A sudden stop in the operation of the refrigerator or its inability to maintain the set temperature often indicates problems with starting the engine. In most models of the domestic brand Atlant a compact but critical unit is responsible for this process - the start-up relay. It is this that supplies the initial impulse to the motor windings and turns it off when overloaded, preventing the burning of an expensive compressor.
If you notice that your Atlant refrigerator hums, but does not start, or turns on for only a few seconds before going silent again, this is most likely the cause lies in this element. Self-diagnosis allows you to save time on calling a technician and accurately determine the need to replace a part, which can be purchased in specialized stores.
Before you begin disassembling, it is important to understand that we are talking about an electrical device that operates under high voltage. Any manipulations with wiring and internal components require compliance with basic safety rules. Checking the relay requires that the device be disconnected from the power supply to avoid electric shock. In this article we will analyze in detail the design of the unit, the symptoms of its breakdown and the algorithm of actions for accurate diagnosis.
Failure symptoms start-up protection relay
Understanding how the refrigerator behaves when the relay breaks down helps to quickly localize the problem without deep intervention. Most often, the owner is faced with a situation where the engine tries to start and makes a characteristic click, but the compressor does not make a full hum. This is a classic sign that the starting winding does not receive the necessary impulse or the circuit is broken by the protective mechanism.
Another alarming signal is the cyclic switching on and off of the unit at intervals of 10–20 seconds. In this case, the compressor housing may heat up, and the temperature inside the chamber gradually increases. Protective relay in such cases it works correctly, opening the circuit when overheating or current overload, but the reason lies in the fact that the trigger mechanism does not perform its function.
Sometimes the malfunction is accompanied by extraneous sounds, reminiscent of rattling or ringing of metal, coming from the rear of the unit. This may indicate mechanical failure of the internal contacts or core inside the relay housing. In rare cases, there is a complete lack of reaction from the refrigerator when plugged in, although the light in the chamber is on.
⚠️ Attention: If you hear a loud crack or see sparking when you try to start, immediately unplug the refrigerator from the outlet. Operating the device with faulty starting equipment can lead to burnout of the compressor windings.
For clarity, we systematize the main signs indicating the need to check the unit:
- 🔊 The compressor hums for 5-10 seconds, then there is a click and there is silence.
- 🌡️ The engine heats up, but the refrigerator does not cool, the temperature in the chambers rises.
- ⚡ When connected to the network, the circuit breakers or plugs immediately knock out.
- 🔌 A visual inspection revealed melting of the relay housing or blackening of the contacts.
Design features and types of relays in Atlant refrigerators
In refrigerators Atlant, as in many other models, start-up protection relays are used, which can be combined in one housing or divided into two separate blocks. The most common are induction (electromagnetic) relays, the operating principle of which is based on the passage of current through a coil. When starting, the current is high, the magnetic field draws in the core and closes the contacts of the starting winding.
As the engine speed increases, the current drops, the core, under the influence of gravity (or a spring), lowers, opening the starting circuit. Thermal protection operates in parallel: the bimetallic plate heats up from the passing current and, when the nominal values are exceeded, bends, breaking the power circuit. In more modern models, there may be posistor relays, where the role of a switch is performed by a thermoelement.
It is important to distinguish between these types, since the methods of their primary diagnosis may differ. Induction relays often produce an audible click when operating properly, while posistor relays can be quieter. Models Atlant typically use relays of the RT, R-1, R-2 series or more modern analogues with markings starting with 100M or 33N.
Marking of Atlant relays
On relay cases there are often codes like 100MN1, 33N, RTK-1X. The first numbers usually indicate the rated current, and the letter designations indicate the type of design and installation orientation (horizontal or vertical).
The location of the relay in refrigerators of this brand is standard: it is located in the rear lower part of the unit, directly on the compressor casing. To access it, it is not always necessary to completely dismantle the rear panel; often it is enough to remove the plastic box covering the engine compartment. Fastening is carried out either with latches or screws, and connection is made through detachable terminals.
Visual inspection and initial diagnosis
The first stage of testing should always be a thorough external inspection. Even without the use of measuring instruments, a number of critical defects can be identified. Remove the compressor cover, disconnect the relay connector from the motor contact group and remove the unit itself. Pay attention to the condition of the plastic case: the presence of cracks, traces of soot or melting indicates overheating and breakdown.
Shake the relay next to your ear. If you hear a clear knocking or rattling sound from loose parts inside, this is a sure sign of destruction of the internal components. In a working induction relay, the core should be fixed or move with little resistance, but not dangle like a rattle. Also inspect the contact pads for oxidation or carbon deposits.
Pay special attention to the contacts that connect to the compressor. If they are blackened or covered with a greenish oxide coating, this creates additional resistance, overheating and unstable starting. Cleaning the contacts at home is possible, but if the plastic around them is deformed, the part must be unconditionally replaced.
Often during a visual inspection you will notice that the hole for the compressor rod to enter the relay is widened or has signs of wear. This leads to a loose fit and malfunction of the switching mechanism. In such cases, even a working electrical part will not ensure correct starting of the engine.
Checking the relay with a multimeter: step-by-step instructions
The most accurate way to determine the performance of the unit is to use a multimeter in resistance (Ohm) measurement mode. First, make sure that the device is working properly and the battery is charged. Switch the regulator to the 200 ohm limit. The test is carried out with the relay removed from the compressor and disconnected from the wires.
First, let's check the integrity of the thermal protection circuit. Locate the contacts going to the bimetal strip (usually these are connected in series with the main power line). Attach the multimeter probes to the corresponding terminals. The device should show a resistance close to zero (0.1–0.5 Ohm). If one (infinity) lights up on the screen, it means that the circuit is broken and the protection does not allow current to pass through.
Next, we check the starting relay coil. The resistance here will be higher, usually in the range of 10-50 ohms, depending on the model. If the multimeter shows zero, a short circuit of the turns is possible, if infinity, the coil is broken. In both cases, the relay will not be able to create a magnetic field to start.
☑️ Test algorithm with a multimeter
For posistor relays the technique is different. A posistor in a cold state has a low resistance, but after voltage is applied it increases sharply. It is difficult to check its performance by simply ringing it, since it can show the norm when cold, but not switch when heated. Therefore, for posistors, the method of exclusion or replacement with a known good sample is often used.
Use thin needles or alligator clips to ensure reliable contact. It is also worth checking the wires going from the relay to the compressor for breaks.
Comparative table of parameters of a working and faulty relay
For ease of diagnosis, we will summarize the main parameters in a table. This will help you quickly navigate the results of measurements and visual inspection.
| Check parameter | Good relay | Faulty relay | Action |
|---|---|---|---|
| Resistance protection | 0.1 - 0.5 Ohm | Infinity (1) | Relay relay |
| Coil resistance | 10 - 50 Ohm | 0 Ohm or infinity | Replacing the relay |
| Sound when shaking | No or dull knock | Loud rattling | Replacement of the relay |
| Contact condition | Clean, without carbon deposits | Melted, black | Replacement of relays and terminals |
As can be seen from the table, deviation from the norm in any of the points is the basis for replacing the part. Repairing a modern sealed relay is economically impractical and technically difficult, since the factory calibration is violated.
When selecting a new part for Atlant refrigerator be guided not only by the appearance, but also by the markings. Compressor power and refrigerant type affect the required starting characteristics. Installing a relay with an inappropriate response current can lead to rapid failure of the new element or the motor itself.
Replacement of the relay and test run of the system
If the diagnostics confirmed the malfunction, we proceed to the replacement. Buy a similar relay corresponding to the power of your compressor (indicated on the motor nameplate). The installation process is the reverse of removal: carefully push the relay onto the compressor contact group until it stops. It should fit tightly, without backlash.
Connect the wires to the relay terminals, observing the polarity and the diagram that you photographed earlier. Make sure the connector snaps into place. Secure the fixing bracket or screws, if provided by the design. Only after installation is complete can you turn on the refrigerator to the network.
⚠️ Attention: The first start after replacement may be accompanied by short-term sparking inside the relay - this is normal for new contacts. However, if the click is repeated frequently and the compressor does not start, immediately turn off the device.
After turning on, listen to the operation of the unit. The compressor should start smoothly, without humming or vibration, and run continuously until the set temperature is reached. If the refrigerator begins to get cold, it means that diagnosis and replacement of the relay were successful.
During the first hours of operation, periodically check the temperature of the relay housing. It may become slightly warm, but should not be so hot that it is impossible to touch. Excessive heating indicates problems with the contact or mismatch of the parameters of the new part.
Frequently asked questions (FAQ)
Is it possible to start an Atlant refrigerator without a relay?
Technically, you can start an asynchronous motor by artificially applying voltage to the starting winding, but doing this in domestic conditions is strictly not recommended. Without a protective relay, the compressor will burn out in a few minutes if it is overloaded or jammed. In addition, the lack of protection can lead to a fire.
Why does a new relay burn out immediately after installation?
This can happen for several reasons: the relay power is incorrectly selected (the operating current does not correspond to the compressor), poor contact in the connector, sparking, or, worst of all, the compressor itself is faulty (interturn short circuit), which creates excessive load on the starting equipment.
Where can I find the relay markings on the Atlant refrigerator?
The markings are applied directly to the plastic housing of the relay (for example, 100MN1, RTK-1X). Also, information about the type of relay required can be found in the technical documentation for the refrigerator or on the compressor nameplate, where its power and model are indicated.
How much does it cost to replace a relay in a service center?
The cost consists of the price of the part itself (which is relatively inexpensive) and the work of the technician. In service centers, the price can be 2-3 times higher than the cost of self-repair, as it includes diagnostics and a guarantee for the work performed.