The situation when freezer compartment continues to properly freeze food, while in the main compartment it is warm or the temperature is significantly higher than normal, is one of the most common problems in the operation of household appliances. Users often encounter this suddenly: the compressor seems to be humming, the light is on, but the milk is turning sour and the vegetables are withering. This indicates that the cooling cycle is disrupted precisely in the area where cold is supplied to the upper or main chamber.
There can be many reasons for such an imbalance: from a simple blockage in the ventilation system to a serious refrigerant leak or failure of the control electronics. In modern models with a No Frost system, the problem often lies in poor air circulation, while in older two-chamber units with a drip defrosting system, the culprit is often the refrigerant itself or the thermostat. Understanding the structure of your refrigerator is the first step to successful diagnostics.
You should not immediately panic and call a technician, since in some cases the malfunction can be eliminated yourself by carrying out a basic inspection of the components. However, ignoring the problem can lead to complete breakdown of the expensive compressor. Below we will analyze in detail the mechanical and electrical causes of the malfunction so that you can accurately determine the source of the problem.
Impaired air circulation in the No Frost system
In refrigerators equipped with a system No Frost (or “wind defrost”), cooling of the main chamber occurs not due to direct contact with the evaporator, but by forced supply of cold air fan. If the freezer is working, then the evaporator is cold, but the air simply does not reach the food in the upper compartment. Most often, the culprit is a frozen duct or a fan malfunction.
Air dampers (dampers) can become stuck in the closed position due to frozen ice or mechanical damage. Also, the fan itself, which is supposed to drive air, may freeze up or fail electrically. In this case, you can hear the motor humming, but there will be no characteristic noise of a working fan.
⚠️ Attention: If you hear an extraneous grinding or humming noise from the rear wall, do not try to forcefully rotate the fan blades with your fingers - this may damage the bushing or bearing, making replacement of the unit mandatory.
For diagnostics, you need to check patency of air ducts. Often ice clogs the hole through which cold air should enter the refrigerator compartment. Defrosting the unit during the day often solves this problem, unless critical icing of the fan motor has occurred.
- ❄️ Check whether the air flow is blocked by products lying close to the back wall.
- 🌀 Listen: does the fan work immediately after turning on the compressor.
- 🧊 Inspect the air supply damper to see if there is ice on it.
- 🔌 Make sure that the air duct cover is not displaced or blocked by a foreign object.
Problems with the thermostat and temperature sensors
The thermostat (or electronic temperature sensor) is the “brain” that gives commands to the compressor turn on or off. If thermostat faulty, it may mistakenly believe that the chamber is already cold enough, based on the freezer readings, and not give the command to cool the main compartment. In electronic models, sensors are responsible for this, which can “lie” over time.
In mechanical systems, the thermostat has a capillary tube, which should fit tightly to the evaporator. If the tube moves away or loses its tightness, the adjustment is lost. As a result, the refrigerator can work indefinitely, freezing the freezer to -24°C, but never cool the upper chamber to the required +4°C.
Electronic control modules are also susceptible to failures. If the sensor is frozen or displays incorrect data, the system will not start a cooling cycle for the refrigerator compartment, considering the temperature to be normal. Replacing the sensor often requires disassembling the internal panel and checking the resistance with a multimeter.
How to check a thermostat with a multimeter?
To check a mechanical thermostat, you need to remove it and “ring” the contacts in cold and warm states. In warm conditions the contacts should be closed (resistance close to 0), and in cold conditions they should be blurred (infinity). If the circuit does not break in the cold or does not close in the heat, the thermostat is faulty and requires replacement.
It is important to consider that in two-compressor models, a separate circuit and its own thermostat are responsible for each chamber. If you have just such a unit, then the problem is local and does not affect the freezer, which simplifies troubleshooting.
Freon leakage and clogged capillary system
One of the most serious reasons why refrigerator stops cooling in the main compartment is a partial leak of refrigerant (freon) or capillary tube clogged. In this case, the compressor works constantly, trying to increase the temperature, but the gas resource is not enough for a full cooling cycle of the two chambers. Usually the cold “reaches” only the freezer, but not the refrigerator compartment.
When freon leaks, the pressure in the system drops. The refrigerant boils ahead of time, completely evaporating while still in the freezer compartment. The gas reaches the upper compartment already warm or in insufficient volume. This is a classic symptom that requires the intervention of a technician with leak detection and refilling equipment.
A clogged capillary tube (often caused by moisture or oil breakdown products) creates a similar picture. The system cannot pump the required volume of freon, and circulation is disrupted. Unlike a leak, if a blockage occurs, the compressor may overheat, and the tubes on the rear grille will only be partially cold.
| Symptom | Probable cause | Nature of compressor operation | Condition of the tubes |
|---|---|---|---|
| The freezer is freezing, the refrigerator is warm | Freon leak | Works without stopping | The tubes are warm or at room temperature |
| Ice only at the entrance to the evaporator | Clogged capillary system | Operates with overheating | One pipe is hot, the other cold sharply |
| Temperature floats | Sensor malfunction | Turns on rarely or often | Normal alternation of temperatures |
| Frost along the entire back wall | Loss of door tightness | Operates normally | Normal |
Failures of the evaporator and defrost heating element
In systems No Frost the evaporator and its system play a critical role defrost. If the defrost heating element, timer or defrost sensor fails, a huge “coat” of ice grows on the evaporator. This ice blocks the ventilation ducts, and cold air physically cannot enter the refrigerator compartment, remaining locked in the freezer.
The user may notice that over time the refrigerator begins to cool worse and worse until it completely stops doing so in the upper compartment. At the same time, the freezer, located closer to the source of cold (evaporator), still copes. Visually, this can be seen by the freezing of ice on the back wall of the freezer or the appearance of lumps.
It is necessary to check the integrity of the defrosting heating element. If the spiral burns out, the ice does not melt automatically. Also, the defrost sensor often breaks down, which “does not see” that the evaporator is covered with ice and does not turn on the heating. As a result, the system works like a regular refrigerator with a drip system, but without water drainage, which leads to an ice block.
- 🔥 Check the resistance of the defrost heating element (should be within normal limits, not a break).
- ⏱️ Test the defrost timer to see if it switches to defrost mode.
- 🌡️ The defrost sensor must close the circuit at a certain low temperature.
- 💧 Inspect the drainage hole to see if it is clogged with dirt or ice.
Mechanical damage to the door seal
It would seem like a simple thing - a rubber seal door, but it is precisely this that is responsible for the tightness of the chamber. If the seal of the refrigerator compartment is damaged, dirty, or simply “tired” and has lost elasticity, warm air from the room constantly flows inside. The compressor tries to compensate for the heat, working for wear, but due to the constant influx of heat, the temperature does not drop to normal.
The freezer may work normally, since its door closes more tightly, or there is simply less air volume for cooling. Often the problem lies in the skew of the door: if the refrigerator is not level, the door may not fit tightly at the bottom or top.
You can check the tightness with a simple test with a sheet of paper. Clamp the sheet with the door around the perimeter: if it pulls out too easily without rubber resistance, then there is no tightness in this place. Dirt and grease also prevent a tight fit, so cleanliness of the seal is the key to proper operation.
Failures operation of the electronic control module
Modern refrigerators, especially brands Samsung, LG or Bosch, are controlled by complex electronics. If the main control module (board) is not operating correctly, it may not supply voltage to the refrigerator door solenoid or may not turn on the cooling fan. Errors in the firmware or power surges often lead to such “glitches.”
In this case, diagnostics require connecting to the service mode or checking the output voltages on the board. Sometimes a complete reset helps, but if the problem is a burnt-out board element (relay, capacitor), soldering or replacing the module will be required.
⚠️ Attention: Electronic boards are sensitive to humidity. If you notice condensation inside the case or oxidation of the contacts, under no circumstances plug the device into the network until the contacts are completely dry and cleaned with alcohol, otherwise a short circuit will completely kill the module.
Often an error code lights up on the display, which indicates a specific node. Deciphering the error code is the fastest way to understanding the problem. For example, codes of the “F” or “E” series with numbers often indicate problems with sensors or the fan.
☑️ Do-it-yourself initial diagnostics
Frequently asked questions and answers (FAQ)
Why after defrosting the refrigerator started working normally, but after a week it stopped cooling again?
This is a classic sign of a malfunction of the defrost system in models No Frost. While you were defrosting the unit manually, the ice melted, the channels became free, and the cold went away. But since the heating element, timer or defrost sensor is faulty, ice accumulated again within a week and blocked the system again. The elements of the defrosting system need to be replaced.
Is it possible to operate the refrigerator if the freezer is freezing and the main chamber is warm?
For a short time - yes, the food will not spoil immediately. Continuous operation in this mode is dangerous for the compressor, which runs non-stop, trying to reach an impossible temperature. This will lead to overheating and costly repairs. It is better to turn off the device and find the reason.
How long does it take to defrost the refrigerator to check?
For complete melting of the ice in the hidden channels and on the evaporator, a minimum of 12, and preferably 24, hours is required. Defrosting for 2-3 hours is often not enough to remove the ice plug deep in the ventilation system.
Does the amount of food in the refrigerator affect cooling?
Yes, it does. If the refrigerator is filled to capacity with food, especially at the back wall and at the ventilation holes, air circulation is disrupted. The cold cannot be distributed evenly. However, an empty refrigerator may also not work correctly if the automation is faulty, but usually a full load aggravates ventilation problems.