The situation when the lower chamber of the refrigerator continues to properly freeze food, and the upper one turns into an ordinary kitchen shelf, is a classic symptom of a number of technical malfunctions. Owners of modern two-chamber models often encounter this phenomenon, not suspecting that the problem lies not in a complete breakdown of the compressor, but in a disruption of the refrigerant circulation or a malfunction of the defrost system.
Before calling a technician or disassembling the unit, it is necessary to carry out an initial visual diagnosis. Often the cause is a simple overload of food or a door that is too tightly closed, preventing normal air exchange. However, if you hear how compressor works without interruption, and the temperatures in the upper compartment are rising, you cannot ignore this.
In this article we will analyze in detail the mechanics of the cooling process, identify hidden defects and help determine whether you can fix the breakdown yourself. Understanding the operating principles of your model Indesit, LG or Atlant will help save time and budget on equipment restoration.
Principles of cold circulation in two-chamber models
To understand why the upper section stops working, you need to briefly recall the physics of the process. In classic single compressor systems, cold air is produced in the evaporator, which is often hidden behind the back wall of the freezer. Then a fan or natural convection distributes this air throughout the entire volume.
In systems No Frost forced circulation: the fan drives air flows through special channels. If these channels become clogged with ice or blocked by food, the upper zone remains without cooling. In drip systems (crying evaporator), cold air simply falls down, and a leak or clogged drainage can upset this balance.
A critical element is damper (damper), which regulates the flow of cold air from the freezer to the refrigerator compartment. If the mechanism is stuck in the closed position, the heat simply does not dissipate. In models with electronic control, this process is responsible control module, which can issue erroneous commands due to power surges.
⚠️ Attention: Do not try to forcefully open the damper or pick at the ice with sharp objects if the system is frozen. Damage to the air supply channel or evaporator will lead to an immediate leak of freon and expensive repairs.
Different manufacturers use different heat removal schemes. For example, in Bosch the Twin Cooling system is often found, where the circuits are separated, and in older Biryusha the principle of natural convection works. Understanding the type of your unit is the first step to success.
Faults in the defrosting system and freezing of channels
One of the most common reasons why the top of the refrigerator does not freeze is a violation of the defrost cycle. In No Frost systems, frost inevitably forms on the evaporator, which must be regularly removed by heating elements. If this process goes wrong, the ice coat grows and tightly blocks the ventilation ducts.
A chain of components is responsible for the defrosting process: Defrost heating element, defrost thermostat (or temperature sensor) and a timer (or electronic module). If at least one element fails, the ice does not melt, and the fan cannot drive air through the ice plug. As a result, it is cold in the freezer, and warm on top.
This problem can be diagnosed by the characteristic hum or crackling sound that the refrigerator makes when trying to run the fan through the ice. Sometimes you may notice that the back wall inside the refrigerator compartment is covered with snow or ice, although normally it should be dry and cool.
☑️ Diagnostics of the defrost system
Often the culprit is defrost thermostat. This is a small part that opens the heating circuit when the ice melts. If it is “stuck” in the open state, the heating element will never turn on. Replacing this part is usually inexpensive and is within the capabilities of a home craftsman with basic skills.
In some cases, especially after power surges, it burns itself out heating element. You can check it with a multimeter in continuity mode: if the circuit does not ring, the heating element must be replaced.
How to quickly defrost a refrigerator for testing?
Disconnect the unit from the network for at least 12-24 hours. Leave the doors open. Do not use a hairdryer or hot water to speed up the process, as this may damage the plastic and seals. After complete defrosting, turn on the refrigerator and check if cold has appeared in the upper chamber. If so, the problem is definitely in the defrost system.
Refrigerant leak and problems with the compressor
If the defrost system is working, but the upper chamber does not cool, there is a high probability of a leak. freon. In double-circuit systems or with certain types of pipeline damage, the refrigerant can circulate only in a small circle (freezer), without reaching the main evaporator of the refrigeration compartment.
Symptoms of a leak often appear gradually. First, the refrigerator starts to work longer, then the compressor practically does not turn off, trying to gain temperature. The side walls (where the capacitor is often sealed) may remain cold to the touch, although normally they should be warm.
The second option is a malfunction of the compressoritself. If its performance has dropped (valve group wear), the pressure is not enough to pump freon through the entire circuit. In this case, the freezer is still at minus, and the temperature in the refrigerator compartment is already above zero.
| Symptom | Probable cause | Nature of failure |
|---|---|---|
| Compressor buzzes, but does not start | Start relay or winding | Electrical part |
| The refrigerator works around the clock | Freon leakage | Sealed circuit |
| The sound of liquid flowing is heard | Lack of refrigerant | Leak or blockage |
| The freezer is freezing, the top is not | Partial leak or blockage | Impaired circulation |
It is impossible to eliminate a freon leak on your own. Special equipment is required to find the location of the damage, solder the tubes and evacuate the system. Attempts to simply “refuel” the refrigerator without eliminating the cause will give a temporary effect for several weeks.
⚠️ Attention: Freon is a colorless and odorless gas. If you hear hissing or smell a specific chemical odor from the oil, immediately ventilate the area. Although modern refrigerants are not toxic in small doses, their concentration in a closed space is undesirable.
Failure of the damper (damper) and thermostat
In modern models with electronic temperature control, the air damper is responsible for the distribution of cold. This is a mechanical valve with an electric drive that opens on command thermostat or an electronic sensor. If the damper is stuck in the closed position, cold air physically cannot enter the upper chamber.
You can check the operation of the damper visually (if it is located in an accessible place) or by ear. When changing temperature settings, you should hear a quiet click or whir from the motor. In some refrigerators Samsung or LG the damper is combined with the control unit and is located behind the plastic panel.
It is also worth paying attention to thermostat. In mechanical models, this is a knob with numbers inside the chamber. If its sensitivity is impaired, it may not give the command to turn on the compressor, believing that the temperature is normal (even if it is not). In electronic models, sensors are responsible for this, which can “lie” due to oxidation of the contacts.
Often the problem is solved by simply adjusting or replacing the sensor. However, if the damper is overgrown with ice due to problems with defrosting (see section above), no electronics will help until the ice is removed.
Failure of tightness and operating errors
The reason does not always lie in complex electronics or freon. Sometimes the upper part does not work due to a banal violation of the thermal regime. The rubber seal on the door dries out, cracks or becomes dirty over time. Warm, moist air enters through the cracks, which the cooling system simply does not have time to cool.
You can check the tightness using a sheet of paper: hold it with a closed door and try to pull it out. If the sheet is pulled out too easily in different places around the perimeter, the seal requires replacement or restoration. Also, the door may not fit properly due to misalignment of the hinges, which often happens when shelves are overloaded with heavy products.
Another common mistake is placing hot products. If you put a pot of soup in the refrigerator, the sensors may go off scale and the humidity will rise sharply, causing an ice crust to form on the evaporator. As a result, the upper chamber will temporarily stop cooling.
Check that the products do not block the ventilation holes inside the chamber. Even in a perfectly working refrigerator, the air flow should not be blocked by bags or boxes.
Diagnostics and troubleshooting: step-by-step algorithm
In order not to guess, but to know exactly the reason, follow the logical algorithm. Start with the simplest and move towards the complex. This will help avoid unnecessary expenses on calling a technician to solve a simple problem.
First, eliminate external factors: check the tightness of the door, the absence of hot products and the correct temperature setting. Then listen to the operation of the unit. If the compressor is silent, the problem is in the electrics or thermostat. If the buzzing is constant, look for a leak or blockage.
If you are confident in your abilities, you can remove the back panel of the freezer and check for ice on the evaporator. A clean evaporator with the compressor running and no cold from above is a sure sign of a freon leak. An iced-up evaporator is a sign of problems with defrosting.
For more accurate diagnostics of electronic components (heating element, sensors, damper), you will need a multimeter. Without this device, checking is reduced to a visual assessment and the method of elimination.
What to do if the refrigerator is humming, but not freezing?
If you hear the hum of the compressor, but there is no cold anywhere (or only in the freezer), check whether the fan is spinning (in No Frost). If the fan is standing still, it may be frozen or burnt out. If the fan works, but there is no cold, there is probably a freon leak or a compressor failure (does not create the required pressure).
Is it possible to operate a refrigerator with a non-working upper chamber?
For a short time - yes, if you use it as a freezer. However, continuous operation in this mode is harmful to the compressor, which will wear out trying to reach a non-existent temperature. In addition, in a warm chamber, bacteria and mold will begin to multiply, the smell of which is then difficult to remove.
How long does it take for the temperature to be restored after defrosting?
After complete defrosting (24 hours) and turning on, the refrigerator takes from 2 to 6 hours to return to operating mode. If after 6-8 hours it is still warm in the upper chamber, but dry inside, the problem is technical, not temporary.
Why is there water in the upper chamber, but no cold?
This may indicate that the food inside has already defrosted and leaked, or a problem with condensate drainage (clogged drainage). If water is pouring from above, check whether the melt water drainage channel is clogged and whether the water collection container above the compressor is leaking.