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The situation when you open the refrigerator door and feel room heat there, while the freezer continues to operate normally mode, often takes you by surprise. This is a classic symptom faced by owners of both old Soviet units and modern No Frost systems. There is no need to panic right away, but you cannot ignore the problem either, since the food in the upper compartment can spoil in a matter of hours.
The reason for this imbalance lies in the disruption of refrigerant circulation or failures in the temperature control system. The refrigeration circuit is single, and if the evaporator in the freezer freezes, but it is warm in the upper compartment, it means that the cold does not physically reach the right place or the thermostat does not give the command to cool. In this article, we will analyze in detail the technical causes, diagnostic methods and methods of troubleshooting on our own or by calling a specialist.
The principle of operation and distribution of cold in the system
To understand why the refrigerator stopped freezing in the upper compartment, you need to briefly refresh your memory of the basic principles of the compressor. In classic two-chamber models, the refrigerant, passing through a capillary tube, first enters the evaporator of the freezer, where the main heat exchange takes place. That is why the freezer always cools first and more intensely.
Next, if the system is working properly, the refrigerant should go to the evaporator of the refrigerator compartment or cold air should be forced there by a fan. If this process is interrupted, we get the situation “ice in the freezer, heat in the refrigerator.” In models with a drip defrosting system, the cold is transferred through the wall, and in systems No Frost - forcibly by a fan.
An imbalance can be caused by either a banal blockage or a serious freon leak. It is important to understand that the compressor may hum and appear to be working, but not perform its full function of pumping gas. Diagnostics begins with assessing the nature of the unit’s operation: it turns on and off cyclically or hums without interruption.
Refrigerant leakage: a hidden threat to the system
One of the most common reasons why the cold is gone in the main chamber is a partial leak of freon. When the amount of refrigerant in the circuit decreases, there is not enough pressure to go through the entire cycle and (reach) the evaporator of the refrigerator compartment. The gas boils and evaporates while still in the freezer, so there is ice there, and then it’s warm.
Often leaks occur in the foamed part of the body or at the joints of the tubes, which corrode over time. You may notice that the compressor is running almost non-stop, trying to build up temperature, but to no avail. In such cases, on the rear grille of the condenser (usually a black panel at the back of the unit), you can observe uneven heating or its complete absence in the lower part.
⚠️ Attention: Self-charging with freon is impossible without special equipment and skills. An attempt to simply “add gas” without finding and eliminating the leak will lead to a repeat breakdown in a few days or weeks.
To confirm the diagnosis, technicians use leak detectors and pressure gauge manifolds. If a leak is confirmed, the system must be evacuated, soldered, and charged with new refrigerant. This is a complex technical process that requires calling a specialist.
Malfunction of the blower fan (for No Frost systems)
In refrigerators with the system No Frost a special fan located behind the back wall of the freezer is responsible for circulating cold air. If the fan does not work, cold air remains in the freezer and does not enter the refrigerator compartment. This is a mechanical breakdown that can often be diagnosed visually or by ear.
Signs of a fan malfunction are quite specific:
- 🌀 It is very cold in the freezer, the food is covered with frost, but in the refrigerator compartment the temperature is higher +10°C.
- 🔇 There is no characteristic noise of the fan when the freezer door is open (on many models it should work constantly or cyclically).
- ❄️ On the back wall of the freezer you can see a “coat” of ice that blocks the air duct channels.
Sometimes the fan is working properly, but its blades are frozen and jammed due to the ice that has formed. In this case, it may be necessary to completely defrost the unit within 24 hours. If after defrosting the fan does not start, most likely its electric motor has burned out or the power circuit has failed.
Clogged capillary tube or filter-drier
Another technical reason why The refrigerator does not maintain the temperature. in the upper compartment is a clogged capillary tube. This is a narrow channel through which freon moves. If there is moisture or oil breakdown products in the system, they can crystallize and create a plug. Most often, the filter drier becomes clogged.
When clogged, the compressor begins to work with increased load, trying to push gas through the obstacle. This can lead to overheating of the motor and its periodic shutdown by the thermal relay. A characteristic sign is that the condenser (grid at the back) can be hot only at the beginning, and then cool down, since the circulation of gas is disrupted.
To eliminate this problem you need:
- 🛠️ Opening the circuit and purging with nitrogen to clean the tubes.
- 🔄 Replacing the filter-drier with a new one (the old one cannot be reused).
- 💉 Repeated vacuuming and refilling the system with freon.
⚠️ Attention: Blowing the circuit requires the use of a cylinder with dry nitrogen and a professional compressor. Home methods of “cleaning” often lead to depressurization and damage to the compressor.
Problems with temperature sensors and thermostat
The refrigerator electronics rely on sensor readings. If thermostat or the air sensor transmits incorrect data about the temperature in the refrigerator compartment, the control module may “think” that it is already cold there and does not turn on the compressor or open the air supply damper.
In models with electronic control, the defrost sensor or evaporator temperature sensor often fails. The system goes into emergency mode or does not manage the cooling cycles correctly. You can check the sensor with a multimeter by measuring its resistance at different temperatures and comparing it with a table of values for a specific model.
Typical symptoms of sensor failure:
- 🌡️ The compressor turns on very rarely or does not turn on at all, although the chamber is warm.
- 🔌 On the display shows an error (for example, a fault code) or the temperature indicators are blinking.
- 🧊 The refrigerator freezes too much or does not freeze at all, ignoring the settings.
How to check a mechanical thermostat?
To check a mechanical thermostat, it must be removed. In a cold state, the contacts should be closed (checked with a multimeter). If you place the thermostat in warm water, the contacts should open. If this does not happen, the part must be replaced.
Compressor malfunction: loss of performance
The compressor is the heart of the refrigerator. It happens that the engine hums and vibrates, but weak freon pumps. This condition is called loss of productivity. The piston group is worn out, the valves do not hold pressure, and the gas simply circulates in a small circle, without creating the necessary temperature difference to cool both chambers.
This can be diagnosed by the temperature of the compressor housing (it can be barely warm or overheat) and by the nature of the sound. Sometimes checking the pressure in the system helps, but this is a job for the service center. If the compressor has died, replacing it is the only solution.
The table below shows comparative characteristics of symptoms for different breakdowns:
| Symptom | Freon leakage | Clogged capillary | Faulty compressor |
|---|---|---|---|
| Motor operation | Constant or frequent | Constant, overheating is possible | Constant, quiet hum |
| Condenser heating | Partial or cold | Hot at the beginning, cold further | Barely warm or cold |
| Ice in the freezer | Yes, but may melt | Yes, sometimes on one side | Little or not |
| Cold in the chamber | Absent | Absent | Absent |
Mechanical damage and distortions of the door
Simple mechanical reasons should not be discounted. If door seal the refrigerator compartment is worn out, torn or simply dirty, warm air from the room constantly enters the chamber. The compressor cannot cope with the heat flow, and the temperature inside rises, even if the system is technically sound.
The door may also be skewed, which is why it does not fit tightly. You can check the tightness in a simple way: clamp a sheet of paper between the seal and the body around the perimeter. If the paper is pulled out without effort in some place, there is an air leak there. Adjusting the loops or replacing the elastic will solve the problem.
Another nuance is the drainage hole being clogged. If the defrost water does not leave, it freezes and can block the air supply channels or sensors, which will lead to incorrect operation of the system.
☑️ Primary diagnostics of the refrigerator
What to do: owner's action algorithm
If If you encounter the problem described, do not rush to disassemble the unit. First, follow the basic steps that will help eliminate simple causes or prepare the equipment for the arrival of the technician. Completely defrosting the refrigerator within 24 hours with the doors open often eliminates the problem of ice blockages in the air ducts.
After defrosting, turn on the refrigerator empty and listen. If after a few hours the situation repeats itself, it means the problem is technical. Check if food is blocking the ventilation holes inside the chamber. Make sure that the “Super Freeze” mode is not constantly turned on, as this may interfere with the operation algorithms.
⚠️ Attention: Do not use sharp objects to chip ice inside the chambers. Damage to the evaporator or plastic panels will lead to expensive repairs or complete replacement of the refrigerator.
If simple methods do not help, you need to call a specialist to diagnose the circuit and electrical part. Independent intervention in the system with freon without a license and equipment is prohibited and dangerous.
Prevention and proper care
To avoid situations where the refrigerator stops freezing, it is important to follow the operating rules. Defrost the unit regularly (even systems No Frost require preventive maintenance once a year), keep the condenser at the back clean and do not put hot foods inside.
Check the condition of the seals and wash the drainage channels in a timely manner. Correct installation of the refrigerator (distance from the walls, level floor) also affects the efficiency of heat transfer and the durability of the compressor.
Frequently asked questions (FAQ)
Is it possible to temporarily use the refrigerator if it does not freeze in the upper compartment?
For a short time - yes, if you store products there that do not require strong cooling (vegetables, drinks). However, it is impossible to operate the equipment in this mode for a long time, since the compressor is overloaded and can burn out, and bacteria will develop in the chamber.
How much does it cost to repair if the cold in the refrigeration chamber has disappeared?
The cost depends on the breakdown. Replacing a sensor or thermostat will cost less than refilling with freon or replacing a compressor. The exact price can only be given after diagnosis by a technician on site.
Why did the refrigerator start working after defrosting, but a week later it stopped again?
This is a sure sign of a freon leak or blockage. Defrosting temporarily removes the ice blockage or allows residual gas to cool the chamber, but the root of the problem (a hole in the circuit or a clogged tube) does not go away.
Could the socket or wiring be to blame?
If the refrigerator turns on and the light is on, then everything is fine with the socket. Problems with the voltage in the network could lead to the combustion of the electronics, but then the freezer would not work, or the unit would not turn on at all.