A sudden stop of the refrigerator LG often becomes an unpleasant surprise, especially when there are perishable foods left inside. In most cases, the cause of the breakdown is the failure of the starting relay, which is responsible for starting the compressor. If you hear a characteristic click, after which the motor hums but does not start, or the unit is simply silent, turns on and turns off immediately, the problem most likely lies in this unit.
Before calling a technician or buying a new refrigerator, it is worth carrying out the initial diagnostics yourself. LG refrigerator relay is a compact but critical device that protects the engine from overloads and ensuring its start. Understanding the principle of its operation and the ability to check its performance using a multimeter will allow you to save a significant amount on repairs. In this article we will analyze in detail the structure of the mechanism, the symptoms of its malfunction and a step-by-step verification algorithm.
To carry out diagnostics, you do not need complex specialized equipment, a basic set of tools is enough. It is important to follow safety precautions, since the work involves electricity. LG refrigerators they are reliable, but even they are subject to wear of parts during power surges or prolonged use. Let's figure out how to accurately determine whether your equipment needs to replace a part.
The principle of operation and the design of the starting relay
The starting relay in refrigerators LG performs the function of an automatic switch of electric motor windings compressor. When the refrigerator is turned on, the motor rotor is stationary, and significantly more current is required to start it than to maintain rotation. It is the relay that supplies voltage to the starting winding, creating the necessary torque. As soon as the rotor picks up speed, the current in the circuit drops, and the relay opens the contacts of the starting winding, switching the engine to work through the main winding.
Modern models most often use posistor relays, although in older versions you can find induction mechanisms with an electromagnetic breaker. Posistor is a ceramic element that When heated by current, it sharply increases its resistance, actually breaking the circuit. It is a simple and reliable solution that requires no mechanical moving parts to open, reducing wear and tear. However, such elements also have their resource and can burn out due to frequent power surges in the network.
In parallel with the starting function, the relay is often combined with a thermal protective device. This component monitors the temperature of the compressor housing. If the motor begins to overheat due to jamming or overload, the thermal protection opens the power circuit, preventing the motor windings from burning out. Thermal relay is a self-healing element: after cooling, it closes the contacts again, trying to start the compressor, which explains the cyclic clicks during a malfunction.
⚠️ Attention: Residual charges may remain inside the relay, and the compressor itself is under high voltage. Before starting any work, be sure to disconnect the refrigerator from the power supply and wait for the capacitors to discharge (about 5-10 minutes).
Understanding exactly how your type of relay works helps in diagnosis. If the mechanism is stuck in a closed state, the starting winding will work constantly, which will lead to rapid overheating and humming. If the contacts are oxidized or the posistor is burned out, the circuit will not close, and the compressor will only hum, trying to start, but without results. LG refrigerator in this mode it will not last long, so a quick check is necessary.
Main symptoms of relay malfunction compressor
It is possible to determine that the problem lies precisely in the starting mechanism by a number of characteristic signs. Users often notice that the refrigerator LG has stopped freezing, while the light in the chamber is on and there are no errors on the control panel. The most striking symptom is the sound of the startup attempt: you hear a click, then the hum of the motor lasts 3-5 seconds, followed by a second click and silence. After some time, the cycle repeats.
Another sign is the strong heating of the compressor. If you put your hand on the back wall of the unit, you will feel that the motor is hot, although no cold is produced in the chambers. This indicates that the engine is trying to start, current flows, but the rotor does not move. In such cases thermal protection works very often, preventing the compressor from burning out completely, but also not allowing the refrigerator to start working.
Sometimes there is complete silence. The refrigerator is plugged in, the indicators are on, but there are no sounds of the motor running. This may indicate that the relay contacts have completely oxidized or burned out, and the voltage simply does not reach the motor windings. It is also worth paying attention to the appearance of the part itself: if soot, melted plastic or a burning smell is visible inside the case, then refrigerator relay definitely requires replacement.
- 🔊 Characteristic frequent clicks when trying to start the motor.
- 🔥 Strong heating of the compressor in the absence of cold in the chambers.
- 🔇 Complete absence of sound from the engine when the power is turned on.
- ⚡ The appearance of a burning or smoke smell in the compressor compartment area.
It is important not to confuse the malfunction relay with a breakdown of the compressor itself. If after replacing the relay the situation does not change, the motor may have jammed or an interturn short circuit has occurred in its windings. However, statistics show that in models LG it is the starting equipment that fails more often than the motor itself, especially if the equipment is operated under unstable voltage conditions.
Preparation for diagnostics: tools and safety
For a high-quality check of the relay, you will need a minimum set of tools that most home craftsmen can find. The main device will be a multimeter (tester), which allows you to measure resistance and check the integrity of the circuit. Without it, the diagnosis will only be approximate. You will also need a screwdriver (usually a Phillips or flat-head screwdriver, depending on the casing fastener) and possibly pliers to carefully remove the terminals.
The first and most important stage of preparation is to completely de-energize the equipment. Unplug the refrigerator LG from the socket. It is not enough to simply turn it off with a button, if there is one, or switch the thermostat to zero. Electrical safety is priority number one. After turning off, let the equipment stand for 10-15 minutes. This time is necessary not only to discharge the capacitors, but also to cool the compressor if it previously tried to start.
Next you need to gain access to the compressor. For refrigerators LG the compressor is usually located in the lower rear part of the unit. You will need to remove the protective metal or plastic panel covering the engine compartment. It is secured with latches or several screws. After removing the panel, you will see a black cylindrical compressor tank, to which a refrigerant tube and an electrical cable fit.
☑️ Preparing to check the relay
Inspect the place where the wires are connected to the compressor. There is a plastic box there - this is the starting relay. It is placed directly on the compressor rod and secured with a metal bracket or plastic clips. Before removing the relay, it is recommended to photograph the location of the wires so as not to confuse the contacts during assembly, although usually they have a unique shape and are inserted only in the correct position.
Removing the relay from the refrigerator compressor
The process of removing the relay in refrigerators LG is quite simple, but requires care so as not to damage the fragile plastic elements or do not tear off the wires. First you need to disconnect the connector with the power wires coming from the refrigerator body. It is usually inserted into the side of the relay. Press the latch and pull the connector towards you.
Then you need to remove the fixing bracket. In most models, it is a U-shaped metal plate that covers the relay housing and presses it against the compressor housing. The bracket can be pryed off with a flat screwdriver or simply squeezed with your fingers, if the design allows, and removed upwards. After this, the relay is held only due to its tight fit on the three contact studs of the compressor.
Grip the relay firmly, but without excessive force, and remove it from the studs using a rocking motion from side to side. Do not pull too hard to avoid damaging the compressor's copper tubes, which can become brittle after long periods of operation. If the relay is sitting very tightly, you can slightly pry it with a flat screwdriver between the relay body and the compressor, using it as a lever, but very carefully.
After dismantling, carefully inspect the inside of the relay and the contact pins on the compressor. If you see traces of soot, melted plastic or oxidation of contacts, this is already 90% confirmation of a malfunction. Also check if moisture has entered inside the relay housing, which often happens when defrosting or washing the floor around the refrigerator. Moisture inside the electrical part is unacceptable and will lead to a short circuit.
⚠️ Warning: Never try to disassemble non-separable relay housing (if it is ultrasonically welded) for the purpose of repairing the internals. Such components can only be completely replaced, since the tightness and calibration of the characteristics will be broken after opening.
Now that you have the relay in your hands, you can proceed to directly checking it. For different types of relays (induction and posistor), the methodology may differ slightly, but the basic principle of dialing remains the same. Visual inspection often provides more information than measurements, so pay special attention to it.
Methods for checking relays with a multimeter
The most reliable diagnostic method is to use a multimeter in resistance (Ohm) measurement mode. Switch the device to the 200 Ohm range or dialing mode. If you have an induction relay (with a coil and a moving core), it has input and output contacts. You need to ring the circuit between the contacts corresponding to the main winding. The resistance should be close to zero or several Ohms, which indicates the integrity of the circuit.
For posistor relays, which are most common in technology LG, the test logic is different. A posistor in a cold state has low resistance. When dialing, you should see a specific value (usually from 5 to 50 Ohms, depending on the model). If the multimeter shows one (infinity) or zero, it means the posistor has burned out. It is also important to check the thermal protection, which is often built into the same housing or located nearby.
Checking the thermal protection is carried out by testing its contacts. When cold (at room temperature), the circuit should ring short (resistance 0 ohm). If the device shows an open circuit, it means that the protection has burned out or is in an open state due to residual heating. Let it cool longer or cool it carefully, but do not heat it on purpose unless necessary.
Nuances of checking a posistor
A posistor is a temperature-sensitive element. If you have just removed the relay from a hot compressor, its resistance may be high. Let it cool completely to room temperature (20-25 degrees) before taking measurements, otherwise the readings will be incorrect.
There is also a “shaking” method. Take the relay in your hand and shake it near your ear. If you hear a rattling sound inside, as if a piece of metal or ceramic has come off, then the relay is definitely faulty. A working device should not have any extraneous sounds when moving. This simple test often allows you to immediately reject the part without using instruments.
For more accurate diagnostics, you can compare the readings with a table of typical resistances for various compressor models. LG. Below are indicative values to help you interpret the measurement results.
| Component type | Normal resistance (Ohm) | Failure symptom | Action |
|---|---|---|---|
| Posistor (cold) | 5 - 50 Ohm | Infinity or 0 Ohm | Relay replacement |
| Thermal protection | 0 Ohm (closed) | Infinity (break) | Replacement of protection |
| Inductor | 1 - 10 Ohm | Open circuit | Replacing the relay |
| Contacts (input-output) | 0 Ohm | High resistance | Cleaning or replacement |
If your measurements coincide with column "Symptom of malfunction", then there can be no doubt - the part requires replacement. Remember that even if the resistance is normal, but traces of overheating are visually visible, the reliability of such a part is in question. Electrical breakdown could change the properties of the materials, and the relay may fail at any time.
Replacement and selection of a new relay for LG
If the diagnostics confirm a malfunction, you are faced with the task of selecting a new part. Relays for refrigerators LG are not universal, although some models can be interchangeable. The key parameters for selection are the compressor power (indicated on the nameplate, for example, 1/5 HP, 1/4 HP) and the type of refrigerant (R134a, R600a). The design of the housing and the location of the contacts are also important.
It is best to look for an original spare part using the article number indicated on the body of the old relay. The number may look like 6440JB0001A or a similar combination. If the original is difficult or expensive to find, you can choose a high-quality analog from well-known electronics manufacturers, such as Danfoss, Start or Pozitron. The main thing is that the electrical characteristics and mounting dimensions match.
The process of installing a new relay is the reverse of the dismantling process. Make sure the compressor studs are clean and not oxidized. If they have deposits, carefully clean them with fine sandpaper or a file, being careful not to damage the threads or drop metal particles inside. Push the new relay onto the studs all the way, making sure that it is seated tightly and evenly.
After mechanical installation, connect the wire connectors. Check that the bracket is securely fastened. Only after you are sure that everything is assembled correctly and no wires touch hot pipes or moving parts (if there is a fan), you can plug in the refrigerator. The first start may be accompanied by a slight click, after which the compressor should start working smoothly and without buzzing.
⚠️ Attention: If, after replacing the relay, the refrigerator turned on, worked for 5-10 minutes and turned off again, do not rush to panic. Perhaps the system has not yet reached the operating mode, or the protection is triggered due to other reasons (freon leakage, thermostat malfunction). Let the equipment work a full cycle.
Successfully replacing the relay often extends the life of the refrigerator LG by several years. This is one of the most cost-effective types of repairs that you can do yourself with minimal skills. The main thing is not to ignore the first symptoms and not to bring the compressor to a state where repair becomes impossible.
Frequently asked questions (FAQ)
Is it possible to start a refrigerator without a relay temporarily?
Technically, you can start the compressor by applying voltage directly to the starting winding, but do this Absolutely not recommended without experience. This is life-threatening (high voltage) and can completely kill the compressor, since the starting winding is not designed for long-term operation and will burn out in seconds. In addition, without thermal protection, you risk a fire.
Why does the relay burn out immediately after replacement?
If the new relay burns out quickly, it is usually not the reason. Most likely, the compressor itself is faulty (interturn short circuit, jamming), there are problems with the wiring or voltage surges in the network. The reason may also be the incorrect selection of relays by power or type. In such cases, in-depth diagnostics of the motor is required.
How much does a relay cost for an LG refrigerator?
The cost of a starting relay varies depending on the model and manufacturer. Original spare parts LG can cost from 1,500 to 3,000 rubles. High-quality analogues are cheaper, in the range of 500–1000 rubles. Price does not always guarantee quality, so it is important to check compatibility.
How to distinguish LG relays from other brands?
Relays of different brands may differ in the shape of the case, the color of the plastic and the location of the contacts. LG often characterized by specific connectors and markings. When purchasing, compare the photo of your part with the photo of the product in the store, paying attention to the number and geometry of the pins.
Is it possible to clean the relay contacts instead of replacing them?
If the relay is collapsible and the contacts are simply oxidized, they can be carefully cleaned with an eraser or fine sandpaper. However, if the cause is a burnt posistor or deformation of the bimetallic plate, cleaning will not help. Considering the low cost of a new part, it is easier and more reliable to make a complete replacement.