The question of what exactly the gas used in household refrigerators is called often arises among equipment owners when problems with cooling or characteristic hissing occur. In everyday life, this substance is called freon, but this is only a trade name for a whole group of chemical compounds known as refrigerants. Modern models may contain substances that are completely different in chemical composition, and they absolutely cannot be confused, since not only the performance of the unit, but also the safety of operation depends on this.
Understanding exactly which refrigerant gas circulates in the circuit of your equipment is necessary not only for repair technicians, but also ordinary users. This knowledge helps to correctly assess the risks of tube damage and understand why some gases are lighter than air and others are heavier. In this article we will analyze in detail the main types of substances, their labeling and physical and chemical properties, which directly affect the energy efficiency of your appliance.
Main types of refrigerants in household appliances
Historically, the refrigeration industry has gone through several stages of changing the types of workers bodies. For a long time, substances designated by the abbreviation R12 (difluorodichloromethane) were considered the standard. They were effective, but caused enormous damage to the ozone layer of the planet. That is why their production was almost completely stopped, and they were replaced by more environmentally friendly, but often more difficult to handle analogues.
Today, two main types of substances can most often be found in modern household refrigerators. The first is R134a (tetrafluoroethane), which became a mass standard in the late 90s and early 2000s. It does not deplete the ozone layer, but has a high global warming potential. The second, and most common in modern technology, is R600a (isobutane), which is a hydrocarbon and has excellent refrigeration properties with small filling volumes.
⚠️ Attention: Never try to determine the type of gas only by smell or appearance. Refrigerants are colorless in their normal state, and some are odorless, although odorants are often added to them to detect leaks.
The choice of a specific substance depends on the compressor design, chamber volume and energy requirements. Engineers choose working fluid so as to ensure maximum heat transfer efficiency. It is important to understand that different gases require different oils to lubricate the compressor, and mixing them can lead to the formation of acids that destroy the system from the inside.
Characteristics of isobutane (R600a)
The most popular refrigerant in modern models, especially those manufactured in Europe, is isobutane. On labels it is designated as R600a. This substance belongs to the class of natural hydrocarbons, which makes it environmentally friendly: it does not destroy the ozone layer and has minimal global warming potential. However, it has one critical feature that every user should be aware of.
The main danger R600a is its high flammability. Unlike its predecessors, isobutane forms an explosive mixture with air at a certain concentration. That is why refrigerators running on this gas use special explosion-proof starting relays and compressors with a sealed housing that prevents sparking.
Despite the risks, R600a has excellent solubility in oil, which allows you to use a smaller amount of substance to achieve the same refrigeration effect. This makes the system quieter and more economical. If you see a warning sign in the form of a flame on the back wall of your unit, it means that this flammable gas is circulating inside.
⚠️ Attention: If there is a smell of gas in the room where there is a refrigerator marked R600a, turn on the lights or electrical appliances. It is necessary to immediately ventilate the room and call a technician.
Features of tetrafluoroethane (R134a)
The second most common substance is R134a. This gas replaced R12 freon and has long been the standard for many manufacturers, including large American and Asian equipment. It belongs to the group of hydrofluorocarbons (HFC) and, unlike isobutane, is absolutely non-flammable and non-toxic under normal operating conditions.
However, R134a has its drawbacks. It requires higher system pressure to operate effectively, which places additional stress on the compressor. In addition, this gas is sensitive to the presence of moisture in the circuit. Even a minimal amount of water can lead to the formation of ice plugs in the capillary tube, completely blocking circulation.
To lubricate compressors operating on R134asynthetic polyester oils (POE) are used, which have high hygroscopicity - the ability to absorb moisture from the air. This imposes strict restrictions on the time of repair work: the system should not be open for more than 15-20 minutes.
Why is R134a being replaced by isobutane?
R134a has a high global warming potential (GWP), which makes it less environmentally friendly compared to R600a. In addition, isobutane provides better energy efficiency with a smaller amount of substance in the circuit, which reduces the cost of production.
When switching from one type of gas to another (for example, when retrofitting old systems), a complete oil change and thorough vacuumization of the system are required. Simply adding a new refrigerant to the old circuit is unacceptable, since chemical incompatibility of oils will lead to rapid failure of the compressor.
How to find out what kind of gas is in your refrigerator
The most reliable way to determine the type of refrigerant used is to study the technical documentation or the factory sticker. Each household refrigerator is equipped with an information plate, which is usually located on the inner wall of the chamber, on the door or on the rear metal panel of the case. It is there that the manufacturer indicates all the critical parameters.
You need to find the field labeled "Refrigerant" or "Refrigerant". The marking will be indicated next to it, for example, R600a or R134a, as well as the amount of the substance in grams. This information is necessary for the technician in case of repair, since filling with the wrong gas can lead to an explosion or ineffective operation.
☑️ Where to look for information about gas
If the sticker is worn off or missing, you can refer to the year of manufacture of the model. Equipment manufactured before 2000-2002 is most likely filled with R12 or transitional R134a. Models released after 2010, especially narrow bodies, are most often used R600a. However, only a visual inspection or analysis by a specialist will give an accurate answer.
| Parameter | R12 (Freon) | R134a (Tetrafluoroethane) | R600a (Isobutane) |
|---|---|---|---|
| Flammability | Non-flammable | Non-flammable | High (explosive) |
| Toxicity | Low | Low | Low (but displaces oxygen) |
| Effect on ozone | Destroys | Safe | Safe |
| System pressure | Average | High | Low |
| Oil type | Mineral | Synthetic (POE) | Mineral |
Signs of leakage and health hazards
The refrigerator's sealed circuit is designed to last for decades without refilling. However, mechanical damage, corrosion or vibration can lead to depressurization. You can understand that the gas has evaporatedby indirect signs: the compressor works continuously without turning off, but the temperature in the chambers does not drop below room temperature, or there are no characteristic warm and cold zones on the rear radiator grille.
Various factors pose a danger to humans. Although modern refrigerants are considered low toxic, in a confined space a high concentration of gas can cause asphyxiation by displacing oxygen. In the case of R600a the risk of ignition in the presence of a spark is added. Old freons, when heated to high temperatures (for example, in a fire), can disintegrate to form phosgene, a chemical warfare agent.
⚠️ Attention: If you hear hissing or smell a sweetish chemical smell, immediately leave the room and provide fresh air. Do not try to solder the tubes yourself without bleeding off any remaining gas.
A common cause of leaks is corrosion of the evaporator in the freezer, especially if you defrosted the refrigerator with sharp objects. Also vulnerable are tube welding areas and foamed areas, where microcracks can form due to vibration. Visual inspection often does not produce results, so technicians use leak detectors or the nitrogen pressure method.
Refilling technology and the need for vacuuming
The process of restoring the functionality of the refrigerator, known as refilling, is a complex technical procedure that requires special equipment. You cannot simply “add gas”: the system must be absolutely clean and dry. First, the technician performs diagnostics, then, if necessary, replaces the filter-drier and compressor, after which the most important stage follows - evacuation.
Evacuation is necessary to remove air and, most importantly, water vapor from the circuit. Moisture in the system is enemy number one. In the capillary tube, where a sharp expansion of gas occurs, water freezes, forming an ice plug that blocks circulation. In addition, moisture reacts with oil and refrigerant, forming aggressive acids.
Evacuation process:1. Connecting the vacuum pump to the service connection.
2. Creating a vacuum of up to 200-300 microns.
3. Hold under vacuum for 30-60 minutes.
4. Control of pressure growth (leakage test).
Only after reaching a deep vacuum is charging with a precisely measured amount of refrigerant carried out. In this case, scales are an important tool, since a deviation of even 5-10 grams can disrupt the operation of the entire system. For R600a the mass filling method is used, and for R134a sometimes control by pressure and temperature is allowed, but the weight method is more accurate.
Modern refueling stations allow you to automate the process, controlling suction and discharge pressure in real time. This allows the technician to fine-tune the system to the specific environmental conditions and the state of the heat exchangers of your refrigerator.
Frequently asked questions (FAQ)
Is it possible to fill the refrigerator with lighter gas?
Absolutely not. Lighter gas is a mixture of propane-butane fractions with impurities, not intended for use in the refrigeration cycle. The use of such gas will lead to destruction of the compressor, clogging of the capillary system and a high risk of explosion. Use only certified refrigerants with appropriate markings.
Why did the refrigerator stop freezing after being idle?
If the refrigerator was turned off for a long time, oil could drain into the circuit. When turned on, the compressor tries to pump liquid, which can lead to water hammer. An ice jam could also form due to moisture. Defrosting for 24 hours and possibly recharging the system is required.
Is it dangerous to breathe freon vapors?
Short-term inhalation of small concentrations of modern refrigerants (R600a, R134a) usually does not lead to severe poisoning, but can cause dizziness or nausea. However, in high concentrations they displace oxygen, causing suffocation. In the event of a fire, freon combustion products are toxic.
How much does it cost to refill a refrigerator with gas?
The cost depends on the type of gas, scope of work and region. Refilling with R600a is often cheaper due to the small volume of the substance, but requires more stringent safety precautions. The price consists of the cost of travel, materials (gas, oil, filter) and the complexity of the work to find the leak.
Is it necessary to change the gas in the refrigerator after the expiration date?
No, in a working sealed circuit, the refrigerant circulates for decades without loss of properties and does not require replacement “on a schedule.” If the refrigerator stops cooling, it means that a leak has occurred, and the gas should not be “changed,” but the seal should be restored and refilled.