Restoring the functionality of a refrigeration unit after combustion compressor requires not just replacing the motor, but also thoroughly cleaning the entire internal line from decay products. Ignoring this stage is almost guaranteed to lead to repeated failure of expensive equipment in the shortest possible time. Acids, varnish deposits and metal shavings formed during the combustion of the windings must be completely removed from hard-to-reach places in the system.
The main difficulty is that capillary tube and the evaporator have an extremely small diameter, where contaminants can get stuck tightly. Simply replacing the filter element will not help here, since the bulk of the dirt will remain in the copper tubes. For high-quality washing, the use of special chemicals is required solventsthat are capable of dissolving organic and inorganic deposits without damaging the circuit materials.
The cleaning process involves the use of inert gas under pressure, which pushes the chemical reagent through all components of the refrigerator. It is important to understand that the choice of fluid depends on the type of refrigerant used and the degree of contamination. An incorrect selection of a product can lead to a chemical reaction, blockage of the system or destruction of the seals, so the procedure must be approached with full responsibility and knowledge of the chemistry of the processes.
⚠️ Attention: Flushing the system is a step that cannot be fully completed at home without a nitrogen cylinder and professional equipment. Attempts to flush the system “by eye” often lead to moisture or chemicals remaining in the line, which kills the new compressor in a matter of hours of operation.
Causes of contamination and consequences for the unit
The main reason for contamination of the refrigeration circuit is thermal decomposition compressor oil and the insulation of the motor windings during overheating or short circuit. As a result of this process, solid resinous substances, acids and copper suspension are formed. The acidic environment is especially aggressive and can quickly corrode metal parts, creating additional pockets of corrosion and debris inside the system.
If these decomposition products are not removed, they will enter the new compressor, where they will begin to act as an abrasive, destroying friction pairs. In addition, the remaining acid will react with fresh oil, reducing its lubricating properties and causing re-overheating. Filter drier It can take part of the blow, but its resource is limited, and if it is heavily contaminated, it will quickly turn into a plug.
The second reason may be moisture getting into the system due to poor evacuation or leakage. Water in combination with oil and refrigerant also forms aggressive compounds. Therefore, flushing is often accompanied by a mandatory deep procedure vacuumto remove even microscopic particles of moisture that are not dissolved in the flushing liquid.
Selection of flushing fluid: types and characteristics
The market offers several types of cleaning fluids, and the choice depends on the specific situation and type of refrigerant. The most common option is to use specialized ones, such as R141b or its modern analogues. These substances have excellent dissolving ability with respect to oils and varnishes, while they are chemically inert to metals and rubber used in refrigeration equipment. fluorinated solvents, such as R141b or its modern analogues. These substances have excellent dissolving ability in relation to oils and varnishes, while they are chemically inert to metals and rubber used in refrigeration equipment.
Some craftsmen use purified Galosh gasoline or isopropyl alcohol, but these products have a number of disadvantages. Gasoline can leave greasy marks and requires perfect drying, while alcohol is hygroscopic and can draw moisture from the air, which is unacceptable. Professional fluids based on hydrofluoroethers evaporate completely, without leaving any residue or foreign odor.
It is important to consider the compatibility of the selected solvent with the type of oil in the system (mineral, polyester POE or polyvinyl ether PVE). For example, systems with essential oils require more active solvents, since they are powerful cleaners in themselves, but can “lift” dirt from the walls of the tubes, which is then difficult to remove. Correct selection chemical composition ensures that after purging only pure metal remains in the system.
Can acetone or solvent be used?
Acetine is too aggressive to some types of rubber and plastic used in valves compressor and may destroy them. The solvent leaves an oily film, which is extremely difficult to remove without long-term drying, so their use is not recommended by professionals.
Nitrogen pressure washing technology
The cleaning process itself is based on creating pulse pressure using nitrogen, which pushes the solvent through the circuit. Nitrogen was not chosen by chance: it is an inert gas that does not react and, unlike air, does not contain moisture and oxygen, preventing oxidation of the internal walls. The pressure during flushing is usually regulated in the range 10-15 bar, which is sufficient to overcome the resistance of the capillary, but is safe for soldering.
Flushing is carried out in stages: first, the old compressor is dismantled, and the liquid is supplied to the condenser on one side, and then to the evaporator. It is often necessary to remove capillary tube or the throttle, since the flow of fluid through them may be obstructed due to contamination. The liquid is poured into the container, its purity is visually assessed, and the procedure is repeated until the emerging solvent becomes transparent.
After chemical cleaning, the stage of purging with dry nitrogen without chemicals must necessarily follow. This allows any remaining solvent to be removed from the system. Purge is carried out until the smell of chemicals is no longer noticeable at the outlet of the tubes. Only after this can you begin soldering the new filter drier and assembling the system.
☑️ Flushing checklist
Changing the oil in compressor and its types
In parallel with flushing the circuit, the question often arises about the oil in the compressor itself. If the new motor is already filled with oil, it must be checked for compliance with the type of refrigerant. For freons of group R12 and R134a, mineral oil or alkylbenzene (AB) is used, and for modern environmentally friendly refrigerants R407C and R410A - exclusively synthetic polyester oils (POE).
There is a misconception that oil is needed in a new compressor definitely change. At the factory, the compressor is filled with technical oil, which often contains preservation additives and may not be compatible with your system if it has been standing for a long time. However, if you are replacing the compressor with a similar one, the factory charge is usually fine. Problems arise when switching from one type of freon to another or when the old system is heavily contaminated.
The process of changing the oil in a compressor involves unsoldering the suction tube, pouring out the old oil and pouring new oil through a funnel or syringe. It is important not to shake the compressor to prevent oil from getting into the discharge tube. The volume of oil is strictly regulated by the manufacturer and is measured in cubic centimeters, so overfilling or underfilling is unacceptable.
| Refrigerant type | Oil type | Hygroscopicity | Compatibility |
|---|---|---|---|
| R12, R134a | Mineral / AB | Low | Does not mix with POE |
| R407C, R410A | Polyester (POE) | High | Requires vacuumization |
| R600a (Isobutane) | Mineral / AB | Low | Explosive |
| R290 (Propane) | Mineral / AB | Low | Explosive |
Vacuuming: a critical stage of preparation
After flushing and assembling the system, before charging with refrigerant, it is necessary to perform a deep evacuation. This process removes air and, more importantly, water vapor from the circuit. Water in the system turns to ice at low temperatures, causing a capillary blockage known as an “ice lock.” In addition, moisture reacts with freon and oil, forming acid.
For high-quality evacuation, a two-stage one is used vacuum pump, capable of creating a vacuum of up to 5 microns (0.005 mm Hg). Household single-stage pumps often cannot provide the required vacuum depth, leaving up to 10-15% moisture in the system, which is critical for modern refrigerants. The evacuation time depends on the length of the line and the power of the pump, but is usually at least 30-40 minutes.
The process is controlled by a vacuum gauge. After stopping the pump, the system is left under vacuum for 15-20 minutes to check for leaks. If the pressure gauge needle creeps up, it means there is somewhere leaks (microcrack, bad soldering) or water is boiling in the system (which happens with a bad vacuum). In this case, the procedure must be repeated.
Comparison of cleaning methods and cost of work
The choice of cleaning method often faces the owner of the equipment: do a complete flush or limit yourself to installing a “contract” (used) compressor with the hope of maybe. A complete flush with replacement of all components is an expensive and time-consuming process that requires qualifications. Installing a used motor is cheaper, but carries risks, since combustion products could remain in the old system.
The cost of the work consists of the price of a new compressor, refrigerant, oil, filter, nitrogen and the work of a technician. Using cheap analogs of flushing fluid can save money, but increases risk. A professional approach involves the use of original spare parts and high-quality chemistry, which guarantees a long service life after repair.
The table below compares two approaches to solving the problem of a contaminated system:
| Parameter | Full flushing of the system | Partial cleaning (without nitrogen) |
|---|---|---|
| Efficiency | 95-98% (removal of all contaminants) | 40-50% (residues in capillary) |
| Risk of re-breakage | Low | High (up to 70%) |
| Cost | High | Average |
| Service life after repair | 5-10 years | 6 months - 2 years |
⚠️ Attention: The type of refrigerant and oil in your refrigerator is indicated on the technical sticker, usually located on the back wall or inside the compartment. Never mix different types of oils (for example, mineral and synthetic POE), as they can coagulate and form an impenetrable mess in the system.
FAQ: Frequently Asked Questions
Is it possible to flush the system with regular gasoline?
Use gasoline only in extreme cases and only “Galosh,” but it’s risky. Gasoline leaves a greasy film that is difficult to remove and is a fire hazard. In addition, gasoline can damage the rubber seals on the compressor valves. It is better to use specialized solvents such as R141b.
Is it necessary to change the filter drier when washing?
Yes, definitely. The filter drier is a disposable item. When the system is opened, it instantly absorbs moisture from the air. Reusing the old filter will negate all efforts to flush and vacuum.
How long does it take to vacuum the system?
The minimum operating time of the vacuum pump is 30 minutes for domestic refrigerators. However, the important indicator is not time, but residual pressure. The system should maintain a vacuum (the arrow should not creep up) after turning off the pump for 15-20 minutes.
What is dangerous about moisture getting into the system?
Moisture causes two main problems: the formation of an ice plug in the capillary tube (the refrigerator stops freezing) and a chemical reaction with oil and freon, leading to the formation acids Acids corrode the compressor windings, causing a short circuit.
Is it possible to flush the system without removing the compressor?
It is impossible to properly flush the system with the compressor installed. The liquid will not be able to fully circulate through the valves and oil channels of the engine. The compressor must be dismantled to effectively clean the condenser and evaporator.