When operating a household refrigerator, many users notice strange sounds similar to gurgling or water pouring inside the case. This sound often causes alarm, especially if there seems to be a leak somewhere liquid. However, in a working unit there should be no external leaks, and the substance circulating inside is part of a closed loop. It is important to understand that the technical liquid in the refrigerator is not water, but a special refrigerant that is under pressure.
The question of what kind of substance provides cooling worries equipment owners who have encountered a breakdown or are simply interested in the physics of the process. Modern models, be it Indesit, LG or Bosch, use gases that, when compressed by a compressor, turn into a liquid state, and when expanded, boil, taking heat from the chambers. It is this cycle that allows you to keep food fresh for months.
In this article we will analyze in detail the composition of refrigerants, their properties and impact on human health. You will learn why The boiling point of freon is about -30°C at normal atmospheric pressure, and what happens inside the system when the compressor starts circulation. Understanding these processes will help you distinguish the normal operation of equipment from a dangerous malfunction.
The main refrigerant: composition and properties
A substance that is mistakenly called "liquid" in everyday life is correctly called a refrigerant or working fluid refrigeration machine. The vast majority of household refrigerators manufactured over the past 30 years use a group of substances known as freons. These are saturated hydrocarbons in which the hydrogen atoms are replaced by fluorine and chlorine atoms. It is these gases that provide effective heat exchange.
The physical properties of freons are selected in such a way that they easily change their state of aggregation depending on pressure. In the condenser (the black grill at the back of the refrigerator), the gas is compressed and turned into a liquid, releasing heat into the room. Then, passing through the capillary tube and evaporator inside the chamber, the pressure drops sharply and boils, turning into gas and absorbing heat from the products. This cycle is repeated endlessly as long as the refrigerator is plugged in. refrigerant boils, turning into gas and absorbing heat from the food. This cycle repeats endlessly as long as the refrigerator is plugged in.
There are several main types of gases used in modern technology. Previously, it was widely used R12, but due to its destructive effect on the ozone layer it was banned. Now manufacturers have switched to more environmentally friendly but effective analogues. For example, in older models Zanussi or Atlant you can still find R134awhich is safe for ozone, but has a greenhouse effect.
- 🧊 R134a is the most common freon in refrigerators manufactured since 2000 to 2015, non-flammable and odorless.
- ❄️ R600a (Isobutane) - a modern standard used in Samsung and LG, it is highly energy efficient, but is flammable.
- 💨 R404A - a mixture of gases, more often used in industrial freezers, but sometimes found in powerful home models.
⚠️ Attention: Although modern freons are considered safe for short-term contact, inhaling vapors in a confined space can cause suffocation or chemical poisoning. If there is a strong smell of gas, ventilate the room immediately.
The peculiarity of refrigerants is that in their normal state they are colorless and odorless. The manufacturer specifically adds odorants to the compressor oil so that in the event of a leak, a malfunction can be detected. If you smell a specific chemical smell, this may indicate depressurization of the circuit, although more often the smell comes from plastic or new products.
Types of gases in modern models
The choice of refrigerant depends on the design of the refrigerator and environmental safety requirements. Engineers are constantly looking for a balance between cooling capacity, energy consumption and environmental friendliness. In modern models, such as Beko or Haieryou can increasingly see the use of hydrocarbon compounds.
Isobutane (R600a) becomes the de facto standard for the European market. This substance has excellent heat capacity and allows compressors to be made smaller and quieter. However, it has a critical drawback - flammability. Concentrations of isobutane in air from 1.3% to 8.4% create an explosive mixture. That is why, when repairing such refrigerators (it is strictly prohibited), use an open flame or a sparking tool.
Another popular type is R134a. It replaced the ozone-depleting R12. This gas does not burn or explode, making it safer to use, but it requires higher system pressure. Refrigerators using this gas often have thicker walls and powerful compressors. In models Whirlpool and Stinol this type of refrigerant is most often found.
⚠️ Attention: Technical characteristics of refrigerants and requirements for their disposal may change depending on new environmental regulations. Always check the technical label on the back of your refrigerator for exact information about the type of gas.
There are also mixtures, for example R407C or R507which are a “cocktail” of several gases. They are used in No Frost systems, where stable operation at low temperatures is required. Such mixtures are more difficult to refill, since when there is a leak, the gas composition changes (fractionated), and simple refilling is impossible - complete removal of residues and refilling is required.
Oil in the compressor: why is it needed?
When talking about what kind of liquid is in the refrigerator, we must not forget about oil. In contrast to the refrigerant, which circulates throughout the entire circuit, compressor oil is located primarily in the motor-compressor. However, a small part of it is always present in the system, moving along with the gas flow. This is necessary to lubricate the rubbing parts of the compressor.
The oil must have the following properties: it should not freeze at low temperatures (in the evaporator) and should not foam at high temperatures (in the compressor). If the oil loses its properties or becomes too low, the compressor will jam and the refrigerator will stop working. Modern units use synthetic oils based on polyesters (POE) or mineral oils, depending on the type of freon.
It is important to understand that freon R134a is not compatible with conventional mineral oils that were used with the old R12 freon. It requires synthetic oil, since R134a is poorly soluble in mineral water. If the oil is incorrectly refilled or replaced, the system can quickly fail due to the formation of plugs in the capillary tube.
- 🛢️ Mineral oil — used with R12 freon, has a high viscosity, is not suitable for new systems.
- 🧪 Synthetic oil (POE/PAG) —necessary for R134a and R134a freons R600a, has excellent solubility and fluidity.
- ⚙️ Lubrication of rubbing pairs is the main function of the oil, preventing wear of the compressor piston group.
Water in the refrigerator: condensation or melted snow
In addition to refrigerant and oil, you can also find ordinary water in the refrigerator (H2O). It appears during operation and is not part of the working cooling system. Moisture is contained in the air that we let into the chamber every time we open the door. When cooled, this air gives off moisture, which settles on the walls in the form of condensation.
In refrigerators with manual defrosting, this condensate freezes on the back wall, forming a “fur coat”. In systems No Frost moisture settles on the evaporator hidden behind a plastic panel. The heating element (heater) is periodically turned on, which melts this ice. The resulting water flows down the groove into the drainage hole and enters a special container above the compressor, where it safely evaporates.
If you notice a puddle of water under the refrigerator or inside on the shelves, this is a signal of a malfunction. Perhaps the drainage hole is clogged and the melt water does not have time to drain away. Or the tightness of the door seal is broken, and too much warm air gets into the chamber, which the water drainage system cannot cope with.
| Type of liquid | Where it is located | Danger to humans | Color and smell |
|---|---|---|---|
| Freon (R134a, R600a) | Inside the tubes and compressor | Low (if leakage may cause suffocation) | Colorless, odorless (usually) |
| Compressor oil | In the compressor crankcase | Skin irritation, dangerous if swallowed | Transparent or yellowish, specific odor |
| Condensation (water) | On the walls, in the drainage | Safe | Transparent, odorless |
| Antifreeze (rarely) | In older models with “crying” wall | Toxic | Colored liquid (green/red) |
What happens if you mix different types of freons?
Mixing different refrigerants (for example, R12 and R134a) leads to chemical reactions, formation of acids and destruction of the insulation of the compressor windings. This is guaranteed to disable the equipment.
What to do if there is a refrigerant leak
Freon leak is one of the most common reasons why a refrigerator stops freezing. Since the circuit is sealed, the disappearance of gas means a violation of the integrity of the tubes. This can occur due to corrosion (especially in models with a foamed evaporator), mechanical damage during cleaning, or a manufacturing defect in the weld.
The first sign of a leak is often a lack of cold when the compressor is running. The engine hums continuously, trying to gain temperature, but cannot do so. In some cases, if the leak is severe, you may hear a hissing sound. However, most leaks occur slowly, through microcracks, and it is impossible to detect them by sound.
Fix the leak yourself and refill the refrigerator impossible. This requires a vacuum pump, a pressure gauge station, scales and, of course, freon itself. Moreover, the location of the leak must be found, often using a leak detector or by immersion in water (if the evaporator is removed), and then soldered. Attempts to “add gas” without eliminating the hole will only give a short-term effect.
⚠️ Attention: If you smell a strong chemical smell or see an oily stain under the refrigerator, immediately unplug the appliance and provide ventilation. Do not try to solder the pipes yourself if you are not qualified - it is life-threatening.
The restoration process looks like this: the technician cuts off the filter drier, evacuates the system (pumps out air and moisture), seals the leak, installs a new filter and refills the exact number of grams of refrigerant indicated on the technical sticker. Only after this the refrigerator will be able to work correctly.
☑️ Actions if a leak is suspected
Danger and impact on health
The issue of refrigerant safety is especially acute for families with children and pets. As mentioned earlier, modern freons are not toxic in low concentrations. However, in the confined space of a small kitchen, a large leak can reduce the oxygen concentration, which will lead to dizziness or loss of consciousness.
Freon R600a (isobutane) is especially dangerous. Since it is a propane-butane gas, it is heavier than air and spreads along the floor. Above 8% concentration in air, any spark (from a refrigerator relay, light switch, or static electricity) can cause an explosion. Therefore, manufacturers have to use explosion-proof components in the electrical circuit of such refrigerators.
When liquid freon gets on the skin (which is only possible through direct contact with the gas escaping under pressure), instant tissue frostbite occurs, similar to a burn. Therefore, when repairing, craftsmen use safety glasses and gloves. In domestic conditions, it is almost impossible to encounter the liquid phase of freon, since it instantly evaporates.
Frequently asked questions (FAQ)
Can liquid leak from an old refrigerator and why is it dangerous?
Compressor oil can leak from an old refrigerator (if the housing is broken motor) or water (condensate). The oil has an unpleasant odor and can be toxic if ingested, but it cannot just lie on the floor - it is viscous. If you see a colored liquid (green or red), it could be antifreeze from the cooling system of some older models, but in 99% of cases only freon gas circulates inside, which is not visible.
Why does the refrigerator gurgle even when it is not working?
The sound of gurgling or liquid pouring is absolutely normal. It occurs due to the fact that the refrigerant (freon) in liquid and gaseous states continues to move through the tubes under the influence of gravity and residual pressure, even when the compressor is turned off. This is not a sign of a breakdown.
What does freon smell like from a refrigerator?
Freon itself has no odor. However, manufacturers often add odorants to the system so that leaks can be detected. The smell may resemble vanilla, chloroform, or simply “chemicals.” If the smell is strong and similar to ammonia, perhaps the problem is not in freon, but in the products or wiring.
How much does it cost to fill a refrigerator with gas?
The cost depends on the type of freon and the complexity of the work. Refilling R600a is usually more expensive due to the need for explosion-proof equipment and precise dosing. The price also includes the cost of evacuating the system and replacing the filter drier. Only a technician can tell you the exact amount after diagnosis.
Does freon need to be changed after its service life?
No, freon is a closed-cycle working fluid. If the system is sealed, the gas is not consumed and does not age. It needs to be changed or added only in case of leakage or after repair of the circuit. In a working refrigerator, freon lasts as long as the unit itself.