The refrigerator is the heart of the kitchen, and when it stops beating, panic reigns in the house. Food begins to spoil, and the flooring turns into an icy river. Often, equipment owners LG face a situation where the motor hums for several seconds, then there is a loud click, and there is silence. It is at this moment that start-up protection relaycomes into play, which is the hero of our today's analysis.
Finding this small but critically important component is not a task for the faint of heart, but it is quite solvable with basic skills. The location of the unit depends on the model of your unit, whether it is a classic two-chamber version or a modern No Frost. In most cases, the relay is hidden in the back of the device, but you won’t be able to get to it without preparation.
Before you grab a screwdriver, you need to understand how the system works. A compressor is an electric motor that requires an impulse to start and current control to protect it. All these functions are performed by the starter protection device. If you hear a characteristic knock or see that the refrigerator is not freezing, the problem probably lies in this connection. Let's figure out where to look for the hero of the occasion.
⚠️ Attention: Any repair work on refrigeration equipment should be carried out only after the device has been completely disconnected from the power supply. Residual voltage can be life-threatening.
Design of the compressor group and the role of the relay
To successfully find the relay, you need to know where exactly to look. The compressor in refrigerators LG is usually located in the lower rear part of the case. This is a black, round or pear-shaped metal tank that has copper tubing attached to it. A special plastic box is put on the motor rod (shaft) protruding from the housing - this is the required unit.
Inside this box there is complex mechanics hidden. Start relay responsible for supplying voltage to the starting winding of the engine only at the moment of starting. As soon as the rotor picks up speed, the mechanism opens the circuit. In parallel, thermal protection operates, which opens the contacts in case of overheating or overcurrent. In modern models, these two elements are often combined into a single unit.
The location of the unit is always standard: it is located directly at the compressor terminals. However, it can be difficult to access. Some models LG requires removing the rear metal cover covering the engine compartment. In other cases, especially in older models, access is open, but accumulated dust and cobwebs interfere.
- 🔍 Start relay — ensures engine starting.
- 🌡️ Thermal relay —protects against overheating.
- ⚡ Capacitor —smoothes inrush currents (in some circuits).
Why do relays fail?
Frequent power surges in the network, rare switching on of the refrigerator (long downtime) or natural wear of contacts lead to sticking or burnout of internal elements relay.
How to access the back panel of the refrigerator
The first step towards repair will be preparing the workplace. You will need to move the refrigerator away from the wall. Make sure the floor is clean so you don't scratch the finish or get your hands dirty with age-old dust. To do this you will need a Phillips screwdriver, possibly some pliers and a flashlight. Without good lighting, it will be difficult to look into the engine compartment.
The rear wall of the refrigerator LG can be closed with a metal sheet secured with screws or plastic clips. Older models may have a lot of screws and may be covered in rust. Carefully unscrew all fasteners, placing them in a magnetic tray or jar so as not to lose them. Remove the cover, being careful not to pull sharply, so as not to damage the soldered tubes.
If you have a model No Frost, the design may differ. Sometimes access to the compressor requires removing the lower decorative panel from the front, near the floor. In such cases, look for ventilation holes and carefully pry off the panel. The main thing is not to use force where there is resistance, plastic is fragile.
☑️ Preparing for access
Visual identification of the start-up protection device
After removing the cover, the compressor will appear to your eyes. On the top of it, where the three electrical contacts come out, you will see a black or white plastic piece. This is start-up protection relay. It can be round, square or rectangular. The manufacturer's logo (for example, LG, Danfoss, Secop) and model number are often stamped on the case.
The relay is attached directly to the terminals of the compressor. It can be fixed with a metal clamp or simply sit tightly on the contacts due to the springy properties of the plastic. If you see that a part is loose or has traces of soot, melting or cracks, this is a sure sign of a malfunction. Normally, the plastic should be intact and clean.
Pay attention to the wires going to the relay. They should not be frayed or melted. Often the problem lies not in the relay itself, but in poor contact at the terminals. However, if the relay emits a burning smell or rattles when shaking (in the off state), its replacement is inevitable.
Types of relays and their markings in LG models
Refrigerators LG are equipped with different types of compressors, and, accordingly, different relays. The most common are posistor (solid-state) and induction relays. PTC models are more modern, reliable and have no moving parts inside, except for a bimetallic protection plate. Induction ones operate on the principle of an electromagnet and mechanical opening.
The markings on the relay body are the key to finding an analogue. Numbers and letters such as PTM R6 or 115102indicate compatibility. It is important to understand that the relay is selected not only by the brand of the refrigerator, but also by the power of the compressor. Installing an unsuitable relay can lead to burnout of the motor windings.
The table below shows the main differences and characteristics that should be taken into account:
| Relay type | Principle of operation | Characteristic feature | Term services |
|---|---|---|---|
| Induction | Electromagnetic | Click at start | Average |
| Posistor | Thermal (posistor) | Silence or quiet hum | High |
| Combined | Combined | Single block | Depends on quality |
| Sealed | Soldered | Not subject to repair | Long-lasting |
⚠️ Attention: Compressor specifications may vary depending on model year. Always check the markings on the old part with spare parts catalogs or a store consultant.
The process of dismantling and installing a new relay
Replacing a relay is a technically simple process, but requires care. First you need to disconnect the wires. They can be mounted on terminals or detachable. Make a note or take a photo of which wire goes where. Usually there are three of them: phase, neutral and ground (or leads to the windings).
Then remove the fixing bracket, if any. It can be spring or screw. After this, the relay can be removed from the compressor terminals. It can be removed by hand, but be careful: the compressor leads are fragile and can be easily broken if handled carelessly. Do not wobble the relay from side to side too much.
Installing a new element is done in the reverse order. Push the relay onto the contacts as far as it will go, making sure it fits snugly. Secure the bracket. Connect the wires according to your diagram or photo. Turn on the refrigerator and listen. The engine should start smoothly, without buzzing or clicking.
Diagnostics of faults without disassembly
Before going inside, you can carry out an initial diagnosis. If the refrigerator hums, clicks and turns off after 5-10 seconds, this is a classic symptom of a faulty start relay or the compressor itself. If the motor is silent, but the light in the chamber is on, the problem may be in the thermostat or control board.
You can check the relay with a multimeter. To do this you need to remove it. Ring the contacts: in a cold state, the resistance of the posistor should be low, and the contacts of the thermal relay should be closed. If the multimeter shows an open or short circuit where there should not be one, the part is faulty.
Also pay attention to the temperature of the relay body after a startup attempt. If it becomes red hot in a couple of seconds, this is a sign that the engine does not start and the current is flowing through the protection. This may be due to a jammed compressor, and not just because of the relay.
Is it possible to repair an old relay?
Theoretically, the induction relay can be disassembled, clean the contacts from carbon deposits and put them back together. However, practice shows that such a measure gives only a temporary effect. The metal is already tired, the spring has weakened. It is safer and safer to buy a new part, which is inexpensive.
Why does a new relay burn out?
If a new relay burns out after a short time, then it is not the reason. Most likely, the compressor itself is faulty (interturn short circuit) or there are problems with the voltage in the network. In this case, professional diagnostics are necessary.
Where to buy a relay for LG?
Original spare parts can be found at authorized LG service centers. Also, a wide range of compatible analogs (for example, Danfoss) are presented in spare parts stores for household appliances and on specialized online sites.
Is the gas inside the compressor dangerous?
Yes, refrigerant circulates in the system. As long as you are not sawing or drilling into the copper tubing, the gas is under pressure, but in a closed loop. It's safe to just remove the relay. Do not bend the tubes when working.