A sudden stop of a refrigeration unit often becomes an unpleasant surprise, especially when there are perishable products in the chamber. Compressor is the heart of the system, and it is its failure that most often leads to complete inoperability of the equipment. Before calling a technician or buying a new unit, it makes sense to try to carry out diagnostics and, perhaps restoring the refrigerator compressor on your own, if the problem lies in the electrical part or loss of lubrication.
However, it is worth immediately defining the boundaries possible: mechanical damage to the piston group or electric motor windings is almost impossible to eliminate at home. In such cases, a complete replacement of the unit is required. However, statistics show that a significant part of the breakdowns is associated with the failure of the start-up relay, sticking valves or a critical decrease in the oil level. About 40% of faulty compressors can be restored if the seal of the housing is not broken and integrity of the windings. In this article we will analyze a step-by-step algorithm of actions that will help bring the equipment back to life.
It is important to understand that working with refrigeration equipment requires compliance with safety precautions and basic skills in working with power tools. Refrigerantlocated in the system can be dangerous if mishandled, and high voltage in the electrical network poses a threat to life. If you are not confident in your abilities, it is better to entrust the work to professionals, but if the decision is made, follow the instructions as precisely as possible.
Primary diagnosis and identification of symptoms
The first step towards recovery is to accurately determine the nature of the malfunction. Often, equipment owners mistakenly believe that the motor has broken down, when the problem lies in the thermostat or freon leak. It is necessary to listen carefully to the operation of the unit when attempting to start. If you hear a characteristic click, followed by a hum that lasts a few seconds, and then another click and silence, this is a sure sign that start relay is trying to start the engine, but is unsuccessful.
In a situation where the compressor is completely silent, without making any sounds, the problem may be no power or open circuit. Check the integrity of the power cord and the presence of voltage at the outlet. It is also worth inspecting the motor housing for visible damage, melting or traces of burning, which may indicate an interturn short circuit. Thermal relay The protection could also have tripped due to overheating, and it needs time to cool down.
⚠️ Attention: If the compressor housing has heated up to a temperature above 60-70 degrees Celsius when the fan is not working (if there is one) or immediately after trying to turn it on, this may indicate a wedge of the mechanical part or a serious electrical breakdown. Further attempts to turn on without diagnostics may lead to a fire.
For deeper diagnostics, you will need a multimeter. With its help, it is necessary to “ring” the motor windings through the contact group on the housing. Lack of resistance on either winding will indicate an open, and too low resistance will indicate a short circuit. In both of these cases restoring the compressor is impossible, and the unit must be replaced.
Checking and replacing the start-protection relay
The most common cause of startup failure is a malfunction of the start-protection relay. This small plastic block, placed on the contact group of the compressor, is responsible for supplying an impulse to the starting winding and protecting against overloads. Inside it there is a coil with a core and a contact group, which over time can oxidize, burn, or simply wear out. A visual inspection often helps identify the problem: if carbon deposits are visible inside the relay and the contacts are blackened, it needs to be replaced.
The replacement process is quite simple, but requires caution. First you need to unplug the refrigerator and remove the back cover. Then carefully remove the relay from the compressor contacts, having previously memorized or photographed the wiring diagram. The new relay must fully correspond to the markings of the old one, since different engine models require different cut-off current parameters. Installing an unsuitable relay can lead to rapid failure of the compressor itself.
Sometimes you can try to restore the relay if its design allows disassembly. Inside, you can clean the contacts with fine sandpaper or a file, removing oxides. However, this is a temporary measure, and the reliability of such a repair is questionable. Starting capacitorif it is present in the circuit (in some models), it is also worth checking for swelling or electrolyte leakage.
☑️ Replacing the starting relay
After installing the new relay, assemble the circuit and try to turn on the refrigerator. If the engine starts and runs smoothly, without humming or vibration, the problem can be considered solved. If the symptoms are repeated, then the reason lies deeper, and more serious intervention in the engine design will be required.
Pumping the compressor and changing the oil
If the electrical part is working properly, but the compressor is humming and does not start or starts with difficulty, the problem may be thickened oil or mechanical jamming of the piston group. In this case, the pumping method is used. To implement it, it is necessary to remove the compressor from the frame of the refrigerator, having previously unsoldered the copper tubes and released the refrigerant (this procedure is best carried out in a well-ventilated area or outside).
The essence of the method is to supply oil directly to the engine lubrication system under pressure. Through a process fitting (usually a sealed tube), special compressor oil is injected with a syringe. Then the fitting is sealed and the compressor is briefly connected to the network. Under the influence of pressure, old, thickened oil is forced out, unblocking the rubbing parts. This procedure sometimes has to be repeated several times.
- 🛠️ Tools: For work you will need a gas torch, solder, a 20 ml syringe, special oil for refrigeration compressors and a container for draining waste.
- 💧 Oil type: It is extremely important to use oil of the same brand and viscosity that was used originally filled (mineral or polyester). Mixing different types of oils is unacceptable, as this will lead to the formation of sediment and coking.
- 🔄 Cycling: The pumping process can take from 15 minutes to several hours, depending on the degree of oldness of the lubricant and the difficulty of accessing the components.
After successfully bleeding and starting the engine, it is necessary to thoroughly rinse the system of old oil residues and wear products if further operation is planned. However, if the compressor has been opened or sealed off, the system has lost its tightness, and it is impossible to simply solder the tubes back - evacuation and refilling with freon is required.
What oil should be used for pumping?
For Frigor, Danfoss, Secop compressors, ISO VG 22 or 32 mineral oil is most often used. Inverter models and compressors running on R134a or R600a freon often require polyester oil (POE). The exact specification can be found on the nameplate of the compressor itself or in the technical documentation of the refrigerator. Using the wrong oil will cause rapid wear and re-wedge.
Eliminating mechanical wedge and jamming
Mechanical wedge is a condition in which the piston or shaft of the engine becomes stuck at a dead point and cannot reciprocate. This may occur due to lack of lubrication, foreign objects (such as pieces of solder or copper shavings), or thermal deformation of parts. An attempt to “unwedge” the compressor by impact methods (tapping with a hammer) at home rarely gives a positive result and often leads to final failure.
A more gentle, but labor-intensive method is to try to rotate the motor shaft manually or using a special device. To do this, the starting relay is removed from the compressor, and torque is applied to the shaft (if there is access) or through a special nozzle. Sometimes it helps to briefly apply voltage to the starting winding, bypassing the relay, which creates a powerful starting impulse. However, this method requires high qualifications and carries the risk of electric shock.
| Symptom | Probable cause | Solution method | Probability of success |
|---|---|---|---|
| Buzzing for 5-10 seconds, then click | Piston group jamming | Oil pumping, vibration | Average (50%) |
| Silence, no reaction | Winding break or relay | Replacing a relay or compressor | High (when replaced) |
| Strong heating of the housing | Interturn short circuit | Replacement compressor | Low (repair impossible) |
| Vibration and noise | Destruction of the engine mount | Suspension repair (rarely) | Low |
If the mechanical wedge is caused by the ingress of solid particles, the only effective way to restore it is to completely disassemble the compressor, which is done in the factory using special equipment. At home, such repairs are practically impossible, and it is more advisable to consider the option of replacing the unit with a new or refurbished analogue.
Evacuation and charging with refrigerant
Any intervention in the system associated with depressurization (unsoldering of pipes, replacing the compressor) requires mandatory evacuation and charging with refrigerant. Simply running the compressor with open tubes can only be used for short-term diagnostics, but for normal operation of the refrigerator, tightness and correct pressure are necessary. Evacuation necessary to remove air and moisture from the system, since moisture can block the capillary tube when freezing.
To perform This procedure will require a vacuum pump and a pressure gauge station. The process takes from 30 minutes to an hour, depending on the volume of the system and residual moisture. After reaching a deep vacuum, the system is charged with freon strictly according to the weight indicated on the refrigerator label. Using freon “by eye” or by pressure is unacceptable, as this will either lead to insufficient cooling or overload the compressor.
⚠️ Attention: The type of refrigerant (R134a, R600a, R12) is indicated on the refrigerator nameplate. Using the wrong type of freon or oil can result in an explosive situation (especially with R600a) or destruction of the compressor. R600a (isobutane) is flammable, so working with it requires special care and the absence of sources of fire.
If you do not have experience working with refrigeration equipment and specialized tools, it is better to entrust the refueling stage to a specialist. Incorrect refilling will negate all previous efforts to restore the compressor.
Prevention and extension of service life services
After successful restoration of the compressor, it is important to create conditions that will prevent recurrence of the breakdown. The main enemy of a refrigeration unit is overheating. Make sure that the refrigerator is installed at least 10 cm away from the wall and that the space around the rear grill is free for air circulation. Regularly cleaning the condenser (black grille at the back) of dust and pet hair significantly improves heat transfer and reduces the load on the motor.
It is also worth monitoring the tightness of the door seals. If the rubber is worn out or dirty, the cold goes away and the compressor is forced to work almost non-stop, which leads to its rapid wear. You can check the seals using a sheet of paper: hold it with the door and try to pull it out - if it comes out too easily, the seal requires replacement or adjustment.
- 🧹 Cleanliness: Once every six months, wipe the back wall of the refrigerator from dust using a vacuum cleaner or soft brush.
- ❄️ Temperature range: Do not set the temperature controller to maximum cooling unless necessary, this will increase wear on parts.
- 🔌 Network stability: Use a voltage stabilizer or surge protector to protect the electronics and motor from power surges in network.
Following these simple rules will help extend the life of the restored compressor and the entire refrigerator as a whole. Remember that prevention is always cheaper than complex repairs or buying new equipment.
Frequently asked questions (FAQ)
Is it possible to restore a compressor if it burns out?
If an inter-turn short circuit of the windings occurs (the engine burns out), it is impossible to restore it at home. Rewinding of the motor is required, which is economically impractical and technically difficult. In this case, the compressor must be completely replaced.
How much does it cost to change the oil in a refrigerator compressor?
The cost depends on the region and service, but the procedure itself (if done independently) will cost the price of oil (about 500-1000 rubles) and tools. In a service center, work on changing the oil and vacuuming can cost from 3,000 to 5,000 rubles, excluding the cost of materials.
Why is the compressor hot, but does not start?
This may indicate a wedge of the mechanical part, a malfunction of the starting relay or thermal protection. Also, the cause may be a freon leak, due to which the engine idles and overheats, trying to create pressure.
Is it possible to use a car compressor to refill a refrigerator?
No, car compressors are not designed to work with refrigerants and cannot create the necessary vacuum. To refuel a refrigerator, specialized equipment is required: a pressure gauge station, a vacuum pump and scales.
How often do you need to change the oil in the compressor?
In hermetic refrigerator compressors, the oil is designed for its entire service life and does not require scheduled replacement. Replacement is made only in case of repair, depressurization of the system, or if the oil has lost its properties (blackened, thickened) due to overheating or moisture.