Modern refrigerators LG are famous for their reliability, but even the highest quality equipment is subject to wear. One of the first symptoms of a serious breakdown is often the incorrect operation of the compressor, which is the heart of the entire cooling system. If you notice that your unit has stopped freezing, is making strange sounds, or is running nonstop, you need to urgently carry out diagnostics.
Checking the motor requires care and safety precautions, since you will be dealing with electric current and refrigerant. In this article, we will look in detail at how to determine whether the engine is working properly, or whether it’s time to replace it. Visual inspection And basic measurements with a multimeter will help you understand the scale of the problem.
Do not panic if the equipment has stopped working. In many cases, the problem lies in the start relay or thermostat, but it compressor remains working. Competent diagnostics will allow you to save significant money on calling a technician or purchasing new equipment.
Primary visual diagnostics and condition assessment
Before taking up the tools, it is necessary to conduct a thorough external inspection. Often signs of a malfunction are visible to the naked eye. Unplug the refrigerator and move it away from the wall to gain access to the back panel. Remove the protective cover covering the compressor compartment.
Carefully inspect the motor-compressor itself. There should be no traces of oil, severe corrosion or melted wire insulation. If you notice oil stains around the fittings or on the body, this may indicate a depressurization of the system, which often requires replacing the entire assembly.
⚠️ Attention! If traces of oil are visible on the compressor tubes, this may indicate a freon leak. In this case, simply replacing the motor without searching for leaks and refueling the system will not work.
Pay attention to the condition of the wiring. The insulation must be intact, without cracks or traces of burning. Oxidized contacts can cause interruptions in operation, creating a false impression of engine failure. Also check the mounting of the motor to the frame: if the shock absorbers are damaged, the vibration will be transmitted to the body, causing a lot of noise.
Tools for checking the serviceability of the compressor
For high-quality diagnostics you will need minimal set of tools. Without them, it will be impossible to check electrical circuit . The main device will be a multimeter (tester), which allows you to measure the resistance and integrity of the windings.
You will also need screwdrivers to remove the casing, pliers and, possibly, insulating tape. If you plan to carry out more in-depth diagnostics, you may need a pressure gauge station to check the pressure, but for an initial assessment of the performance of the motor, electrical measurements are sufficient.
Make sure that the multimeter is working and has charged batteries. Poor-quality readings from the device can lead to erroneous conclusions about the condition of an expensive component. All work must be carried out with the refrigerator completely disconnected from the power supply.
How to check the starting relay and thermal protection
Often the cause of compressor failure is not the motor itself, but the starting relay or thermal protection relay. These components are responsible for starting the engine and protecting it from overheating. They are usually located directly on the compressor housing or next to it.
Remove the start relay by carefully disconnecting it from the compressor contacts. Visually assess its condition: there should be no burning inside, and the contacts should be clean. Try shaking the relay: if you hear a knock inside, it means the mechanism is damaged and requires replacement.
Check the integrity of the relay circuit using a multimeter in test mode. If the device shows a break, the part is faulty. Replacing the relay is a simple and inexpensive procedure that often brings the refrigerator back to life.
☑️ Checking the relay and protection
The thermal relay also plays an important role. It opens the circuit when the windings overheat. If it is stuck open, no current will flow to the motor. Check its contacts for oxidation and ring the tester.
Checking the compressor windings with a multimeter
The most accurate way to determine the condition of the electric motor is to measure the resistance of its windings. There are usually three terminals on the compressor housing, covered with a lid. After removing the cover, you will see three contacts, often labeled as C (Common), S (Start) and R (Run).
Switch the multimeter to resistance (Ohm) measurement mode. First measure the resistance between pairs of contacts. Normal values may vary depending on the model LG, but usually range from 10 to 30 Ohms for the starting winding and slightly less for the working winding.
It is important to check for a short to body. Touch one multimeter probe to any contact, and the other to a cleaned area on the metal body of the compressor. The device should show infinity (one in the most significant digit). If resistance is visible, it means that the winding is broken into the housing, and the motor must be disposed of.
| Pair of contacts | Normal resistance (Ohm) | What does deviation mean |
|---|---|---|
| Starting - Working | Amount winding resistance | Open or short circuit in the circuit |
| Working - General | 10 - 25 Ohm | Interturn short circuit |
| Starting - General | 20 - 40 Ohm | Malfunction of the starting winding |
| Any - Housing | Infinity (∞) | Insulation breakdown (dangerous!) |
If the resistance values are very different from the norm or show zero/infinity where they should not be, this is a sign interturn short circuit or a break. In this case, repairing the motor is not economically feasible.
Diagnostics of LG inverter compressors
Refrigerators LG are often equipped with inverter compressors that work on a different principle than classical models. They do not have a start relay in the traditional sense, but are controlled by an electronic module. It is more difficult to check such a motor with a conventional multimeter.
In inverter systems, the condition of the control board is important. If the compressor does not start, the problem may be in the motor itself or in the inverter unit. For diagnostics, it is often necessary to connect pressure gauges to measure the pressure created.
⚠️ Attention! Inverter compressors are sensitive to voltage surges. Before replacing the motor, be sure to check the stability of the electrical network in your home.
To test the inverter motor, specialists use the direct start method through a special tester that simulates the operation of the control board. At home, you can only check the windings for breakdown and the absence of a mechanical wedge.
Why are inverter compressors quieter?
Inverter motors do not turn off completely, but only reduce the speed, so there are no relay clicks and noise at each start.
Mechanical faults and jamming
Sometimes the electrical part is working properly, but the motor does not start due to a mechanical breakdown. This may be jamming of the piston group or destruction of the valves. If a humming sound is heard when turning on, but the shaft does not turn, a “wedge” is possible.
Attempts to unblock such a compressor by applying increased voltage are dangerous and rarely give a long-term effect. Mechanical wear of internal parts means the need to replace the entire assembly.
It is also worth checking the condition of the pipelines. If the tubes are deformed or pinched, the compressor will work under overload, which will lead to its rapid failure. The vibration of a running motor should not be transmitted to copper tubes.
Frequent diagnostic questions (FAQ)
Is it possible to replace an LG compressor yourself?
Theoretically it is possible, but this requires special equipment: a vacuum pump, a pressure gauge station and a supply of freon. Copper pipe soldering skills are also required. Without sealing the system, the refrigerator will not work.
How much does a new motor for an LG refrigerator cost?
The price depends on the type of compressor (linear or inverter) and the model of the refrigerator. The cost can vary from several thousand to tens of thousands of rubles, not counting replacement and refueling work.
Why is the compressor hot to the touch?
In operating condition, the compressor heats up to 60-90 degrees Celsius, which is the norm. However, if it is hot to the point where you cannot touch it, or smells like burnt insulation, this is a sign of overheating or a short circuit.
How often should a compressor be replaced?
The service life of a compressor is usually 10-15 years or more. Forced replacement is required only if a malfunction is detected. Preventative replacement is not required.