Many owners of household appliances, faced with loss of cold or characteristic hissing, wonder: what is the correct name for the liquid that circulates inside the refrigerator system? In everyday life it is often called simply “coolant”, but the technically correct name is refrigerant or, using a more common term, freon. This substance is the “blood” of the refrigeration unit, without which the function of cooling products is impossible.
It is worth immediately clarifying an important physical nuance. Unlike antifreeze in a car, which remains in a liquid state, the working fluid of the refrigerator constantly changes its state of aggregation. It changes from liquid to gas and back again as it passes through the compressor, condenser and evaporator. It is this cycle that allows heat to be removed from the inner chamber and released to the outside.
Understanding what exactly is in the tubes of your refrigerator is critical when diagnosing problems. Different types of gases require different equipment for refilling and have different environmental classes. Modern refrigerants (R600a) are explosive, unlike old freons, which requires special care when repairing. Next we will analyze in detail the types of substances, their properties and signs of the need for replacement.
Chemical nature and types of refrigerants
What is popularly called “refrigerator liquid” is actually a group of chemical compounds. Historically, the most famous brand became DuPont Freon, so the name became a common noun for all refrigerants. However, the chemical composition of these substances has changed over the decades for the sake of efficiency and environmental safety.
In old models of refrigerators produced before the mid-90s, R12 (difluorodichloromethane) was widely used. This substance did an excellent job of cooling, but had enormous destructive potential for the Earth's ozone layer. Its leakage was considered normal during dismantling, which is now strictly prohibited by international protocols. Modern analogues are devoid of chlorine and are less harmful to the atmosphere.
Today, two main types of substances dominate in household appliances. The first one is R134a, which replaced the R12. It is ozone friendly but has a high global warming potential. The second, and most common in modern models (especially built-in and European brands) is R600a (isobutane). It is a hydrocarbon gas that is more efficient and cheaper to produce, but requires the highest level of sealing.
⚠️ Warning: Never try to determine the type of gas by smell or color. Refrigerants are colorless and generally odorless (except for added odorants in some industrial blends). The type of substance is indicated only on the technical sticker of the compressor.
The difference in chemistry also dictates the difference in approaches to maintenance. While R134a requires synthetic POE oil, R600a often uses mineral oil. Mixing oils or using the wrong refrigerant will lead to the formation of acids inside the circuit and rapid failure of the compressor. Therefore, knowing the exact markings is the first step to successful repairs.
Why can’t you mix different types of freon?
Mixing different refrigerants (for example, R134a and R600a) leads to unpredictable chemical reactions, changes in pressure in the system and the formation of explosive mixtures. In addition, the compressor will not be able to operate in the designed mode, which will cause it to overheat and wedge for several hours or days.
Functional purpose and principle of operation
The main task of the refrigerant is the transfer of thermal energy. The liquid boils at very low temperatures when the pressure in the system drops. Passing through a thin evaporator tube inside the freezer, it actively absorbs heat from the air, turning into steam. This vapor is then compressed by a compressor, heating up even more, and enters the condenser (grid at the back), where it releases heat into the room and becomes a liquid again.
The effectiveness of this process depends on the physical properties of the particular substance. Boiling point at atmospheric pressure, R600a is about -11°C, and R134a is about -26°C. This means that they behave differently in the system. Engineers design the length of the capillary tube and the volume of the compressor strictly for a specific type of gas. Replacing one with another without recalculating the entire system is impossible.
It is important to understand that the refrigerant is not consumed during operation, like gasoline in a car or water in a kettle. This is a closed system. If your refrigerator runs out of “liquid,” this means only one thing: depressurization has occurred. A microcrack has formed somewhere, through which the gas has escaped into the atmosphere.
The circulation of the substance is ensured by the pressure difference created by the motor-compressor. In one part of the circuit (high pressure) the substance is in a compressed liquid state, in the other (low pressure) - in a rarefied gaseous state. An imbalance, for example, the presence of air or moisture in the system, completely stops the refrigeration capacity.
Signs of a leak and the need for refilling
How can you tell that “liquid” has left the system? The most obvious sign is a gradual or sudden increase in temperature in the chambers. Food begins to spoil, the ice in the freezer melts. However, before committing a freon leak, it is worth ruling out other causes: thermostat failure, compressor malfunction, or a simple lack of electricity.
The second sign is the operation of the compressor. If there is a refrigerant leak, the engine may run non-stop, trying to get up to temperature, but not turning off. In other cases, if the leak is complete, the compressor may not start at all or may turn on for a couple of seconds and click (the thermal protection relay is triggered). This happens because the gas also cools the motor windings, and without it, rapid overheating occurs.
Visually it is extremely difficult to detect a leak, since the gas evaporates instantly. However, traces of oil can sometimes be seen where R134a or R12 exits. Since the refrigerant circulates along with oil to lubricate the compressor, when the tube ruptures, the oil flows out, leaving a characteristic greasy stain.
- 🌡️ The temperature in the chamber is higher than the set temperature, the products thaw.
- 🔊 The compressor hums continuously or, conversely, is silent and clicks.
- 💧 Traces of an oily liquid are visible on the floor or near the back wall.
- ❄️ There is no uniform layer of frost on the evaporator (inside the freezer), there are only individual islands.
⚠️ Attention: If you smell it burnt wiring or plastic, immediately unplug the refrigerator. Continuing to operate when there is a leak and overheating of the compressor can lead to a fire.
It is almost impossible to diagnose a leak at home without special equipment (a leak detector or a soap solution with the circuit removed). Therefore, if you observe the symptoms described, you need to call a specialist with a pressure gauge manifold. It will connect to the service fitting and see if there is pressure there.
Replacement technology and equipment used
The process of restoring the functionality of the refrigerator, colloquially called “charging freon,” is a complex engineering procedure. It does not come down to simply adding gas from a cylinder. First of all, the technician must find the leak, eliminate it (solder or replace the tube) and, what is critically important, evacuate the system.
Evacuation is necessary to remove air and, most importantly, moisture. Water that enters the system along with air freezes in the capillary tube at low temperatures, forming an ice plug. This blocks the circulation of refrigerant. In addition, moisture reacts with oil and freon, forming aggressive acids that corrode the compressor windings from the inside.
To carry out the work, the following set of tools is used:
1. Vacuum pump — creates a deep vacuum in the circuit.
2. Gauge manifold —allows control the pressure during injection.
3. Electronic scales —for refrigerant dosage accurate to the gram.
4. Gas burner —for soldering copper tubes in a nitrogen environment (so that scale does not form inside).
| Parameter | R134a (Tetrafluoroethane) | R600a (Isobutane) | R12 (Obsolete) |
|---|---|---|---|
| Chemical group | Hydrofluorocarbon (HFC) | Hydrocarbon (HC) | Chlorofluorocarbon (CFC) |
| Ozone Harm Potential | 0 (Safe) | 0 (Safe) | High (Prohibited) |
| Explosive | Non-flammable | Explosive | Non-flammable |
| Oil type | Synthetic (POE) | Mineral | Mineral |
The charging process takes from 40 minutes to 2 hours, depending on the complexity of access to the circuit and the type of refrigerant. They work especially carefully with R600a: due to its explosion hazard, all work is carried out in well-ventilated areas, away from open fire, and the amount of gas is limited (usually up to 150 grams in household models).
Is it possible to refuel the refrigerator yourself
On the Internet you can find many videos where enthusiasts try to refuel the refrigerator with their own manually, using car kits or cans of freon. Experts categorically do not recommend repeating this experience. The main problem is not the difficulty of connecting the hose, but the inability to create the correct vacuum and accurately dose the substance.
Handicraft filling “by eye” or by pressure (without weighing) leads to air remaining in the system. This causes an “air lock” effect, increased discharge pressure and, as a result, rupture of the condenser or breakdown of the compressor. In addition, cylinders sold in regular stores often contain mixtures of unknown quality that may be incompatible with the oil of your unit.
Another factor is legal and environmental. The release of freon into the atmosphere is prohibited by law in many countries. Professional services are licensed to work with refrigerants and have equipment for their disposal or recovery. Self-repair will deprive you of the warranty on the equipment and may cost more, since after an unsuccessful attempt you will have to replace the burned-out compressor.
☑️ Check before calling a technician
Environmental regulations and the future of refrigerants
The refrigeration industry is under constant pressure ecologists. The Kigali Amendment to the Montreal Protocol dictates the phasing out of fluorinated gases with high global warming potential (GWP). That is why R134a, which until recently was the standard, is gradually being replaced by more environmentally friendly, but difficult to handle analogues.
The future belongs to natural refrigerants (Natural Refrigerants). In addition to the already mentioned isobutane (R600a), it is increasingly used on an industrial scale and in large commercial refrigerators. CO2 does not deplete the ozone layer at all and has a GWP of one, which makes it ideal from an environmental point of view, although it requires operation at very high pressures. ammonia (R717) And carbon dioxide (R744). CO2 does not deplete the ozone layer at all and has a GWP of one, making it ideal from an environmental point of view, although it requires operation at very high pressures.
For the end user, this means that the repair of older models that work at R12, will become increasingly more expensive due to gas shortages (remaining inventories or recovered gas). Owners of such equipment should think about replacing the unit with a modern one that will save energy and use safe R600a.
⚠️ Attention: Technical regulations and the availability of certain types of refrigerants may vary depending on the country and year. Before ordering a service, check with the specialist what gases he works with and whether they are officially available.
Frequently asked questions (FAQ)
How much freon is needed to refill a regular refrigerator?
The amount of refrigerant is strictly individual for each model and is indicated on the factory tag (usually on the compressor or inside the chamber). Weight can vary from 30 to 150 grams. An overdose is just as dangerous as an underfill, so refilling is done only by scale.
Can freon run out on its own without a hole?
No, it cannot. The refrigerant circulates in a closed, sealed circuit. If there is no gas, it means that a hole has formed somewhere (microcrack from corrosion, mechanical damage, poor-quality factory soldering). Freon is not a consumable material.
What is the danger of inhaling freon vapors?
Most modern refrigerants are heavier than air and displace oxygen. In high concentrations they cause suffocation. In addition, when exposed to an open flame, some types of freons can decompose to form toxic phosgene. R600a at a high concentration in the air forms an explosive mixture.
Why does the refrigerator freeze worse after refilling?
There may be several reasons: there may be air or moisture left in the system (poor evacuation), the type of oil is incorrectly selected, the capillary tube or filter drier is clogged, or the dose of refrigerant does not correspond to the norm. Repeated diagnostics are required.
Is it necessary to change the oil when filling with freon?
During scheduled refueling due to a leak, the oil is usually not changed, since it remains in the system. However, if the compressor has been changed or serious depressurization has occurred with moisture ingress, replacing the oil and filter-drier is mandatory.