The situation when the refrigerator seems to be turned on, the compressor is humming, but the main chamber is warm, and the food starts spoil, causes panic in any home cook. Often in such cases, the upper chamber remains warm while the lower freezing section continues to operate normally or, conversely, freezes too much. This is a classic symptom of poor refrigerant circulation or a malfunction in the temperature control system. Before calling a technician, it is worth conducting an initial diagnosis to understand the scale of the problem and the approximate cost of future repairs.
It is important to understand that modern two-chamber units, be it Indesit, Atlant or LG, often have a single cooling system with one compressor. If the cold stops flowing into the refrigerator compartment, this does not always mean a complete breakdown of the entire device. Sometimes it’s a clogged capillary or a burnt-out defrost heating element, and sometimes it’s a serious freon leak. Diagnostics begins with an assessment of the external signs and sounds that the equipment produces.
In this article we will analyze in detail the mechanical and electrical causes of the malfunction, we will explain how to distinguish clogged from a leak, and we’ll tell you which components require immediate replacement. You should not ignore the first signs of incorrect operation, since long-term operation in this mode can lead to failure of the most expensive unit - the compressor compressor.
The principle of operation of two-chamber No Frost and static cooling systems
To understand why the cold does not reach the upper chamber, you need to briefly recall the physics of the process. In refrigerators with the No Frost system, the cold is generated in the evaporator, which is usually hidden behind the back wall of the freezer. The fan drives this cold air through special channels into the refrigerator compartment. If the system is static (drip), then the evaporator is located at the top, and the cold air falls down naturally, and the condensate flows down the back wall.
The key element here is the correct circulation of refrigerant and air. In the system No Frost dampers and a fan are responsible for distribution. If they jam or stop opening, the air simply remains in the freezer. In drip models, the problem often lies in the amount of refrigerant or the patency of the tubes. Freon circulation This is the heart of any refrigeration cycle, and any violation here immediately affects the temperature.
Modern models are often equipped with electronic control, where temperature sensors read the readings and give a command to turn on compressor or opening the air damper. If one of the sensors is lying, the control board may “think” that it is already cold in the chamber and not supply air there. Therefore, electronics also often become the culprit for temperature imbalances between chambers.
⚠️ Attention: Trying to disassemble the cooling system yourself without soldering and vacuuming skills can lead to complete failure of the unit and moisture getting inside the circuit.
Refrigerant leakage: the most common culprit of the problem
If you notice that the refrigerator works almost non-stop, it hums continuously, but in the main chamber the temperature is higher than normal, and the freezer is barely freezing or, conversely, it freezes only at the back wall - this is a sure sign of a leak. Freon is a working fluid that transfers heat. If there is not enough of it in the system, it simply does not reach the end of the circuit, having time to completely evaporate in the freezer.
Leaks most often occur at soldering points, in the foamed part of the body (aluminum evaporator) or in the heating circuit of the door perimeter. In models with a foamed evaporator (for example, some series Beko or Stinol), corrosion can corrode the tube from the inside. It is difficult to determine this visually; often the problem is indicated only by swelling of the rear wall inside the chamber or rust on the outside.
You can diagnose a leak yourself by touching the condenser (grid on the back). If it is only half hot or completely cold, although the compressor is running, then there is no gas in the system. Also a sign may be the absence of a characteristic hissing when the case is punctured (if you did it professionally) or the absence of cold after a long period of inactivity.
Repair in the event of a leak is always comprehensive: searching for the location of damage, soldering, vacuuming systems and refilling with new freon. You cannot simply “add gas”, since there is air and moisture in the system, which will lead to the formation of ice plugs and acids that destroy the compressor from the inside.
Clogged capillary tube and filter-drier
Another common reason why the refrigerator stops cooling in the upper compartment is a clogged capillary tube. This is a thin copper pipeline through which freon enters the evaporator under pressure. Over time, oil oxidation products, moisture or microscopic dust can accumulate in the system, which clog the narrow section of the tube.
Symptoms of a blockage are very similar to a leak: the compressor works long and hard, trying to pump the refrigerant, the condenser may be hot, but the cold does not reach the evaporator or does not reach the evaporator in sufficient quantities. Often you can hear gurgling sounds inside the case. The filter drier, which stands in front of the capillary, takes the brunt of the blow and gets clogged first.
To eliminate this problem, you need to replace the filter drier and purge the system with nitrogen under high pressure. In difficult cases, the technician can replace a section of the capillary tube. This is a technically complex procedure that requires special equipment for filling and vacuuming.
| Symptom | Probable cause | Nature of compressor operation |
|---|---|---|
| The freezer is freezing, the top is warm | Freon leak | Works without stopping |
| Frost only at the entrance of the tubes | Capillary clogged | Buzzing, overheating |
| Ice coat on rear wall | Faulty sensor/heating element | Cyclic mode |
| There is cold, but weak | Compressor wear | Works quietly or frequently |
Problems with the defrost system in No Frost refrigerators
In units with the system No Frost the proper operation of the defrost system is critically important. The evaporator located in the freezer becomes covered with frost during operation. Periodically (usually every 8-12 hours) the defrosting heating element is turned on, which melts this ice. If the heating element burns out, the defrost thermostat or timer fails, the ice does not melt.
The snow coat grows and freezes on the fan and air ducts. As a result, the ice plug blocks the channel through which cold air should flow into the refrigerator compartment. The freezer works fine (and even better, since the ice acts as an insulator), and it becomes warm at the top. Often a problem is signaled by ice on the back wall of the freezer or a strange fan noise that touches the ice.
☑️ Diagnostics of the No Frost system
To repair, you need to defrost the refrigerator (turn it off for 24 hours with the doors open), and then replace the burnt elements: heating element, thermostat or defrost sensor. It is also important to check the drainage hole through which water flows into the tray above the compressor. If it is clogged, the water freezes and also blocks the circulation.
⚠️ Attention: If after complete defrosting the refrigerator began to work normally, but after 3-5 days the problem returned, this is a 100% malfunction of the defrosting system, and not a freon leak.
Faults of the compressor and starting relay
A compressor is a motor that pumps freon. If its power drops (valve group wear), it may not create enough pressure to push freon through the entire circuit. In this case, freon boils at the beginning of the circuit (in the freezer), and reaches the refrigerator compartment as a warm gas. The compressor may operate quietly or, conversely, with a strong knock.
The starting relay, the device that starts the motor, also often fails. If the relay “sticks” or does not open the starting winding, the compressor may hum, click, but not start, or start and immediately stall due to overload. In some cases, the relay works, but intermittently, which leads to unstable cooling.
Diagnostics of the compressor requires measuring the outlet pressure and current. If the current is low and there is no pressure, the compressor has “died” or lost performance. Replacing a compressor is an expensive repair that often requires replacing both the filter drier and a complete recharge of the system.
Can a compressor be restored?
There is a myth that you can “revive” a weak compressor by adding freon under high pressure. This is strictly forbidden - this will lead to water hammer and final breakdown of the motor.
Electronic malfunctions: sensors and control module
In modern electronically controlled refrigerators (where there is a display on the door), sensors are responsible for the temperature. If the temperature sensor in the refrigerator compartment fails and shows incorrect data (for example, that it is -5°C, although in fact it is +15°C), the control module simply will not give a command to cool this zone.
The evaporator sensor or the air damper (damper), which regulates the air flow, may also break. The damper may become stuck in the closed position due to icing or motor failure. In this case, physically cold air cannot enter the upper chamber, even if the cooling system is working properly.
Electronics diagnostics are carried out using a multimeter (checking the resistance of sensors at different temperatures) or through the service mode (if the model has one). Often the error is displayed as a code on the display (for example, F1, E2), the decoding of which can be found in the instructions for the specific model Samsung or Whirlpool.
What you can do yourself before the technician arrives
If you find that it’s warm in the refrigerator, don’t panic. First of all, estimate the quantity of products. If the chamber is jammed, air cannot circulate. Try unloading the shelves and check if the cold has appeared. Also make sure that the products do not block the outlet openings of the air ducts (in No Frost) or are not pressed against the back wall (in drip).
Carry out a complete defrost. Unplug the refrigerator, open the doors and leave for at least 24 hours (preferably a day). This will help if the problem was an ice plug in the defrost system or channels. After switching on, listen to see if the characteristic sounds of liquid flow appear.
Check the tightness of the sealing rubber. If warm air constantly enters the chamber, the refrigerator may not have time to cool the food, creating the illusion of a breakdown. Press the rubber against the body, check for cracks or peeling.
⚠️ Attention: Specifications and location of elements may vary depending on the model and year of manufacture. Always check the manufacturer's official documentation before starting any work.
When exactly you need to call a specialist
Independent repair of the cooling system is only possible if the light bulb, seal or defrost is replaced. All manipulations related to tubes, gas, soldering and live electrical circuits require qualifications. If after defrosting the problem does not go away, or you see swelling, rust, or hear unusual sounds, it’s time to call service.
The technician will arrive with equipment: a leak detector, a pressure gauge station, a vacuum pump. He will accurately determine whether refilling with freon, replacing the compressor, or simply cleaning the drainage is necessary. Remember that an attempt to save on calling a technician in the event of a freon leak often leads to the purchase of a new refrigerator, since a compressor that has burned out due to dry operation cannot be repaired.
In conclusion, it is worth noting that regular preventive maintenance, cleaning the condenser at the back of the refrigerator from dust and monitoring the condition of the seals prolong the life of the equipment. Do not ignore the first “bells”, such as longer operation of the motor or the appearance of excess ice, and your refrigerator will last for many years.
Why does the freezer work, but is it warm in the refrigerator?
Most often this indicates a freon leak (gas does not reach the end of the circuit) or a clogged capillary tube. A malfunction of the defrost system in No Frost models is also possible when ice blocks the air supply channels.
How long does it take to defrost the refrigerator to check?
To completely defrost the evaporator and defrost ice plugs in the channels, you must keep the refrigerator turned off with the doors open for at least 24 hours.
Is it possible to add freon yourself?
No, this is impossible without special equipment. In addition, you cannot simply “top up” gas - you need to find a leak, seal it, evacuate the system and fill in a strictly defined amount of freon indicated on the tag.
What to do if the compressor is hot but there is no cold?
This is a sign that the compressor is working, but the freon is not circulating (clogged) or there is little of it (leakage). You need to turn off the device and call a technician to diagnose the pressure in the system.
Does the amount of food affect cooling?
Yes, if there are too many products and they block the air circulation (especially in No Frost), the cold will not be distributed evenly. Warm air can also enter through a door that is not tightly closed.