To understand the operating principle of modern refrigeration equipment, it is necessary to clearly understand where exactly the working substance circulates. Refrigerant It is not located in any one specific place, but constantly moves along a closed circuit, changing its state of aggregation. The entire system is sealed, and in good condition, freon does not require refilling throughout the entire service life of the household appliance.
It is impossible to visually see the gas, since the main lines are hidden by thermal insulation or foamed in the housing. However, knowledge of the flow pattern freon allows you to diagnose many malfunctions, such as leaks or blockages of the capillary tube. In this article we will analyze in detail the path of the refrigerant from the compressor and back.
The principle of circulation of the working substance
The basis of any refrigerator is a closed cycle in which the refrigerant acts as a heat carrier. Freon takes thermal energy inside the chamber and releases it to the environment through the back wall or radiator. This process is possible due to the physical properties of gas to compress and expand under pressure.
Circulation is ensured by the operation of a motor-compressor, which creates a pressure difference in the system. In a zone of high pressure, gas condenses into liquid, and in a zone of low pressure it boils and evaporates. It is this phase transition that causes the cooling of the products.
- 🔵 The compressor compresses the gaseous freon, increasing its temperature.
- 🔴 In the condenser, the hot gas cools and turns into liquid.
- 🔵 In the evaporator, the liquid boils, actively absorbing heat from chambers.
It is important to understand that the amount of refrigerant is strictly regulated by the manufacturer. Disadvantage or excess gas leads to incorrect operation of the system and increased energy consumption. In modern models with the No Frost system, the gas path may be more complex due to the presence of additional circuits.
⚠️ Attention: Opening pipelines on your own is dangerous. The refrigerant is under pressure, and its contact with an open flame can lead to the formation of toxic compounds.
The path of freon from the compressor to the capillary
The starting point of the route is always compressor. It is the hot discharge tube that comes out through which the gas moves to the condenser. The compressor is located, as a rule, in the lower rear part of the refrigerator and is the “heart” of the entire system.
Next, the refrigerant enters the condenser. In older models, this is a coil mounted on the outer grille at the rear. In newer units, the pipes can be mounted directly into the side walls of the housing. Here the main process of heat exchange with the room air occurs.
After passing the entire condensation circuit, where the gas cools and becomes liquid, it enters the filter drier. This small cylinder is necessary for cleaning freon from moisture and microscopic contaminants. Without this component, the capillary tube would quickly become clogged with an ice plug.
From the filter, the substance enters the capillary tube. This is the narrowest section of the system, where the cross-sectional diameter is a fraction of a millimeter. Here there is a sharp drop in pressure, and the liquid refrigerant is ready to evaporate.
- 🔵 The discharge tube removes the gas from the compressor.
- 🔴 The condenser cools the gas, turning it into liquid.
- 🔵 The filter drier removes moisture from circuit.
⚠️ Attention: The filter drier is a disposable element. When repairing a system associated with depressurization, its replacement is mandatory, even if visually it looks intact.
Evaporator location and cooling zone
The lowest temperature is achieved in the evaporator. Depending on the design of the refrigerator, it may be located in different ways. In classic models, this is a channel foamed into the wall or an open tube on the back wall of the freezer.
In systems No Frost the hidden evaporator is located behind a plastic panel in the freezer compartment. This is where the refrigerant boils at low pressure, turning into a gas and actively cooling the surface of the tubes. The fan drives air through this radiator, distributing the cold throughout the entire volume.
Why is no ice visible on the walls in No Frost?
In such models, the evaporator is hidden behind a plastic partition. The ice that forms on it during operation is periodically thawed by heating elements, and water flows into the pan. Therefore, there is no ice inside the chamber, but the evaporator itself is located in the technical compartment.
After the evaporator, gaseous freon passes through a heat exchanger (if provided by the design), where it cools the return tube, and returns to the compressor. The cycle closes and the process repeats continuously until the thermostat gives the command to stop the motor.
Access to the evaporator in No Frost models requires dismantling the rear panel of the freezer. In “crying” refrigerators, the evaporator is often the inner surface of the rear wall of the refrigeration compartment itself.
Table: Main elements of the refrigerant circuit
To systematize information about where the refrigerant is located at different stages, it is convenient to use a pivot table. It will help to understand the logic of the movement of matter and its state at each point.
| System element | Aggregative state | Temperature | Pressure |
|---|---|---|---|
| Supercharger | Gas | High (+70°C...+90°C) | High |
| Condenser | Liquid / Gas | Medium (approx. +40°C) | High |
| Capillary tube | Liquid | Decreasing | Falling |
| Evaporator | Gas / Liquid | Low (from -24°C) | Low |
The table shows that critical changes occur precisely at the moment of pressure transition. Capillary tube acts as a throttle separating the high and low pressure zones. Malfunction of any of these components leads to a stop in the cooling process.
☑️ Signs of a refrigerant leak
Types of refrigerants and their features
Modern refrigerators use various types of gases. Old models produced before 2010 often ran on R12 (freon-12). This gas is safe for humans, but destructive to the ozone layer, so its production is prohibited.
Modern units are often filled with freon R600a (isobutane). This is a hydrocarbon gas that has excellent refrigeration properties and does not harm the environment. However, it is explosive when concentrated in air, which requires special care during repairs.
- 🔵 R134a is a common safe analogue of old freons.
- 🔴 R600a is an economical but flammable gas (used in 80% of new refrigerators).
- 🔵 R407C is a mixture of gases used in industrial equipment.
The type of refrigerant used is always indicated on a special sticker located on the compressor or inside the refrigeration chamber. Replacement from one type of gas to another without deep alteration of the system is impossible and will lead to breakdown.
⚠️ Attention: When working with R600a, it is strictly forbidden to use an open flame and create sparks. Repair of such systems should only be carried out in a well-ventilated area.
Diagnostics of the amount of refrigerant
How to understand that there is something wrong with the refrigerant? Since it cannot be seen, technicians rely on indirect signs and the operation of the compressor. If there is not enough gas in the system, the motor will work continuously, trying to gain temperature, but the cold will not appear.
One of the simple ways to check is tactile. When the refrigerator is working properly, the condenser (grid at the back) should be warm or hot. If the tubes are cold and the motor is humming, a leak or blockage is likely.
It is also worth listening to the sounds. Normal operation is accompanied by a quiet gurgling or hissing sound when the compressor stops. Complete silence in the pipelines while the engine is running may indicate that freon has evaporated somewhere.
For accurate diagnosis, manometric manifolds are used. They are connected to the process fitting (usually on the compressor) and indicate the pressure in the system. Normal values depend on the type of gas and ambient temperature.
Frequent problems and places of leaks
Refrigerant can only leave the circuit through an opening. Most often, leaks occur in places where tubes are soldered, where a microcrack forms over time due to vibration or corrosion. The entry points of the tubes into the foamed housing are also vulnerable.
In refrigerators with the No Frost system, corrosion of the evaporator, which is located inside the plastic box of the freezer, becomes a common problem. If you damaged the wall of the freezer with a knife during defrosting, gas could escape through this puncture.
Another vulnerable spot is the defrost circuit, which runs along the perimeter of the freezer cameras. It is heated in specific cycles to prevent freezing, and temperature changes can weaken the metal.
If you suspect a leak, don't try to simply "add" gas. Without finding and fixing the hole, the coolant will leak out again within a few days or weeks. High-quality repairs always begin with finding the place of depressurization.
Is it possible to replace the refrigerant in the refrigerator yourself?
Theoretically, this is possible if you have a vacuum pump, scales and pressure gauges, but in practice it is extremely difficult and dangerous. Especially if R600a fuel is used. An error in dosage or the presence of air in the system will lead to compressor failure.
Why does the refrigerator not freeze after a power outage?
If after a long period of inactivity or a power surge the cold disappears, there may be a water hammer in the compressor or a capillary blockage. A microcrack could also have formed through which gas escaped.
How long does the refrigerant last in the system?
In a working, sealed refrigerator, freon circulates for decades without loss. It doesn’t need “refueling” like fuel in a car. If the gas has escaped somewhere, it means that the tightness of the circuit has been broken.