The situation when your Atlant refrigerator stops freezing, and the compressor is either silent or makes clicks and buzzes for a couple of seconds, often indicates a failure of the start-up relay. This small device is responsible for starting the engine and protecting it from overheating, being one of the most vulnerable structural elements. Replacing this part is one of the most common and affordable self-repair procedures that does not require complex specialized equipment.
However, the replacement process requires care and compliance with safety precautions, since the work is carried out with high voltage electric current. Incorrect connection can lead to burnout of the compressor windings or even a short circuit in the apartment wiring. In this article, we will analyze in detail the algorithm of actions, the connection diagram and the nuances of choosing compatible spare parts for different series of equipment.
Before starting disassembly, make sure that you have accurately diagnosed the problem, ruling out other possible causes, such as a freon leak or a thermostat malfunction. If the compressor is hot, but does not start, or starts and immediately stalls, the likelihood of a malfunction in the starting unit is extremely high. Let's look at how to correctly carry out the replacement and not damage an expensive unit.
Diagnostics of a faulty starting relay
The first sign that starting relay has failed is a characteristic sound. You may hear a loud click followed by a hum from the compressor that lasts 3-5 seconds, followed by another click and silence. This means that the engine is trying to start, but the starting winding does not receive the necessary impulse, and the thermal release breaks the circuit.
Visual inspection can also provide important clues. If traces of burning, melting of plastic or black soot are visible on the relay body, the part definitely requires replacement. Often inside the case you can notice the smell of burnt insulation, which indicates an interturn short circuit or overheating of the contacts.
For more accurate diagnostics, you can use a multimeter in dial mode. The resistance between the contacts of a working thermal release should be close to zero, and the starting coil (if the relay is electromagnetic) should have a certain resistance, depending on the model. If the device shows an open or short circuit where it should not be, the part is faulty.
⚠️ Attention: Before any diagnostics and removal of parts, be sure to disconnect the refrigerator from the power supply! Working with live electrical wiring is deadly.
Sometimes the problem lies not in the relay itself, but in a jammed compressor. To exclude this option, you can try to briefly apply voltage directly to the working winding (only for experienced craftsmen). If the motor hums and does not spin even with direct power supply, most likely the compressor itself is jammed, and replacing the relay will not help here.
Choosing a compatible relay for your model
Refrigerators Atlant are equipped with different types of compressors, so they are universal the relay does not exist. Most often, devices of the RTP, RT series or more modern analogues from third-party manufacturers like Danfoss or Secopare used. It is critically important to select a part with identical electrical characteristics and contact geometry.
The main parameter when choosing is the rated current. It should match the capacity of your compressor. If you install a relay with a lower current, it will constantly turn off the motor, preventing it from starting. If it is large, the motor winding may burn out during startup, since the protection will not work in time.
Pay attention to the type of fastening and the location of the contacts. In some models, the relay is inserted directly onto the three pins of the compressor, in others it is connected through a terminal block. Orientation is also important: there is always an arrow on the case indicating the “Up” position, which must be observed during installation.
| Relay type | Compatible Atlant series | Design features |
|---|---|---|
| RTP-1 (127-135) | Old models, MXM-1600, 1700 | Electromagnetic, requires precise position |
| RTK (1-3, 1-4) | MXM-1000, 102, 103 | Thermal, sensitive to overloads |
| LS-40B (Danfoss) | Modern models with Secop compressors | High reliability, universal fasteners |
| 3-FR | Two-compressor models | Compact, often comes complete with a capacitor |
Can I use a relay from another brand?
Yes, you can use analogues from Danfoss, Secop or Indesit if the electrical parameters (current, voltage) and the contact connection diagram match. The main thing is that the pinout and type match (induction/thermal).
When purchasing a new part, be sure to check the markings on the old device. Even if the appearance is the same, the internal characteristics may differ. Modern spare parts stores often use cross-tabs that allow you to select an analogue based on the number of your old relay.
Preparation for replacement and necessary tools
To carry out a high-quality replacement, you will need a minimum set of tools that most men have in their homes. The main thing is to provide convenient access to the rear of the unit and good lighting of the work area. You should not try to do this “by touch” or with a dim light bulb.
You will need the following tools:
- 🛠️ Screwdriver (Phillips and flat) to remove the protective casing.
- 🔧 Pliers or pliers for careful removal terminals.
- 📸 Smartphone or camera for photographing the connection diagram before disassembly.
- 🧤 Dielectric gloves (recommended for additional safety).
Before starting work, move the refrigerator away from the wall, providing access to the back panel. Remove the cardboard or metal cover covering the compressor area. It is usually secured with four bolts or latches. Be careful not to damage the cooling system tubes; they are thin and easily deformed.
Be sure to take a photo of how the old relay is connected. Despite the fact that the circuit is standard, different modifications may have nuances in the location of the wires. The photo will be your insurance if you forget which wire went where.
☑️ Preparation for repair
Inspect the surrounding elements. If you see a swollen capacitor or melted wires going to the relay, it is also better to replace them. Ignoring associated problems can lead to the new relay burning out in a short time.
Step-by-step instructions for connecting the relay
The process of removing and installing the relay takes no more than 15-20 minutes if you act carefully. The main difficulty is not to mix up the contacts and damage fragile elements. Follow the instructions sequentially, without haste.
First remove the retaining bracket or bar that presses the relay to the compressor housing. Then carefully disconnect the block with wires. If the wires are soldered (in older models), they will have to be cut off with side cutters, leaving a reserve for subsequent soldering, but most modern Atlases use a detachable connection.
Remove the old relay from the compressor pins. It may be a tight fit, so rock it slightly from side to side. Do not use excessive force to avoid breaking the ceramic insulator or damaging the tubes.
⚠️ Attention: Do not turn the relay upside down when removing! Inside there is a moving core or ball that can fall out or get stuck in the wrong position, which will make the part inoperable.
Install the new relay in place, strictly observing the orientation (arrow UP or UP should look up). Push it onto the three contacts of the compressor until it stops. Make sure it fits tightly and does not loosen.
Connect the wires in accordance with the photo or diagram taken earlier. Usually the scheme is as follows: two wires (phase and zero) go to the relay input terminals, and the third (ground or second wire of the motor) goes separately. Check the secure fit of the terminals - they should not fall off with a slight tug.
After connecting all the wires, return the retaining bar to its place. Make sure that the wires do not touch hot parts of the compressor or sharp edges of the case to avoid melting the insulation when heated.
Wiring diagram and pinout
Understanding the wiring diagram is necessary if you are changing the type of relay or the wires have been torn off. The compressor has three terminals arranged in a triangle. The upper contact (often one) is the common point (Common), the lower two are the starting (Start) and working (Run) windings.
In the classical circuit RTP or RTK, the phase wire comes to the input of the thermal release, then goes to the working winding. In parallel, an impulse is applied to the starting winding through the starting coil or contacts. The neutral wire is connected directly to the second terminal of the working winding.
If you are using a universal relay, carefully study the markings on its body. Contacts can be designated by numbers 1, 2, 3 or letters S, R, C (Start, Run, Common). An error in the connection can lead to the fact that the compressor will hum, but will not start, or the machine in the panel will immediately knock out.
Here are the basic principles of marking:
- 🔌 C (Common) — common wire, power is supplied here.
- ⚡ S (Start) —starting winding, connected through the starting device.
- 🔄 R (Run) —working winding, connected directly or through a thermal fuse.
For two-compressor refrigerators the scheme is doubled, but the principle remains the same. Each relay serves its own motor-compressor independently. When replacing, check each relay separately, as they may wear unevenly depending on the load.
Checking operation after replacement
After assembly, do not rush to close the back cover completely. Do a test run first. Plug in the refrigerator and listen. The compressor should start with a characteristic sound and operate smoothly, without humming or vibration.
Pay attention to the operation of the thermal relay. During the first minutes of operation, the compressor may become slightly warm, this is normal. However, if after 10-15 minutes of operation the relay body becomes too hot (it is impossible to hold your hand), it means that the wrong thermal relay has been selected or there are problems with ventilation.
Check whether the chamber is freezing. Run the refrigerator for 30-40 minutes, then check the internal temperature. If the evaporator is covered with frost and cold appears, it means that the repair was completed successfully. If the compressor works, but there is no cold, the problem may be a freon leak, and not the relay.
⚠️ Attention: If, after replacing the relay, the compressor starts clicking and stalling again, immediately turn off the device. Restarting it can finally kill the engine. Check that the connection is correct and the rating of the compressor power relay matches.
It is also worth checking the current consumed by the refrigerator using a current clamp, if possible. The current must not exceed the rated values indicated on the compressor nameplate. Excess current indicates an overload or malfunction of the windings.
How long should the compressor operate normally?
Depending on the load and temperature in the room, the operating cycle can range from 10 to 40 minutes, followed by a pause. If the refrigerator works without stopping for hours, this is a sign of a malfunction of the thermoregulation system or a leak.
Common mistakes during self-repair
Beginners often make typical mistakes that nullify all efforts. The most common one is ignoring the relay orientation. As mentioned earlier, many relays only work in a vertical position, and installing them sideways will cause the contacts to stick.
Another mistake is using electrical tape instead of firmly connecting the terminals. Compressor vibration over time loosens loose contacts, which leads to sparking and heating. All connections must be tightened or secured with factory clamps.
Some craftsmen try to “reanimate” the old relay by cleaning the contacts or knocking out the core. This is absolutely not worth doing. The service life of such restored parts is extremely short, and the risk of fire or compressor failure is too great. The price of a new relay is not commensurate with the risks.
It is also a mistake to install a relay “at random”, without checking the type of compressor. Atlant compressors can be induction or asynchronous, and their relays are fundamentally different. An inductive relay has a coil, and an asynchronous relay has a posistor (thermistor). It is impossible to confuse them, since they have different designs, but it is useful to know about this difference.
What to do if the new relay burns out immediately?
If the new relay burns out instantly, most likely the problem is not in it, but in the compressor. There may be an interturn short circuit in the motor windings, due to which the starting current exceeds the permissible values several times. The cause may also be a malfunction of the capacitor (if there is one in the circuit), which gives too powerful a pulse. Compressor diagnostics are required.
Is it possible to start a refrigerator without a relay?
Theoretically, you can start a compressor without a starting device using a button or an external circuit to supply a pulse to the starting winding. However, operating the refrigerator in this mode is prohibited. Without protection, the compressor will burn out at the first overload or power surge, since the relay acts as a fuse.
Why does the compressor hum after replacing the relay?
The hum can be caused by several reasons: incorrect connection (the windings are mixed up), jamming of the mechanical part of the compressor (wear of the piston group) or insufficient voltage in networks. If the hum is accompanied by heating and subsequent shutdown, the problem is in the starting circuit or jamming.
How often do you need to change the starting relay?
The service life of the relay depends on the quality of the electrical network and the frequency of switching on of the refrigerator. On average, a high-quality relay lasts 5-10 years. Frequent voltage surges and unstable network operation significantly reduce this period. No planned replacement is required, they are changed only in the event of a malfunction.