A sudden stop in the operation of refrigeration equipment often takes you by surprise, especially when there are perishable products in the chambers. Equipment owners Atlant often encounter a situation where the compressor hums, but does not start, or turns off after a few seconds with a characteristic click. In most cases, the reason for this behavior is the failure of the start-up relay, which is responsible for starting the engine and protecting it from overloads.
Diagnostics of this unit does not require complex equipment, however, it requires strict adherence to safety precautions and basic knowledge of electrical circuits. Start relay is a key element in the motor power supply circuit, and its malfunction blocks the operation of the entire cooling system. Understanding the principle of its operation will allow you to independently determine the need to replace the part without calling a technician.
In this article we will analyze in detail the algorithm for removing and checking the relay using various methods. You will learn how to distinguish a burnt winding from stuck contacts and what tools you will need for an accurate diagnosis. A competent approach to repair will help save budget and time, returning the refrigerator to full functionality.
Signs of a malfunctioning start relay
You can determine that the problem lies in the starting mechanism by a number of characteristic symptoms that appear in the operation of the compressor. Most often, users notice that the refrigerator turns on, there is a loud click, followed by silence or a hum that ends abruptly. After a certain period of time, usually from 10 to 20 minutes, the cycle repeats again.
Another alarming signal is the strong heating of the compressor housing in the absence of cold in the chambers. If the engine tries to start, but the relay does not close the starting winding, the current in the working winding increases sharply, which leads to overheating and thermal protection. A visual inspection can also reveal traces of burning, melting of plastic or oxidation of contacts on the relay itself.
- 🔊 The compressor makes a loud click and immediately goes silent.
- 🔥 The motor housing gets very hot, but no cold is produced.
- ⚡ When turned on, you can hear hum, but the starter does not start.
- 🌫️ The appearance of a burning smell or smoke in the compressor compartment area.
It is important to note that similar symptoms can be observed with an interturn short circuit in the engine itself. That is why checking the relay must be carried out comprehensively to avoid more serious breakdowns. Ignoring these signs can lead to the final failure of the compressor, which will require not replacing a cheap part, but expensive repairs or purchasing a new unit
ata.⚠️ Attention: If after clicking the relay you feel a persistent smell of burnt wiring, immediately disconnect the refrigerator from the network. Further attempts to start may lead to a fire hazard.
Design and principle of operation of the relay
In order to carry out quality diagnostics, you need to understand how this small but important unit works. In refrigerators Atlant electromagnetic starting relays are most often used, the operation of which is based on the principle of closing contacts under the influence of a magnetic field. Inside the case there is a coil through which the current of the working winding of the motor passes, and a movable core with a contact group.
When the refrigerator is turned on, the current passes through the coil, creating a magnetic field that draws in the core and closes the contacts of the starting winding. The engine begins to accelerate. As soon as the speed reaches the nominal values, the current drops, the magnetic field weakens, and the core, under the influence of gravity and the spring, returns to its original position, opening the circuit. In parallel with this, thermal protection works, turning off the motor when it overheats.
There are also relays with a posistor (thermistor), which operate on a different principle. In them, current passes through a ceramic element, which heats up and increases its resistance, opening the starting winding circuit. You can determine the type of your relay by its markings or appearance: devices with a posistor, as a rule, do not have moving mechanical parts inside and are often called “solid-state.”
Removing the relay for testing
Before starting any diagnostic work, you must completely de-energize the refrigerator. Unplug the power cord and make sure there is no voltage at the compressor terminals. Only after this can you begin to remove the protective cover located at the lower rear part of the unit.
The relay on compressors Atlant is usually attached directly to the side output of the engine and secured with a metal bracket or plastic latches. Carefully remove the retaining bar and disconnect the connector with wires. Be careful: the wires may be stiff due to aging insulation, and sudden tugging can damage them.
Remove the relay from the compressor pins. It can fit tightly, so slight rocking from side to side is allowed. Pay attention to the condition of the contact group on the relay itself and the response pins of the motor. If black deposits or oxidation are visible on the metal, they must be cleaned before installing a new part.
Visual inspection and initial diagnostics
The first stage of testing should be a thorough visual inspection of the removed device. Shake the relay near your ear: if you hear the ringing of a detached element inside, it means that the mechanism is destroyed and the part requires mandatory replacement. The integrity of the case also plays an important role: cracks can allow moisture and dust to pass through, which leads to a short circuit
any.Inspect the contact pads. If they are blackened or covered with soot, this indicates a spark has slipped and poor contact. In some cases, carbon deposits can be carefully cleaned with fine sandpaper or a file, but if the plastic around has melted, it is better not to risk it and install a new component. Thermal protection, built into the case, should also not have signs of overheating.
For models with a posistor, there may not be a visual defect obvious. Cracks in a ceramic element or a change in its color indicate that it has been exposed to critical temperatures. However, even an apparently serviceable posistor may not hold the required resistance, so without an instrument test you cannot rely only on inspection.
Checking a relay with a multimeter
The most accurate diagnostic method is to use a multimeter (tester). Switch the device to resistance measurement mode (Ohms). To check the electromagnetic relay, you need to ring the coil. The probes are applied to the corresponding contacts: the resistance of a working coil is usually several tens of ohms (for example, from 20 to 60 ohms, depending on the model).
If the device shows one (infinity), then there is a break in the coil, and the relay will not create a magnetic field to start. If the resistance is close to zero, an interturn short circuit is possible. Next, the thermal protection is checked: in a cold state it should ring (resistance is close to 0 Ohm). When heated (you can gently warm it up with a hairdryer), the contacts should open.
For posistor relays, the technique is slightly different. When cold, the resistance between the contacts should be low (about 10-50 ohms). After applying voltage (which is difficult to do at home without a circuit), the resistance should increase sharply. If the posistor “rings” like zero or like infinity in a cold state, it is faulty.
| Test type | Normal readings | Signs of malfunction | Action |
|---|---|---|---|
| Resistance coils | 20 - 60 Ohm | Infinity or 0 Ohm | Relay replacement |
| Thermal protection (cold) | 0 Ohm (Ringing) | Infinity | Replacing the relay |
| Posistor (cold) | 10 - 50 Ohm | Infinity or short circuit | Replacing the relay |
| Contacts (visual) | Pure metal | Scale, oxidation | Cleaning or replacement |
If you have just removed part from a working (or trying to work) compressor, let it sit for 15-20 minutes. The thermal protection may be open due to residual heat, which will give a false signal of a malfunction.
Frequent diagnostic errors
Many novice masters make typical mistakes that lead to false conclusions. One of them is to check the relay, which is not removed from the compressor, without disconnecting the wires. In this case, you measure the resistance of the entire motor circuit, and not the relay itself, which makes diagnostics meaningless.
Another common mistake is ignoring the condition of the compressor pins. Even a new relay will not work if the contacts on the motor itself have oxidized. They also often forget to check the integrity of the supply wires, which may be broken or rubbed against the body.
- ❌ Trying to start a refrigerator with a known faulty relay "for testing."
- ❌ Using a relay from another model without checking compatibility.
- ❌ Ignoring the condition of the wiring and terminal block.
You should also not forget that frequent operation of the protection can be caused not only by a breakdown of the relay, but also by problems with the compressor itself (for example, the piston group wedge) or low voltage in the network. Therefore, if replacing the relay does not help, it is necessary to carry out a more in-depth diagnosis of the refrigeration unit.
⚠️ Attention: The characteristics of the relay (compressor power, refrigerant type, contact location) must strictly correspond to the original. Installing an unsuitable part can lead to burnout of the motor windings.
Replacement and testing after repair
If diagnostics confirm a malfunction, you must purchase a similar relay. When purchasing, pay attention to the markings: compressor power, type of refrigerant (R134a or R600a) and contact location. Universal relays require careful selection according to current parameters and connection diagram.
Installation of a new part is carried out in the reverse order of removal. Make sure that the relay is seated on the pins all the way and secured with a bracket. Connect the wires according to the diagram or photograph taken earlier. After assembly, do not rush to close the back panel.
Plug in the refrigerator and listen. The compressor should start with a characteristic hum, the relay may click once at start, after which the engine runs smoothly. After 5-10 minutes, check the heating of the condenser (grid at the back) - it should begin to warm up, which indicates the start of refrigerant circulation.
In conclusion, it is worth noting that regular maintenance and timely replacement of worn-out elements extend the life of the refrigerator Atlant for many years. Checking the relay yourself is a skill that can help out at a critical moment and save your products.
Is it possible to temporarily start a refrigerator without a relay?
Technically, you can start the compressor by applying voltage directly to the starting winding, but doing this is strictly not recommended without special knowledge. This can lead to engine combustion or a fire, since the thermal protection will not work.
How much does a new relay cost for Atlant?
The cost of a start-up protection relay varies from 300 to 1500 rubles, depending on the type (electromagnetic or posistor) and the manufacturer of the spare part. Original parts are more expensive than analogues.
Why does a new relay burn out after a short time?
A common reason is problems with the compressor itself (difficult starting, wedge) or unstable voltage in the network. It is also possible to use a relay with unsuitable power parameters.