The appearance of extraneous sounds, whistling or uncharacteristic humming in the operation of a refrigeration unit often indicates problems in the refrigerant circulation circuit. Owners of household appliances may be faced with a situation where, after unprofessional repairs or due to a manufacturing defect, an excess amount of working substance appears in the system. Increased pressure inside the circuit creates a critical load on the compressor, which in the shortest possible time can lead to its complete failure.
Before taking any action, you must clearly understand: the refrigerant, often called freon in everyday life, is a chemical that requires careful handling. Modern models, be it Indesit, Atlant or LG, can be filled with different types of gases, each of which has unique physical properties. Independent release of freon in residential premises is strictly prohibited by environmental standards and safety regulations.
However However, understanding the processes occurring inside the refrigeration machine will help you diagnose the problem and make the right decision about calling a technician or carrying out complex manipulations in compliance with all safety precautions. In this article we will analyze in detail the physics of the process, the symptoms of excess gas and the technical nuances of working with a sealed circuit.
Symptoms and signs of excess pressure in the system
It is possible to determine that there really is too much refrigerant in the circuit by a number of indirect signs that appear in the operation of the motor-compressor. The first and most obvious symptom is an unnaturally loud noise when the unit starts up and operates. If your refrigerator begins to hum much stronger than usual, and this sound does not stop after the temperature rises, this is a reason to be wary.
The second important indicator is the thermal regime of the condenser - the same grille that is usually located on the back wall of the device. If there is an excess of freon, the condenser tubes may heat up unevenly or, conversely, be hot along the entire length, including the outlet section, which disrupts the normal condensation cycle. Overheating compressor It is also a sure sign: the motor is working with increased load, trying to push the excess mass of gas through the narrow channels of the capillary tube.
⚠️ Attention: If you observe that the compressor is running non-stop and vibrating strongly, immediately unplug the device. Continuing operation in this mode is guaranteed to lead to jamming of the piston group or combustion of the electric motor windings.
The third sign may be the formation of an ice crust on the evaporator inside the freezer or on the back wall of the refrigerator compartment, even if the No Frost system is working. Excessive pressure disrupts the boiling process of freon, and it does not have time to completely transform into a gaseous state, entering the compressor in liquid form, which causes water hammer.
- 🔊 The appearance of whistling or hissing sounds in the area of the compressor and pipelines.
- 🌡️ Abnormally high temperature of the compressor housing, which is impossible to touch with your hand.
- ❄️ Ice formation in the area of the suction tube immediately after exiting the evaporator.
- 📉 Reduced cooling efficiency during constant operation of the motor.
Causes of excess freon getting into the circuit
In factory conditions, refrigerators are refilled to the nearest gram, so the likelihood of errors on the conveyor is minimal. However, in real life, a situation with an excess of refrigerant almost always arises after human intervention. The most common reason is unqualified repairs, when a technician, without a scale for dosing, adds gas “by eye” or according to the readings of only a low-pressure pressure gauge, ignoring the current characteristics of the compressor.
Another reason may be the use of the wrong type of refrigerant when replacing. Different brands of freon, such as R134a, R600a or R407Chave different densities and operating pressures. If freon with different characteristics is mistakenly poured into a system designed for isobutane, this will lead to a pressure imbalance. Technological error When evacuation of the system, it also plays a role: if there is air or moisture left in the circuit, they create additional pressure, which is mistakenly taken for excess freon.
Sometimes users themselves try to “adjust” the refrigerator, noticing poor cooling, not realizing that the problem may be an oil leak or a dirty capillary filter, and not a lack of gas. Such actions lead to critical overflow of the system.
Required tools and safety measures
The procedure for removing excess refrigerant is classified as a high-risk job and requires specialized equipment. You cannot simply open the valve and release the gas into the atmosphere - this violates environmental standards and can be hazardous to health. To perform the operation you will need a vacuum pumpa manifold with pressure gauges, high-precision scales and a container for collecting refrigerant.
Particular attention should be paid to the protection of the respiratory and visual organs. Although modern freons are considered low-toxic, in concentration they displace oxygen, which can cause suffocation. In addition, with a sharp expansion, the gas cools to extremely low temperatures, which can lead to frostbite of the skin. It is necessary to work in a well-ventilated area, away from open sources of fire, since some types of refrigerants (for example, R600a) are flammable.
To access the system, you will need a tool for cutting copper pipes: a pipe cutter, rolling and a torch for brazing. The use of hacksaws for metal is strictly prohibited, since copper shavings that get into the circuit can permanently clog the capillary tube.
| Type of equipment | Purpose | Criticality |
|---|---|---|
| Vacuum pump | Removing air and moisture, creating a vacuum | High |
| Gauge station | Controlling pressure in the circuit (low/high) | High |
| Electronic scales | Accurate refrigerant dosage when refilling | High |
| Leak detector | Searching for leaks before refilling | Average |
Technology for bleeding freon through the Schrader valve
If a service fitting (Schrader valve) is installed in the system, the task is simplified, since depressurization of the circuit by cutting pipes is not required. This valve is a spring-loaded spool similar to a car valve. To get started, you need to connect the hose from the pressure manifold to the fitting. Make sure that the connection is tight before opening the valve on the manifold.
The bleeding process should take place slowly and under constant monitoring of the pressure gauge. A sudden release of pressure can lead to the removal of oil from the compressor along with gas, which will disrupt the lubrication of the rubbing parts. Throttle the flow is carried out by smoothly opening the valve on the manifold. It is necessary to ensure that the pressure gauge needle drops gradually.
⚠️ Attention: Never release freon in an enclosed space with a volume of less than 4 cubic meters. The gas concentration may exceed permissible limits, which will cause dizziness or loss of consciousness.
If there is no Schrader valve, its installation is a mandatory step in professional repair. To do this, a brass fitting is welded into the compressor process tube. After installing the fitting, you can manipulate the pressure without violating the integrity of the main line each time.
☑️ Procedure for relieving pressure
Removing refrigerant through a cut in the process tube
In cases where there is no service valve and it is impossible to install it, the method of cutting the compressor process tube is used. This method is more risky and requires high qualifications, since after its implementation the system will have to be soldered again. The tube is cut or sawed with a pipe cutter in a place remote from the soldering zone, so as not to damage the insulation of the windings.
After the cut, gas will begin to escape under pressure. It is important to direct the stream into a prepared container or hose led outside to minimize the entry of freon into the room. Gas release rate is adjusted by the degree of compression of the tube or by using a clamp. As soon as the pressure reaches atmospheric pressure, air may enter the system, so further actions must be quick.
The next step is vacuuming. Simply venting excess gas is not enough - it is necessary to remove the remaining freon and air trapped in the circuit. A vacuum pump is connected to the incision site and the system is evacuated until a deep vacuum is reached (usually around 200-300 microns). Only after this is the exact amount of refrigerant refilled.
Why can’t you just release the gas and seal it?
If you don’t vacuum after bleeding, a mixture of freon, air and moisture will remain in the system. When moisture freezes, it forms an ice plug in the capillary, and the air creates excess pressure and oxidizes the oil, turning it into acid, which corrodes the engine from the inside.
Evacuating and refilling the system
After the excess freon is removed, the circuit is in an unstable state. The presence of even microscopic amounts of moisture can lead to the formation of acids that will destroy the engine insulation. Therefore, the evacuation stage is no less important than pumping out the gas itself. The pump must run for at least 20-30 minutes to evaporate all the moisture from the oil and tubes.
Refilling is carried out strictly according to the weight indicated on the information plate of the refrigerator (usually located on the back wall or inside the chamber). Do not use a refrigerant cylinder without a scale. The cylinder is turned over (if the filling is in the liquid phase) or placed directly (if with gas), and the gas is supplied to the system with the compressor running or statically, depending on the type of refrigerant.
Control of correct filling is carried out not only by scales, but also by the current consumption of the compressor and the discharge temperature. Rated current should not exceed the values specified in the documentation. If after refueling the refrigerator operates quietly, the condenser heats up evenly, and the desired temperature is reached in the chamber, the procedure can be considered complete.
The final step is sealing. The process tube is clamped with a clamp, sealed with a torch, and the soldering area is checked with a soap solution or a leak detector for leaks. Only after making sure of the tightness can you install the compressor in its original place.
Frequently asked questions (FAQ)
Is it possible to release freon simply in the room by opening the tube?
Doing this is extremely undesirable. Although freon is not toxic in small doses, it is heavier than air and displaces oxygen, which can cause asphyxiation. In addition, a sudden release of gas will raise a cloud of oil dust. It is better to use a hose to vent gas out the window or outside.
How much does professional pumping and refilling cost?
The cost depends on the region and type of refrigerant. The technician's work usually includes travel, vacuuming, filling and materials. The price may vary, since tariffs for services and the cost of gases change, so it is better to check the exact amount in the service centers of your city.
Why does the refrigerator freeze after refueling, but then stops?
Most likely, there is moisture left in the system, which froze in the capillary tube, forming an ice plug. The cause may also be poor vacuuming or the presence of an air lock. A repeat procedure with careful pumping is required.
Is it dangerous to touch the escaping freon?
Yes, it is dangerous. When leaving a cylinder or system under pressure, the gas expands sharply and cools to temperatures below -40°C. This causes instant frostbite to the skin and damage to the eyes. Always wear protective gloves and goggles.
Is it necessary to change the oil in the compressor when bleeding freon?
Usually, a complete oil change is not required if the system was sealed. However, if moisture or acid gets into the compressor, the oil may turn black and lose its properties. In such cases, it is necessary to flush the system and change the oil, which only a specialist can do.