The situation when two-chamber refrigerator properly freezes food in the lower compartment, but stops cooling the upper chamber, is one of the most common and alarming for household owners technology. Unlike a complete compressor failure when the house becomes quiet, here the unit continues to hum, creating the illusion of normal operation until the food in the main compartment begins to spoil. This behavior of the equipment indicates a violation of the refrigerant circulation or a malfunction in the temperature control system.
Before calling a technician, it is necessary to carry out an initial visual diagnosis, since in 30% of cases the problem lies in simple things that do not require expensive intervention. Modern models with the No Frost system and old units with a drip defrosting system may have different causes of malfunction, but the general principle of troubleshooting remains similar. Understanding the physics of the process will help you avoid unnecessary expenses or, conversely, notice a critical breakdown in a timely manner.
The main task of the refrigeration circuit is to remove heat from the chambers to the outside. If the compressor is running, but there is no cold in the upper compartment, it means that the freon either does not reach the evaporator of the upper chamber, or heat exchange does not occur there due to an ice plug. It is critically important not to try to defrost the unit using a hairdryer or sharp objects if you are not sure of the integrity of the tubes evaporator. Further actions depend on the exact determination of the symptoms.
The main reasons for the violation of cold circulation
The most common culprit in the situation when freezer works, but the refrigeration unit does not, is a violation of air circulation. In models with the system No Frost cold air is forced by a fan from the freezer into the upper compartment through special channels. If these ducts become clogged with ice or snow, air simply cannot get where it is needed.
Another common cause is a refrigerant leak. Freon is a gas that circulates in a closed circuit. If a hole has formed in the system, the pressure drops and there is only enough refrigerant to cool the first section of the circuit, which is usually located in the freezer area. In this case, compressor can work non-stop, trying to gain temperature, but its efficiency drops to zero.
Problems with electronics also cannot be ruled out. Temperature sensors located at different points in the chamber may transmit incorrect data to control module. If the upper chamber sensor is “frozen” or faulty, it can tell the controller that it is already cold there, which is why the cold supply stops. In older models with one compressor and one circuit, the thermostat often fails and simply does not turn on the compressor when the temperature in the refrigerator compartment rises.
⚠️ Attention: If you hear gurgling or hissing inside the refrigerator, and there is no characteristic heating on the rear grille (condenser) over the entire area, this is almost guaranteed to indicate a leak freon or clogged capillary tube.
Diagnostics of the No Frost system and fan
In refrigerators with automatic defrosting, the key element of cold distribution is the fan. It is located in the freezer and drives cold air upward. If fan stopped due to icing of the blades or combustion of the motor, circulation stops. As a result, the freezer operates in enhanced mode (since the cold does not go anywhere), and the upper chamber remains warm.
You can check the operation of the fan by opening the freezer door. In many models, when the door is open, the fan should stop (the limit switch is activated), but if it does not make noise even with the door closed during the first minutes of the compressor operation, this is an alarming sign. It is also worth inspecting the air ducts: if they are clogged with slush, the air flow is physically blocked.
Often the cause of the fan stopping is a malfunction Defrost heating element or the defrost timer. If the evaporator in the freezer becomes covered with a thick layer of ice, it blocks the air supply channels. Ice acts as a heat insulator, and even a running fan will not be able to break through the ice plug. In this case, complete defrosting of the refrigerator is required for up to 24 hours.
- ❄️ Check whether the cold air outlet is blocked by food or packaging.
- 🔊 Listen: does the fan make extraneous sounds or hum before stopping.
- 🧊 Inspect the back wall of the freezer: the presence of a “fur coat” or uneven ice indicates problems with defrosting.
How to check the fan without disassembling?
Put your ear to the back wall of the freezer. If you hear a quiet hum from the motor but no air is blowing, the blades may be frozen. If there is complete silence while the compressor is running, the motor could burn out.
Faults of the compressor and start relay
The compressor is the heart of the refrigerator. Dual-chamber models often use one compressor to cool both chambers. If starting relay faulty, the compressor may try to start, click and shut down, or only run at half power. In this state, the freon pressure is only enough for the freezing circuit.
There is also the concept of “turn-to-turn short circuit” of the compressor winding. In this case, the engine hums, heats up, but does not develop the required pressure. Specialists this is determined by the current strength: it will be higher than the nominal one, and the pressure in the system will be low. It is impossible to repair the compressor on your own; it needs to be replaced.
In models with two compressors (separate for each chamber), the situation is simpler: if the upper chamber does not work, it means that it is the upper compressor or its control circuit that has failed. The lower one continues to freeze as if nothing had happened. This is more expensive to repair, but a more understandable case to diagnose.
⚠️ Attention: If the compressor operates continuously for more than 12 hours without shutting down, and the temperature in the refrigerator compartment does not drop below +10°C, immediately disconnect the device from the power supply. Long-term wear and tear will lead to the motor burning out.
Problems with sensors and thermostat
The electronics of a modern refrigerator are completely dependent on sensor readings. Temperature sensor in the fridge compartment may fail and show underestimated values. Receiving a signal that “there is enough cold,” the control module simply does not issue a command to cool. Visually, it looks like it’s working properly: the light is on, the compressor turns on according to the schedule, but there is no cold.
In mechanical refrigerators, the role of electronics is played by thermostat (thermostat). This is a device that opens the compressor power circuit when the desired temperature is reached. If its capillary tube has lost sensitivity or the contacts are burnt, the refrigerator may not “see” that there is heat in the chamber. Replacing a thermostat is one of the simplest and cheapest repair procedures.
It is important to distinguish a sensor malfunction from an incorrect setting. Sometimes users accidentally change the settings in the menu or turn the control knob to minimum. It is also worth checking the “Vacation” or “Super Freeze” mode, which can block the normal operating cycle.
Freon leakage and clogged capillary tube
If all electrical components are working properly and the fan is spinning, but there is no cold, the problem lies in the hydraulic circuit. Freon leakage occurs more often just in the places where the tubes are soldered or in the foamed part of the body (where the evaporator is located). Freon evaporates, and its quantity is not enough to complete the full cycle.
The second option for a hydraulic problem is clogging of the capillary tube. Oil circulates in the system, which over time can thicken or mix with compressor wear products, forming a plug. Freon cannot pass through the narrow hole, the pressure drops and cooling stops. A characteristic sign of a blockage is a hot compressor and only the first section of the condenser grill is cold.
To eliminate these malfunctions, you need to call a technician with equipment for evacuation of the system and charging the refrigerant. Finding a leak in a foamed evaporator on your own is almost impossible without special equipment.
| Symptom | Probable cause | Difficulty of repair |
|---|---|---|
| The compressor is silent | Faulty start relay or thermostat | Low |
| Humming, but not freezing | Freon leak or blockage | High |
| The freezer is working, the top is warm | The defrost fan or heating element is faulty | Medium |
| Ice only at the entrance to the chamber | Clogged capillary tube | High |
Algorithm for self-checking before calling a technician
What you should not do right away is disassembling the refrigerator. Start with simple steps to help narrow your search. First step - complete defrosting. Even if you use the No Frost system, leave the refrigerator turned off with the doors open for 24 hours. This will eliminate ice plugs in the channels if they were the cause.
After defrosting, turn on the device and listen. If after 30-40 minutes of operation the back wall of the refrigerator compartment does not become cold, and frost appears in the freezer only near the entrance of the tubes, the problem is serious (freon or blockage). If the cold starts, but after a week the situation repeats, look for a problem in the defrosting system (heating element, timer, sensor).
Check the tightness of the door. If the seal rubber cuff is worn out or the door is skewed, warm, moist air constantly enters the chamber. This leads to increased formation of ice on the evaporator and, as a result, to stopping the cooling of the upper chamber.
☑️ Primary diagnostic checklist
⚠️ Attention: Technical characteristics and arrangement of elements may vary depending by brand (Indesit, Bosch, LG, Samsung) and year of manufacture. Always check the technical documentation of your model before starting work.
Frequently asked questions (FAQ)
Is it possible to operate the refrigerator if the upper chamber does not work?
Short-term operation is possible, but undesirable. If the cause is a freon leak, the compressor will work without stopping, which will lead to its overheating and final failure. If the problem is in the electronics, the food in the upper chamber will quickly deteriorate.
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 (No Frost). Ice builds up again on the evaporator and blocks the channels. It is necessary to check the defrost heating element, defrost sensor or timer.
How much does repair cost if the compressor burns out?
Replacing a compressor is an expensive repair, often amounting to 50-70% of the cost of a new refrigerator. In such cases, it is often more advisable to buy new equipment, especially if the refrigerator is more than 7-10 years old.
Does the voltage level in the network affect this problem?
Yes, low voltage may prevent the compressor from developing the required power to pump freon through both circuits. Check the voltage in the outlet using a multimeter.