The situation when food in the refrigerator compartment begins to deteriorate, but in the freezer compartment everything remains frozen is a classic a symptom of a refrigerant circulation problem. Many owners of household appliances mistakenly believe that if the compressor is humming and the freezer is cold, then the unit is working and the problem will solve itself. However, this misconception often leads to complete damage to the contents and failure of expensive system components.
In two-chamber models, especially with a system No Frost or static cooling, the temperature regime in different zones depends on the uninterrupted operation of the evaporator and the cold removal system. When the upper chamber stops cooling, this signals that cold air or freon stops flowing into this circuit, concentrating only in the lower part. Understanding the physics of the process will help you quickly diagnose a malfunction.
It is important not to ignore the first signs: the appearance of condensation on the walls, a change in the sound of the motor, or cyclic switching on and off without reaching the desired temperature. Timely reaction can save the compressor from overheating, and your products from being thrown away. Next, we will analyze in detail the mechanics of this process and the main reasons for the failure.
⚠️ Attention: If you notice that the refrigerator is working continuously, trying to cool the upper chamber, immediately unplug it. Long-term operation in this mode can lead to combustion of the motor-compressor winding.
Principles of operation of the cooling system in two-chamber models
To understand why the temperature balance is disturbed, you need to remember the basic operating diagram. Most modern refrigerators use one compressor and one evaporator, usually located in the freezer compartment. Cold is supplied to the upper compartment either forcibly by a fan (in systems No Frost), or due to natural convection (in drip systems).
If the upper chamber does not freeze, and the lower one is working properly, this means that the cold source is functioning, but the path of cold transmission is blocked or disrupted. In models with a single evaporator, the refrigerant flows through the entire circuit, but if air circulation is stopped, the upper zone remains warm. In models with two evaporators, the problem may lie in the valves that regulate the supply of freon.
The key element here is a thermostat or an electronic control module that reads sensor readings. If the upper chamber sensor is “lying” or has failed, the controller may “think” that it is already cold enough there, and does not turn on the refrigerant supply or the fan. Air circulation is what combines the temperature zones into a single system.
Differences in design also determine the specifics of the breakdown. In simple models, the cold exhaust channel is often clogged with ice, and in complex systems with electronics, the damper can burn out. Therefore, diagnostics always begin with determining the type of your model and understanding exactly how it is implemented heat transfer between the chambers.
Icing of the evaporator and impaired air circulation
The most common reason why the upper compartment stops to cool down is simply icing of the evaporator. In systems No Frost ice freezes on the radiator located behind the rear wall of the freezer. The fan moves the air, but the ice coat blocks the airflow, and the cold simply does not reach the top of the unit.
The process of ice accumulation occurs due to a malfunction of the defrost system. The heater heating element, defrost timer or defrost sensor may fail. As a result, the ice does not melt in the prescribed time, but accumulates layer by layer until it completely blocks the channels. Visually this may not be noticeable, since the evaporator is hidden under plastic panels.
- ❄️ Ice blocks the intake holes through which the fan sucks warm air from the chambers.
- ❄️ The fan continues to work, but only circulates air inside the freezer, without lifting it up.
- ❄️ Temperature sensors may show incorrect values due to ice crust.
- ❄️ The compressor works hard, trying to break through the temperature barrier.
Often owners notice that the back wall in the freezer is covered with a thick layer of frost or ice, and in the refrigerator the compartment is warm. This is a sure sign that complete defrosting is required. Manual defrosting for a period of 24 to 48 hours (until all the ice inside has melted) often brings the unit back to life if other components are working properly.
☑️ Actions in case of icing
If after a long period After defrosting, the refrigerator worked fine, but after 1-2 weeks the problem recurred, which means that the defrosting system is really faulty and requires replacement of components. Ignoring this fact will lead to ice reaching the fan, and it may jam or burn out.
Faults in the defrosting system
The defrosting system is the “Achilles heel” of many modern refrigerators. It consists of several key elements: a heating element (heating element), a defrost sensor, a fuse and, in some models, a timer or an electronic control module. If at least one of these elements fails, the defrosting cycle does not start.
Most often the heating element of the evaporator itself burns out. It is a tube built into the fins of the radiator or located under it. Over time, the nichrome thread becomes thinner and breaks. You can check it with a multimeter for resistance. If the device shows a break, the element must be replaced. Also often the defrost sensor, which should record the temperature of the evaporator and give a command to turn on the heating element, “glitches.” data-i="92">Evaporator heating element
| Component | Function | Symptom of failure | Diagnostics |
|---|---|---|---|
| Evaporator heating element | Heating ice to melt | Increasing "coat" of ice | Ringing with a multimeter (no resistance) |
| Defrost sensor | Radiator temperature control | The heating element is not turned on | Resistance measurement at different temperatures |
| Fuse | Overheat protection | Open power circuit Heating element | Visual inspection or ringing |
| Control module | Cycle coordination | Chaotic operation or stop | Checking the output voltage |
It is important to note that some models Indesit, Ariston or Atlant use a fuse that burns out when the heating element overheats. Replacing it without eliminating the cause of overheating (for example, sticking relay contacts) will lead to re-combustion. Therefore, simply replacing parts without in-depth diagnostics of the circuit may not give a long-term result.
⚠️ Attention: When replacing heating elements or sensors, be sure to use original spare parts or high-quality analogues with identical characteristics. Installing parts with a different power may lead to a fire or repeated breakdown.
Problems with the fan and air supply damper
In refrigerators with a system No Frost the fan is responsible for moving cold air. If it stops, the cold air remains in the freezer (where it is produced) and does not enter the upper compartment. As a result, it becomes warm there, and frost below.
The reasons for the fan stopping can be mechanical and electrical. The mechanical reason is the same icing mentioned above: the blades freeze and cannot rotate. Electrical cause - the motor winding is burned out or the contact is broken. When the compressor is running, you may not hear the characteristic fan noise, which is the first sign of its malfunction.
The second important element is the air damper. It regulates the amount of cold air flowing from the freezer into the refrigerator compartment. The damper is controlled by a separate motor or solenoid valve. If the damper is closed in the “closed” position and jammed, the upper chamber will remain without cooling. This often happens due to a breakdown of the damper drive or a foreign object (a piece of ice, crumbs) getting in there.
How to check the fan?
Open the freezer door (in some models you need to press the door sensor button, simulating closing) and listen. If the compressor is humming and the fan is silent, the problem is in it or in its power supply. Be careful not to stick your fingers into the blades!
Diagnostics of the damper requires removing the plastic panels at the top of the refrigerator compartment. Visually check that the channel is not blocked by ice or food. If there are no mechanical obstacles, most likely the drive motor has failed. In models with electronic control, an error may appear on the display indicating a malfunction of the damper (for example, an error code F with a number).
Refrigerant leak and capillary tube clogged
If defrosting did not help, the fan spins and the damper is open, but the upper chamber still does not freeze, the problem may be more serious - in the freon circulation circuit. There are two main scenarios here: a refrigerant leak or a clogged capillary tube.
When freon leaks, its amount in the system decreases. Since the refrigerant begins to boil and cool at the beginning of the circuit (in the freezer), it simply does not reach the upper part of the evaporator (which is responsible for the refrigeration compartment). In this case, the freezer works, but the refrigerator does not. Over time, the lower chamber will also stop freezing.
Clogging of the capillary tube occurs due to moisture entering the system or wear products of the compressor oil. An ice plug or paraffin coating forms in a narrow channel, which physically blocks the freon flow. The pressure at the entrance to the capillary increases, and at the outlet it decreases. The symptoms are similar to a leak: the freezer is working, the refrigerator is warm.
- 🛑 The compressor works almost non-stop, trying to gain temperature.
- 🛑 The condenser (grid at the back) may be only partially warm or completely cold.
- 🛑 At the site of a clog or at the beginning of the leak, swelling or, conversely, the absence of a characteristic hissing may be observed.
- 🛑 When there is a leak, oily spots are often visible under the refrigerator or at the site of damage to the tubes.
Diagnosis of these faults requires professional equipment: a pressure gauge manifold and a leak detector. Finding a leak or breaking through a blockage on your own is almost impossible without evacuating the system and refilling it with new freon. This is a job for a master.
Malfunctions of the thermostat and electronic module
In simple mechanical refrigerators, the thermostat is responsible for the temperature. If its sensing element (bellows) has failed or is displaced, it may not command the compressor to turn on when it is warm in the upper chamber. Although more often, if the thermostat breaks down, the refrigerator either does not turn on at all or works without stopping.
In modern models with electronic control, the role of a thermostat is performed by temperature sensors (thermistors). If the sensor in the refrigerator compartment “lies” and shows that it is -5°C, although in fact it is +15°C, the control module will not start refrigeration. Replacing the sensor is a simple procedure, but requires precise selection of resistance.
The most expensive and complex failure is the failure of the main control module (board). The “brains” of the refrigerator can burn out from a power surge or simply from old age. In this case, signals from the sensors are not processed correctly, and commands to the compressor, fan or heating element are not received. Diagnostics of the board requires knowledge in electronics and the availability of circuits.
⚠️ Attention: Before replacing any electronic components, make sure that they are the problem. Often a “dead” module is a consequence, not a cause (for example, after a power surge or a short circuit in the wiring).
Sometimes the problem is solved by flashing the module or simply resetting errors (reset). To do this, the refrigerator is disconnected from the network for a long time (more than 30 minutes) or using combinations of buttons specific to the brand (for example, holding the “Super Freeze” and “Temperature” buttons for a long time).
The influence of improper operation on the operation of the cameras
The reason does not always lie in a breakdown. Often, users themselves create conditions under which the upper chamber stops freezing. For example, loading hot foods into the refrigerator. The steam instantly condenses on the walls and turns into ice, which can block the air circulation channels even in a working unit.
Another common mistake is a loose fit of the refrigerator compartment door. If the seal (elastic band) is worn out, dirty, or the door is skewed, warm air constantly enters the chamber. The cooling system cannot cope with this amount of heat, and the temperature in the upper zone rises. Check the tightness of the fit using a sheet of paper: clamp it around the perimeter of the closed door - it should be removed with force.
It is also worth checking whether the ventilation holes inside the chamber are not blocked by products. If you place the pan right before the cold air comes out, the circulation will be disrupted and the top will become warm. Compliance with operating rules is the first step to the longevity of the equipment.
When you need to call a technician
If complete defrosting (at least 24 hours) does not bring results, and the fan and damper are visually in good working order, professional repairs will most likely be required. Especially if you suspect a freon leak or a clogged capillary. These works require a license, special equipment and soldering skills.
You also need a master if you hear unusual sounds: gurgling, whistling, loud relay clicks. This may indicate problems with the compressor or water hammer in the system. Trying to repair it yourself in the case of a sealed circuit often leads to an increase in the cost of repairs by 2-3 times.
It is worth thinking about calling a specialist if the refrigerator is old (more than 10 years) and requires replacing the compressor. In this case, it is more economically feasible to consider purchasing new equipment, since the cost of a new motor and work to replace it can be up to 50-60% of the price of a new refrigerator.
Is it possible to restore the operation of the refrigerator without defrosting?
No, if the reason is an ice plug (which happens in 80% of cases), then without complete melting of the ice inside the case, restore air circulation is impossible. Forced chipping of ice can damage the evaporator.
Why, after defrosting, did the refrigerator stop freezing again after a week?
This indicates a malfunction of the defrosting system (heating element, sensor, timer). Ice accumulated again and blocked the channels. Diagnosis and replacement of the burnt element of the defrosting system is required.
Is it dangerous to use a refrigerator if the upper chamber does not freeze?
You cannot use it to store food - they will spoil. This is also harmful for equipment: the compressor works non-stop, which leads to its overheating and rapid failure.
How much does it cost to repair if a defrost heating element burns out?
The cost consists of the price of the spare part (heating element, sensor) and the work of a disassembly/assembly technician. Usually this is not the most expensive type of repair, since it does not require working with freon and soldering tubes.
Could the compressor be to blame if the freezer is working?
The compressor itself is unlikely, since it creates pressure and freezes the lower chamber. But if its performance has decreased (valve wear), it may not be able to cope with two chambers, giving priority to the first (freezer). However, more often the reason is still in the distribution of cold.