The winter period often becomes a test not only for people, but also for household appliances installed in unheated rooms or on balconies. Owners of refrigerators may be faced with a paradoxical situation: the unit hums, cooling fan works properly, creating a feeling of active operation, but inside there is an inexplicable rise in temperature. A particularly alarming signal is the heating of liquid products, such as bottled water or vegetable oil.
This phenomenon seems illogical, because the environment is cold, and the equipment should operate in a light mode. However thermodynamic processes the inside of the chamber is more complicated than just “pumping out” heat. If you notice that the oil has become warm and the water is no longer icy, this indicates a violation of heat exchange or a failure in the compressor control algorithms.
In this article we will analyze in detail the physical reasons for this phenomenon, the effect of low temperatures on the refrigerant and electronics, and also determine when this is the norm and when it is required urgent refrigerator repair. Understanding these processes will help you preserve food and prevent breakdowns of expensive equipment.
Physics of the process: why food heats up
At first glance, it seems that if the room is cold, then the refrigerator should be even colder. However principle of operation of the compressor assumes the active release of heat during the process of compression of the refrigerant. When the refrigerator is installed in a room with a temperature below +10°C, the sensors may incorrectly read the data, causing the system to think that it is already cold enough inside.
As a result, the compressor turns on rarely or operates in short cycles. But if the fan spins constantly, it begins to circulate air around the heat exchangers, which do not have time to cool between cycles, or mixing of air layers occurs. Warm air from the engine compartment or simply from a running engine can enter the chamber.
Liquids such as water and oil have high heat capacity. They cool slowly, but just as slowly they give off heat. If the air exchange in the chamber is disrupted or the temperature sensor is “deceived” by external cold, these products are the first to react to a change in the thermal balance. Oil, solidifying at low temperatures, can change its structure, but if it is warm, this is a clear sign that refrigeration circuit does not fulfill its function.
⚠️ Attention: Long-term storage of oil and water at elevated temperatures (above +10°C) in conditions of a working but not cooling refrigerator can lead to food spoilage and the development of bacteria, even if this is not visually noticeable.
In addition, it is worth considering the “heat pump” effect. If the temperature difference between the evaporator and the chamber is minimal, the efficiency of heat removal decreases. The fan in this situation only creates the illusion of active operation, mixing the air, the temperature of which may be higher than the temperature of the frozen products.
The influence of low ambient temperature
Operation of refrigeration equipment outside the recommended temperature range is one of the main causes of failures. Most manufacturers indicate in the instructions climate class, which is usually from +10°C to +32°C or +43°C. In winter, on an unheated dacha or balcony, the temperature can drop below zero.
Under such conditions compressor oil it thickens in the engine. This leads to the fact that the compressor experiences enormous loads at start-up. Electronics can block startup or, conversely, give a command to operate without reaching full power. The fan, being an electrical device with lower requirements for lubricant viscosity, continues to work.
As a result, we see the situation described in the request: the fan is noisy, but there is no cold. Moreover, due to the fact that the freon in the evaporator may not boil (do not turn into gas due to the low temperature in the chamber), heat is not removed. In this case, water and food gradually heat up from the heat generated by a working but inefficient motor and lighting.
It is also important to note the influence of humidity. In winter, the air is drier, but in unheated rooms, temperature changes can cause condensation to form on electronic boards. This leads to oxidation of the contacts of the temperature sensors, which begin to transmit incorrect data to the control module.
Problems with the No Frost system and the fan
The system No Frost (or “Windy cold”) is completely dependent on forced air circulation. If you hear the fan operating, but the temperature is rising, the problem may lie in obstruction of the air flow or frosting of the ducts.
In winter, due to rare door openings or the use of equipment for other purposes (for example, storing only empty bottles), the humidity in the chamber can behave unpredictably. The evaporator may become covered with a “fur coat” that the standard defrost heating element does not have time to melt if the operating cycles are disrupted. The fan drives air, but this air does not pass through the cold evaporator, but circulates in a circle, gradually heating up from the motor.
Let's consider the main symptoms of a malfunction of the circulation system:
- ❄️ A strong hum or whistle from the refrigerator compartment, indicating that the fan is operating at high speeds idle.
- 💧 The appearance of puddles under the vegetable boxes, which indicates the melting of ice in hidden channels.
- 🌡️ Temperature difference in different corners of the chamber (it is warm in one corner, colder in the other).
If air does not reach the products, they are not cooled. Water in bottles placed in the path of the flow may cool, but if the flow is blocked by ice, it will remain warm. The oil, having low thermal conductivity, will maintain the ambient temperature or be heated by the walls of the chamber.
Malfunctions of the thermostat and temperature sensors
The “brain” of the refrigerator is the thermostat or electronic temperature sensor. It is he who decides when to turn on the compressor. In winter, when the room is cold, the sensor may “think” that the desired temperature has already been reached inside the chamber and not give a command to start the compressor.
However, in some models with electronic control (Full No Frost system), the algorithms may work differently. If the evaporator sensor fails, the system may turn on the fan to “ventilate” or distribute residual cold, but the compressor will not start. As a result, the products heat up slowly.
Checking the sensors requires special equipment, but the initial diagnosis can be done visually:
- 🔍 Inspect the capillary tube of the mechanical thermostat (if there is one) for damage or disconnection.
- 📉 Pay attention to whether the temperature indicator on the display is flashing, which often indicates a sensor error.
- 🔌 Try changing the temperature set point briefly to see if the system responds by turning on the compressor.
How to check the thermostat with a multimeter?
To check the mechanical thermostat, you need to remove it and “ring” the contacts with a multimeter in ohmmeter mode. At low temperatures (if the sensing element is immersed in cold water), the contacts should open or close depending on the design. If the circuit does not open or close when the temperature changes, the thermostat is faulty.
It is important to understand that replacing the sensor is not always a solution to the problem. If the control board itself, which processes the signals, is “buggy”, then a new sensor will not help. In winter, power surges can also damage electronics, causing chaotic behavior of the system.
Freon leakage and refrigerant problems
One of the most serious reasons for the temperature rise when the fan is running is a refrigerant (freon) leak. In winter, the pressure in the system drops naturally due to the cold, and if there is a microcrack, the leak may worsen or, conversely, become less noticeable to the ear, but critical for cooling.
When the freon level is low, the compressor works, the fan hums, but the “cooling capacity” of the system is close to zero. The refrigerant simply does not have time to cool in the condenser and boil in the evaporator with the required intensity. The products in the chamber begin to heat up from the heat of the motor and the environment.
Symptoms of a freon leak:
- 🔥 The condenser (grid at the back) remains only partially cold or warm, although the compressor is running.
- 🧊 On the evaporator (inside freezer) there is no uniform layer of frost, only individual areas are visible.
- 🔊 The compressor works almost without interruption, trying to gain temperature.
In winter, diagnosing leaks is complicated by the fact that the low ambient temperature masks the heating of the condenser. Therefore, you should not rely only on the tactile sensations of the back wall in winter. You need a professional pressure measurement in the system.
Comparison table: Normal or breakdown?
To make it easier for you to navigate the situation, we have prepared a table that helps distinguish normal work in difficult conditions from serious malfunction.
| Symptom | Probable cause | Status | Action |
|---|---|---|---|
| The fan is working, there is cold, but less so | Low temperature in the room | Conventionally normal | Insulate the room or move equipment |
| Water and oil are warm, the compressor is silent | Thermostat or sensor failure | Failure | Replacing the sensor/thermostat |
| The fan is noisy, the compressor is running, there is no cold | Freon leak or blockage | Serious breakdown | Call a technician, refill with freon |
| The oil is frozen, the water is cold | The temperature in the chamber is too low | Normal (for the freezer) | Check temperature settings |
As can be seen from the table, the situation when products heat up when the fan is running most often indicates malfunctionand not a feature of operation. Ignoring these signs can lead to compressor failure.
What to do: step-by-step instructions
If you encounter the problem described, do not panic. Follow these steps for initial diagnosis and elimination of simple causes.
First, provide the equipment with the right conditions. If the refrigerator is located on the balcony, where the temperature is below +5°C, it must either be moved to a warm place or the room must be heated. Remember that warranty repairs in such cases are often impossible due to violation of operating conditions.
Secondly, defrost. Even if you have a No Frost system, sometimes failures occur and the channels become clogged with ice. Unplug the refrigerator for 12-24 hours (until the ice disappears completely). This will help reset the electronics error and melt the ice jams.
☑️ Checklist of actions when heating food
Thirdly, check the settings. Make sure that the Holiday or Eco mode is not activated, which could limit the compressor's operation. Also check if the temperature settings on the display have gone wrong.
⚠️ Attention: If, after complete defrosting and checking the settings, the situation repeats within 24 hours, further self-diagnosis is dangerous. The refrigerant may need to be replaced or the control board repaired.
Finally, if the refrigerator is old, the compressor may have worn out. In winter, when starting in a cold room, its resource is depleted faster. In this case, it is more economically feasible to consider purchasing a new model with a suitable climate class.
Frequently asked questions (FAQ)
Is it possible to turn on a refrigerator in winter on an unheated balcony?
It is strictly not recommended. The oil in the compressor thickens, which leads to its breakdown upon startup. In addition, electronics may not work correctly at low temperatures, causing the temperature inside the chambers to rise.
Why is the water in the refrigerator warm, but the freezer is freezing?
This may indicate a malfunction of the damper that regulates the flow of cold air from the freezer to the refrigerator, or a failure of the temperature sensor in the upper compartment. A partial leak of freon is also possible.
Is it dangerous to store oil in a warm, running refrigerator?
Yes, it is dangerous. If the temperature inside exceeds +10°C, oxidation processes may begin in the oil, and if it contains water impurities or is open, bacteria may multiply. It is better to move the food to a warm place until the problem is fixed.
How does the climate class affect operation in winter?
The climate class determines the range of ambient temperatures at which the refrigerator operates effectively. Class SN (subnormal) allows operation up to +10°C, but below this threshold problems with oil and thermostats begin in most models.