The sudden silence of your of the Atlant refrigerator or, conversely, its refusal to turn on when the backlight is working often indicates about problems in the compressor starting circuit. It is the start-protection relay that is responsible for starting the engine and protecting it from overloads, being one of the most vulnerable components of the entire system. If you hear clicks, a hum, but the motor does not start, or the unit does not respond at all when plugged in, the first thing you should do is check this small but critical element.
Diagnostics of the relay does not require complex professional equipment, however, it requires compliance with strict safety rules and the presence of basic skills in working with electrical measuring instruments. In this article we will analyze in detail how to correctly remove the part, what operating modes of the multimeter to use and what readings are considered normal for various modifications ATLANT. Understanding the principle of operation of this device will help you save time on calling a technician or confirm the need for replacement.
The principle of operation and types of relays in Atlant refrigerators
The starting protection relay in refrigerators Atlant performs a dual function: it supplies a starting pulse to the electric motor winding and opens the circuit when it reaches operating conditions speed, and also turns off the power when the current increases critically. Depending on the year of manufacture and model of your refrigerator, there may be different types of devices inside, each of which has its own diagnostic features. The most common are induction (electromagnetic) and posistor (thermal) mechanisms.
Induction relays, often found in older models, work due to electromagnetic induction. When voltage is applied, current passes through the coil, creating a magnetic field that draws in the core and closes the contacts of the starting winding. As soon as the compressor rotor picks up speed, the current drops, the spring returns the core, and the circuit opens. Posistor relays, characteristic of newer series, use the thermistor effect: when heated, the resistance of the element increases sharply, actually breaking the starting winding circuit.
⚠️ Attention: An attempt to ring the relay without disconnecting the refrigerator from the power supply may result in electric shock or failure of the measuring device. Always remove the plug from the socket before starting work!
You can visually determine the type of relay by its appearance and markings. Induction devices usually have a more massive body with a visible coil inside, while posistor devices often look like small plastic boxes with one or two contacts. Understanding the type of device is necessary to select the correct testing method, since diagnostic algorithm it may differ for them.
What is dangerous about contact sticking?
If the contacts inside the relay stick in the closed position, the compressor starting winding remains energized constantly. This leads to rapid overheating of the engine, humming and, ultimately, combustion of the compressor windings, which is a very expensive breakdown.
Preparation for diagnostics: tools and safety
Before proceeding with the direct inspection, it is necessary to prepare the workplace and tools. You will need a Phillips screwdriver to remove the rear protective panel, pliers to carefully remove the terminals and, of course, a working multimeter (tester). Without a quality instrument, measurements will be inaccurate, which can lead to an erroneous diagnosis and unnecessary replacement of working parts.
The preparation process includes not only finding tools, but also ensuring safe access to the compressor. The refrigerator must be moved away from the wall, providing a clear view of the rear wall. If the unit has just been running, let it cool for 15-20 minutes to avoid getting burned by hot condenser tubes or the compressor itself.
- 🔧 Multimeter with working probes and a working battery for accurate resistance measurements.
- 🪛 Set of screwdrivers (phillips and flat) for dismantling the compressor protective casing.
- 🧤 Dielectric gloves for additional protection when working with electrical contacts.
- 📱 A smartphone with a camera to photograph the wiring diagram before disconnecting them.
Pay special attention to visual inspection of the wires. Before unscrewing anything, make sure that there are no cracks in the insulation and that the contacts are not oxidized. If you find melted insulation or blackened terminals, this may indicate that the problem is not only in the relay, but also in contact group or wiring.
Removing the start-up protection device
Access to the relay in refrigerators Atlant is usually through the lower part of the rear wall of the unit. There is a compressor covered with a metal or plastic casing. Removing the casing is the first step, which requires care so as not to damage the copper tubes of the refrigeration circuit that fit to the motor.
After removing the cover, you will see the compressor itself (the black “tank”), to the shank of which is attached a small plastic or metal casing. This is the required relay. It fits directly onto the contacts coming out of the compressor housing. To remove it, you need to carefully press the fixing tabs or simply pull it down, if the design allows, after first disconnecting the suitable wires.
☑️ Procedure for removing the relay
When removing the relay, act without excessive force. The plastic in old refrigerators becomes brittle and can burst from careless movement. If the relay is holding tightly, rock it slightly from side to side. It is important not to pull the wires, but to grab it by the body of the device, so as not to break the thin strands inside the insulation.
Method of testing with a multimeter: step-by-step algorithm
The most reliable way to check the serviceability of an element is to measure the resistance of its internal circuits. Switch the multimeter to resistance measurement mode (indicated by the Ω symbol), selecting a limit of 200 ohms or beep mode. First, check the integrity of the circuit as a whole by applying probes to the input contact and output to the compressor.
For induction relays, it is important to check the resistance of the coil. The probes are connected to the corresponding coil contacts. Normal resistance should be in a certain range, usually from tens to hundreds of ohms. If the device shows one (infinity), it means that the coil is in breakand the relay must be replaced. If the resistance is close to zero, a short circuit turns have occurred.
⚠️ Attention: When checking a posistor relay, remember that a cold posistor should have low resistance (20-50 Ohms). If immediately after turning off the refrigerator (when the posistor is hot) the resistance is high, this is normal. Let it cool for 5-10 minutes to check correctly.
Separately, it is worth checking the thermal protection, which is often built into the relay housing or located nearby. Ring the bimetallic strip: when cold, it should ring (resistance is close to 0 Ohm). If the circuit does not ring, it means that the protection has tripped due to overheating and has not returned to its original state, or it is faulty. In some cases, light tapping can return the contacts to their place, but this is a temporary solution.
Table of normal readings and fault codes
For accurate diagnostics, it is useful to focus on typical resistance values for various relay models used in refrigerators Atlant. Although the exact numbers may vary depending on the manufacturer of the relay itself (RCT, Danfoss, etc.), general ranges allow you to quickly weed out clearly faulty parts.
| Relay Type / Model | Coil Resistance (Ohm) | Posistor resistance (Ohm) | Thermal protection |
|---|---|---|---|
| RKT-1 (Induction) | 25 - 35 Ohm | Not applicable | Closed (0 Ohm) |
| RKT-2 (Induction) | 18 - 25 Ohm | Not applicable | Closed (0 Ohm) |
| Posistor (general) | Not applicable | 20 - 50 Ohm (cold) | Closed (0 Ohm) |
| Faulty relay | ∞ (Infinity) | ∞ or 0 (Short circuit) | ∞ (Break) |
If your measurements differ radically from the values given in the table, for example, they show a complete absence of conductivity where it should be, or vice versa - short short circuit, the part is considered defective. Also pay attention to the condition of the internal contacts: if they are burnt or covered with carbon deposits, this increases the contact resistance and interferes with normal startup.
It is important to consider that the table is for reference only. For some specific modifications Atlant with inverter compressors (although there the relay is often replaced by an electronic module), the parameters may differ. Always check the technical documentation of a specific model, if available.
Typical errors during testing and replacement
One of the most common mistakes is trying to check the relay without removing it from the compressor. In this case, you can "ring" the circuit through the windings of the motor itself, which will give a false positive result. Always ensure that the element being tested is isolated from the rest of the circuit.
Another mistake is ignoring the state of the contacts on the compressor itself. Even a new relay will not work if the pins on which it fits are oxidized or burnt. Before installing a new part, be sure to clean the compressor contacts with fine sandpaper or a file, being careful.
- ❌ Measuring resistance without turning off the power (will lead to burnout of the tester).
- ❌ Installing a relay of the wrong model (protection or start may not work).
- ❌ Ignoring checking thermal protection (a common cause of repeated breakdowns).
- ❌ Trying to repair a burnt-out relay by gluing the case (does not restore the properties of a posistor or coil).
Also, you should not try to “reanimate” the relay by tapping or calcining, if this is the case about modern sealed models. The time and cost of a new relay are not comparable with the risk of burning the compressor with incorrect experiments. If in doubt, it is better to replace the part with a known good one.
Replacement of the relay and final check of the system
The process of replacing relays in refrigerators Atlant is technically simple, but requires care. The new part must fully match the markings of the old one. Install the relay in place, pressing it tightly onto the compressor contacts until a characteristic click or stop occurs. Connect the wires according to the photograph or color marking taken earlier.
After assembly, do not rush to put the refrigerator against the wall. Plug it in and listen. Start-up should be relatively quiet, with one or two clicks, after which the compressor returns to its operating rhythm. If you hear a repeated crackling or buzzing sound without starting, immediately turn off the power, which means the problem is deeper (the compressor or interturn short circuit is faulty).
⚠️ Attention: If after replacing the relay the refrigerator started working, but after a while the compressor stopped turning on again, do not change the relay again. Check the voltage in the network and the condition of the wiring - perhaps the cause is power surges that kill new parts.
After making sure that the operation is stable, install the back cover in place. After 30-40 minutes, check the appearance of cold in the chambers. If the temperature begins to drop and the compressor cycles (turns on and off), the repair can be considered successful. Otherwise, a more in-depth diagnosis of the refrigeration circuit is required.
Is it possible to use a relay from another brand?
In most cases, it is possible if the electrical characteristics (current, type of compressor) and the geometric dimensions of the seat match. However, the original Atlant relays are guaranteed to meet all parameters.
Frequently asked questions (FAQ)
Is it possible to check a refrigerator relay without a multimeter?
It is impossible to check qualitatively without a device. Visual inspection (carbon deposits, cracks) gives only indirect signs. Theoretically, you can apply voltage directly, but this is dangerous and can kill the compressor. A multimeter is a must-have tool for accurate diagnostics.
Why does a new relay burn out immediately after installation?
There may be several reasons: poor contact at the compressor terminals, an interturn short circuit in the windings of the motor itself, or unstable voltage in the electrical network. It is also possible that a relay with incorrect current parameters was selected.
Where can I find the relay markings to purchase a replacement?
The markings are usually applied to the top or side of the plastic relay case (for example, RKT-1, RKT-2, 100N0011). If the inscription is erased, look for the number on the sticker of the compressor itself and select a relay from compatibility catalogs for this model Atlant.
How much does it cost to replace a relay in a service compared to self-repair?
Independent replacement will cost the cost of the part (usually from 500 to 1500 rubles). The service will add to this amount the cost of the technician’s visit and work, which can increase the total by 2-3 times. If you have the skills, it is more profitable to do it yourself.