The situation when the upper chamber of the refrigerator stops cooling food, while the lower section (freezer) continues to freeze properly, is one of the most common and alarming for the owner of the equipment. This phenomenon often takes you by surprise, since at first glance the compressor hums, the light inside comes on, and the device appears to be functioning normally. However, the lack of cold in the main compartment can lead to rapid spoilage of food, so you need to react quickly, but without panic.
The reasons for such a temperature imbalance can be completely different: from a banal blockage of the ventilation system to a serious freon leak or compressor failure. Understanding the operating principle of your unit, be it Indesit, LG or Atlant, will help narrow down the search for the problem. In some cases, it is enough to simply defrost the equipment, in others, the intervention of a specialist will be required to replace expensive components.
In this article we will analyze in detail the main breakdown scenarios, explain why this happens, and tell you what steps you can take yourself, and when it is better not to risk it.
The principle of operation of the cooling system and air circulation
To understand why the temperature regime was disrupted, it is necessary to briefly consider how a modern refrigeration chamber works. In most models, especially those equipped with a No Frostsystem, the cold is generated exclusively in the freezer compartment. It is there that the evaporator is located, which freezes out moisture and lowers the temperature of the refrigerant.
Next, a special fan comes into play, which forcibly drives cold air from the freezer into the main chamber through special air ducts. Circulation occurs in a closed cycle: cooled air flows upward, transfers heat to the products, and then returns back for re-cooling. If this process is disrupted, the freezer continues to operate normally, and the upper compartment becomes warm.
In models with a drip system (crying evaporator), the principle is different: here the evaporator is located behind the back wall of the main chamber, and the cold is transmitted through it. However, even in such units there are refrigerant flow channels, the malfunction of which leads to the described problem. Understanding which system you have - Full No Frost or drip - is key for diagnosis.
- ❄️ In No Frost systems, air is forced by a fan from the freezer into the refrigerator compartment.
- 💧 In drip systems, the cold is transferred through the back wall of the main chamber.
- 🔄 Impaired air circulation is the most common cause of temperature differences.
- 🌡️ Temperature sensors monitor the operating modes of the compressor and fans.
⚠️ Attention: Do not attempt to disassemble the back panel inside the chamber until the unit is completely defrosted and unplugged for at least 12 hours. Residual pressure or ice can damage fragile plastic parts and tubes.
Failure of the defrost system (Defrost)
One of the most likely reasons why the refrigerator has stopped cooling, but the freezer is working, is the banal fouling of the evaporator with ice. In No Frost systems, the defrost mode must be periodically turned on, during which the heating element heats the evaporator, melting frozen frost. The water flows into the drain pan and evaporates.
If one of the elements of the defrosting system fails, the ice does not have time to melt and gradually accumulates. Sooner or later, the snow coat becomes so thick that it blocks the channels through which the fan should supply cold air into the main chamber. As a result, the freezer is filled with ice and continues to freeze, and there is heat in the refrigerator compartment.
The defrost system includes three main components, the release of any of which leads to a problem:
1. defrost heating element —a heating element that can burn out.
2. Defrost (defrost) sensor —monitors the temperature of the evaporator and gives a command to turn the heating element on/off.
3. Defrost timer (or electronic control module)—sets the operating intervals of the defrost mode.
How to check the defrosting system without instruments?
For the initial check, you can completely defrost the refrigerator (leave it turned off for a day with the doors open). If after turning it on it worked normally, but after 1-2 weeks the situation repeated itself, the problem is definitely in the defrosting system (heating element, sensor or timer).
Diagnostics of these elements requires the use of a multimeter to “test” the circuits for an open. Most often, the heating element itself burns out or the sensor gets stuck. In models Bosch and Siemens there is often a malfunction of the timer itself, which simply “gets stuck” in the cooling mode and never switches to defrosting.
Freon leak and problems with the compressor
A more serious and expensive problem is a refrigerant leak (freon) from the circuit or compressor malfunction. Freon circulates through a system of tubes, changing its state of aggregation and taking away heat. If the tightness of the circuit is broken, there is not enough gas to fully cool both compartments.
Why, in this case, is the freezer still working? With a small leak or in the initial stages of a breakdown, the compressor tries to compensate for the lack of refrigerant, working almost non-stop. The freezer, being closer to the evaporator or having a smaller volume, still manages to reach the desired temperature, while the “weak” refrigerant simply does not reach the upper chamber or does not have time to cool a large volume of air.
Signs of a freon leak or problems with the compressor:
- 🔊 The compressor hums continuously, not turning off for rest.
- 🔥 The condenser grille (at the back or on the sides) remains cold or heats unevenly.
- 🧊 The evaporator in the freezer is unevenly covered with ice or has “bald” areas.
- 💤 Unit can turn on for a short time and turn off immediately (thermal protection).
It is impossible to eliminate the leak on your own. It requires searching for the location of the damage, soldering, evacuating the system and refilling with new freom. This is work for a professional technician with a license.
Fan malfunction and clogged air ducts
If you are sure that everything is in order with the defrost system and the amount of freon, you should pay attention to mechanical part of air circulation. The fan is the “heart” of the No Frost system, and if it stops, cold air remains trapped in the freezer.
The reasons for the fan stopping can vary. The most common one is ice. If the defrost system is not working properly, ice can jam the fan blades, preventing the fan from rotating. It is also possible that the contacts may oxidize or the fan motor winding may fail. In some models Samsung and LG there is a design defect when the fan bushing wears out, and it begins to make noise and then jams.
In addition, the air ducts can be physically clogged with foreign objects. Users sometimes pack shelves too tightly against the back wall, blocking the air outlets. Products, packaging or ice plugs in the channels completely block the flow.
To check the fan, partial disassembly of the freezer is often required. It is necessary to remove the plastic panel covering the evaporator and check the free movement of the blades. If the fan spins easily by hand, but does not start when turned on, there is a problem with the electrics (the module or the motor itself).
Problems with the thermostat and temperature sensors
Electronics controls all processes in a modern refrigerator. Sensors (thermistors) and thermostats are responsible for maintaining the temperature. If the main temperature sensor in the refrigerator compartment is “lying” and sends a signal to the control module that “there is enough cold,” the compressor will not turn on and the temperature will begin to rise.
At the same time, the sensor in the freezer may show normal, and the system will assume that everything is in order. Or, on the contrary, the sensor is faulty and constantly requires cooling, causing the compressor to work hard, but due to an error in the control logic, the cold is distributed incorrectly. In older models with a mechanical thermostat, the problem may be in the capillary tube, which has lost sensitivity.
Often, a sensor malfunction is accompanied by the appearance of an error code on the display (if there is one) or blinking indicators. For example, Indesit blinking temperature light may indicate problems with the evaporator sensor.
| Symptom | Possible cause | Nature of failure |
|---|---|---|
| The refrigerator is not freezes, there is ice in the freezer | Defrost system (heating element, sensor) | Clogged channels with ice |
| Compressor does not turn on | Thermostat / Sensor | No signal to start |
| The compressor is humming, but there is no cold | Freon leak / Compressor | Lack of refrigerant |
| Noise and lack of circulation | Fan | Mechanical stop |
Diagnostics and procedure for the user
Before calling a technician, you can carry out a number of safe manipulations that will help identify the essence of the problem or even temporarily solve it. The main rule is to act consistently and not ignore obvious signs.
The first step should always be complete defrosting. Even if you use a No Frost system, ice may have accumulated in hidden cavities. Unplug the refrigerator, open all doors and leave it for at least 24 hours (preferably two days). Place rags as there may be a lot of water. After this, turn on the unit and listen: has cold appeared in the upper chamber? If yes, and after a couple of weeks the situation repeated itself, look for a problem in the defrosting system (heating element, timer).
If defrosting did not help, check the tightness of the door. Weak seals allow warm, moist air to pass through, which instantly turns into an ice plug in the channels. Also check whether the ventilation openings are not blocked by products.
☑️ Primary diagnostic checklist
⚠️ Attention: It is strictly forbidden to use sharp objects (knives, screwdrivers) to chip ice inside the chamber or in the channels. One awkward movement can break through the evaporator, and a freon leak will become guaranteed, turning a simple repair into a complex and expensive one.
If, after defrosting, the refrigerator worked for several days and again stopped cooling in the upper compartment, and ice has frozen in the freezer - this is 100% sign of a malfunction of the defrost system. In this case, replacement of the heating element, sensor or timer is required. You can do this yourself if you have the skills to work with a multimeter and a soldering iron, but it is better to entrust it to a specialist.
When you need to call a specialist
There are a number of situations when independent repair is not only useless, but also dangerous. If you observe the following symptoms, further operation of the equipment may lead to complete failure of the compressor:
1. Constant operation of the compressor without shutdowns for a day or more, while the cold in the chambers is absent or weak. This indicates a leak or loss of motor performance.
2. Extraneous sounds: knocking, clanging, loud hum, whistling. This may indicate a destruction of the compressor suspension or a foreign object getting into the fan.
3. A burning smell or melted wiring in the compressor area.
4. Bloating of the rear wall of the refrigerator (in the place of foaming). This is a sign of corrosion and microcracks in the foamed circuit.
Repair of the refrigerant circulation system (filling with freon, soldering tubes) requires special equipment: a vacuum pump, a pressure gauge station, scales and the refrigerant itself. Without this equipment, high-quality repairs are impossible.
Why did the refrigerator work after defrosting, but after a week again stopped?
This is a classic symptom of a malfunction of the automatic defrost system. During manual defrosting, you removed the ice and the air started flowing again. But since the heating element, timer or sensor are not working, the ice began to build up again during normal operation. A week later, its volume again became critical and blocked the channels.
Is it possible to continue to use the refrigerator if the upper chamber does not work?
For a short time - yes, if you store food in the freezer. However, prolonged operation in this mode is harmful to the compressor, which may overheat, trying to reach an unattainable temperature. In addition, bacteria and mold will begin to multiply in a warm chamber.
How much does it cost to repair a No Frost system?
The cost consists of the price of spare parts (heating element, sensor, timer) and the work of the technician. Replacing a heating element or sensor usually costs less than repairing a compressor or finding a leak. The exact price can be found out only after diagnosing a specific model.
Does the temperature in the room affect the operation of the refrigerator?
Yes, if the room is too hot (above +30°C) or too cold (below +10°C), the refrigerator may not work correctly. In cold weather, the compressor may not start or the thermostat may not work correctly, and in hot weather it will work at the limit of its capabilities, not having time to cool.