The situation when the refrigerator stops freezing, but the compressor works non-stop or, conversely, is silent, often frightens owners of household appliances. In most cases, the cause is a refrigerant leak, and the only solution is a complex procedure that professionals call freon charging. Understanding exactly how this process occurs is necessary not only for those who are planning independent repairs, but also for any owner who wants to control the quality of the master’s services.
Refilling the refrigeration system is not just adding gas, as is the case with refilling a gas cylinder in the kitchen. This is a complex technological process that requires deep evacuation of the system, accurate calculation of the mass of the substance and hermetically sealed connections of all components. Errors at any stage can lead to failure of an expensive compressor or complete inoperability of the unit.
Video materials demonstrating the work of specialists allow visual assess the scale of work and equipment used. However, even with a recording before your eyes, it is important to understand the physical and chemical processes occurring inside the circuit. Refrigerants different types (R134a, R600a) require an individual approach, and violation of safety precautions can be hazardous to health.
System diagnostics and leak detection
Before starting any actions with gas, the technician must make sure there is a leak and, if possible, find its location. Simply adding freon to a system with a hole is a waste of money and time, as the gas will escape again within a few days or weeks. Primary diagnosis begins with an external examination and listening to the operation of the compressor.
Experts pay attention to how the evaporator behaves inside the freezer. If only a small area is covered with ice or it is completely absent, this is a sure sign of a lack of refrigerant. Also an important indicator is the temperature of the condenser (grid at the back): normally it should be hot evenly, but if there is a leak, it can remain cold or warm only partially.
⚠️ Attention: Using a soap solution to find leaks is effective only if there is obvious mechanical damage to the tubes. Microcracks in sealed areas often remain invisible to the eye and require the use of special equipment.
To accurately determine the location of depressurization, leak detector or the nitrogen pressure test method is used. Nitrogen is supplied to the system under high pressure, and a drop in pressure gauge readings indicates a leak. This stage is critically important, since the quality of soldering of the leak site directly affects the durability of the repair.
In some cases, especially with hidden leaks in a foamed circuit (inside the walls of the refrigerator), the search may take considerable time. The technician may decide to install an external evaporator (“crying”) if restoring the standard system is impossible or economically unfeasible.
Necessary equipment and tools
High-quality refilling of the refrigerator is impossible without a specialized set of tools. An amateur approach using cans “for refueling” often leads to damage to equipment, since such methods do not provide for vacuuming and precise dosing. The professional kit of the master includes a vacuum pump, a pressure gauge station and scales.
A vacuum pump is necessary to remove air and moisture from the system. The moisture remaining inside the circuit at low temperatures turns into ice plugs that block the capillary tube, and in combination with oil and refrigerant can form aggressive acids that destroy the compressor windings The pressure gauge station (manifold) allows you to control the pressure in the system in real time. It consists of two circuits (high and low pressure) and pressure gauges, according to the readings of which the master judges the condition of the system. For different types of freon, different hoses and pressure gauges are used, since their operating pressures are different..
The pressure gauge station (manifold) allows you to monitor the pressure in the system in real time. It consists of two circuits (high and low pressure) and pressure gauges, according to the readings of which the master judges the condition of the system. Different hoses and pressure gauges are used for different types of freon, since their operating pressures are different.
| Tool | Purpose | Criticality |
|---|---|---|
| Vacuum pump | Removing air and moisture from circuit | High |
| Gauge station | Pressure control during refueling | High |
| Electronic scales | Precise weighing refrigerant | Medium |
| Burner (gas/oxygen) | Soldering of copper tubes | High |
Another element is a burner for soldering copper tubes Typically a propane-butane mixture or oxy-acetylene equipment is used. For soldering, solders containing silver are used, which ensure high strength and tightness of the connection during vibrations and temperature changes.
☑️ Checking readiness for repair
Stage of vacuuming the refrigeration system
Vacuuming is perhaps the most important stage in the entire repair process, which is often ignored by unscrupulous craftsmen or "homemade". The essence of the process is to create a deep vacuum inside the circuit, which allows the moisture contained in the system to boil away and remove the remaining old refrigerant and air.
The procedure is performed using a vacuum pump connected to the service pipe. The pump is turned on for a certain time, depending on the volume of the system and the degree of contamination. The process usually takes from 15 to 30 minutes. The vacuum gauge readings should reach values close to -1 bar (or 750 mmHg and below).
After turning on the pump, it is necessary to close the valve on the manifold and turn off the pump to check the tightness of the system. If the pressure gauge needle begins to creep up, it means that there is a leak in the system, and all previous leak detection work was performed poorly. Re-soldering in this case, it is inevitable.
⚠️ Attention: Never try to start the compressor to create a vacuum (“self-vacuum”). This will lead to air being sucked through the shaft seals, moisture and dirt getting inside the motor, which is guaranteed to damage it in the shortest possible time.
High-quality vacuuming also checks the ability of the system to hold a vacuum. If after turning off the pump the pressure does not change within 10-15 minutes, you can proceed to the next stage. Ignoring this step leads to the formation of an “air lock”, an increase in condensation pressure and overload of the compressor.
Refrigerant charging technology
There are two main ways to charge a refrigerator: by mass and by pressure (current). The most accurate method recommended by manufacturers is filling by mass. On the back wall of the refrigerator, on the service sticker, the exact amount of refrigerant in grams is always indicated (for example, R134a - 120g).
To implement this method, a cylinder with freon is installed on an electronic scale. The master opens the valve on the cylinder and supplies gas to the system, monitoring the decrease in weight on the scale display. As soon as the weight decreased by the required value, the supply stops. This method eliminates overfilling or underfilling, which is critical for the correct operation of the capillary tube. Filling by pressure (or current) is used mainly for older models or in the absence of scales, but requires high qualifications of the master to control the pressure on the low pressure gauge and the current consumed by the compressor. the method is highly dependent on the ambient temperature and may produce errors. capillary tube.
Charging by pressure (or current) is used mainly for older models or in the absence of scales, but requires high qualifications. The technician monitors the pressure on the low pressure gauge and the current drawn by the compressor. However, this method is highly dependent on the ambient temperature and may produce errors.
Isobutane (R600a), which is used in modern refrigerators, is explosive and requires special care when soldering and refilling. Its amount in the system is usually less than that of R134a freon.
Why not? mix different types of freon?
Mixing different refrigerants (for example, R134a and R12) leads to a chemical reaction, the formation of acids and resins, which clog the filter drier and destroy the compressor windings.
Sealing the service pipe and checking
After the required amount of fron has been filled into the system, it is necessary to hermetically seal the filling fitting. To do this, a copper tube is used, which is clamped with a special tool (pipe clamp) at the very base, and then bitten off and sealed. This prevents gas from escaping when the hoses are disconnected.
The technician must quickly disconnect the pressure gauge station hose and immediately seal the hole. Speed is key here to minimize gas loss and air ingress. The soldering area is checked with a soap solution or a leak detector for bubbles.
The final check includes starting the refrigerator and monitoring its operation for some time. Evaluated:
1. Uniform heating of the condenser.
2. Cooling the evaporator in the freezer.
3. No extraneous noise.
4. Achieving the specified temperature conditions.
⚠️ Attention: If after refueling, freezing begins only at the entrance to the evaporator, and the rest of the part is cold, this is a sign of a clogged capillary tube or underfilling. Repeated diagnostics are required.
The client is recommended not to load the refrigerator with food in the first day after repair so that the system reaches a stable operating mode. It is also worth checking the operation of the thermostat: it should turn off the compressor when the desired temperature is reached.
Typical errors and risks of self-repair
An attempt to refuel a refrigerator yourself without the appropriate experience and equipment is associated with high risks. The most common mistake is ignoring replacement filter drier. This element is disposable, and when the system depressurizes, it absorbs moisture from the air. If it is not replaced, moisture will enter the capillary and cause an ice plug.
Another common problem is the use of the wrong oil. Compressors are designed to work with certain types of oils (mineral, polyester POE, alkylbenzene AB). Mixing oils or using oil with the wrong viscosity will lead to jamming of the piston group.
Unprofessional soldering can lead to the formation of an oxide film inside the tubes or, worse, to burning through the thin walls of the evaporator. In the case of aluminum evaporators in modern models, conventional soldering is impossible - argon arc welding or special solders are required, which requires expensive equipment.
In addition, working with refrigerants requires compliance with safety measures. Some gases, when in contact with an open flame, form phosgene, a chemical warfare agent. Therefore, any soldering work must be carried out with the complete removal of freon from the circuit.
Cost of work and feasibility of repair
When making a decision about repairs, it is important to take into account the economic component. Refilling with freon is only part of the cost of restoration. The price also includes diagnostics, leak detection, soldering, replacement of the filter drier and the cost of the materials themselves (freon, solder, gas).
If the leak occurs in a foamed circuit (inside the case), repairs may require the installation of an external “crying” evaporator, which spoils the appearance of the inside of the refrigerator. In older models, such repairs can be comparable in price to purchasing used equipment.
Modern refrigerators with a system No Frost and electronic control are more difficult to diagnose. A leak can be caused not only by mechanical damage, but also by corrosion of the “heat exchanger” (the heating circuit of the door perimeter), which is a design flaw in many models.
Before agreeing to repairs, inquire about the warranty on the work. High-quality repairs with filter replacement and vacuuming are usually guaranteed by a specialist for a period of 6 months to 2 years. The lack of a guarantee or the promise to “fill and forget” should alert you.
How much freon is needed to fill a regular refrigerator?
Usually, household refrigerators are filled with 30 to 150 grams of refrigerant. The exact quantity is always indicated on the service sticker located on the back wall or inside the camera. An overdose of freon is just as dangerous as its shortage, since liquid freon can get into the compressor and cause water hammer.
Is it possible to fill the refrigerator yourself without a vacuum pump?
Theoretically, using the displacement method (purging the system with freon itself), you can try to fill the circuit, but this is extremely ineffective. Without a vacuum pump, moisture and air will remain in the system, which will lead to rapid breakdown of the compressor and clogged capillary. Professional repairs without a vacuum degasser are impossible.
Why does the refrigerator not freeze after refueling?
There may be several reasons: an incorrectly calculated dose of freon (underfilling or overfilling), the filter drier has not been replaced (wet plug), the capillary tube is clogged with oxidation products, or poor-quality soldering leading to repeated leak. The compressor itself could also fail due to overheating during diagnostics.
Is it dangerous to breathe freon vapors?
Most modern refrigerants (R134a, R600a) are not toxic in low concentrations, but they displace oxygen. In a confined space, a large leak may cause suffocation. When heated with an open flame, freon decomposes, releasing toxic substances, so smoking or using an open fire near a working refrigerator is prohibited.