A sudden change in temperature in the refrigerator compartment is a signal that cannot be ignored. If you notice that food has begun to become covered with an icy crust, and fresh herbs wither in a matter of hours, it means that changes have occurred in the system. Impaired temperature balance can be caused by either a simple settings failure or a serious compressor breakdown or refrigerant leak. Ignoring the problem often leads to damage to inventory and costly repairs.
Primary diagnosis requires careful monitoring of the operation of the unit. Often, equipment owners do not immediately notice that the refrigerator began to freeze it is more intense until they discover frozen vegetables in the drawers or ice build-ups on the back wall. It is important to understand that modern control systems require accurate sensor readings, and the slightest failure in the circuit can lead to the unit working for wear, trying to cool the chamber to unrealistically low values.
In this article we will analyze in detail the mechanical and electronic causes of failures. You will learn how to distinguish a harmless failure from a critical malfunction, and when you should call a technician and when you can handle it yourself. Correct fault diagnosis will save your budget and extend the life of household appliances.
Errors in setting the temperature mode
The most common and easily eliminated reason is the human factor. Often, users accidentally touch the temperature control or change settings in the electronic menu without realizing the consequences. On mechanically controlled models, the slider may have moved to the "Maximum" position when loading food or washing the chamber. In digital systems, a failure could occur due to a power surge or children accidentally pressing buttons.
You need to check the current settings. If you see on the display values below +2°C for the refrigerator compartment, this is already a risk zone. Optimal temperature mode should be in the range from +3°C to +5°C. At lower levels, water in products begins to crystallize, destroying their structure. It is also worth checking whether the “Super Freeze” or “Quick Cool” mode is turned on, which is designed to quickly cool a large volume of food, but should not work constantly.
⚠️ Attention: Long-term operation in extreme cooling mode leads to increased energy consumption and accelerated wear of the compressor. Do not leave the advanced freezing modes on for more than 24 hours.
To correct the settings, please refer to the instructions for your model. In most cases, it is enough to move the regulator to the middle position or reset the settings to factory settings. If, after changing the parameters, refrigerator continues to work in the same mode for several hours, the problem lies deeper.
Malfunction of the thermostat or temperature sensor
If the settings are normal, but the refrigerator is very coldmost likely it has failed The thermostat (in mechanical models) or the air temperature sensor (in No Frost systems) is faulty. A thermostat is a device that physically opens the electrical circuit of the compressor when the set temperature is reached. If its contacts are “stuck” or the capillary tube has lost sensitivity, the compressor will work continuously without receiving a signal to stop.
In modern models with electronic control, thermal sensors (thermistors) are responsible for control. They change their resistance depending on the air temperature in the chamber. If the sensor “lies” and shows the controller that it is hot in the chamber, the system will increase the cooling power. Often such sensors fail due to moisture, oxidation of contacts, or simply aging of components.
How to check a temperature sensor with a multimeter?
To check, you need to remove the sensor and test it with a multimeter in resistance measurement mode. When the temperature changes (for example, if you hold the sensor in your hand), the resistance should change smoothly. If the readings stay the same or are equal to zero/infinity, the sensor is faulty and requires replacement.
Replacing the thermostat in mechanical models is often within the power of a home craftsman, since this is a mechanical device. However, in systems with electronics, replacement temperature sensor requires disassembling the internal panel and the availability of a compatible spare part. It is important to use original components or high-quality analogues, since cheap sensors may have incorrect temperature characteristics.
Problems with the defrost system (No Frost)
In refrigerator systems No Frost the serviceability of the defrost system is critically important. If the evaporator becomes clogged with ice due to a malfunction of the defrost heating element, timer or defrost sensor, the air channels become clogged. As a result, cold air cannot circulate normally, and the sensor at the top of the chamber (where the air does not reach) gives the command to continue operating the compressor. As a result, in the freezer the temperature drops to extreme values, and in the refrigerator it may be warm, or, with severe freezing, the cold begins to “break through” in jerks.
A frequent cause is failure. Defrost heating element. The heating element burns out and the ice does not melt. The water release valve may also become stuck or the fan may stop working. In such cases, the refrigerator operates in cycles, but cooling efficiency decreases and energy consumption increases. The system “thinks” that there is not enough cold, and works at the limit of its capabilities.
☑️ Diagnostics of the No Frost system
For diagnostics, you need to remove the back panel in the freezer and visually assess the condition of the evaporator. If it is covered with a thick coat of ice or frost, the defrost system does not function. In this case the refrigerator freezes unevenly, and a comprehensive repair of the defrost unit is required.
Freon leakage and compressor operation
Paradoxically, a refrigerant (freon) leak can also lead to increased frost in certain areas, although the overall temperature in the chamber may rise. With a partial leak compressor works almost non-stop, trying to compensate for the lack of cooling capacity. As a result, the evaporator can become overcooled in the initial areas, creating local zones of extreme cold while the rest of the chamber is warm.
In addition, if there is a leak, moisture or air can enter the system, which disrupts the circulation cycle. The compressor overheats, hums louder than usual and does not turn off. This is a critical situation that requires the intervention of a specialist. Repairing the leak and refilling the system yourself with freon without special equipment and skills is impossible and dangerous.
| Symptom | Probable cause | Necessary actions |
|---|---|---|
| The compressor hums, but does not start | Malfunction of the start relay or compressor | Call a technician, do not try to start it manually |
| The refrigerator runs without stopping | Freon leakage or thermostat failure | Check the settings, if they are normal - diagnostics of the master |
| Ice only at the back wall | Break tightness of the door or seal | Check the fit of the seal, replace if wear |
| Strong frost in the freezer, heat below | Clogged capillary tube or problem with No Frost | Defrost for 24 hours, if that doesn’t help - repair |
Clogged capillary tube
Another technical reason why the refrigerator began to freeze incorrect - this is a clogged capillary tube. In the freon circulation system, this is the narrowest section. If moisture, oil or decomposition products get into the system, an ice or oil plug may form there. This disrupts the circulation of the refrigerant.
If the system is partially clogged, the pressure in the system changes and evaporation occurs incorrectly. This is often accompanied by whistling or gurgling sounds. The compressor is overloaded. In some cases, the area before the blockage may experience extreme cold while the rest of the system is not operating efficiently. This is a complex malfunction that requires purging the system, replacing the filter-drier and refilling.
⚠️ Attention: Attempts to break through the blockage by increasing pressure or heating can lead to rupture of the tubes and complete failure of the compressor. Entrust this work to professionals.
Violation of the chamber seal
The problem may lie not inside, but outside the unit. If sealing rubber band the door is worn out, dirty or deformed, warm, moist air constantly enters the chamber. The cooling system reacts to rising temperatures and begins to work harder, trying to compensate for the heat gain. As a result, food near the back wall may freeze, and ice appears on the walls of the chamber.
Check the tightness using a simple test with a sheet of paper. Clamp the sheet with the door around the perimeter. If it pulls out easily without resistance, it means the seal is broken. Also check whether the door is warped and whether it fits tightly to the body. Sometimes it is enough to simply wash and degrease the seal to restore its properties.
The influence of external factors and placement
Do not forget about external conditions. If refrigerator is installed next to a battery, stove or in direct sunlight, it has to work in enhanced mode. The same thing happens if the ventilation of the rear grille is impaired (the unit is standing close to the wall). In such conditions, the thermostat may not have time to respond to local overheating, and the compressor will work longer than necessary, causing freezing.
How you load food is also important. If you put a large amount of warm food in the chamber or cover the ventilation holes inside the chamber with boxes, the air circulation will be impaired. The temperature sensor does not see the real state in the chamber, and cold air blows directly onto the products, freezing them.
Frequently asked questions (FAQ)
Why does the refrigerator freeze only in one corner?
Most often this is due to the fact that the products lie close to the back wall, where there is a cold air outlet or evaporator. This may also indicate a malfunction of the air distribution damper in two-compressor models or the onset of problems with the No Frost system.
Can you use a refrigerator if it gets very cold?
Short-term - yes, but this will lead to food spoilage and increased electricity bills. Long-term operation in this mode wears out the compressor. It is recommended to eliminate the cause: check the settings, defrost or call a technician.
How to defrost a refrigerator if it stops turning off?
You must completely disconnect the unit from the network, remove all food and leave the doors open for at least 24 hours. This will help melt the ice in the hidden cavities of the evaporator if the problem is in the defrost system. After defrosting, turn on the empty refrigerator and check the operation.
Does the amount of freon affect the strength of frost?
Yes, but ambiguous. If there is a shortage of freon, the refrigerator may run non-stop, trying to gain temperature, which sometimes creates the illusion of severe frost at the beginning of the cycle, but overall the temperature will be higher than normal. Only a technician with a pressure gauge will make an accurate diagnosis.