Refrigerators Posis with the system No Frost have become the standard for modern kitchens, offering users comfort comparable to premium brands. The principle of their operation is radically different from classic models with a weeping evaporator, which required periodic defrosting. In this case, moisture is removed automatically, which prevents the formation of an ice coat on the inner walls of the chamber.
Understanding exactly how this mechanism functions will help owners operate the equipment correctly and avoid common mistakes. Air circulation in such units it is organized along a closed circuit, covering all shelves. This ensures uniform cooling of the products, regardless of which shelf they are on.
The equipment Posis is equipped with reliable compressors and a well-thought-out air duct system. However, like any complex mechanism, it requires careful attention to installation and loading conditions. The main difference between the No Frost system is a hidden evaporator located behind the back panel of the freezer or refrigerator compartment, and not on the visible surface.
The basic concept of air circulation flows
The basis of operation of any refrigerator with a system No Frost is forced ventilation. Unlike natural convection, where cold air simply falls down, here a special fan is responsible for the movement of masses. It forces cooled air through a system of hidden channels, distributing it throughout the entire internal volume of the chamber.
In refrigerators Posis air flows move along a strictly specified trajectory. Cold air is supplied through the top or side openings, washes the food and returns back to the evaporator through the lower ventilation grilles. This cycle ensures that there are no areas with high temperatures where bacteria could multiply.
The speed of air movement is regulated by electronics, which read the readings of temperature sensors. If you notice that food in one part of the chamber freezes more than in another, the air flow geometry may be disrupted. Often the cause is too tightly loaded shelves or placement of hot dishes.
The device of a hidden evaporator and the cooling process
The heart of the cooling system is the evaporator, which in models Posis with No Frost is hidden from the user’s eyes. It is a radiator with tubes through which refrigerant circulates. During the boiling process, freon takes heat from the internal space of the chamber, cooling the radiator fins to negative temperatures.
The moisture contained in the air and released by the products settles on the cold fins of the evaporator in the form of frost. This is a key point: ice does not form on the food or on the walls of the chamber, but on a special heat exchanger. That is why the inside of the refrigerator is always dry and clean.
The heat removal process is controlled by a thermostat or an electronic control module. As soon as the temperature in the chamber reaches the set value, the compressor turns off, but the fan can continue to work for some time to level out the temperature gradient.
⚠️ Attention: If you hear a characteristic crackling or clicking sound immediately after the compressor stops, this is normal - this is how the plastic of the case expands or contracts due to temperature changes, and the mechanism does not break.
The efficiency of heat transfer directly depends on the cleanliness of the evaporator. The layer of ice on it should be minimal and uniform. If the system is working correctly, the thickness of the ice does not exceed a few millimeters before the start of the defrost cycle. Violation of the door seal can lead to excessive moisture formation and freezing of the channels.
Automatic defrosting system (Defrost)
Since frost is constantly growing on the evaporator, it must be removed periodically, otherwise the ice mass will block the air supply to the radiator. Refrigerators Pozis have an automatic defrosting system, which is activated by a timer or according to sensor readings. The frequency of switching on depends on the model and operating conditions, but usually the cycle is repeated every 8-12 hours.
When the defrost mode starts, the compressor and fan are turned off. At the same time, the heating element (heating element) located in the lower part of the evaporator is turned on. The heat from the heating element melts the accumulated ice, turning it into water. This process takes from 15 to 40 minutes depending on the amount of ice.
Why does it sometimes seem that the refrigerator takes too long to defrost?
If you often open the door or there is high humidity in the room, more ice forms on the evaporator. The system requires additional time to completely melt the massive ice crust before starting cooling again.
The resulting melt water flows down a special chute into the drainage system. At the bottom of the refrigerator, usually above the compressor, there is a bath. Water drips onto the hot compressor housing and evaporates into the environment. Thus, the user never has to drain the water manually.
This process is controlled by a defrost sensor (defroster). It monitors the temperature of the evaporator and opens the power supply circuit of the heating element when the ice has completely melted and the temperature rises above a critical level. This prevents overheating of plastic parts and excessive energy consumption.
Typical malfunctions of the No Frost system
Despite the reliability of the equipment Posis, complex systems with many sensors and mechanical parts are subject to wear. Most often, problems are associated with a violation of the defrost cycle. If the heating element burns out or the sensor “sticks,” the ice stops melting and gradually turns into a monolithic lump that blocks the fan.
As a result, cold stops flowing into the chamber, although the compressor can work continuously. Products begin to deteriorate, and ice may appear on the back wall inside the chamber, which is an alarming signal for the No Frost system. Also, the fan itself often fails, especially if its blades touch accumulated ice.
Below is a table of the main symptoms and probable causes of malfunctions:
| Symptom | Probable cause | Necessary actions |
|---|---|---|
| Noise, humming, crackling | The fan touches the ice | Complete defrosting within 24 hours |
| Does not cool, the compressor works | Frozen evaporator | Checking the heating element and defrost sensor |
| Water on the floor under the refrigerator | Clogged drainage channel | Cleaning the drain pipe |
| The refrigerator rarely turns on | Thermostat malfunction | Replacing the temperature controller |
Diagnostics of electronic components requires special knowledge and tools, such as a multimeter. Replacing the heating element yourself is possible, but requires complete disassembly of the freezer chamber and removal of the back panel.
☑️ Diagnosis of cooling problems
The influence of the operating mode on the operation of the equipment
Refrigerator operating life Posis directly depends on how you use it. Frequent and prolonged opening of doors leads to the entry of a large volume of warm, humid air inside. The system has to spend more time and energy cooling this air, and significantly more ice forms on the evaporator.
Loading hot food is another common mistake. Steam from hot soup or compote instantly condenses on cold elements, creating an increased load on the defrosting system. In the long term, this can shorten the life of the heating element and lead to more frequent breakdowns.
⚠️ Attention: Do not store food in open containers without lids. This not only mixes odors, but also saturates the air in the chamber with excess moisture, accelerating the freezing of the evaporator.
It is also important to monitor the tightness of the door. If the seal is dirty or damaged, warm air is constantly sucked into the chamber. This causes the refrigerator to work almost non-stop, trying to maintain the set temperature. In such conditions, the No Frost system operates in extreme mode.
Rules of care and maintenance
Although the system No Frost frees you from the need for regular defrosting, minimal care is still required. It is recommended to carry out preventive defrosting of the refrigerator at least once a year. This allows you to remove contaminants that are not visible to the eye and give the system a rest.
Particular attention should be paid to the cleanliness of the drainage hole. If it becomes clogged with crumbs or mold, melt water will flow into the chamber or onto the floor during defrosting. You can clean the channel using a soft wire or a special brush, having first disconnected the device from the power supply.
Regular washing of the internal surfaces with mild detergents will help maintain hygiene and prevent the appearance of unpleasant odors. Abrasive powders and aggressive chemicals cannot be used, as they can damage the plastic and coating of the evaporator.
Following these simple rules ensures that your refrigerator Pozis will serve for many years without major repairs. The No Frost system is a convenient and reliable mechanism that, when handled with care, fully justifies the investment.
Why does a little ice still appear in the No Frost refrigerator?
A small amount of frost on the back wall or products is acceptable if the humidity in the room is very high or the door is often opened. However, if a thick crust of ice forms, this is a sign of a malfunction of the defrosting system or a loose seal.
How often should you wash the Pozis refrigerator with No Frost?
It is recommended to carry out general cleaning with defrosting 1-2 times a year. The rest of the time, it is enough to wipe the shelves and remove dirt as it appears to maintain hygiene and operational efficiency.
Is it possible to disable the No Frost function?
No, the No Frost system in Pozis refrigerators is a design feature and does not have a shutdown button. An attempt to change the operating algorithm of an electronic module without special knowledge will lead to spoilage of products and breakdown of equipment.