It is impossible to imagine a modern refrigerator without a refrigerant, which is often called freon. This substance is the heart of the cooling system, allowing you to keep food fresh for a long time. Without it, any, even the most expensive unit, would turn into an ordinary kitchen cabinet.
Owners of household appliances are often faced with a situation where the compressor runs continuously, but no cold appears inside the chamber. In most cases, the cause is trivial Freon leak, requiring the intervention of professionals. Understanding how this gas works and why it can disappear will help you diagnose the problem faster and avoid unnecessary expenses.
Historically, the term “Freon” has become a household word, although technically it is only a trademark of the DuPont company. Today, this name refers to a whole group of saturated fluorinated hydrocarbons that have the necessary thermodynamic properties for effective heat removal.
The principle of operation of the refrigerant in the cooling system
The basis of the operation of any household refrigerator is based on the physical property of liquids to absorb heat during evaporation and release it when condensation. Refrigerant circulates in a closed circuit consisting of a compressor, condenser, capillary tube and evaporator. The engine compresses the gaseous substance, increasing its pressure and temperature.
Next, the heated gas enters the condenser, usually located on the rear wall of the unit. Here it cools and turns into a liquid state, giving off heat to the environment. Passing through a narrow capillary tube, the pressure drops sharply and the liquid boils at low temperatures. This process occurs in evaporatorwhich cools the interior of the chamber.
⚠️ Attention: Freon is not consumed during operation, like fuel in a car. If your refrigerator runs out of gas, this means a violation of the tightness of the circuit, which requires searching for a puncture or fistula.
The cycle is repeated continuously until the thermostat registers the achievement of the set temperature. It is important to understand that the system is under pressure, and any manipulation with it without special equipment is strictly prohibited.
The main types of refrigerants in household appliances
Over the decades of development of the refrigeration industry, the chemical composition of the gases used has changed. This was due to both increased energy efficiency and environmental requirements to protect the ozone layer. Modern models use safe mixtures, but knowledge of their type is important when servicing.
In old Soviet and post-Soviet models, R12 (difluorodichloromethane) was often used. It had excellent cooling performance, but was considered hazardous to the environment. Now its use is completely prohibited by international protocols, and when repairing old units it is replaced with modern analogues.
The most common today is R134a (tetrafluoroethane). This gas does not destroy the ozone layer and is widely used in dual-compressor models and refrigerators with the No Frost system. It is fireproof, but requires the use of synthetic oil to lubricate the compressor, which makes the system sensitive to moisture.
In the last decade, manufacturers such as Liebherr, Bosch and Indesithave massively switched to isobutane R600a. This is a hydrocarbon gas that has excellent cooling performance with minimal energy consumption. However, it is explosive at high concentrations, which requires special care when carrying out welding work during repairs.
Why can’t you mix different types of freon?
Mixing different refrigerants (for example, R134a and R600a) leads to an unpredictable chemical reaction, pressure changes in the system and possible compressor failure. In addition, different types of oils are used for different gases, which can coagulate upon contact.
Comparative table of freon characteristics
For clarity, consider the key differences between the main types of gases used in household appliances. This data will help you understand why it is important for the technician to know the brand of your refrigerator before starting work.
| Refrigerant type | Chemical formula | Safety | Application |
|---|---|---|---|
| R12 | CF2Cl2 | Safe, but harmful for the environment | Old models (before 2000) |
| R134a | CH2FCF3 | Fireproof | Modern two-compressor |
| R600a | C4H10 | Explosive | Most new models |
| R407C | Mixture | Conditionally safe | Industrial and large refrigerators |
As can be seen from the table, modern gases require more stringent compliance with safety precautions. This is especially true isobutane R600a, which, with a concentration in the air of only 13%, can ignite from a spark. That is why repairs of such refrigerators are often carried out using nitrogen to purge the system before sealing.
The choice of oil also depends on the type of freon. For R12, mineral oil was used, which is not hygroscopic. R134a and R600a require synthetic oil (polyester), which instantly absorbs moisture from the air. Moisture entering a system with synthetic oil leads to the formation of acid, which corrodes the motor windings from the inside.
Signs of a freon leak and diagnostics
You can determine that there is not enough refrigerant in the system by a number of indirect signs. The most obvious symptom is the compressor running without shutting down. The temperature sensor cannot detect cold, so the motor tries to compensate for the lack of freon by continuous operation.
The second sign is the absence of cold or its insufficient level. In two-chamber models with one compressor, food in the freezer may freeze, but the refrigerator compartment will be warm. In systems No Frost you can often hear that the fan is running, but no cold air comes out of the air ducts.
It is extremely difficult to visually detect a leak, since the gas is colorless and odorless. However, oily spots may appear at the pipe connections or on the evaporator. Since freon circulates along with the oil, the release of gas is often accompanied by the release of lubricant to the outside.
- 🔊 Constant hum: The compressor hums 24 hours a day without rest cycles.
- ❄️ Heat in the chamber: Products spoil, despite the maximum setting of the thermostat.
- 💧 Oil traces: Grease stains on the rear grille or inside the chamber near the wall.
- 🧊 Ice coat: In models with a drip system, a huge lump of ice may form in one corner, and the rest of the evaporator will warm.
There is also a diagnostic method using a soap solution, but it is effective only for obvious, large damage, which is often visible without it. To find microcracks, technicians use an electronic leak detector or an ultraviolet oil additive.
⚠️ Attention: Do not try to find a leak by piercing the tubes or removing the back panel yourself. You can damage the evaporator foamed into the housing, which will make repairs economically unfeasible.
Why leakage occurs: the main reasons
The sealed circuit of the refrigerator is designed for the entire service life of the unit, but external factors can compromise its integrity. One of the most common reasons is corrosion. Moisture that gets on metal elements (especially in the lower part, where condensation accumulates) slowly corrodes the tubes.
Mechanical damage also occurs quite often. Owners may pierce the evaporator with a knife when trying to remove frozen food or ice. The aluminum from which modern evaporators are made is very soft and is damaged even by a slight touch with a sharp object.
Another reason is a factory defect or poor-quality soldering of connections. Over time, the vibration of a running compressor can lead to microcracks at the joints of copper tubes. It is also worth mentioning a clogged system, which is not formally a leak, but gives similar symptoms and requires similar restoration actions.
☑️ Diagnostics before calling a technician
The process of refueling and restoring the system
Repairing the cooling system is a complex technological process that cannot be performed at home conditions. It requires a vacuum pump, a pressure gauge station, a scale and a torch. First, the technician must find and repair the leak.
If the foamed evaporator is damaged, it is often necessary to install an external (“crying”) evaporator inside the chamber or on the back wall. After eliminating the physical malfunction, the system is evacuated. This is a critically important stage: it is necessary to remove all air and moisture from the tubes.
Evacuation: -0.98 bar (minimum 15-20 minutes)Only after creating a deep vacuum is refilling dosed quantity freon. The amount of gas is measured to the nearest gram, since an excess or lack of refrigerant will lead to incorrect operation of the refrigerator. At the end, the process pipe is sealed and the system is checked for leaks.
The cost of such repairs consists of the work of the technician, the cost of materials (freon, oil, filter drier) and the difficulty of accessing the damaged unit. In some cases, especially with corrosion, it is cheaper to buy a new refrigerator than to restore an old one.
Frequently asked questions (FAQ)
Is freon from the refrigerator dangerous for humans?
Modern freons (R134a, R600a) in small quantities contained in household refrigerator, non-toxic to humans. However, when heated strongly, they can release harmful substances. R600a (isobutane) is explosive, so if you smell gas in the room, you should ventilate the room and do not turn on electrical appliances.
Is it possible to fill a refrigerator with freon yourself?
Theoretically, it is possible if you have the equipment, but in practice this is impossible without skills. You need to find the leak, solder it, pump out the air with a vacuum pump and fill it strictly according to the scale. Without a vacuum, the system will fail in a few days or hours due to moisture.
Why did the refrigerator stop freezing after defrosting?
Most often this is due to damage to the evaporator with a sharp object while cleaning the ice. If you heard a hissing sound or saw an oil stain, there was a freon leak. Less commonly, the cause may be a burnt-out thermostat or start relay.
How long does freon last in a refrigerator?
In a working, sealed circuit, freon lasts indefinitely (infinitely). It is not consumed and does not age. If the gas has disappeared somewhere, then there is a hole in the system that needs to be found and sealed.
Which freon is better: R134a or R600a?
R600a is more economical and quieter, allowing you to make the walls of the refrigerator thinner. R134a is considered safer in terms of ignition, but requires a more powerful compressor. Both options are reliable with proper maintenance.