Determining the exact amount of refrigerant in the cooling system is a fundamental task when repairing or servicing air conditioning equipment. For owners of premium German equipment Liebherr this issue becomes critically important when diagnosing a leak or completely refilling the circuit is required. Unlike budget analogues, Liebherr refrigerators have a complex heat exchanger architecture, which requires strict adherence to technological standards when refueling.
Many users mistakenly believe that the volume of gas can be determined “by eye” or using standard tables for other brands, but this is a grave mistake. German engineers design a system with micron precision, where a deviation of even 5-10 grams can lead to incorrect operation of the compressor or the formation of an ice coat. Therefore, it is important to understand where to get information from and how to correctly interpret technical data.
In this article we will look in detail where to look for information about refilling, what types of refrigerants are used in different generations of equipment and why self-refilling without scales often leads to breakdown of expensive equipment. You will learn how to distinguish a factory sticker from a makeshift one and what parameters are really important for the master.
Where to find accurate information about the amount of freon
The first and most reliable place where the exact weight of the refrigerant is indicated is the factory technical sticker. It is usually located on the inside wall of the refrigerator compartment, on the back wall or on the base of the device. It is these data that are the ultimate truth for a specific modification Liebherr, since even within the same series the filling volume can vary.
On the sticker you will find several key parameters: the type of gas used (for example, R600a or R134a), its mass in grams and sometimes the test pressure. Ignoring these numbers is unacceptable. If the sticker is erased or missing, you need to look for information in the official service manual (service book) for a specific model, and not in general tables from the Internet.
⚠️ Attention: Never rely on the volume of freon in refrigerators of other brands or even other Liebherr series. The difference in the length of the capillary tube and the volume of the evaporator can be up to 30%, which is fatal for the system.
It is also worth considering that in some modern models with a system NoFrost and two cooling circuits (one for the refrigerator, the other for the freezer), freon can be distributed between two independent systems. In this case, the sticker will indicate two mass values, and they cannot be summed up for one refill.
Types of refrigerants used in Liebherr refrigerators
Historically, the German manufacturer used various types of working substances, and the transition from one type to another marked entire eras in the development of refrigeration equipment. Understanding the chemical composition of gas is important not only for refueling, but also for safety, since different gases have different flammability and toxicity.
In modern models released after 2010, isobutane (R600a)dominates. It is a natural refrigerant that has excellent cooling properties and minimal impact on the ozone layer. However, it is explosive at high concentrations, which requires special care when carrying out soldering work and vacuuming the system.
Previously, in models of the 90s and early 2000s, R134a (tetrafluoroethane) was actively used. It does not burn, but requires higher system pressure and the use of synthetic oil. Even older models could run on R12 freon, which is now prohibited for production due to environmental damage, although it can still be found in old Liebherr refrigerators.
Why can’t you mix different types of freon?
Mixing different refrigerants (for example, R134a and R600a) leads to a change in the thermodynamic properties of the mixture, an increase in pressure in the system, and destruction oil in the compressor and guaranteed failure of the unit. The remnants of the old gas must be completely removed with nitrogen.
When switching to a new type of gas, it is often necessary to replace the compressor and flush the entire system, since oils for different freons are not compatible. Mineral oil used with R12 does not work with R134a, which requires synthetic oil (POE).
Freon charging table for popular models
Below is a reference table with charging data for some common series of Liebherr refrigerators. Remember that this data is for informational purposes only, and the data on the sticker of your specific device always takes precedence.
| Refrigerator model | Refrigerant type | Charge weight (grams) | Compressor type |
|---|---|---|---|
| Liebherr CT 2931 | R600a | 55 - 65 g | Piston |
| Liebherr CN 4015 | R600a | 90 - 100 g | Inverter |
| Liebherr CBN 3956 | R600a | 115 - 125 g | Inverter |
| Liebherr TP 1720 | R134a | 110 - 120 g | Piston |
| Liebherr SBS 7212 | R600a | 140 - 150 g | Two compressors |
As can be seen from the table, the filling volume directly depends on the volume of the chambers and the number of circuits. In two-compressor models (Side-by-Side), each circuit is charged separately, and the total weight of gas can be significantly higher. For models with inverter compressor accuracy of filling is even more critical, since they are sensitive to water hammer.
⚠️ Attention: Technical characteristics and refrigerants used may vary depending on the year of manufacture and region of sale. Always check the data with the markings on your device before starting work.
Signs of a lack of freon in the system
Diagnosing a leak is a process that requires attention to detail. If your Liebherr refrigerator is no longer cold, this does not always mean that the compressor has broken down. Often the problem lies in a banal depressurization of the circuit. One of the first signs is that the compressor works almost non-stop, trying to reach the set temperature.
Visually, a leak can be suspected by swelling of the side walls of the refrigerator (in places where the evaporator is foaming) or the appearance of yellow rust spots on the rear grille. In systems with NoFrost a sign may be uneven defrosting or a complete lack of cold when the fan is running.
- 🌡️ The compressor hums continuously, but the temperature in the chambers does not drop below +10°C.
- ❄️ The freezer operates normally, but in the refrigerator heat separation (or vice versa, depending on the location of the leak).
- 🔥 The condenser grille at the back remains cold or only partially warm (at the beginning or at the end).
- 🧊 Ice appears in only one corner of the evaporator when opening the system.
If you observe these symptoms, use a sealant to fix a leak at home - a temporary and risky solution. For Liebherr equipment, where durability is valued, the correct solution is to find the leak using a leak detector and pressurized nitrogen.
Refilling process: why grams are important
The process of restoring the functionality of the Liebherr refrigerator begins not with connecting the cylinder, but with a thorough vacuum. Residual moisture and air in the system are the main enemies. Moisture reacts with oil and freon, forming acid, which corrodes the compressor windings from the inside, and the air creates an “air lock,” increasing the condensation pressure.
Filling the refrigerant must be done strictly according to the scales. Professional repairs use electronic scales with an accuracy of up to 1 gram. Filling “on pressure” or “on intuition” for modern systems with a capillary tube is unacceptable, since the static pressure (when the compressor is turned off) depends on the ambient temperature and does not indicate the amount of substance in the system.
☑️ Correct filling algorithm
After refueling, it is necessary to let the refrigerator operate and check the suction and discharge pressure, as well as the temperature in different parts of the circuit. If you fill less than the norm, the compressor will overheat; if more, there will be a water hammer or liquid reflux into the compressor, which will lead to its mechanical destruction.
Common mistakes during self-repair
Independent repair of refrigeration equipment attracts many, but the statistics of service centers are inexorable: more than 60% of devices that have been in the hands of “home craftsmen”, they receive secondary damage, often incompatible with life. The most common mistake is ignoring the replacement filter-drier.
The filter-drier is a disposable element. When the circuit is opened, it instantly absorbs moisture from the air. If you do not replace this component (copper cylinder on the circuit) during refilling, moisture will finish off the compressor in a short time or clog the capillary tube with ice.
⚠️ Attention: Using automotive kits for refilling air conditioners with a pressure gauge station without scales for Liebherr household refrigerators will lead to incorrect operation. The pressure in household systems is too low for accurate calibration with automotive instruments.
Another mistake is using the wrong oil. If you are changing the type of freon or simply adding it, make sure that the oil in the system matches the type of refrigerant. R600a and R134a require different lubricating fluids, the mixing of which turns the oil into a tar-like mass.
FAQ: Answers to frequently asked questions
Is it possible to fill a Liebherr refrigerator with freon from a can for car air conditioners?
Absolutely not. Car air conditioners use R134a (sometimes R1234yf) freon, and most modern Liebherr refrigerators use R600a (isobutane). These are different substances with different pressures and properties. In addition, the cans often contain additives and dyes that are dangerous for the capillary system of the refrigerator.
How much does professional freon refilling cost?
The cost depends on the region, model of the refrigerator and the complexity of access to the circuit. The price usually includes a technician’s visit, labor, consumables (freon, filter, solder) and vacuuming. On average, the price varies, but trying to save on calling a technician when using isobutane (an explosive gas) may cost more.
How long does the refrigerator work after a freon leak?
It will work until the pressure in the system is equal to atmospheric pressure or until the compressor burns out from overheating due to operation without cooling. However, food will begin to deteriorate within a few hours. It is impossible to operate equipment with a leak, as this leads to combustion of the motor-compressor.
Is it necessary to vacuum the system if you just add freon?
Yes, always. Any intervention in the sealed circuit requires evacuation. Even if you simply unscrewed the valve to connect the hose, air entered the system. Without a vacuum pump, it is impossible to remove this air and moisture, which will lead to previous breakdown.