longer enough cold to reach the upper cold compartment.
It is also worth considering the location of the evaporator. In two-chamber models, it is most often located in the freezer. Disruption of heat exchange or clogging of air ducts leads to the fact that the temperature gradient between the chambers becomes critical. Modern models can be equipped with two cooling circuits, which complicates diagnostics, but makes the system more energy efficient.
⚠️ Attention: Attempts to independently open the cooling system without special equipment and skills will lead to complete loss of warranty and possible damage to the compressor.
How does the refrigeration cycle work?
The refrigerant is compressed by the compressor, heated, passes through the condenser (grid at the back), cools and turns into liquid. Then, through a capillary tube, it enters the evaporator, where it boils and takes heat from the chambers.
Compressor malfunctions: when one motor is not enough
One of the common causes of uneven cooling is the failure of one of the compressors in dual-engine models or a decrease in the performance of a single unit. If you have a refrigerator with two compressors (separate for the chamber and freezer), then the failure of the upper motor is obvious: it simply does not turn on or hums, but does not start. In this case, the freezer operates independently and properly.
In models with one compressor, the situation is more complicated. The engine may work continuously, trying to increase the temperature in the main chamber, but due to exhaustion or problems with the valves, it does not create enough pressure. Compressor This is the heart of the refrigerator, and its incorrect operation is often accompanied by overheating of the body or an unusual sound.
Sometimes the problem lies in start relay. If the relay is stuck or burnt out, the compressor may hum and click for a few seconds, but will not start. In such cases, the freezer can retain cold inertia or due to residual pressure in the system, but a full cooling cycle does not occur.
Refrigerant leak: the invisible enemy of the system
Freon leak is perhaps the most insidious reason why the refrigerator does not cool well in the upper compartment. The refrigerant circulates in a closed circuit, and if a microscopic hole is formed in the tubes, the gas gradually evaporates. The first sign is often that the freezer is still freezing, but the temperature in the main chamber is rising.
This happens because the amount of freon remaining in the system is only enough for the first section of the circuit (freezer chamber). Having reached the evaporator of the refrigeration compartment, the refrigerant has already completely evaporated and does not have time to absorb heat. Leakage may occur due to corrosion of tubes, mechanical damage during transportation or manufacturing defects in welds.
It is almost impossible to diagnose a leak visually, since freon is colorless and odorless. The master uses a leak detector or the method of washing joints. If you notice that the condenser grille on the back wall heats up unevenly (only partially), this is a sure sign of a lack of refrigerant.
⚠️ Attention: Filling a refrigerator with freon is not just “topping up gas.” The procedure requires evacuating the system, replacing the filter drier and accurately weighing the refrigerant by gram.
It is important to understand that different models require different types of freon. For example, in older models it was used R12, in newer ones - R134a, and in modern environmentally friendly units it is used R600a (isobutane). Using the wrong refrigerant will damage the compressor.
Clogged capillary tube and problems with the filter drier
The capillary tube is a very thin channel through which liquid freon is supplied to the evaporator. Its diameter is so small that even a microscopic particle of debris, a piece of oxide or a clot of oil can cause a blockage. Clogging disturbs the circulation of the refrigerant: the pressure in front of the plug rises and behind it drops, causing the cooling capacity to sharply decrease.
Often the blockage is accompanied by freezing of moisture in the tube if there is water in the system. The filter drier, which is supposed to retain moisture and oil breakdown products, eventually ceases to cope with its task. As a result, moisture crystallizes in the narrowest point of the system, blocking the freon flow.
Symptoms of a blockage are similar to a leak: the compressor runs for a long time and overheats, the freezer is cold, and the refrigerator compartment is warm. Sometimes the unit can thaw on its own and begin to freeze again after a few hours, when the ice plug in the tube melts. This phenomenon is called a “floating clog.”
Failure of the sensors and thermostat
The electronics of a modern refrigerator controls all processes. If thermostat or the electronic temperature sensor in the main chamber fails, it may send an incorrect signal to the control module. For example, the sensor “thinks” that it is already -5°C in the chamber and turns off the compressor, although in reality it is +10°C.
In models with the No Frost system, the evaporator defrost sensor often fails. If he does not see that the evaporator is frozen, the heating element will not turn on, and the ice will block the air supply channels. As a result, the fan will blow air, but the cold will not enter the chamber due to the ice wall.
It is also worth checking the settings. Sometimes users accidentally set the refrigerator to "Vacation" or "Eco" mode, in which the main compartment is not cooled and the freezer operates in normal mode to preserve frozen food. Check the display and control panel.
Diagnostic table: symptoms and probable causes
For the convenience of initial diagnosis, we have prepared a summary table that will help compare the observed symptoms with possible malfunctions.
| Symptom | Probable cause | Difficulty of repair |
|---|---|---|
| The freezer is freezing, the chamber is warm, the compressor is silent | Malfunction of the thermostat or sensor | Low |
| The compressor hums, but does not start, clicks | Problem with the start relay or compressor | Medium |
| The refrigerator is running non-stop, there is little cold | Freon leakage or capillary blockage | High |
| The sound of the fan running is heard, but there is no cold | Freezing evaporator (No Frost) | Average |
| Uneven heating of the rear grille | Lack of refrigerant (leakage) | High |
Analysis of this The table allows you to roughly determine the search vector for the problem. However, an accurate diagnosis can only be made by a specialist using a pressure gauge manifold and other tools.
What you can do yourself before the technician arrives
If you find that the refrigerator It stopped cooling normally, so don’t panic right away. There are a number of actions that you can perform yourself to eliminate simple causes or make the work of the technician easier. The first thing to do is to defrost the refrigerator completely.
Unplug the unit, remove all food and leave the doors open for at least 24 hours (preferably two days). This is necessary so that any ice that may have formed in hidden channels or on the evaporator is completely melted. Often, after a long defrosting, the refrigerator begins to work properly if the problem was a “floating” blockage or freezing.
During defrosting, check the rubber seals on the doors. If they do not fit tightly, warm air enters the chamber, which settles in the form of frost and disrupts the operation of the system. Wipe the rubber bands and check their elasticity.
☑️ Actions in case of loss of cold
It is also recommended to check whether the refrigerator is overloaded with food. If the air channels are clogged with bags, air circulation is impossible. Clear the area around the air ducts.
When professional repairs are needed
If completely defrosting and checking the settings did not help, and the refrigerator still does not cool well, then the problem is of a technical nature. The intervention of a specialist is required to replace the filter-drier, evacuate the system and refill with freon. These operations cannot be performed at home without special tools.
Also, a technician may be required to replace the compressor if an interturn short circuit or engine wedge is diagnosed. Repairing the system No Frost, including replacing the heating element, defrost timer or sensors, is also best left to professionals, as it requires disassembling the internal plastic and checking the electrical circuits.
⚠️ Attention: Do not try to pierce the system or solder the pipes yourself. This is life-threatening and can lead to an explosion of the refrigerant upon contact with air.
A timely call to a technician will save you money, since operating a faulty refrigerator “finishes off” the compressor. The sooner you eliminate the leak or blockage, the higher the chance of saving the main unit.
Why did the refrigerator work after defrosting, but after a week it stopped again?
This is a classic sign of a clogged capillary tube or the presence of moisture in the system. During defrosting, the ice plug melts and the system temporarily starts working. However, the moisture does not go away and during the next cycle of operation it freezes again in the narrowest place, blocking the freon flow. The system needs to be purged with nitrogen and the filter-drier needs to be replaced.
Is it possible to operate the refrigerator if it does not freeze well?
It is not recommended at all. If the cause is a leak, the compressor will work hard, trying to gain temperature, which will lead to overheating and burnout of the windings. If the cause is oil, it can completely clog the system. It is better to turn off the device before repair.
How long does it take to repair a freon leak?
Searching for a leak can take from 1 to 3 hours, depending on the complexity of access. The elimination procedure itself (soldering, vacuuming, refilling) takes about 1-2 more hours. In rare cases, if the leak is in the foamed part of the case, repair may not be economically feasible.