Sudden stop of the compressor or characteristic clicks repeated at regular intervals often signal a failure of the motor starting mechanism. In Belarusian-made refrigerators Atlant this part is one of the most vulnerable elements of the electrical circuit. If your unit has stopped freezing, but the light is on inside, and the compressor itself is either silent or hums for a few seconds and then goes silent, the problem most likely lies in this unit.
Independent replacing the start relay is a procedure that is accessible even to a person without deep knowledge in electrical engineering, subject to compliance with safety regulations. You don't need a complex professional tool; a basic home craftsman's kit is enough. A correctly selected and installed part can bring the refrigerator back to life, avoiding an expensive service visit.
However, before starting work, you need to make sure of the diagnosis, since similar symptoms can also appear with other malfunctions, for example, when the piston group is jammed or the motor windings are broken. In this article, we will analyze in detail the algorithm of actions, methods of checking the functionality of old components and the nuances of choosing a new spare part for various modifications of equipment.
Diagnostics of a malfunction and signs of breakdown
The first step in any repair is to accurately identify the problem. In the case of refrigerators Atlant, the symptoms of a malfunction of the start-up protection relay (PPR) are quite specific and noticeable to the naked eye, as well as by ear. The main symptom is the cyclic turning on and off of the motor-compressor at intervals of approximately 10–20 seconds.
When you try to start, you can hear a loud metallic click, followed by a humming sound from the engine, lasting several seconds, followed by another click and silence. This means that start relay tries to start the engine, but due to an internal malfunction it opens the circuit, the thermal protection is activated, and the cycle repeats.
⚠️ Attention: If when the refrigerator is running you feel a persistent burning smell or see sparking in the compressor area, immediately turn off the device from the network. Operation in this condition can lead to fire or complete combustion of the motor windings.
It is also worth paying attention to the temperature of the compressor housing. If it heats up to very high temperatures within a short time of operation, this may indicate that the starting winding remains energized for too long or is not switched off at all. In normal operation, the relay should cut off the starting winding immediately after the engine reaches the required speed.
Design and principle of operation of the starting relay
To correctly replace a part, you need to understand how it works. In refrigerators Atlant most often there are two types of relays: posistor and induction. Posistor models, such as RTP-1, RT, work due to the properties of the semiconductor material to increase resistance when heated, opening the starting winding circuit.
Induction relays, for example, the R-1, R-2, R-3 series, use the principle of an electromagnet. When current passes through the coil, a magnetic field is created, which draws in the core and opens the contacts. There is also often built-in protection inside the case, which opens the circuit when there is an overcurrent or overheating of the compressor. thermal relay protection that opens the circuit in case of overcurrent or overheating of the compressor.
Structurally, the device is a plastic case, inside which there are contacts, springs, a coil or posistor, as well as a moving mechanism. Wires are connected to the relay from below, and from above it is put on the contacts of the compressor. It is important to understand that this is a disposable element: if the internal filling is burnt out or deformed, it cannot be repaired, only replaced.
- 🔌 Contact group —provides voltage to the motor windings.
- 🧲 Electromagnetic coil (in induction relays)—creates a field to open the circuit.
- 🌡️ Posistor (in RTP type relays) - heats up with current and increases resistance.
- 🛡️ Bimetallic plate - thermal protection element that responds to overheating.
Different models of refrigerators Atlant can be equipped with different types of relays depending on the power of the installed compressor. For example, for powerful two-compressor models, more massive devices capable of switching high currents can be used.
Necessary tools and preparation for work
Before starting disassembly, it is necessary to prepare the workplace and tools. Replacing a relay does not require specialized equipment, but care and the availability of basic tools are required. You will need a standard Phillips screwdriver, pliers and, preferably, a multimeter for preliminary testing.
Safety is critical. All manipulations inside the electrical circuit of the refrigerator are carried out only with the device completely disconnected from the network. Unplug the power cord from the outlet and make sure that there is no condensation or moisture on the back wall of the unit.
☑️ Preparing to replace the relay
It is also recommended to find out the exact model of your refrigerator in advance. This information is located on a sticker located inside the camera or on the back wall. Knowing the model, you will be able to select an identical spare part, which will eliminate problems with compatibility of seats and electrical characteristics.
⚠️ Attention: Do not attempt to diagnose or replace while standing on a wet floor or holding metal water pipes with your other hand. This can lead to electric shock if accidentally turned on or breakdown of the insulation.
Removing the old start relay
The process of removing the faulty part begins with access to the compressor. Move the refrigerator away from the wall to gain clear access to the lower rear of the cabinet. On some models Atlant you may need to remove the metal cover covering the engine compartment, which is secured with bolts or latches.
Locate the black cylindrical or pear-shaped compressor tank. There is a plastic box on the side or top of it - this is our desired relay. It may be covered with an additional metal casing, which must be carefully removed by bending the fasteners or unscrewing the screws.
Before pulling the relay, carefully inspect the method of its fastening. In most cases, it simply slides onto the three pins of the compressor and is secured with a spring clip or plastic tabs. If there is a bracket, it must be carefully pressed out with pliers.
- 📸 Take a photo of the location of the wires before disconnecting so as not to confuse them when installing a new relay.
- 🔌 Carefully remove the terminal block with the wires if it is not integrated into the relay body.
- 🔧 Remove the retaining bracket or bar holding the relay in place.
- 🖐️ Rocking from side to side, pull the relay down from the compressor contacts.
If the relay is stuck or is sitting very tightly, do not use excessive force to avoid damaging the tubes compressor. Gently wiggling and gently pulling downwards will usually help remove the part. Pay attention to the condition of the contacts: if they are blackened or melted, this is a sure sign of overload or poor contact.
What to do if the relay cannot be removed?
Sometimes over years of use, the plastic can become deformed due to temperature. Try warming the case slightly with a hairdryer (without overheating!) or using a thin screwdriver to gently release the latches without breaking them.
Correspondence table and selection of a new part
Choosing the right analogue is the key to successful repair. Relays are selected primarily based on compressor power and refrigerant type, although visually they may look similar. Installing an unsuitable part may result in the engine not starting or, conversely, the starting winding not being switched off, which will quickly damage the motor.
In refrigerators Atlant the most common relays are the RT (induction) and RTP (posistor) series. Below is a correspondence table that will help you navigate when purchasing spare parts in the store.
| Relay marking | Type | Compressor power | Compatibility |
|---|---|---|---|
| RT-21 | Induction | up to 200 W | Refrigerators with compressors SKN, SKNB |
| RT-23 | Induction | up to 250 W | Powerful single-compressor models |
| RTP-1 | Posistor | up to 100 W | Low-power models, freezers |
| RTP-5 | Posistor | up to 150 W | Average power, wide compatibility |
When purchasing, pay attention not only to the markings, but also to the location of the contacts and the shape of the case. Some modern universal relays may have adapters included, but Atlanta it is better to look for original or proven analogues (for example, Danfoss/Tecumseh with the appropriate adapter) so as not to deal with the "collective farm" with wires.
If you do not find the exact marking on the body of the old relay (it could have been erased or burned), be guided by the compressor model, which is stamped on the metal tag of the motor itself. The permissible power and the type of starting device required are always indicated there.
Installation and connection instructions
Installation of a new relay is carried out in the reverse order of dismantling. Take the new part and make sure there is no visible damage. Insert the relay onto the compressor contacts. It should fit tightly, without play, but also without excessive force.
It is important to orient the part correctly: on the body there is usually a marking UP (top) or an arrow pointing upward. Also, on the back wall of the relay there is often a connection diagram, which indicates which contact is responsible for what (start, operation, general). Follow this diagram.
Connection diagram (standard):L (Line) - Phase (common wire)
S (Start) - Start winding
R (Run) - Working winding
After mechanical installation, connect the wires. If your case uses a terminal block, simply insert the wires into the appropriate sockets until they click into place. If the wires are soldered or placed on separate contacts, make sure the connection is secure.
⚠️ Attention: Make sure the wires do not touch hot parts of the compressor or condenser tubes. When heated, the insulation may melt, which will lead to a short circuit.
Secure the relay with a retaining strip or bracket. Reinstall the protective metal casing and rear engine compartment cover. Check that all fasteners are tightened and the wires are not subject to vibration.
Checking functionality after replacement
After assembly, you can proceed to testing. Plug in the refrigerator. In the first seconds, you can hear a characteristic click and hum, which should quickly (after 1-2 seconds) turn into a smooth hum of a working compressor. If the motor started working and began to gain temperature, the replacement was successful.
Pay attention to the operation of the refrigerator during the first hour. The compressor should not switch off every 10 seconds. It should work in cycles: for example, it works for 20 minutes, rests for 10 minutes (the parameters depend on the settings of the thermostat and the loading of the chamber).
- ✅ The compressor started the first time without buzzing or clicking.
- ✅ After 15-20 minutes, the tubes in the freezer became cold.
- ✅ The relay body does not heat up to the point where it is impossible to touch.
- ✅ There is no smell of burning or melted plastic.
If, after turning on, clicks are heard again and the motor is silent, immediately turn off the device. This may mean that the new relay is also faulty, selected incorrectly, or the problem lies deeper - in the compressor itself (interturn short circuit, jamming).
Why does the new relay heat up?
Slight heating up to 60-70 degrees for some types of relays (especially posistor) is the norm. However, if the body melts or smokes, this is an emergency.
Common mistakes during self-repair
Despite the apparent simplicity, beginners often make mistakes that can negate all efforts or damage the equipment. One of the most common mistakes is ignoring markings UP. Installing the relay upside down disrupts the operation of the mechanical group of contacts, and the engine simply will not start.
Another mistake is trying to clean the contacts of the old relay with sandpaper and it. In refrigerator conditions, this is a temporary measure, which often leads to burning of the contacts after a few days. In addition, the calibration of the thermal protection is violated, which is dangerous for the motor.
Also, do not neglect checking the capacitor if it is in the circuit. In some circuits, there is a starting capacitor in parallel with the starting relay. If it is swollen or has lost capacity, even a new relay will not be able to start the engine correctly.
Remember that starting relay is a consumable item with a limited resource. Replacing it every 5-10 years is normal practice to extend the life of the refrigerator Atlant. Regular maintenance and timely replacement of this inexpensive part will save you from buying a new unit.
Is it possible to use a relay from another brand, for example, Denmark (Danfoss)?
Yes, it is possible, but only if you have a special adapter, which comes complete with universal relays. The Danish relay may not fit directly onto the contacts of the Belarusian compressor due to the different geometry of the pins. It is also important to ensure that the power matches.
Why does the relay burn out again after a short time?
If the new relay fails quickly, then it is not the reason. Most likely, the problem is in the compressor itself: interturn short circuit of the windings, wear of the piston group, or problems with the motor cooling system. Also, the cause may be a power surge in the network.
How to determine whether a compressor is working without a relay?
There is a “direct start” method, when voltage is supplied directly to the working and starting windings, bypassing the relay. This is a dangerous procedure that requires the skills of an electrician. If, during direct start, the motor hums, but does not spin, and the shaft does not turn manually, the compressor is jammed.
Where can I find the power marking on an old relay?
Usually the power (for example, 1/5 HP, 1/4 HP or in Watts) is indicated on the side or top edge of the plastic case. If the inscription is erased, look for markings in the form of a code (for example, 16.16, 18.18), the decoding of which can be found in the manufacturer’s reference tables.