The situation when in a two-chamber refrigerator the lower compartment continues to freeze, and the upper one stops cooling, is one of the most common problems faced by owners of household appliances. Violation of the temperature regime can lead to food spoilage, so it is important to quickly identify the source of the problem. Often the cause is not a complex breakdown of the compressor, but a simple blockage or failure in the defrost system.
Modern units, be it Indesit, Atlant or LG, are designed on a similar principle of circulation of refrigerant and air. If everything is fine in the freezer, it means that the compressor and the main circuit are working properly, and the problem is localized in the cold supply system to the upper section or in the control unit. In 80% of cases, the reason for the lack of cold in the upper compartment is the freezing of an ice coat on the evaporator, which blocks the air duct channels.
Further diagnostics requires sequential exclusion simple reasons before calling a specialist. In this article, we will analyze in detail the mechanical and electrical faults that lead to the described problem, and will help you understand whether you can fix them yourself.
Checking the settings and operating mode
Before disassembling the unit or looking for spare parts, it is necessary to exclude the human factor. Sometimes users accidentally change settings, activate special modes, or do not close the door tightly, which leads to poor air circulation. In models with electronic control, a failure could occur due to a power surge.
Check whether the mode "Super Freeze" (Super Freeze) is turned on. In some models, when this function is activated, the compressor works only on the freezer compartment, ignoring the upper compartment until the mode is manually turned off. You should also make sure that the thermostat is not turned to minimum.
If you have a model with an electronic scoreboard, try performing a full reset. To do this, it is usually enough to disconnect the device from the network for 10-15 minutes. This action reboots control module, eliminating software errors that could block the operation of the fan or damper.
⚠️ Attention: If after defrosting for 24 hours the problem does not disappear, further operation of the equipment may lead to failure of the compressor due to overheating.
Problems with the No Frost system and defrosting
In system refrigerators No Frost cold is pumped into the upper chamber by a fan through special air ducts. If the evaporator, located behind the back wall of the freezer, becomes covered with ice, the air flow is blocked. This is the most common reason why the refrigerator compartment stops working even if the freezer is working.
A chain of parts is responsible for the defrosting process: Defrost heating element, a defrost thermostat (defroster) and a timer (or electronic module). If at least one element of this chain fails, the ice stops melting, building up layer by layer. As a result, after a few days, the ice plug completely blocks the channels.
Diagnosis of this malfunction often requires a visual inspection of the evaporator. To do this, you will have to remove the back panel in the freezer compartment. If you see a massive layer of ice or snow blocking the fan, the problem is in the defrost system.
☑️ Diagnostics of the No Frost system
It often fails itself Heating element, which simply burns out over time. The thermostat, which should send a signal to turn on the heater, may also “stick” or lose contact. In models with a mechanical defrost timer, the timer motor may jam, and the unit will forever remain in cooling mode, forgetting about defrosting.
Faulty air damper (Damper)
In two-chamber refrigerators, especially in models with one compressor, the temperature is adjusted in the upper separation is often carried out using an air damper (damper). This mechanism opens and closes at the command of a thermostat or electronic module, letting cold air from the freezer upward.
If the damper is stuck in the closed position, cold air physically cannot enter the refrigerator compartment. This causes food in the freezer to be stone frozen and warm at the top. The damper mechanism may jam due to ice or due to a breakdown of the electric drive.
In electronic models, the damper drive is a small motor with gears. Over time, the plastic gear can wear down or crack. In mechanical models, the damper is controlled by a thermostat through a bellows tube, which may lose its seal or become deformed.
| Symptom | Probable cause | Check method |
|---|---|---|
| It's cold in the freezer, warm on top | The damper is closed | Visual inspection of the damper position |
| A hum is heard, but there is no cold | The damper motor is jammed | Checking the resistance of the motor winding |
| Temperature fluctuates | Temperature sensor is faulty | Sensor resistance measurement |
| Ice on the back wall of the top | The damper does not close | Check circuit tightness |
Repairs often require replacing the damper motor assembly. This is a part that is difficult to repair; it is easier to replace it with a new one. It is also important to check whether frozen ice is interfering with the movement of the damper, which again brings us back to the problems of the defrost system.
How to check the damper motor?
To check the damper motor, you need to apply 220V voltage to it (or 12V/24V depending on the model) and listen to whether it makes an operating sound and moves whether the stock If the motor hums but does not move, the mechanics are destroyed. If it is silent, the winding has burned out or there is no power.
Freon leak and capillary tube blockage
Although the compressor is working and the freezer is functioning, a partial refrigerant leak or blockage in the circulation system can manifest itself in this way. Freon circulating along the circuit first passes through the evaporator of the freezer, giving off part of the cold there, and then must go to the evaporator of the refrigeration compartment.
When freon leak its quantity is not enough for the full cycle. The gas completely evaporates in the first compartment (freezer), and the coolant simply does not reach the upper compartment. In this case, the freezer works, but weakly, and the upper chamber is warm.
A similar situation occurs when clogged capillary tube. The microscopic opening of the tube becomes clogged with oxidation products or moisture. The circulation of freon is disrupted, the pressure drops, and the cold stops flowing into the second circuit. This is a serious malfunction that requires the intervention of a specialist with the equipment.
⚠️ Attention: You cannot try to find a leak or clean the capillary yourself without a vacuum pump and pressure gauges. You may permanently damage the system or get injured.
Signs of these problems may also be: a hot condenser (grid at the back) only partially, the compressor running without stopping and the absence of the characteristic gurgling of freon when the unit is operating. If you hear the refrigerator humming constantly, but there has been no cold in the upper compartment for several days, most likely the problem is gas.
Fan malfunctions
In systems No Frost the fan is the heart of the cold distribution system. If it stops spinning, cold air remains in the freezer compartment and does not enter the refrigerator compartment at all. The fan may stop for several reasons.
Most often, banal freezing of the blades or motor bushing occurs. The ice blocks the rotation, and the motor hums, but does not turn. The second reason is wear of the plain bearings, which causes the shaft to jam. The third option is an electrical malfunction of the motor itself or lack of power to it.
Checking the fan is not difficult: you need to get to it (usually it is located behind the back wall of the freezer) and try to turn the blades by hand (with the refrigerator unplugged!). If they spin tightly, the bearing requires replacement or lubrication. If it’s easy, but the motor does not start, check the voltage at the contacts.
Malfunction of the thermostat or temperature sensor
Control of the compressor and damper operation depends on the readings of the sensors. In mechanical refrigerators, this is responsible thermostat, in electronic refrigerators - NTC sensors. If the sensor that controls the temperature in the refrigerator compartment transmits incorrect data (for example, that it is already -10°C, although in fact it is +15°C), the control module will not open the damper or turn on the compressor.
Sensors often “lie” when changing your resistance. Over time, their characteristics (float away). The test is carried out with a multimeter: the resistance is measured at a certain temperature and compared with the table of ratings for a specific refrigerator model.
In mechanical thermostats (for example, TAM-133), the bellows tube may weaken or gas may leak from the sensitive element. In this case, the contacts will simply stop closing, and the compressor will not turn on at the command of the upper sensor, working only according to the freezer sensor (if there is one) or not working at all.
Replacing the sensor is a simple procedure, but it requires selecting an element with similar characteristics. Installing a sensor with a different resistance value will lead to incorrect operation of the entire unit: either the products will freeze or spoil.
Frequently asked questions and answers (FAQ)
Is it possible to operate a 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 non-stop, trying to gain temperature, which will lead to overheating and burnout of the windings. If the problem is in the defrost system, the ice may damage the plastic or the fan. It is better to eliminate the malfunction.
How long does it take to defrost the refrigerator to check?
It takes at least 24 hours for complete defrosting and water to drain from the hidden drainage channels. Simply turning it off overnight (8-10 hours) is often not enough to melt the ice blockage deep in the air ducts. It is recommended to keep the doors open for a day.
Why did the refrigerator start working after defrosting, but after a week it stopped again?
This is a classic sign of a malfunction of the defrosting system (heating element, timer or thermostat). Defrosting eliminated the effect (ice), but not the cause. Ice will build up again once the cooling cycle starts and block the channels again. A faulty defrost circuit element needs to be replaced.
Is it possible to replace a single-chamber thermostat with a two-chamber one?
No, these are different devices with different characteristics and capillary tube lengths. Installing an incorrect thermostat will result in the refrigerator not operating correctly. It is necessary to look for an analogue with the same marking data.
Where can I find an electrical connection diagram for my refrigerator?
The diagrams are usually located on the back of the unit or inside the compressor compartment on a sticker. Also, electrical diagrams can be found in service manuals (service manuals) for a specific model, which are often available on the Internet at the request “model + service manual.”