The situation when freezer compartment is working properly freezes food, but the main compartment is warm or the food simply thaws, is one of the most common and alarming problems for owners of household appliances. This is not just discomfort, it is a direct threat of inventory damage and loss of expensive products. Users often mistakenly believe that since there is cold air, it means that the compressor is working properly, and the problem is not critical, but this misconception can lead to expensive repairs.
In fact, such a temperature asymmetry indicates a violation of the refrigerant circulation or a failure in the control system temperature conditions. In modern models, especially with the No Frost system, air is pumped into the freezer, and from there it is redistributed to the refrigerator compartment. If this process is disrupted, we get exactly this picture: ice below and heat above. Understanding the operating principle of your model Indesit, Bosch or LG will help you quickly localize the fault.
In this article we will analyze in detail the mechanical and electrical causes of temperature imbalance. You will learn how to carry out initial diagnostics yourself, which components fail most often and when it is really necessary to call a specialist. You should not ignore the first signs of a malfunction, since timely intervention can often save the compressor from overload and complete failure.
The principle of operation of the cooling system and the distribution of cold
To understand why a temperature imbalance occurs, it is necessary to briefly consider the structure of a modern refrigerator. In units with a No Frost or Low Frost system, cooling occurs not due to direct contact of products with a cold evaporator, but due to forced air circulation. A special fan drives air masses through an evaporator, usually located in the freezer, where the air is cooled and dried.
After cooling, the air is directed through special channels into the refrigeration compartment. The amount of cold supplied is controlled by a damper controlled electronically or by a thermostat. If this chain is broken at any stage - from the operation of the fan to the opening of the air damper - it ceases to be cold in the upper compartment, although the freezer continues to operate as normal.
In single-compressor models, which make up the majority of the market, refrigerant first passes through the evaporator of the freezer, where it boils at very low temperatures, and then enters the refrigeration circuit. If there is little freon in the system or there is a blockage, it may only be enough for the first section of the path (the freezer), and the refrigerant simply does not reach the upper compartment in the required aggregate state.
⚠️ Attention: In two-compressor models (where each compartment has its own motor), this problem indicates a malfunction of the refrigeration circuit chambers, since the freezer operates autonomously.
Malfunctions of the thermostat and temperature sensors
One of the first reasons why the refrigerator stops cooling the upper chamber is failure of thermostat (thermostat). This device is responsible for turning the compressor on and off depending on the temperature inside the chambers. If the thermostat is installed only in the freezer compartment (which often happens in older models), then when the temperature in the refrigerator compartment rises, it may not “feel” this and may not give a command to turn on the motor until the freezer becomes too warm.
In modern models with electronic control, the role of the thermostat is performed temperature sensors (thermistors). There may be several of them: one in the freezer, one in the refrigerator compartment, one on the evaporator. If the sensor in the refrigerator compartment “lies” and shows that there is -5°C, although in fact it is +10°C, the control module will not start cooling.
Diagnostics of a mechanical thermostat is often carried out by elimination or direct replacement. Electronic sensors are checked with a multimeter for changes in resistance when temperature changes.
⚠️ Attention: When replacing a thermostat, it is important to consider the length of the capillary tube and the sensitivity of a particular element. Installing an unsuitable model will lead to incorrect operation of the entire system.
Problems with freon circulation: leaks and blockages
The most serious technical problem that causes the described symptom is refrigerant leak or clogging of the capillary tube. In both cases, the normal passage of freon through the circuit is disrupted. When there is a leak, the amount of gas in the system becomes critically small. The compressor tries to pump what is left, and this is only enough for the first circuit of the evaporator (usually a freezer).
When the capillary tube is clogged (often caused by moisture or oil breakdown products), freon is physically cannot go beyond a certain area. The pressure at the inlet to the compressor drops, and the refrigerator stops cooling in the second compartment. A characteristic sign of a leak or blockage is a hot back wall (condenser) or, conversely, a cold grille at the back if there is no circulation at all.
How to distinguish a leak from a blockage?
When there is a leak, the compressor works almost non-stop, trying to gain temperature, and the pressure in the system is low on both sides. If there is a blockage, the pressure on the suction side will be vacuum, and on the discharge side it will be increased. An accurate diagnosis can only be made by a specialist with a pressure gauge station.
The table below shows the main differences in symptoms for quick reference:
| Symptom | Probable cause | Characteristic symptom |
|---|---|---|
| Frost freezing, top is warm | Freon leak | Compressor is hot, runs non-stop |
| Ice only at the entrance to the evaporator | Clogged capillary system | Low pressure on suction |
| Frost all over the back wall | Faulty defrost sensor | Problems with defrosting |
Failure of the defrost system (No Frost)
For owners refrigerators Samsung, LG, Indesit and other brands with a No Frost system are the most common cause of problems. The essence of the system is that the evaporator (which is hidden behind a plastic panel) periodically turns on defrost heating element, melting the frozen frost. The water flows into the drainage.
If one of the elements of this chain breaks (the heating element, defrost sensor, timer or fuse), the evaporator becomes covered with a “coat” of ice. The fan cannot blow air through this icy shell. As a result, cold does not enter the refrigeration compartment, although in the freezer, where the unit itself is located, the cold still remains for some time.
You can diagnose this problem by listening to the operation of the refrigerator. If you don't hear the sound of the fan inside your freezer, although the compressor is humming, it's likely that ice is blocking the air path. Also, swelling or ice may appear on the back wall inside the refrigerator.
☑️ Diagnostics of the No Frost system
Fan and air damper malfunction
In systems with forced air circulation, the key role plays fan. It is he who drives cold air from the evaporator to the products. If the fan impeller is frozen, jammed, or its motor is burned out, circulation stops. The cold remains localized in the evaporator area (freezer), and does not enter the main chamber.
Another important element is air damper. It opens and closes to regulate the flow of cold air. If the damper is stuck in the closed position (mechanically or due to combustion of the actuator), cooled air stops flowing into the refrigerator compartment. This is often found in two-chamber models with one compressor.
Checking the fan usually does not require disassembling the entire unit. It is enough to remove the back panel in the freezer (after defrosting the refrigerator) and check whether the blade rotates by hand and whether there is resistance on the motor windings.
Mechanical damage and wear of seals
Sometimes the problem lies not in the “internals”, but in the tightness of the circuit. If sealing rubber band the doors of the refrigerator compartment are worn out, dirty or deformed, warm air from the room constantly flows inside. The compressor and cooling system simply do not have time to compensate for this heat influx, although the freezer (the door of which is opened less often and is better insulated) keeps the cold.
It is also worth checking the door hinges. If the door is warped and does not fit tightly, the effect will be similar. Visually this may not be noticeable, but it is enough to insert a sheet of paper between the door and the body and close it: if the sheet is easily pulled out, the seal is broken.
⚠️ Attention: Specifications and location of components may vary depending on the specific model and year of manufacture. Always check the manufacturer’s official documentation for your refrigerator modification.
Self-diagnosis algorithm and procedure
If you encounter a problem when the freezer is working but the refrigerator is not, do not panic and immediately look for the technician’s phone number. Follow these steps to weed out simple causes.
1. Full defrosting. Unplug the refrigerator, open the doors and leave it for at least 12-24 hours. This is necessary so that the hidden ice on the evaporator melts (if the problem is in the No Frost system) and the operation of the sensors is restored.
2. Checking the startup. After defrosting, turn on the unit. If it began to gain cold in the upper chamber, then the problem was in the defrost system (the heating element, timer or sensor burned out).
3. Load audit. Make sure that the products do not block the ventilation holes inside the chambers.
4. Listening to operation. When the compressor is running, listen to the sound of the fan in the freezer.
If defrosting did not help and the symptoms recurred, parts may need to be replaced or refilled with freon. In this case, independent repairs without equipment and skills can lead to permanent breakdown of the compressor.
Frequently asked questions (FAQ)
Is it possible to operate a refrigerator if the upper chamber does not work?
For a short time - yes, the food in the freezer will not spoil. However, running in this mode is harmful to the compressor, which may run non-stop trying to reach the set temperature. In addition, bacteria will begin to multiply in a warm chamber.
Why did the refrigerator start working normally after defrosting, but after a week it stopped working again?
This is a classic sign of a malfunction of the automatic defrosting system (No Frost). Ice builds up on the evaporator again, since the heating element or sensor does not turn on at the right time, and again blocks the air circulation channels.
How long does it take to defrost the refrigerator for diagnostics?
To fully guarantee that all the ice in the hidden cavities of the evaporator will melt, it takes from 12 to 24 hours. Defrosting for 2-3 hours is often insufficient for a thorough diagnosis of No Frost problems.
Is it dangerous to change the freon in the refrigerator yourself?
Yes, it is dangerous and requires special equipment (vacuum pump, pressure gauges, scales). Incorrect refueling or the presence of moisture in the system will lead to rapid failure of the compressor. This work should be performed by a master.