Modern refrigeration units of the Korean brand LG are deservedly considered the standard of reliability, but understanding exactly how cooling occurs is necessary not only for engineers. An owner who knows the basic principles of the thermodynamics of his device will be able to operate the equipment more efficiently and notice signs of malfunction in time. The whole process is based on continuous circulation refrigerant inside a closed loop, which changes its state of aggregation under the influence of pressure.
The key element here is the compressor, which is often called the “heart” of the system. Unlike older models, where the motor worked jerkily, modern LG solutions use inverter technology to maintain a stable temperature. This means that cooling happens more smoothly, without sudden jumps, which has a positive effect on the safety of products and the noise level.
It is important to understand that cold is not created out of nowhere, but is the result of heat extraction from the internal chamber of the refrigerator. This heat exchange occurs through the evaporator, which is hidden from the user's view, but plays a critical role in the operation of the entire unit. It is here that liquid freon boils at low temperatures, turning into gas and actively absorbing thermal energy from the surrounding space.
⚠️ Attention: Any attempts to independently open the pipe system or replace the refrigerant without special equipment and a license are strictly prohibited. Freon is under high pressure, and its leak can lead to irreversible damage to the compressor.
The role of the Linear Cooling inverter compressor
The central link in the cooling chain is the compressor, and in LG technology models like this are most often used Linear Inverter. The principle of their operation is radically different from traditional piston analogues, which are constantly turned on and off, creating vibration and temperature changes. The inverter motor operates continuously, but with variable rotation speed, which allows you to maintain the set temperature with high accuracy.
When you open the door or load warm food, sensors detect an increase in temperature, and the compressor increases speed to quickly restore cold. In quiet mode, it operates at minimum power, consuming less electricity. Such a system Linear Cooling provides the stability necessary for long-term storage of perishable products.
The absence of sudden starting currents significantly extends the service life of mechanical parts. The internal structure of such compressors is simplified: fewer rubbing parts mean less wear and reduced noise levels. This is especially important for studio apartments or kitchens combined with a living room, where silence is a priority.
Refrigerant circulation cycle in the system
The cooling process is impossible without the movement of the working substance - the refrigerant, which circulates through a closed circuit of copper tubes. LG refrigerators most often use environmentally friendly gases, such as R600a (isobutane). The cycle begins with the compressor compressing freon gas, increasing its pressure and temperature to high values.
The heated gas enters the condenser, usually located on the rear wall or in the base of the unit. Here it gives off heat to the environment and condenses, turning into liquid. Moving further along a narrow capillary pipeline, the pressure drops sharply, and the liquid enters the evaporator, where the key moment occurs - boiling at low temperatures.
It is at the moment of evaporation that the refrigerant takes heat from the products. After this, the gas is sucked back into the compressor and the cycle repeats. The effectiveness of this process directly depends on the tightness of the system and the cleanliness of the condenser tubes, which require periodic cleaning from dust.
| System element | Refrigerant condition | Temperature | Pressure |
|---|---|---|---|
| Compressor (output) | Gas | High (+60...80°C) | High |
| Condenser | Liquid | Average (about room temperature) | High |
| Capillary | Liquid/Gas | Decreasing | Sharp drop |
| Evaporator | Gas | Low (-20...-25°C) | Low |
The principle of operation of the No Frost and Multi Air Flow system
In LG refrigerators with marking No Frost cooling occurs differently than in classic models with a crying evaporator. There is no direct contact of products with a cold wall. Instead, air is forced to circulate inside the chambers thanks to a system of fans and special channels.
Technology Multi Air Flow involves the supply of cold air through many holes located at different levels of the refrigerator compartment. This allows you to create a uniform temperature background throughout the entire volume, excluding overheating zones. The air is constantly mixed, which prevents the formation of condensation on the products.
The evaporator in such models is hidden behind the rear panel of the freezer. The fan forces air through the fins of the evaporator, where it is cooled, and then distributes it among the chambers. Periodically, the system automatically starts the defrostingmode, heating the evaporator to melt the frost frozen on it, which then evaporates.
Why does food dry in No Frost?
With active air circulation moisture from the surface of food evaporates faster. To avoid this, store food in containers or under film, as the system removes excess moisture from the chamber air.
An important advantage of such a system is that there is no need for manual defrosting. However, it is worth considering that a constant flow of air can lead to faster airing of products if they are not packaged. Therefore, proper organization of storage here plays an even greater role than in conventional refrigerators.
Freshness zone and precise temperature zoning
Modern LG models are often equipped with special zones for storing products with different temperature requirements. For example, the compartment Fresh Zone or DoorCooling+ allows you to maintain conditions ideal for meat, fish or vegetables. Cooling in these zones is carried out due to directed air flows.
The technology DoorCooling+ implements the supply of cold air directly to the door through additional holes in the upper part of the chamber. This compensates for the loss of cold when opening the door and ensures rapid restoration of temperature in the storage area for drinks and sauces, which is traditionally considered the warmest.
Some models use a system Smart Coolingthat includes several temperature sensors. If one of the sensors detects a local increase in heat, the system directs an additional flow of cold air to that area. This allows you to avoid a situation where food at the back wall freezes and spoils at the door.
⚠️ Attention: Do not block the ventilation holes inside the refrigerator with food. Blocking the channels Multi Air Flow disrupts circulation, which leads to incorrect operation of the sensors and overload of the compressor.
Sensors and electronic cooling control
The entire cooling process is monitored by complex electronics. The main control element is a board that reads the readings of temperature sensors located at different points in the refrigerator and freezer compartments, as well as on the evaporator. Based on these data, a decision is made on the compressor rotation speed.
If the temperature rises above the set one, the controller gives a command to increase the power. When the target values are reached, the speed is reduced to a minimum. Such accuracy is impossible without proper operation thermostats and defrost sensors. In models with Smart Diagnosis the system can independently check the operation of these components.
The user can influence the operation of the system through the control panel by selecting the “Holiday”, “Quick Cooling” or “Eco” modes. In fast freezing mode (Express Freeze), the compressor operates at maximum speed continuously for a specified time, ignoring standard pause cycles, in order to quickly freeze fresh food.
☑️ Checking the cooling system
Typical cooling problems and their causes
Despite its reliability, the cooling system may fail. Most often, users encounter insufficient cooling or a complete absence of cold. One of the common causes is freon leakage, which can occur due to mechanical damage to the tubes or corrosion of the evaporator.
Another common problem is the failure of the fan in the No Frost system. If the fan stops, the cool air stops circulating and the chamber becomes warm, although the compressor may continue to run. The water drainage channel may also freeze, which will lead to the formation of an ice plug and blockage of the airflow.
A malfunction of the temperature sensor can lead to the compressor working without stopping or not turning on at all. In such cases, the electronics receive incorrect data and make erroneous decisions. Diagnosing such problems requires the use of a multimeter and knowledge of the electrical circuits of a specific model LG.
Operating rules for maintaining cold
In order for the cooling system to work effectively for many years, it is important to follow the operating rules. Do not place the refrigerator close to the wall: for the condenser to work, a gap of at least 10 cm is required for free air circulation. Overheating the rear panel reduces heat transfer efficiency and increases the load on the compressor.
Do not load hot food into the chamber. This causes a sudden jump in temperature and humidity, causing the system to work in extreme mode and leading to the formation of excessive ice on the evaporator. Allow food to cool to room temperature before putting it in the refrigerator.
Regular defrosting (for drip-type models) or cleaning the drainage hole (for No Frost) is also required. The accumulation of dirt and ice disrupts heat transfer. Keep the door seals clean, as a loose fit leads to a constant influx of warm, moist air from the outside.
Why does the LG refrigerator hum loudly when cooling?
A loud hum can be caused by several reasons: incorrect installation (misalignment), contact of the condenser tubes with the wall or cabinet, wear of the fan bearings in No Frost system or compressor operation at high speeds when loading warm products. If the hum appears suddenly and is accompanied by vibration, you should call a technician.
How long does an LG refrigerator need to cool for the first time?
After the first turn on or long-term transportation, the refrigerator needs time to stabilize the temperature. This process usually takes from 2 to 4 hours. It is recommended to load products only after the unit has been empty for at least 2 hours and reaches the specified mode.
What does a flashing temperature indicator mean?
A flashing indicator usually signals that the temperature in the chamber has risen above the permissible limit. This can happen after loading a large amount of food or when the door is not closed tightly. If the blinking continues for more than a day with the door closed, this indicates a malfunction of the cooling system or sensors.
Is it possible to adjust the cooling strength manually?
Most LG models do not directly adjust the cooling “strength” in percentage. You set the target temperature (for example, +3°C or -18°C), and smart electronics automatically select the necessary compressor power to maintain it. The “Fast Cooling” modes only temporarily speed up this process.