Compressor failure is often the most serious and expensive diagnosis that a refrigerator owner can hear. When the motor stops starting, hums, but does not pump freon, or runs endlessly without gaining temperature, the user is faced with a difficult choice: call a technician, buy new equipment, or do it yourself. Understanding exactly how this unit changes will help you assess the risks and complexity of the upcoming process. replacement of the compressor on one's own. Understanding exactly how this node changes will help you assess the risks and complexity of the upcoming process.
It is worth immediately noting that this process requires not only technical skills, but also special equipment, such as a vacuum pump and burner. Without a sealed connection and proper refrigerant charge, the refrigerator turns into a simple metal box. In this article, we will analyze in detail all the stages, from diagnostics to the final start-up, so that you can make an informed decision about repairs.
Before taking up the tools, you need to make sure that the repair is appropriate. Often, the cost of a new compressor and its installation is a significant part of the price of a new refrigerator, especially when it comes to budget models or old devices with a system No Frostwhere access to the unit is complicated by the design.
Diagnostics of a motor-compressor malfunction
The first step is always to accurately identify the problem. The absence of cold does not always mean the death of the engine; Sometimes the start relay or thermostat is to blame. However, if you hear a characteristic click, followed by a hum, and then silence, or the motor runs continuously without turning off, most likely the problem is compression or mechanical jamming.
The test begins with a visual inspection and testing the windings with a multimeter. It is necessary to remove the casing and disconnect the start-up relay. At the compressor terminals, the resistance between the contacts is measured. If the device shows an open circuit (infinity) or a short circuit (close to zero), then electric motor it is faulty and requires replacement.
⚠️ Attention: If the compressor is heated to a high temperature and the winding resistance is normal, this may indicate interturn short circuit or mechanical wear of the piston group, which also requires a complete replacement of the unit.
It is also important to check the condition of the starting relay. Sometimes replacing this small and cheap element brings the refrigerator back to life without having to open the circuit. But if the diagnosis clearly points to the motor, then (preparation) must be thorough.
- 🔌 Check the integrity of the power cable and the absence of burn marks on the wiring.
- 🔊 Listen to the sound: a steady hum is better than a knocking or intermittent hum.
- 🌡️ Feel the case: excessive heating of the lower part of the motor is a bad sign.
Required tools and selection of spare parts
For a successful replacement, you will need not only a new compressor, but also a specific set of tools. A regular set of screwdrivers will not be enough here. It is critically important to choose the right motor model, since they differ in power, type of refrigerant (R600a or R134a), dimensions and type of starting equipment.
When choosing a new unit, pay attention to the markings. The use of a compressor designed for freon R600ain a system where it previously circulated R134ais unacceptable without a complete resoldering and oil change, since oils for different refrigerants have different chemical bases and do not mix.
Below is a table that helps compare the types of compressors and their features, which will simplify the search for an analogue for your refrigerator model, be it Indesit, Atlant or Liebherr.
| Refrigerant type | Oil features | Motor type | Compatibility |
|---|---|---|---|
| R134a | Synthetic (POE) | Often with 1/8" tubes | R134a only |
| R600a | Mineral | Often smaller volume | Only R600a |
| R12 (old) | Mineral | Powerful, noisy | Replacement with R134a/R600a |
| Inverter | Specific | With an electronic unit | Original only |
In addition to the compressor itself, you will need: a pipe cutter, rolling, torch (gas or oxygen), solder and flux, as well as a vacuum pump and a pressure gauge station for without evacuating the system, the moisture remaining inside will turn into ice and clog the capillary tube.
Preparing the refrigerator for dismantling
Before starting any work, the refrigerator must be completely defrosted and dried. The presence of water in the lower part of the unit is unacceptable, as this will create a risk of short circuit and corrosion during soldering. unit from the mains and move it away from the wall, providing access from all sides.
Remove the back panel (or bottom, depending on the model) to gain access to the compressor compartment. In refrigerators with the system No Frost it may be necessary to partially disassemble the interior to access the evaporator if the capillary tube is soldered to it.
☑️ Preparation for repair
Pay special attention to safety when working with open flames. flammable gases (freon) requires a fire extinguisher and good ventilation of the room. Make sure that there are no flammable objects nearby.
⚠️ Attention: Freon R600a (isobutane) is an explosive gas. Before biting off the pipes, make sure that there are no sparking sources in the room, and act as quickly as possible to minimize the release of gas.
The process of dismantling the old compressor
Dismantling begins with cutting the filling tube (usually it has a characteristic bend or plug). This must be done sharply so that the gas comes out quickly and does not have time to ignite from a possible spark. After releasing the residual pressure, you can begin to unsolder the tubes.
Using a torch, heat the solder joints on the discharge and suction tubes. It is important not to overheat the compressor housing itself or the copper tubes leading to the condenser. Once the solder has melted, the tubes can be easily removed. The third tube - the capillary tube - often breaks off inside the filter-drier, so the filter must also be replaced.
After disconnecting all the tubes and wires from the start relay, the compressor is unscrewed from the frame. It is usually mounted on four bolts with rubber shock absorbers. Remove the old unit and prepare the area for installing the new one.
What to do with broken pipes?
If during dismantling you broke the copper one. condenser or evaporator tube, do not panic. Carefully cut off the damaged area with a pipe cutter. If the length allows, you can simply solder the joint. If the tube goes deep into the body, you will need to carefully bend the wall of the refrigerator or use an extension from a copper tube of a suitable diameter.
At this stage, it is often discovered that the condenser (grid at the back) is clogged with dust or damaged by corrosion. opened the system, it makes sense to purge the condenser with nitrogen or simply clean it thoroughly so that the new compressor does not work with overload.
Installation and soldering of the new unit
Installation of the new compressor is carried out in the reverse order. First, secure the motor to the frame, using new shock absorbers, if the old ones have become unusable. Then connect the electrical one. part - the starting and protective relay must correspond to the model of the new engine.
The most important step is soldering. A new one must be installed on the suction tube. The capillary tube is inserted into the filter and sealed. The connection of the compressor discharge tube to the condenser is also soldered with hard solder. sealed. filter drier. The capillary tube is inserted into the filter and sealed. The connection between the compressor discharge tube and the condenser is also soldered with hard solder. All connections must be tight.
- 🔥 Use flux for better soldering, but remove its residues after work.
- 💧 Do not allow moisture to get inside the open pipes of the system.
- 🛡️ Protect the plastic parts of the refrigerator with a screen from the heat of the burner.
After soldering all connections, the system is sealed tightly, only the filling tube (or service fitting, if you have installed it) remains open. The system is now ready to vacuum.
Evacuating and charging with refrigerant
Without removing air and moisture from the circuit, the refrigerator will not work correctly. A pressure manifold and a vacuum pump are connected to the filling tube. The pump is turned on for 15-30 minutes until a deep vacuum is achieved. This removes moisture, which at low temperatures would turn into an ice plug.
After evacuation, the valve on the manifold is closed, the pump is turned off, and the system is checked for leaks for some time (the pressure gauge needle should not creep up). If the vacuum is maintained, charging begins.
The refrigerant is charged in the liquid phase (the container is turned upside down) or in the gas phase, depending on the type of freon and the manufacturer’s recommendations. For R600a, refilling is often done with the compressor running in a gas state, strictly by weight. The amount of freon is indicated on the refrigerator tag (for example, 58 g).
⚠️ Attention: The exact amount of refrigerant is critically important. Undercharging will lead to poor cold, and overcharging will lead to increased pressure and possible rupture of tubes or compressor failure. Use electronic scales.
After refueling, the filling tube is clamped with a special clamp and sealed. The soldering area is checked with a soap solution for bubbles. If there are no bubbles, you can turn on the refrigerator.
Frequent errors and checking the result
After starting the refrigerator, do not wait for an immediate result. The unit needs time (from 1 to 2 hours) to reach the temperature and turn off. During this time, do not open the doors often: it should work cyclically, turning on. and turning off.
One of the common mistakes is using the wrong oil or not purging with nitrogen, which leads to clogging of the capillary with copper oxides. Also, beginners often forget to replace the filter drier, considering it to be reusable, which is a fatal mistake.
Check the temperature in the freezer chambers after a few hours of operation. the chamber should freeze to -18°C, and in the refrigerator it should be about +4...+5°C. If there is cold, but the compressor does not turn off, there may still be a leak or the amount of freon is incorrect.
- ❌ They forgot to remove the shipping plugs from the fittings of the new compressor.
- ❌ Overheating of the start relay when soldering adjacent tubes.
- ❌ Incomplete evacuation, leaving moisture in the system.
If the refrigerator is working properly, put the back cover in place. Remember that independent repair of complex equipment always carries risks, and in case of doubt, it is better to entrust the work to licensed professionals.
How long does it take? replacing the compressor?
In a workshop where all the tools and gases are available, the work takes from 1.5 to 3 hours. At home, without experience, the process can take the whole day, especially if there are difficulties with soldering or finding leaks.
Is it possible to use a compressor from another refrigerator?
Yes, if the power, type of refrigerant, overall dimensions and type of starting equipment match. However, it is better to look for the original model or its direct analogues indicated in the manufacturers' conformity tables.
Why does the new compressor get very hot?
Slight heating is normal. Strong heating can be caused by recharging. freon, blockage in the system, malfunction of the condenser (poor airflow) or operation in conditions of high ambient temperature.
Is it necessary to change the oil in a new compressor?
No, new compressors are supplied already filled with the required amount of oil. It is strictly forbidden to open them and change the oil, as this will break the tightness and. balancing.