The situation when the upper chamber in the refrigerator suddenly stops freezing can take any owner of household appliances by surprise. This is especially worrying if the freezer contains large quantities of food that require deep freezing. Often users notice the problem too late, when the ice begins to melt or the ice cream begins to soften. Understanding the causes of the malfunction is the first step to preserving products and preventing costly repairs.
Modern units, be it Indesit, Atlant or LG, are designed according to similar principles of cold circulation. A violation of the temperature regime in one compartment can signal either a banal overload or a serious technical failure. In this material, we will analyze in detail the mechanics of the system, typical breakdowns and ways to identify them without calling a technician to your home.
The principle of operation of the cooling system and air circulation
To understand why there is heat instead of cold, it is necessary to consider the basic operating diagram of the refrigeration unit. Most models use a closed circuit where the refrigerant circulates, changing its state of aggregation. Compressor compresses gaseous freon, increasing its pressure and temperature, after which the hot gas enters the condenser (radiator), usually located on the rear wall.
In the condenser the gas cools down and turns into liquid, releasing heat to the environment. The liquid refrigerant then passes through the filter drier and capillary tube to enter the evaporator. It is in the evaporator, which is most often hidden behind the back panel in the freezer, that a sharp expansion of freon and its boiling occurs. This process is accompanied by active absorption of heat from the internal volume of the chamber.
In systems No Frost a fan is responsible for the distribution of cold. It blows cooled air from the freezer into the refrigerator compartment through special channels. If the upper chamber does not freeze, this often means that the chain of cold transmission is broken. Either the cold itself is not produced, or it does not reach the consumer due to an ice jam or a broken fan.
Sealing problems and refrigerant leakage
One of the most common causes of loss of performance is leakage freon. The refrigerant circulates in the system under pressure, and any violation of the tightness of the tubes or soldering joints leads to its gradual release to the outside. It is impossible to visually notice a gas leak, since freon has neither color nor odor. However, the consequences of its shortage are clearly visible.
When the amount of refrigerant in the system decreases, the pressure drops, and the boiling efficiency in the evaporator sharply decreases. The compressor starts working almost without interruption, trying to reach the set temperature, but there is not enough cold even for the freezer compartment, not to mention the upper compartment. Often the first sign is that the back wall inside the chamber is no longer covered with an even layer of frost or becomes warm.
⚠️ Attention: If you notice an oily stain on the floor under the refrigerator or at the junction of the tubes, this is a sure sign of a freon leak along with the oil. It is impossible to operate the equipment in this condition - the compressor may burn out due to overheating.
It is difficult to diagnose a leak on your own, but you can pay attention to the operation of the motor. If it hums constantly, and the temperature inside does not drop below +5...+10 degrees, the probability of loss of tightness is very high. In such cases, you need to call a technician to find the leak, evacuate the system and refill with new gas.
Malfunctions of the thermostat and temperature sensors
A (thermostat) or an electronic temperature sensor is responsible for maintaining the set temperature. Older models use a mechanical device with a bellows that responds to changes in pressure inside the capillary tube. If the thermostat fails, it may “stick” in the “Off” position, not giving a command to start the compressor. thermostat (thermostat) or electronic temperature sensor. Older models use a mechanical device with a bellows that responds to changes in pressure inside the capillary tube. If the thermostat fails, it may become stuck in the "Off" position, preventing the compressor from starting.
In modern models with electronic control, the control function is performed by sensors (thermistors). They transmit signals to the control module. If the sensor in the freezer shows incorrect data (for example, it reports that it is -20°C, although it is really -5°C), the controller will not turn on the compressor. As a result, the upper chamber, which depends on the cold generated from below, stops freezing.
Checking the thermostat in mechanical refrigerators is possible at home. To do this, you need to remove the regulator and close the contacts coming from it directly. If, when shorted, the compressor starts and cold appears, then the problem is in the thermostat. However, with electronic sensors everything is more complicated - you need to test with a multimeter and check the resistance at different temperatures.
How to check the thermostat with a multimeter?
Unplug the refrigerator. Remove the thermostat. Place its sensing tube in a container of ice water (around 0°C). Ring the contacts: they should be closed (resistance close to 0). When heated in the hands, the contacts should open (resistance is infinite).
Clogging of the capillary tube and filter-drier
The capillary tube is a thin copper coil that creates resistance to the flow of refrigerant. It is here that throttling occurs (a sharp drop in pressure) necessary for freon to boil. The diameter of the hole inside the tube is extremely small, so it is very sensitive to contamination. The main enemy of the system is moisture and oxidation products that can form inside the circuit.
If moisture circulates in the system, it can freeze at the narrowest point of the capillary, forming an ice plug. This phenomenon is called "hydraulic blockage". A characteristic sign of such a malfunction is cyclical operation: the refrigerator freezes for some time, then stops (the plug is frozen), then starts again (the plug thaws). As a result, the upper chamber does not have time to cool.
The filter-drier, which is located in front of the capillary tube, also often becomes clogged. Its task is to retain moisture and mechanical particles. During long-term use or after poor-quality repairs, the filter loses its properties and becomes an obstacle to the flow of freon. The pressure in front of the filter increases, and behind it drops, which leads to a lack of cold.
Failures in the No Frost system
In refrigerators with a system No Frost the problem of lack of cold in the upper chamber often lies not in a lack of refrigerant, but in a violation of its air circulation. The evaporator in such models is located behind a plastic panel in the freezer. The fan forces air through the evaporator and directs it to the upper compartment. If this process is disrupted, the cold remains below, and the heat remains on top.
Main causes of system failure No Frost:
- ❄️ Fan malfunction: if the impeller does not rotate, cold air does not enter the upper chamber. This may be wear on the motor bearings or a break in the winding.
- 🧊 Frozen channels: If the evaporator defrost system does not work, ice builds up and blocks the air ducts. Air physically cannot pass through an ice block.
- 🔌 Failure of the defrost timer or heating element: the heating element or defrost shutdown timer could have failed, which is why the ice is not removed on time.
For diagnostics You need to remove the back panel in the freezer compartment. If you see that the evaporator is covered with a thick layer of ice ("coat"), and the fan is running, then the problem is in the defrost system. If the evaporator is clean, but the fan is standing, we change the fan.
☑️ Diagnostics No Frost
The influence of the compressor on performance
The compressor is the heart of the refrigerator. If it does not work correctly, the entire cooling system stops functioning. However, a complete stop of the engine does not always indicate its breakdown. There is a concept of “loss of performance” when the compressor hums, vibrates, but does not create the necessary pressure for freon circulation.
This often happens when the valves inside the compressor burn out. In this case, the gas is simply pumped from one side to the other without compression. The pressure in the system is equalized and boiling does not occur in the evaporator. This can be determined by ear: a working but faulty compressor often produces a quieter, monotonous hum, and the tubes at the outlet remain warm and not hot, as it should be during normal operation.
It is also worth taking into account the service life of the engine. If the refrigerator is more than 10-12 years old, wear and tear on the mechanical parts is inevitable. In some cases, replacing the compressor is not economically feasible, and it is easier to purchase new equipment. But only a specialist can make an accurate diagnosis by measuring the current consumption and pressure in the system.
⚠️ Attention: Do not try to open the compressor yourself or change the start relay if you do not have the skills to work with live electrical equipment. The starting relay is under high voltage, and incorrect installation can lead to a short circuit.
Operational errors and external factors
Before sounding the alarm and calling repairmen, it is worth eliminating trivial causes associated with improper operation. Often, users themselves create conditions under which the upper chamber stops freezing, even if the equipment is fully operational. Carefully analyze how you have been using the refrigerator lately.
Common mistakes that affect the temperature:
- 🍲 Loading hot items products: Placing a pot of soup or a hot dish sharply increases the temperature inside and causes the compressor to wear out, unable to cope with the volume of heat.
- 🚪 Loose door fit: if the seal (elastic band) on the door of the upper chamber is worn out, dirty or damaged, warm air constantly flows inside. This leads to constant freezing and an increase in temperature.
- 📦 Violation of loading rules: If the products lie close to the back wall or completely block the ventilation holes, air circulation is disrupted. The cold simply does not reach the center of the chamber.
It is also important to consider the location of the refrigerator. If it is placed too close to a wall, a radiator, or in direct sunlight, the heat transfer efficiency of the condenser will decrease. In a hot room or with poor ventilation at the back, the unit may simply not cope with heat removal.
Diagnostic table of main faults
For convenience, we systematize the main symptoms and probable causes in a summary table. This will help you quickly understand the nature of the problem before visiting a specialist or starting repairs yourself.
| Symptom | Probable cause | Characteristic symptom | Difficulty of repair |
|---|---|---|---|
| The compressor does not turn on | Thermostat or relay is faulty | Silence, no humming | Low |
| Humming, but no cold | Freon leak or blockage | Warm condenser, no frost | High |
| The freezer is freezing, the top is not | Problem with the fan No Frost | Fan noise or lack thereof | Average |
| Periodic on/off | Ice plug in the capillary | Cyclic operation (it freezes, then no) | High |
| The compressor runs without stopping | Leakage or wear of the compressor | Hot motor housing, weak cold | High |
Analysis of the table shows that most serious problems (leaks, blockages, compressor failure) require professional intervention and special equipment. You can only fix simple faults yourself, such as replacing the thermostat (in mechanics), cleaning the fan or defrosting.
FAQ: Frequently asked questions questions
Is it possible to temporarily use the refrigerator if the upper chamber does not freeze?
You can use the refrigerator in this mode only for a short time while you are waiting for the technician. Products in the upper chamber will quickly deteriorate, and constant operation of the compressor at the limit of its capabilities can lead to its final failure. If the problem is a leak, further operation will speed up the process.
How long does it take to repair a freon leak?
The standard procedure for finding a leak, troubleshooting, evacuation and refilling takes from 1.5 to 3 hours. However, if a compressor replacement or a complex search for a hidden leak in the foamed part of the housing is required, the time may increase to a day or require transportation to a service center.
Why, after defrosting, did the refrigerator stop freezing again after a week?
This is a classic symptom of an ice plug in the capillary tube or a malfunction of the defrost system in models No Frost. Defrosting temporarily removes the ice, but the reason for its appearance (faulty heating element, timer or sensor) does not go away. Replacement of defective parts of the defrosting system is required.
Does the amount of food in the chamber affect the freezing speed?
Yes, it does significantly. An empty refrigerator cools faster, but it also loses cold faster when the door is opened. A full load creates thermal mass, which stabilizes the temperature. However, if there are too many products and they block the air flow, the operating efficiency drops.
What to do if an unpleasant odor appears in the refrigerator after repair?
If the smell appears after refilling with freon, this may be due to the use of low-quality gas or oil residues. Usually the smell disappears in 1-2 days. If the smell persists, there may be combustion products left inside from soldering or aggressive cleaning agents were used. Thorough washing and ventilation is required.