The situation when the refrigerator stops cooling food, and the compressor runs almost non-stop, often indicates a refrigerant leak. Owners of household appliances, faced with such a problem, often wonder about restoring the unit’s functionality on their own. The process of replenishing the system with refrigerant is technically possible, but it requires specific equipment and a deep understanding of thermodynamics.
Before taking active steps, you need to realize that charging with freon is only the final stage of a comprehensive repair. Simply adding gas to a leaky system is pointless, as it will evaporate again after a short time. The primary task is to find the place where the circuit is depressurized, solder it and then check for strength.
In addition, modern models often use mixtures of refrigerants, such as R600a or R134awhich require strict dosage and high-quality vacuuming. Errors at the preparation stage can lead to failure of an expensive compressor or the formation of ice plugs in the capillary tube. In this material, we will analyze in detail the technological process of restoring the system.
Diagnostics of leaks and preparation of equipment
The first step in restoring the functionality of the refrigerator is to accurately determine the fact of the leak and localize the damaged area. Often a visual inspection does not produce results, so craftsmen use a soap solution or special electronic leak detectors. Fistula detection is critically important, since without eliminating it, further work becomes meaningless.
After finding and sealing the hole, it is necessary to prepare the workplace and tools. For high-quality refueling, you will need a professional kit, including a pressure gauge station, a vacuum pump and high-precision scales. Without a vacuum pump, it is impossible to remove moisture and air from the system, which will inevitably lead to corrosion of internal parts.
⚠️ Attention: Using automotive compressors or “makeshift” refueling methods without vacuuming is guaranteed to lead to compressor failure within several months due to oil oxidation and acid formation.
It is also important to prepare the correct type refrigerant indicated on the compressor nameplate. The use of unsuitable gas, for example, replacing R134a to R12 without changing the oil and filter-drier, is unacceptable. Each type of freon has its own physical and chemical properties and requires compatible system components.
Required tools and materials
To perform maintenance work on the refrigeration circuit, a specialized tool is required that allows you to control the pressure and amount of the substance. The main device is manometric manifold stationequipped with two pressure gauges: blue for low pressure and red for high. The presence of hoses with Schrader valves is also required.
The quality of the work performed directly depends on the condition of the vacuum pump. For household refrigerators, a pump with a capacity of about 1-2 cubic meters per hour is sufficient. It is important to monitor the oil level in the pump and change it in a timely manner to ensure a residual vacuum pressure of no worse than 0.5-1 mbar.
- 🛠️ Pressure gauge station with a set of adapters for different types of valves.
- 🔌 Vacuum pump with a check valve to prevent reverse oil flow.
- ⚖️ Electronic scales with an accuracy of 1 gram to control the mass of refilled freon.
- 🔥 Burner (gas or oxygen) and solder for sealing the system after repair.
Do not forget about personal protective equipment. Although modern freons are considered low-toxic, they can form harmful compounds when in contact with an open flame. Work should be carried out in a well-ventilated area, away from sources of open flame, except for the moment of soldering.
The process of vacuuming the system
Vacuuming is the most important stage, which is often ignored by beginners, trying to get the equipment up and running faster. The purpose of the procedure is to remove air and, more importantly, water vapor from the circuit. The moisture remaining in the system turns into ice at low temperatures and clogs the capillary tube, and also reacts with the oil, forming aggressive acids.
The technological process begins by connecting the vacuum pump to the service pipe of the compressor. After turning on the pump, it is necessary to monitor the pressure gauge readings. The needle should drop below zero, reaching the vacuum zone. The operating time of the pump depends on the volume of the system and the degree of its contamination, but usually is at least 30-40 minutes.
⚠️ Attention: If, after stopping the vacuum pump, the pressure gauge needle begins to creep up, this indicates a leak in the system. In this case, refilling with freon is prohibited until all leaks have been eliminated.
To increase the efficiency of moisture removal, it is recommended to use the “warm-up-vacuum” method. During the pumping process, you can carefully warm up the compressor and condenser with a hairdryer (no higher than 60-70 degrees), which will help evaporate the moisture accumulated on the inner walls and in the oil. After warming up, the evacuation procedure is repeated.
Table of freon pressure and temperature conditions
Orienting solely by pressure when refueling is a common mistake. The pressure in the system is a variable value that directly depends on the ambient temperature and the temperature inside the refrigerator chambers. Therefore correspondence table pressure and temperature is an indispensable reference for the master.
Below are the average data for the most common refrigerants at an ambient temperature of about +25°C. It is worth remembering that actual readings may differ depending on the design of a particular refrigerator and the condition of the heat exchangers.
| Refrigerant type | Suction pressure (bar) | Eboiling point (°C) | Condensing pressure (bar) |
|---|---|---|---|
| R134a | 0.6 - 0.8 | -26.1 | 6.5 - 8.0 |
| R600a (Isobutane) | 0.4 - 0.6 | -11.5 | 4.0 - 5.5 |
| R12 (Obsolete) | 1.0 - 1.2 | -29.8 | 9.0 - 10.5 |
| R404A | 1.8 - 2.2 | -46.5 | 15.0 - 18.0 |
When analyzing the pressure gauge readings, it is necessary to take into account that the suction pressure (low) must correspond to the boiling point of freon in the evaporator. If the pressure is too low, the evaporator will not freeze evenly, and if it is too high, liquid freon may enter the compressor, which will cause water hammer.
Refrigerant charging technology
There are two main charging methods: by mass (weights) and by pressure (thermodynamic method). The most accurate and recommended by manufacturers is refilling by scale. The compressor nameplate or technical documentation always indicates the exact number of grams of refrigerant required for a given model.
The process of refilling by scale is as follows: a cylinder with freon is installed on the scales, the readings are recorded. Then the valve on the manifold opens, and gas under its own pressure (or using a scale, if the cylinder is upside down, for the liquid phase, which is acceptable for some mixtures, but usually for R600a and R134a it is charged in the vapor phase or strictly according to the instructions) enters the system. As soon as the scales show the required number of grams, the supply is shut off.
☑️ Refilling checklist
If refueling is done by pressure (which is a less accurate method and requires experience), you need to start the compressor and monitor the pressure gauge readings dynamics. The pressure will increase as the internal volume cools. In this case the key parameter is not the number on the pressure gauge, but the temperature at the outlet of the evaporator and the nature of the compressor operation.
There are nuances for different types of freons. For example, R600a (isobutane) is a flammable gas. When working with it, it is strictly forbidden to use an open flame near the refrigerator during refueling, and all connections must be perfectly sealed. Isobutane cylinders often have check valves that prevent gas from escaping without a special adapter.
Monitoring and adjusting the system
After refueling and turning off the gas station, it is necessary to conduct a final check of the operation of the refrigerator. The compressor should operate cyclically: turn on, cool the chamber to the set temperature and turn off. If the refrigerator operates without stopping, this may indicate an underfilling of freon or the presence of an air lock.
An important indicator of proper operation is the temperature of the compressor and condenser housing. The condenser (grid at the back) should be uniformly warm or hot (depending on the zone). If the bottom is cold and the top is hot, the system may be low on freon. If the entire condenser is barely warm and the compressor is very hot, overheating is possible due to incorrect pressure or oil problems.
⚠️ Attention: When working with a system under pressure, never try to disconnect the hoses or unscrew the nuts. This may cause injury to the eyes or skin from the jet of cold gas and oil.
You should also pay attention to freezing of the evaporator. In a normally operating “crying” type refrigerator, the evaporator should freeze evenly. The presence of a “coat” only at the beginning of the tubes or, conversely, the absence of frost when the compressor is running indicates a violation of the refrigerant circulation.
What to do if an ice plug has formed after refilling?
If you observe that the refrigerator is cooling, but then stops, and an ice build-up is visible on the capillary, this is a sign waterlogging of the system. In this case, it is necessary to evacuate the system again by replacing the filter drier. Simply adding freon will not help; a complete refill is required with thorough evacuation (at least 1 hour) and possibly warming up the compressor to remove moisture from the oil.">Hidden text with details
Typical errors and safety measures
Independent repair of refrigerators is fraught with risks, and most often failures are associated with a violation of technology. One of The most common mistakes are insufficient vacuuming. Beginners often keep the pump turned on for 10-15 minutes, considering this to be sufficient, but it takes more time to completely remove moisture, especially if the system has been open for a long time.
Another mistake is filling “by eye” or by the temperature of the compressor housing. without taking into account the type of freon. Different refrigerants require different amounts of oil and have different solubility in oil. For example, POE synthetic oil is used, which is very hygroscopic (absorbs moisture), so the time of contact of the system with the atmosphere should be minimal. R134a synthetic POE oil is used, which is very hygroscopic (absorbs moisture), so the time of contact of the system with the atmosphere should be minimal.
- ❌ Filling more freon than indicated in passport, will lead to an increase in condensation pressure and overload of the compressor.
- ❌ Using oxygen instead of nitrogen to purge the system (check for leaks) can cause an explosion during subsequent soldering.
- ❌ Ignoring the replacement of the filter-drier when the circuit is depressurized, which is guaranteed to lead to clogging of the capillary systems.
Safety should be a priority. Freons are heavier than air and, if there is a large leak in a confined space, can displace oxygen, causing suffocation. In addition, if it comes into contact with the skin, liquid freon causes severe frostbite ("cold burn") due to instant evaporation.
FAQ: Frequently asked questions
Is it possible to fill a refrigerator with regular automotive freon?
No, this is strictly prohibited. Automotive freons (often mixtures) and household ones have different properties, types of oils and operating pressures. Using the wrong refrigerant will lead to destruction of the compressor and a fire hazard.
How long should it be kept. is the vacuum pump turned on?
The minimum evacuation time is 30 minutes for systems with a small leak. If the system has been open for a long time or the compressor has been replaced, the evacuation time should be increased to 1-2 hours to ensure moisture removal.
Why does the refrigerator freeze after refueling, but does not turn off?
This may indicate a freon leak (underfilling), a clogged capillary tube or a malfunction of the thermostat. Also, the cause may be a leak in the door seal, due to which heat constantly enters the chamber.
Is it necessary to change the oil in the compressor when refueling?
During normal refueling. due to a leak, the oil does not need to be changed if the system has not been open for a long time and moisture has not gotten inside. However, when replacing the compressor or long-term repairs with an open circuit, it is recommended to replace it with fresh oil of the appropriate type.