The situation when the refrigerator suddenly stops freezing the upper chamber takes any home cook by surprise. Products begin to deteriorate, and condensation appears on the shelves or, conversely, everything thaws. This is a common problem that can be caused by either a simple overload or a serious breakdown of the compressor or defrost system.
Before calling a technician, it is worth conducting independent diagnostics to eliminate simple operating errors. Often the cause is a violation of the operating mode or clogging of the ventilation ducts. Understanding the operating principles of your model will help you quickly determine the source of the malfunction and save your budget.
In this article we will examine in detail the main reasons for poor cooling in the freezer compartment. You will learn how to check the serviceability of the main components, when defrosting is required, and in what cases you need to call a specialist. We will also consider the operating features of various cooling systems, such as No Frost and the drip system.
Violation of operating and loading rules
The most common reason that the upper chamber has stopped freezing lies in improper operation. If you've just loaded a large load of warm food, the compressor may simply not be able to handle the sudden rise in temperature. In this case, the unit takes time to reach operating mode.
Densely packing the freezer also blocks the circulation of cold air. In models with the system No Frost air must flow freely through special channels. If you block the ventilation holes with food, the cold will stop flowing into remote areas of the chamber.
⚠️ Attention: Never place hot pots or pans in the freezer. This causes instant freezing of the evaporator and a sharp jump in the load on the compressor, which can lead to its breakdown.
Check whether the door is pressed by foreign objects. Even a small gap leads to a constant flow of warm, moist air. As a result, a “fur coat” is formed on the walls, which insulates the food from the cold, and the temperature sensors begin to work incorrectly.
Particular attention should be paid to the tightness of the seal. If the elastic is worn out or dirty, there will be no tight fit. Check the condition of the cuff around the entire perimeter, paying attention to the corners and the bottom of the door, where dirt most often accumulates.
Problems with the defrost system (for No Frost)
In refrigerators with the system No Frost the lack of cold is often associated with a malfunction of the defrost circuit. The evaporator, hidden behind the back wall, becomes covered with ice, which blocks the fan. As a result, cold air does not enter the chamber, although the compressor can operate continuously.
Three main elements are responsible for the defrosting process: a heating element, a defrost thermostat (or sensor) and a timer (or electronic module). If at least one of them fails, the ice does not melt, but accumulates, turning into a monolithic block. This physically blocks the air channels.
Diagnostics of the system requires testing the elements with a multimeter. The heating element must have a resistance within the normal range, usually from 200 to 600 Ohms, depending on the power of the model. An open circuit indicates the need to replace the heater.
How to check the defrost heating element?
To check, you need to get to the evaporator by removing the back panel in the freezer. Disconnect the wires from the heating element and measure the resistance. If the device shows one or infinity, the heater has burned out and requires replacement. Be careful not to damage the aluminum evaporator tubes with a sharp tool!
The defrost thermostat opens the circuit when a certain temperature is reached. If it is “stuck” in the open state, the command to turn on the heating element will never be received. It is difficult to visually check its condition; replacement with a known good analogue is required.
Malfunctions of the thermostat and sensors
The thermostat (thermostat) is the “brain” that commands the compressor to turn on and off. If it is faulty, the refrigerator may simply not know that the temperature in the chamber has risen above normal. In mechanical models this is a capillary tube, in electronic models it is temperature sensors.
If a mechanical thermostat breaks down, the contacts may oxidize or stick. You can turn the adjustment knob, there will be no click, and the engine will not start. In some cases, temporarily closing the contacts helps, but this is only a measure to test the hypothesis.
In modern models with electronic control, sensors are responsible for the temperature. There may be several of them: in the freezer, in the refrigerator compartment, on the evaporator. If the sensor in the upper chamber “lies” and shows that it is -20°C, although in fact it is 0°C, the compressor will not turn on.
Diagnostics of electronic sensors is carried out by measuring their resistance at different temperatures. Often the problem lies not in the sensor itself, but in broken wiring or oxidation of contacts in the connector, especially if the refrigerator was operated in conditions of high humidity.
Refrigerant leak and problems with the compressor
If you hear the motor running, but there is no cold anywhere, or it is very weak, a freon leak is likely. The refrigerant circulates in a closed circuit, and if a microcrack appears in the system, the gas gradually evaporates. The pressure drops and the ability to cool food disappears.
Signs of a leak are often a hot condenser (grid at the back) only at the beginning or, conversely, a cold one when the compressor is running. You may also experience swelling of the inner wall of the refrigerator at the sealing site of the evaporator if the tubes are mounted in the housing.
The compressor is the heart of the refrigerator. If it hums but doesn't start, or starts for a few seconds and clicks (the thermal relay trips), the problem may be with the start relay or the motor windings. In this case, professional diagnostics are required.
⚠️ Attention: Self-filling the refrigerator with freon is prohibited without special equipment and a license. Refrigerants can be flammable or toxic, and the wrong amount of gas will lead to rapid compressor failure.
Sometimes the compressor works, but does not create the required pressure due to inter-turn shorting or loss of valve performance. In this case, the unit works constantly, trying to gain temperature, but unsuccessfully, consuming a lot of electricity.
Clogged capillary tube
Another technical reason for the lack of cold is a clogged capillary tube. This is a narrow channel through which freon enters the evaporator. Over time, oxidation products or paraffin plugs may form in the system, which block the refrigerant flow.
Signs of a blockage are similar to a leak: the compressor works, but the evaporator does not cool or only cools at the beginning of the circuit. Often, the condenser (heat exchanger at the rear) remains only partially cold or warm.
Fixing this problem requires purging the system with high pressure nitrogen and replacing the filter drier. It is impossible to carry out this procedure efficiently at home; a vacuum pump and a pressure gauge station are required.
Sometimes the blockage is temporary (ice plug at the point of moisture release), and after the refrigerator is completely defrosted within 24 hours, circulation can be restored. However, this is a temporary measure, and the problem is likely to recur.
Diagnostics and fault table
To simplify the search for the problem, you can use the elimination method. Start with simple steps: defrost the refrigerator, check that the door is closed tightly, listen to the operation of the motor. If simple measures do not help, proceed to analyzing the symptoms.
Below is a table that will help compare symptoms with possible causes. This is not a replacement for professional diagnostics, but a good guide to understanding the extent of the problem.
| Symptom | Probable cause | Difficulty of repair |
|---|---|---|
| Compressor does not start, no light | No power, socket burnt out, relay faulty | Low |
| The motor hums, clicks, but does not start | The starting relay is faulty, the compressor is jammed | Medium/High |
| The freezer is covered with ice, there is no cold | The defrosting system is faulty (heating element, timer, sensor) | Average |
| The compressor runs constantly, there is little cold | Freon leakage, capillary tube clogged | High (a technician is needed) |
| The refrigerator turns on and off frequently | The thermostat is faulty, the seal is broken | Medium |
If you find that the problem falls into the “High” complexity category, it is better not to risk it. An attempt to independently repair the refrigerant circulation system can lead to complete failure of the equipment.
☑️ Primary diagnostics of the refrigerator
When complete defrosting is necessary
Even if you have a refrigerator with a No Frostsystem, sometimes complete defrosting is required. For example, if you haven’t cleaned the refrigerator for a long time or a lot of moisture got into the system when loading warm food. Ice could block the channels, and the automation cannot cope.
For proper defrosting, you need to turn off the refrigerator from the network, completely empty the chambers of food and leave the doors open for at least 12, and preferably 24 hours. This is the only way to melt the ice in hard-to-reach places, for example, inside the case behind the panels.
Do not use a hair dryer or hot water to speed up the process! Sudden temperature changes can damage the plastic and lead to cracks in the evaporator. Ice should melt naturally at room temperature.
After defrosting, wipe all surfaces dry and turn on the refrigerator empty for several hours. If after this procedure the cold appears and remains stable, then the problem was in the “snow coat.”
Prevention and proper care
In order for the upper chamber to always freeze perfectly, it is important to follow the operating rules. Clean the refrigerator regularly using special products or a weak soda solution. Cleanliness promotes better heat transfer and prevents the appearance of unpleasant odors.
Monitor the condition of the seal. Periodically wash it with warm water and check the fit. Once a year, you can lubricate it with silicone grease to prevent the rubber from drying out and cracking.
Do not overload the freezer. Leave space for air to circulate, especially around vents. Products must lie freely so that cold air can wash them from all sides.
⚠️ Attention: Features and control interfaces may vary depending on the model and year of manufacture. Always check the manufacturer's instructions for your specific equipment, since the location of the sensors and operating algorithms may be unique.
Following these simple recommendations will extend the life of your refrigerator and save you from unexpected breakdowns. Remember that prevention is always cheaper and easier than complex repairs.
Frequently asked questions (FAQ)
Why does the refrigerator still not freeze after defrosting?
If after a complete 24-hour defrosting the problem does not disappear, then the reason is of a technical nature. Most likely, one of the components of the cooling system has failed: defrost heating element, thermostat, sensor, or a freon leak has occurred. Diagnostics by a specialist is required.
Is it possible to operate the refrigerator if it does not freeze well?
For a short time, it is possible, but not recommended. Constant idling of the compressor leads to overheating and rapid wear. In addition, food in such conditions may deteriorate, which is hazardous to health. It is better to eliminate the malfunction.
How to understand that the compressor has burned out?
Main symptoms: the compressor hums, but does not start; the thermal relay is triggered (a click is heard a few seconds after switching on); the motor gets very hot; When starting it knocks out traffic jams in the apartment. Only a specialist with a device can make an accurate diagnosis.
Why is there ice in the freezer, but the food is melting?
This is a classic sign of air circulation problems. An ice plug (often at the evaporator outlet or in the air supply duct) blocks the passage of cold air into the chamber. In this case, the evaporator itself may be frozen, but the cold does not reach the food. It is often treated by defrosting or repairing the defrost system.
How long does it take the refrigerator to gain temperature after turning it on?
Usually it takes from 2 to 12 hours to initially set the temperature, depending on the volume of the chambers and the ambient temperature. If after 12 hours of operation of an empty refrigerator the temperature has not dropped to operating values, this is a cause for concern.