The situation when the upper chamber in the refrigerator stops freezing is one of the most common complaints of owners of household appliances. Often this happens suddenly: you open the door for groceries, and the ice cream has already started to melt or the milk has turned sour, while the lower compartment continues to operate as normal. Such an asymmetry of temperature conditions indicates that the cooling system is not functioning fully, and ignoring the problem can lead to spoilage of a large supply of food.
There can be many reasons for such a failure: from a simple blockage in the condensate drainage system to a serious refrigerant leak or failure of electronic control components. Diagnostics requires a careful approach, since the symptoms often overlap. In this material, we will analyze in detail the mechanical and electrical causes of the breakdown so that you can understand the scale of the problem and decide whether it is worth calling a technician or you can handle it yourself.
The first thing that needs to be done is to assess the nature of the compressor's operation. If it hums continuously without turning off, or, conversely, is silent when it should be working, these are already important clues for troubleshooting. Do not rush to throw away food or buy a new unit until you have carried out a basic check of the system.
Violation of operating rules and natural defrosting
Before looking for complex technical faults, it is worth eliminating the human factor. Users often forget that modern refrigerators, even with the No Frostsystem, require periodic defrosting or compliance with certain loading rules. If you recently defrosted the unit and turned it on too early, or loaded a large amount of warm food into the freezer, the system may not be able to cope with a sharp increase in temperature.
In refrigerators with a drip defrosting system (“crying wall”), the upper chamber may stop freezing due to the formation of an ice coat on the evaporator, which is hidden behind the rear panel. If the ice layer becomes too thick, it blocks heat transfer. In models No Frost the problem may lie in impaired air circulation due to improper placement of products that blocked the ventilation holes.
It is also worth checking the tightness of the door. If the rubber seal is dirty, damaged, or simply does not fit tightly due to the door being misaligned, warm air constantly enters the chamber. The compressor tries to compensate for the heat, working for wear, but the upper part of the refrigerator still does not freeze to the required values.
- 🧊 Check that the ventilation grilles are not blocked by food or packaging.
- 🚪 Inspect the rubber door seal for cracks and dirt.
- ⏳ Make sure that enough time has passed since the last defrosting for the mode to stabilize (at least 4-6 hours).
- 🌡️ Do not load hot or warm foods into the chamber, let them cool to room temperature.
⚠️ Attention: If you notice that the door is skewed and does not close tightly, do not try to force slam it shut. This may damage the hinges or the seal itself. Adjusting the hinges requires care and the right tools.
Problems with the defrosting system in No Frost refrigerators
In units equipped with the system No Frost, the lack of cold in the upper chamber when the compressor is running most often indicates a malfunction automatic defrost cycle. The essence of the system is to periodically turn on the heating element (heating element), which melts the frost on the evaporator. If this process is disrupted, the evaporator becomes overgrown with ice, the fan stops moving air, and the cold stops flowing into the chamber.
The main culprits here are three components: the evaporator heating element, the defrost sensor and the timer (or electronic module) that controls the cycles. If it burns Heating element, the ice does not melt, a “fur coat” grows, and air circulation is blocked. If the sensor is faulty, it may “think” that the temperature is already high and does not give a command to turn on the heater, or, conversely, does not turn off the heating in time.
How to check the defrosting heating element with a multimeter?
To check, you need to get to the evaporator (remove the back panel in freezer). Disconnect the wires from the heating element and test it with a multimeter in resistance measurement mode. If the device shows infinity (break), it means that the heating element has burned out and requires replacement.
Diagnostics of the defrost system requires partial disassembly of the freezer. You will need to remove the back plastic panel to assess the condition of the evaporator. If you see a thick layer of ice, especially at the bottom of the radiator, this is almost guaranteed to indicate a defrost problem. In some cases, ice can even block the fan blades, which is accompanied by characteristic noise or crackling.
☑️ Diagnostics of the No Frost system
Refrigerant leak and problems with the compressor
If the refrigerator is humming, but not it freezes neither in the upper nor in the lower chamber (or freezes very slightly), and the condenser (rear grille or side walls) remains cold, most likely there is a freon leak. The refrigerant is the working fluid of the refrigerator, and without a sufficient amount of it, heat exchange is impossible. Leaks can occur in places where tubes are soldered, due to corrosion of the evaporator (especially if it was damaged with a knife during defrosting) or through manufacturing defects.
Another serious problem is a malfunction of the compressor itself. It may hum, but not create the necessary pressure in the system. This often happens when the windings are shorted between turns or the piston group is mechanically jammed. In such cases, the motor tries to start, clicks the start relay, but after a few seconds it turns off due to thermal protection.
It is important to distinguish normal operation from emergency operation. In a working refrigerator, the compressor operates in cycles: turned on, worked, turned off. If it works without a break for days, trying to increase the temperature, but there is no result, this is a sign of loss of performance or leakage.
| Symptom | Probable cause | Nature of compressor operation | Condenser temperature |
|---|---|---|---|
| The refrigerator does not freeze | Freon leak | Works constantly or does not turn on | Cold or barely warm |
| Weak cooling | Clogged capillary tube | Works without stopping | Hot only at the beginning |
| No cold | Compressor malfunction | Clicks and turns off | Cold |
| Unstable temperature | Thermostat malfunction | Does not turn on or off | Depends on the cycle |
⚠️ Attention: Self-refueling of the refrigerator freon is impossible without special equipment and skills. An attempt to simply “add gas” without finding and eliminating the leak will only lead to a temporary effect and repeated breakdown after a short time.
Malfunctions of the thermostat and temperature sensors
Electronics are the “brains” of your refrigerator. If the upper chamber does not freeze, the problem may be that the “brain” simply does not see the problem. Thermostats (in mechanical models) or air sensors (in electronic models) are responsible for temperature control. If the thermostat is “stuck” in the “Off” position or its sensitive element has lost contact with the internal environment, the compressor will not receive a command to start.
In models with electronic control, evaporator sensors or air sensors in the chamber often fail. They transmit incorrect data to the control module. For example, the sensor may show that it is -20°C in the chamber, although it is +5°C. Naturally, the refrigerator will not turn on the cooling, “thinking” that the temperature is already normal.
Replacing sensors is a technically simple procedure, but requires precision. The new sensor must have exactly the same characteristics (resistance at a certain temperature) as the old one. Installing an unsuitable sensor will lead to incorrect operation of the entire unit.
Clogged capillary tube and filter-drier
One of the hidden but common reasons why the upper chamber does not freeze is a clogged capillary tube. This thin copper line serves to throttle freon. Over time, oil oxidation products, paraffin or moisture can accumulate inside the system, which turns into an ice plug in the narrowest place.
Signs of a blockage are specific: the compressor runs constantly and gets very hot, the condenser can be hot only in the first third, and the rest - cold. In this case, at the site of the blockage (usually at the entrance to the evaporator), swelling of the tube or, conversely, its flattening may be observed. In some cases, during defrosting, the ice plug melts and the refrigerator begins to work normally for several days until it freezes again.
Fixing this problem requires professional purging of the system with nitrogen under pressure, replacing the filter-drier and vacuuming. This is a complex technical procedure that cannot be performed at home without a set of tools from a refrigeration technician.
The filter drier located in front of the capillary tube can also become clogged. Its task is to retain moisture and mechanical impurities. If it is saturated with moisture or clogged with dirt, the permeability of the system drops and the circulation of the refrigerant is disrupted.
Ventilation and cold distribution
In two-chamber refrigerators, cold is usually generated in the freezer (or in a special compartment), and then distributed to the rest of the compartments. If the upper chamber (refrigerator) is warm, but the lower chamber (freezer) is cold, this may indicate problems with the air supply duct. In the system No Frost the fan is responsible for this. If its blades are iced up or the motor is burned out, the cold air simply does not reach the top.
It is also worth checking the air flow regulator damper. In some models it is controlled mechanically or electronically. If the damper is stuck in the closed position, the upper chamber remains isolated from the cold source. This is often accompanied by the fact that food freezes in the freezer and spoils in the refrigerator compartment.
Do not forget about simple hygiene. Dust and fluff collected in the condenser grille at the back of the refrigerator impair heat transfer. The compressor overheats, the efficiency of the system decreases, and it is the upper chamber that suffers first, where the temperature requirements are less stringent than in the freezer.
Frequently asked questions (FAQ)
Why does the refrigerator freeze but does not turn off?
This is a classic sign of a freon leak or a clogged capillary system. The compressor tries to increase the temperature, but due to a lack of refrigerant or circulation problems, it cannot do this. Also, the reason may be a faulty thermostat that does not give a signal to turn off.
Is it possible to use a refrigerator if it does not freeze the upper chamber?
For a short time - yes, if you use it only as a freezer. However, prolonged operation in this mode is harmful to the compressor, which will work without rest. In addition, the food in the upper chamber will quickly deteriorate.
How long does it take to defrost the refrigerator to remove the ice plug?
For complete and high-quality defrosting, especially if there is a suspicion of ice in hidden channels or on the evaporator No Frost, the unit should stand disconnected from the network with open doors for at least 24 hours. 2-3 hours alone may not be enough.
Why doesn’t the refrigerator start to freeze after defrosting?
Modern refrigerants and oils require time to stabilize pressure and distribute throughout the system after inactivity. Typically, the process of reaching operating mode takes from 2 to 6 hours. If during this time the temperature does not begin to drop, it is possible that the wiring was damaged during defrosting or a hidden fault appeared.
What to do if the refrigerator smells burnt and it has stopped freezing?
Immediately unplug the appliance! A burning smell indicates overheating of the wiring, start relay or compressor windings. Continued activation may result in a fire. You need to call a technician to diagnose the electrical part.