The situation when freezer compartment continues to freeze hard, and in the upper compartment the temperature rises to room temperature, which is one of the most common complaints of owners of modern refrigeration equipment. Many users mistakenly believe that if the compressor is humming and there is ice underneath, then everything is fine with the unit and the problem will solve itself. However, such a temperature asymmetry always indicates a specific technical failure in the refrigerant circulation or control system.
In modern models, especially with the system No Frost, the cold from the freezer does not pass into the refrigeration compartment by gravity, but is forced through special channels. If this process is disrupted, the products at the top begin to deteriorate, while at the bottom there is still a deep minus. The critical point is the reaction time: if the equipment has been standing without refrigeration for more than 4-6 hours, the risk of spoilage of perishable products becomes irreversible.
Understanding the principle of operation of your model is the key to quick diagnosis. In single-compressor systems, one motor is responsible for cooling both circuits, and the redistribution of cold is controlled by dampers or electronics. Two-compressor units, where each circuit is independent, with such symptoms indicate problems specifically in the refrigeration chamber circuit, while the freezer is functioning normally.
Fundamental differences in the operation of cooling systems
In order to correctly diagnose a breakdown, it is necessary to clearly understand how exactly the cold gets into the upper compartment. In older models with manual defrosting and in modern systems Low Frost cooling occurs due to natural convection or through common evaporators located in the rear wall. If in such units the freezer is working and the top is “warm”, a refrigerant leak or a clogged capillary is most often to blame.
A completely different picture is observed in systems No Frost. Here, the evaporator is hidden behind a plastic panel in the freezer, and cold air is forced by a fan through the air ducts into the refrigerator compartment. Temperature regulation occurs via an air damper. If the fan stops or the damper gets stuck in the closed position, the upper compartment stops receiving cold, even if the compressor is running at full capacity.
Electronic control adds another layer of complexity. Temperature sensors located at different points in the chambers transmit signals to the control module. If the sensor in the refrigerator compartment “lies” and shows that it is already quite cold there, the module may not give a command to open the damper or turn on the compressor, although in fact it is warm there.
Freon leakage as the main cause of temperature asymmetry
The most likely reason why refrigerator stopped cooling in the upper compartment when working freezer, there is a partial leak of refrigerant. There is enough freon left in the system to freeze a small volume of the freezer chamber, but there is no longer enough pressure for a full cooling cycle of both chambers. This is a classic symptom for systems with a single evaporator or sequential connection of circuits.
A leak can occur anywhere in the circuit: in the foamed part of the housing, in places where tubes are soldered, or through microcracks in the evaporator. Often, owners do not even notice the moment of damage, as the process can be slow. The first sign is usually that the compressor starts working longer than usual, practically not turning off, trying to reach the set temperature.
⚠️ Attention: Self-refueling the refrigerator without finding and eliminating the leak is a waste of money. The freon will leave again in a few days or weeks, and the compressor may fail due to wear and tear.
To diagnose leaks, professionals use leak detectors or a painting method by adding a special marker to the system. At home, you can only indirectly judge the problem by the behavior of the unit: if the freezer freezes weakly, but the top is cold, and at the same time the temperature is distributed unevenly on the rear grille (condenser) (for example, only a piece of the grille is hot), this is an almost guaranteed leak.
Faults in the defrost system No Frost
If you are the owner of equipment with a system No Frost, then the problem of a “warm top” often lies in a violation of the evaporator defrost cycle. A snow “coat” growing on the hidden evaporator blocks the ventilation ducts through which cold air should enter the upper chamber. As a result, the fan circulates air inside the freezer, but it simply does not reach the refrigerator compartment.
Three key elements are responsible for the defrosting process: Defrost heating element, defrost thermostat (or sensor) and timer (or electronic module). If any of these components fail, the ice does not melt, the channels become overgrown, and circulation stops. Often, a malfunction is indicated by water flowing from under the refrigerator, or ice build-up visible when removing the back panel of the freezer.
☑️ Symptoms of problems with defrosting
Diagnostics requires disassembling the freezer. It is necessary to remove the back panel and inspect the evaporator for the presence of ice. If there is a “coat”, check the integrity of the heating element with a multimeter (there must be a circuit) and the resistance of the defrost sensor. It is also important to check if the fan is spinning. If the blades are frozen in an ice cocoon, the fan motor may burn out or jam.
Clogged capillary tube and problems with the filter
Another technical reason why upper chamber does not cool is a clogged capillary tube or filter-drier. Oil oxidation products, moisture or paraffin plugs may accumulate in the freon circulation system (especially if the wrong refrigerant was used during a previous repair). This creates hydraulic resistance, disrupting the flow of refrigerant.
When there is partial blockage, the pressure at the inlet to the evaporator drops, and the cooling capacity decreases sharply. This often manifests itself this way: the freezer still copes somewhat (since it is closer to the beginning of the cycle or has a smaller volume), and the freon reaches the refrigeration chamber already “used up” and warm. A characteristic sign of a blockage is the behavior of the condenser: it may be cold or at room temperature, although the compressor is running.
| Symptom | Probable cause | Characteristic sound |
|---|---|---|
| The freezer is freezing, top warm | Freon leak / Clogged | The compressor hums continuously |
| Both chambers are warm | Complete leak / Compressor | Silence or relay clicks |
| Ice in the freezer, the top is warm | Problems with defrosting (No Frost) | Ice cracking, fan noise |
| Uneven cold | Fault dampers | Air whistling or silence |
Removing blockages at home is impossible. A professional purging of the system with nitrogen, replacement of the filter drier and evacuation is required. Attempts to “break through” the blockage by heating the tube can lead to depressurization of the solder or ignition of the oil if there is residual oxygen in the system.
Failure of the air damper and fan
In modern models, where cold is forced in, air damperplays a critical role. This is a mechanical or electronic curtain that opens at the command of the thermostat, letting cold air from the freezer into the refrigerator compartment. If the mechanism is clogged with crumbs, ice, or simply stuck in the closed position, the upper chamber remains without cooling.
Checking the damper often requires access to the channel between the chambers. In some models Indesit or Atlant the damper is located directly in the partition. You need to make sure she walks freely. In electronic systems, a small drive motor is responsible for its movement, which could burn out. It is also worth checking the fan itself: if its impeller is damaged or the bearing is dry, the air flow will be too weak.
How to check the fan without disassembling?
Turn on the refrigerator and open the freezer door. In many models, when the door is opened, the fan should stop (the door sensor works). Press the door sensor with your finger to simulate closing. If the fan does not start and there is no air noise, there is a problem in it or in the power circuit.
It is interesting that sometimes the damper does not close completely, which leads to the opposite effect - freezing of food in the refrigerator compartment. But in the context of our topic, we are interested in precisely the absence of cold. A common cause of jamming is ice, which forms due to a loose fit of the door seal or frequent opening of the doors.
Failures of the electronic module and sensors
The “brain” of the refrigerator - the electronic control module - receives information from temperature sensors. If the sensor in the refrigerator compartment fails and shows false data to the module (for example, that it is -5°C, although in fact it is +15°C), the module will not issue a command to cool. As a result, the freezer can operate in normal mode (if it has its own sensor), and the top will remain warm.
Failures in the control board itself are also possible: burnt triacs that control heating elements or a fan, or oxidized contacts. On models with a display on the door, you can often see error codes that will indicate a specific component. For example, series codes F or E with digital indices often indicate problems with sensors.
⚠️ Attention: Before replacing electronics, make sure that the problem is not power surges in the network. Unstable power supply is a common cause of failure of control modules. Use surge protectors.
Electronics diagnostics require multimeter skills and knowledge of electrical circuits. It is necessary to “ring” the sensors at different temperatures, comparing their resistance with the tabulated values for a specific model. If the resistance of the sensor is infinite or equal to zero, it must be replaced.
Self-diagnosis algorithm
Before calling a technician, try to conduct an initial diagnosis to narrow down search circle. This will help you more accurately describe the problem to a specialist and avoid unnecessary expenses. Start with a visual inspection and listening to the operation of the unit.
- Check the tightness of the doors and the condition of the seals. If the door does not close tightly, warm air enters the chamber and the system cannot cope.
- Evaluate the operation of the compressor: is it getting hot? Does it run cyclically or hum continuously? A hot compressor with a cold condenser is a sign of a leak or compressor.
- For No Frost systems: defrost the refrigerator completely (for 24 hours with the doors open). If after turning on the problem disappeared for a couple of days and then returned, the defrosting system is definitely faulty.
If after complete defrosting the problem is not solved, or the compressor runs continuously without cooling the top, most likely the problem is a freon leak or a blockage. Here you cannot do without the intervention of a service center.
Frequently asked questions (FAQ)
Is it possible to operate a refrigerator if the upper chamber does not cool?
Short-term - yes, but the food in the upper chamber will quickly spoil. However, prolonged operation in this mode is dangerous for the compressor, which will wear out, trying to reach a non-existent temperature. It is better to turn off the unit before repair.
How long does it take to defrost the refrigerator to check?
To completely defrost the ice in the hidden cavities of the evaporator, the No Frost system requires at least 24 hours. Defrosting for 2-3 hours is often insufficient, and the ice plug remains in the channels, which leads to a false diagnosis.
Why did the refrigerator work after defrosting, but after a week it stopped again?
This is a classic sign of a malfunction of the defrost system (the heating element, timer or sensor burned out). Defrosting temporarily removes the ice plug, but since the defrosting mechanism does not work, the ice builds up again and blocks the channels.
Replacing freon is expensive?
The cost depends on the type of refrigerant (R600a is cheaper, R134a is more expensive) and the complexity of access to the system. However, the main expense item is not gas, but the work of the technician and finding leaks. Cheap refilling without looking for a leak is a temporary solution.
Could the thermostat be to blame?
Yes, if the thermostat is “stuck” in the “off” position or does not read the temperature correctly, it will not give the command to turn on the compressor or open the damper. In mechanical models, this is a frequent and inexpensive breakdown to repair.