A sudden stop of the compressor is always an alarm for the owner of household appliances, especially if there are products inside. Refrigerators Atlant are famous for their reliability, but even their electrical components wear out over time, in particular the start-up relay. It is this small unit that is responsible for starting the engine and protecting it from overloads, so its serviceability is critical for the operation of the entire system.
If you notice that the motor is humming, but does not start, or turns on for just a few seconds and immediately stalls, there is a high probability that a replacement or proper reconnection of the relay is required. Performing this procedure yourself is possible, but requires strict adherence to safety precautions and an understanding of the principles of operation of the electrical circuit. Incorrect actions can lead to failure of an expensive compressor.
In this material we will look in detail at how to correctly diagnose a malfunction, remove the old device and connect a new relay to the refrigerator Atlant. You will learn about the nuances of connecting contacts, the differences between relay models and the precautions that must be observed during operation.
The principle of operation and the role of a starting protection relay
A starting protection relay is an electromechanical switch that supplies current to the starting winding compressor only at startup. As soon as the engine reaches the required speed, the relay opens the starting winding circuit, and the motor continues to operate only on the working winding. Modern models Atlant often use posistor-type relays, where the role of a switch is performed by a thermoelement.
The second function of the device is overheating protection. Inside the housing there is a bimetallic plate that opens the power circuit if the current exceeds the permissible limits or if the compressor overheats. Ignoring signs of relay malfunction can lead to burnout of the motor windings, which will make repairs economically unfeasible.
⚠️ Attention: Before any manipulations with the electrical components of the refrigerator, be sure to disconnect the device from the power supply. Working under voltage is deadly!
There are two main types of relays installed on Belarusian-made equipment: induction (electromagnetic) and posistor. Induction models have a movable core and often have a stem that can be adjusted by turning the device over. PTC devices do not have moving mechanical parts in the traditional sense and react to temperature changes.
Fault diagnosis before replacement
Before buying a new part and disassembling the unit, you need to make sure that the problem lies in the relay. Often the symptoms of compressor and relay failure are similar, so a thorough check is important. Primary diagnostics are carried out visually and by ear.
If, when you turn on the refrigerator, you hear a quiet hum lasting 5-10 seconds, followed by a loud click and silence, this is a classic sign of a “wedge” or a malfunction of the trigger mechanism. The compressor tries to start, the current increases, the thermal protection is triggered, and the circuit opens. It is also worth checking the contacts for oxidation or carbon deposits.
- 🔍 Visual inspection: Remove the relay and inspect the internal contacts. The presence of black soot, melted plastic or a burning smell indicates a breakdown.
- 🔊 Audio test: Shake the relay near your ear. If a knocking or rattling sound is heard inside (as from broken glass), it means that the ceramic posistor or mechanical part is damaged.
- 🔌 Checking the circuit: Using a multimeter in dial mode, check the integrity of the contacts. In a cold state, the posistor resistance should be low and the thermal protection contacts should be closed.
It is important to note that if the compressor does not respond at all to being turned on (there is not even a buzz), the problem may be in the thermostat or power circuit, and not in the relay. However, if the motor hums and knocks out the protection - in 90% of cases, it is the starter protection device that is to blame.
Preparation of tools and selection of components
To successfully replace the relay, you will need a minimum set of tools. You should not use complex devices, since the task is to mechanically replace the unit. The main thing is to provide access to the compressor, which is usually located in a niche at the back of the refrigerator.
You will need a flathead and Phillips screwdriver to remove the protective cover, pliers to fix the wires (if the terminals are tight) and, preferably, a multimeter for the final check. Also prepare a dry rag to clean the contacts from dust.
When choosing a new relay, it is critical to pay attention to the compressor model and the type of refrigerant. Refrigerators Atlant can be equipped with motors from different manufacturers (Atlant, Danfoss, Embraco), and relays for them are not always interchangeable. There is always a marking on the relay body, for example, RKT, RT, R-10 or R-3.
Pay attention to the number of contacts. The standard relay for single-compressor models has 3 or 4 contacts. If you install a relay with more terminals than on the old one, the extra ones are simply not used, but the seat must match perfectly.
| Relay marking | Compressor type | Power (W) | Features |
|---|---|---|---|
| RKT-1 | Atlant (SKN/SK) | up to 130 | Induction, adjustable |
| RTK-X-1 | Atlant | up to 170 | Posistor, universal |
| 17.501.15 | Danfoss/Secop | 1/5 - 1/4 HP | Posistor, requires adapter |
| P-10 | Atlant | up to 250 | For two-compressor models |
Removing the old start relay
The process of removing a faulty device begins with providing access to the compressor. Move the refrigerator away from the wall so you can work from behind. Remove the metal cover covering the engine compartment by unscrewing the mounting bolts.
On the compressor you will see a plastic box that is placed directly on three (or four) pins coming out of the motor housing. This is our relay. It can be fixed with a metal clamp or simply sit tightly on the contacts. If there is a bracket, carefully bend it with pliers.
Remove the relay carefully, slightly rocking it from side to side. Do not use excessive force to avoid damaging the ceramic insulators on the compressor. After removing the motor from the terminals, disconnect the wires coming from the capacitor and the power plug. It is recommended to photograph the connection diagram in advance so as not to confuse the colors of the wires when installing a new element.
⚠️ Attention: The compressor contacts are very fragile. If you remove the relay carelessly, you can break the ceramic bushings, which will lead to depressurization of the system and expensive repairs with refilling freon.
If the wires are stuck or oxidized, they need to be carefully cleaned. In some models Atlant the wires can be soldered to the relay terminals. In this case, you will need a soldering iron and solder for careful disconnection.
Connection diagram and installation of a new relay
Installation of a new device is carried out in the reverse order of dismantling. First of all, you need to connect the wires to the appropriate terminals. Standard markings on the relay body will help you navigate: L (Line) - phase, N (Neutral) - nl, C (Common) - common contact, R (Run) - working winding, S (Start) - starting.
In refrigerators Atlant the following logic is often used: the wire from the capacitor goes to the starting winding, the mains wire goes to the relay input. If you are using a universal relay, carefully study the diagram printed on the side of it. It may differ from the original one.
After connecting the wires, put the relay on the pins of the compressor. It should fit tightly, without distortion. Make sure the pins are fully seated in the sockets. If the relay is induction, check the position of the rod (core) - it should move freely inside the coil.
Sequence of actions:1. Connect the wires to the terminals according to the diagram.
2. Place the relay on the compressor terminals.
3. Secure with a metal bracket (if there was one).
4. Install the plastic protective cover.
5. Connect the refrigerator to the network.
Pay special attention to the orientation of the device. An arrow or inscription UPindicating the upper position is often stamped on the relay body. Incorrect orientation will lead to the fact that gravity will not be able to return the contacts to their original position, and the start will not occur.
Check performance and first launch
After assembly, do not rush to download the products. The first start after repair is a test mode. Plug in the refrigerator and listen. You should hear a confident start of the motor, no extraneous clicks (except for one starting click, if the relay is induction) and a smooth hum.
Check the heating of the relay housing during operation. It may warm up slightly in the first 10-15 minutes, but should not be so hot that it is impossible to touch. If the relay gets hot or a crackling sound is heard, immediately turn off the device.
- ✅ Successful start: The motor started working, after 5-10 minutes cold appeared in the chamber, the relay clicked (opened the starting circuit) and no longer makes sounds.
- ❌ Failure to start: The motor hums, but does not spins, or starts for a second and stalls. This may mean that the relay is selected incorrectly (does not match the current) or the problem is deeper (the compressor is jammed).
- 🔥 Overheating: If the relay gets very hot, the contact at the junction of the wires may be broken or the current consumption of the compressor is higher than the relay rating.
Let the refrigerator run idle for about 2 hours. During this time, it should gain temperature and turn off according to the thermostat signal. If the cycle was successful, the repair can be considered complete.
⚠️ Attention: If after replacing the relay the compressor knocks out the protection again, do not continue trying to start. This may indicate an interturn short circuit in the motor windings or a mechanical wedge of the piston group.
Frequent errors and precautions
When doing self-repair, beginners often make mistakes that nullify all efforts or lead to new breakdowns. One of the most common is ignoring the markings and installing the relay “by eye”. Even if the contacts are suitable in distance, the current characteristics may differ.
Another error is poor contact of the wires. If you simply twist the wires or clamp the terminal loosely, a transition resistance will arise at the connection. This will lead to local heating, melting of the insulation and possible fire. All connections must be reliable.
Also, do not forget about the capacitor. In some circuits, the starting capacitor is paired with a relay. If the capacitor is swollen or has lost capacity, the new relay may burn out the first time it is started due to incorrect phase shift. Always check the condition of adjacent elements.
Remember that warranty for the refrigerator tampering with the electrical part will be invalidated. If the equipment is still under warranty, it is better to contact an authorized service center.
Is it possible to repair the old relay, or is it only necessary to replace it?
Repair of the start-up relay is possible only if it is inductive and the problem is stuck contacts. They can be carefully cleaned with fine sandpaper. PTC relays cannot be repaired - if the ceramic element is destroyed, only a complete replacement of the unit will save you.
Why does the relay heat up during operation?
Slight heating up to 50-60 degrees is normal for a working relay. If the temperature is higher, the reasons may be poor contact of the wires, an incorrectly selected relay rating (too low current) or a malfunction of the compressor itself, which consumes increased current.
How to determine that it is the compressor that has burned out, and not the relay?
Ring the compressor windings with a multimeter, turning off the relay. If the resistance between the contacts shows infinity (break) or zero (short circuit), or the resistance between the housing and the contacts is not infinite (ground fault), the compressor is faulty.
Do I need to wait after shutting down before turning it on again?
Yes, definitely. After turning off the refrigerator, at least 5-10 minutes should pass. This time is necessary to equalize the pressure in the system and, more importantly, to cool down the posistor in the relay. If you turn it on immediately, the posistor will not have time to cool down and will not start the compressor.