Loss of cold in a cell is always stressful, because food supplies are at risk. The most common cause is a leak of refrigerant, which is the working fluid in the cooling system. Many owners, wanting to save on calling a technician, are wondering whether it is possible to perform filling with freon on their own, using instructions from the Internet.
This process is technically complex and requires specific equipment, without which it is impossible to restore the sealed circuit. You will have to not only add gas, but also find the leak, seal it and create a deep vacuum inside the system. Mistakes at any stage can lead to the final failure of the compressor or, in the worst case, to an explosion.
Before taking up a tool, you need to soberly assess your strengths and the availability of special tools. In this article we will analyze the entire technological process, from finding the hole to the final launch compressor. Read carefully, since working with gases under pressure requires strict adherence to safety rules.
Necessary tools and materials
For successful work, a standard set of household tools will not be enough. You will need specialized equipment, which is usually available from professionals, but can be purchased or rented. Without vacuum pump a pressure gauge station it is pointless to start work, since air and moisture will kill the system in a matter of hours.
The second critical element is the refrigerant itself. In modern household refrigerators, R134a or R600aare most often used. These gases are not interchangeable, and charging with the wrong freon will result in incorrect operation or a fire hazard, especially in the case of isobutane.
⚠️ Attention: Freon R600a (isobutane) is a flammable gas. Any spark when working with it can lead to a volumetric explosion in the room. You can work with it only with ideal ventilation and the absence of open flame sources.
You will also need consumables to seal the system. Copper tubing, solder and a torch are required to install the service fitting. Don't forget about the scales, since the refrigerant dosage is carried out with an accuracy of the gram, and not "by eye" by pressure.
Finding and eliminating refrigerant leaks
Simply adding gas to a system where there is a hole is a waste of time and money. Freon will disappear in a few days or even hours. The first step is always to find the location of the depressurization. It is often impossible to visually notice a microcrack on evaporator or in the foamed part of the housing.
The most reliable method is nitrogen pressure testing. The system is filled with inert gas under pressure, after which the joints and suspicious areas are coated with a soap solution. The appearance of bubbles will indicate the location of the leak. If the defect is found in an accessible place, it is sealed.
- 🔍 Visual inspection for oil stains (freon carries oil with it).
- 💨 Pressure testing with nitrogen and listening to the characteristic hissing.
- 🧼 Treatment of joints with soap emulsion to identify microbubbles.
If a leak occurs in the foam layer of the housing (tubes inside the wall often rot), repairs become economically impractical. In such cases, craftsmen often suggest installing an external evaporator (“weeping box”), which changes the aesthetics of the refrigerator, but returns it to functionality.
Why can’t you use oxygen?
Oxygen mixed with compressor oil forms an explosive mixture. If the pressure or temperature increases, a powerful explosion may occur. Use only nitrogen or dry air (in extreme cases).
Installing a service fitting and soldering
Factory refrigerators do not have valves for connecting hoses, since the circuit is designed to operate in a closed mode for the entire service life. To pump in freon, you need to cut in the service fitting. It is usually mounted on a compressor process tube or on a filter drier.
The process requires careful soldering of copper connections. The insertion site is cleaned, heated with a burner and sealed with brass or copper-phosphorus solder. It is important not to overheat the tube, so as not to burn through it, and not to underheat, otherwise the connection will leak under pressure.
⚠️ Attention: When soldering, be sure to use a damp cloth to cool nearby plastic parts and the compressor itself. Overheating of the electric motor windings can lead to a short circuit.
After installing the fitting, a pressure gauge manifold is connected to it. This device allows you to control the pressure in the system and see the evacuation process. The tightness of the assembled structure is checked by repeated pressure testing before the main stage.
Evacuation of the cooling system
The most important stage, which is often ignored by beginners, believing that they can simply bleed off the remaining old gas and immediately pump in a new one. This is a grave mistake. Air and, worse, water vapor always remain in the system. When working with freon, moisture turns into ice plugs and acid, which corrodes compressor from the inside.
A vacuum pump is used to remove non-condensable gases and moisture. It connects to a pressure gauge station and pumps out the contents of the circuit to a deep vacuum. The process should last at least 30-40 minutes, and for systems with R600a even longer due to cleanliness requirements.
☑️ Evacuation checklist
The criterion for high-quality evacuation is the stability of the pressure gauge readings after turning off the pump. If the arrow begins to creep up, it means that there is a leak in the system or moisture is actively evaporating. In this case, the procedure is repeated, sometimes with replacement of the filter-drier.
| Parameter | Normal value | Critical deviation |
|---|---|---|
| Vacuum pressure | up to -1 bar (30 inHg) | Above -0.8 bar |
| Pumpdown time | 30-60 minutes | Less than 15 minutes |
| Pressure drop after shutdown | Absent (the arrow is standing) | The arrow creeps to the right |
Calculation and charging of refrigerant
The amount of freon is strictly regulated by the manufacturer for each specific model. This information is contained on a technical sticker, which is usually located inside the refrigerator compartment or on the rear wall of the unit. Filling “by eye” or only by pressure in the system is unacceptable, since the pressure depends on the ambient temperature.
The most accurate method is filling by scale. The freon cylinder is placed on electronic scales, and exactly the same number of grams as indicated in the instructions are released into the system. For R134a, the dose is usually from 60 to 140 grams, for R600a it is even less, about 50-60 grams.
The refueling process occurs while the compressor is running. Gas is supplied slowly, in small portions, with pauses to stabilize the pressure in the system. It is important to monitor the temperature of the condenser (grid at the back) - it should warm up evenly, at about 2/3 of its height.
If you use the pressure charging method (which is less accurate), you need to focus on the current consumption of the compressor. It should not exceed the nominal value indicated on the relay or sticker. Exceeding the current indicates an overload of the motor, which is dangerous.
Completion of work and sealing
After the required amount of freon has been pumped in, it is necessary to properly preserve the system. While the compressor continues to operate, the service pipe is clamped with a special clamp (crab) a few millimeters from the soldering point. This is done so that when biting off the tube, air does not get inside.
Then the pipe is sealed. The quality of the seam is checked with a soap solution. Only after making sure that it is completely sealed can you remove the clamping tool. After this, the refrigerator is unplugged and allowed to stand for several hours to equalize the oil pressure and temperature.
⚠️ Attention: Never leave the system open or under vacuum for a long time unattended. This can lead to moisture being sucked out of the air or thin-walled evaporator tubes collapsing.
The final test run is carried out after 3-4 hours. The unit should reach temperature, turn off by thermostat, and turn on again. Cyclical operation is the main sign of serviceability after repair. If the refrigerator runs continuously without turning off, there may be not enough freon or there is an air lock in the system.
Frequently asked questions (FAQ)
Is it possible to fill a refrigerator with freon without a vacuum pump?
It is technically possible to purge the system with freon itself (gas purging), displacing air, but this is an extremely ineffective method. Residual moisture will still remain and will quickly destroy the compressor. For long-term repairs, a vacuum pump is required.
Why does the refrigerator not freeze after refueling?
There may be several reasons: insufficient amount of freon, an air lock in the system, a malfunction of the thermostat or compressor. It is also possible that the filter drier is clogged and does not allow refrigerant to pass through.
Is it dangerous to change R600a freon yourself?
Yes, it is dangerous. Isobutane is explosive. Requires non-sparking tools and excellent ventilation. If you do not have experience working with flammable gases, it is better not to take risks and call a specialist.
How often do you need to change freon in the refrigerator?
Freon is not a consumable item. In a working, sealed refrigerator, it circulates for decades without replacement. If the gas has escaped somewhere, it means there is a hole in the system that needs to be found and fixed.