The situation when a refrigerator Atlant stops freezing or works intermittently often confuses the owner. The most expensive and complex part of the unit is the compressor, which in everyday life is often called the engine. It is on its serviceability that it depends whether the refrigerant will circulate through the system and whether the required temperature in the chambers will be maintained. Before calling a technician or buying a new unit, it is worth carrying out an initial diagnosis to understand whether the problem lies in the motor or in other components.
Checking electric motor requires some care and compliance with safety precautions, since you will be working with electric current. Lack of cold does not always mean engine failure; Sometimes the culprits are a thermostat, a freon leak, or a simple power surge. However, if you hear strange clicks, hums, or, conversely, silence when plugged in, then the likelihood of a malfunction in the power unit is high. In this article we will look at step by step how to identify the problem without complex equipment.
The first thing to do is a visual inspection and listening to the operation of the device. If, when plugged into the socket, compressor does not make any sounds, but the light inside is on, this may indicate an open circuit or failure of the starting relay. If the motor hums but does not start, or starts for a few seconds and turns off with a characteristic click, this often indicates a jammed piston group or an interturn short circuit. It is important to distinguish the normal quiet hum of a working unit from alarm signals of a malfunction.
Primary diagnostics without tools
You can start checking the engine of the refrigerator Atlant without using measuring instruments. This stage helps to weed out obvious faults and determine whether it makes sense to go deeper. First of all, pay attention to the temperature of the compressor housing. If it is cold when the power is on, it means that no current is flowing to the windings. If it is heated to the point where it is impossible to touch it, but there is no cold, this may indicate a breakdown of the valves or a freon leak, although the motor itself may be in good order.
The second important aspect is the analysis of the sound. A serviceable engine runs rhythmically, with a barely noticeable hum. If you hear metallic clanging, knocking, or an intermittent hum that fades in and out, this is a bad sign. Often such sounds are made by starting relay, which is trying to start the motor, but cannot due to high resistance or mechanical jamming. It is also worth checking whether the body of the refrigerator itself is vibrating excessively, as this may indicate problems with the motor mounting or its internal shock absorbers.
⚠️ Attention: Before any manipulations with the electrical components of the refrigerator, be sure to unplug it! Even brief contact with current can cause serious injury.
The third step is to check the heat dissipation system. If the condenser (grid at the back) is hot, but the evaporator inside is cold, and the motor runs continuously, the problem may not be with the motor, but with a clogged capillary tube. However, if the engine is hot and the grille is cold, and the engine is silent or hums in vain, then suspicion falls on it. In some models Atlant with two compressors, the malfunction of one of them is immediately evident by the temperature difference in the chambers.
Checking the starting relay and protective device
Before “sinning” on the engine itself, it is necessary to eliminate the malfunction start relay. This small plastic block, placed over the compressor contacts, is responsible for starting the rotor and protecting against overloads. Refrigerators Atlant relays of the RT or PSO series are often used. If the relay is faulty, it does not supply an impulse to the starting winding, and the motor cannot start rotating, remaining in a humming state.
To check, remove the relay from the compressor pins. Shake it gently near your ear. If a ringing or knocking sound is heard inside, it means that the core is broken or the mechanism is jammed, and the part requires replacement. Also inspect the contacts for carbon deposits or melting. If the plastic turns black, it means that too much current was passing through the relay, which often happens when there is an interturn short circuit in the windings of the motor itself. In this case, replacing the relay will not help - it will burn out again after a few minutes of operation.
It is also important to check the thermal protection relay, which is often built into the starter housing or located nearby. It opens the circuit when the compressor overheats. If the contacts inside are “stuck” in the open state, the current simply will not reach the windings. Ring the contacts with a multimeter: when cold they should ring (show zero or resistance close to it). If the device shows a break, the relay is faulty.
Sometimes the cause of problems is oxidation of the contacts at the compressor terminals. Before installing a new relay, clean the contact pads with fine sandpaper or alcohol. Make sure the connectors are firmly seated on the pins and are not loose. Poor contact causes sparking, heating and, ultimately, can lead to burnout of the control board or the relay itself.
Diagnostics of motor windings with a multimeter
The most accurate way to determine the condition of the electrical part of the motor is to test the windings using a multimeter. To do this, you need to gain access to the compressor contact group by removing the start relay and protective device. At the end of the motor you will see three leads forming a triangle. Usually they are marked, but if there is no marking, you need to determine them experimentally.
The conclusions are divided into three types: general (C), starting (P) and working (P). The resistance between them is measured in Ohms. Normal values for motors Atlant vary, but there is a pattern: the resistance between the working and common terminals is always less than between the starting and common terminals. The total resistance between the working and starting terminals must be equal to the sum of the resistances of the other two pairs. If the multimeter shows infinity (open) or zero (short circuit) on any pair of contacts, the motor is faulty.
| Pair of contacts | Normal resistance (Ohm) | Possible malfunction |
|---|---|---|
| Working - Common | 10 - 25 Ohm | Open or short circuit of the working winding |
| Starting - Common | 20 - 45 Ohm | Open winding |
| Working - Starting | Sum of the two above | Interturn short circuit |
| Any output - Housing | Infinity (∞) | Breakthrough to the housing (dangerous!) |
Particular attention should be paid to checking for breakdown of the housing. One multimeter probe is applied to any of the three contacts, and the second is applied to a cleaned area on the metal body of the compressor (you can scrape off a little paint). The device should show infinite resistance. If the arrow deviates or the device beeps, it means that the insulation of the windings is broken, and the current goes to the case. Operation of such a refrigerator is deadly, since the entire metal case may be under voltage of 220 Volts.
☑️ Checklist multimeter
Mechanical check and direct connection test
If the electrical part is normal (the windings are intact, there is no breakdown in the housing), but the motor does not start even with a new relay, the piston group may have become mechanically jammed. This happens due to oil burnout, moisture entering the system, or prolonged downtime of equipment. In such cases, the engine rotor is clamped and cannot turn. For diagnosis, specialists use the direct connection method, but it requires extreme caution.
The essence of the method is to supply 220V voltage directly to the working and starting windings, bypassing the standard relay. For this, a special cord with a button is used (or without it, if the activation is short-term). Power is supplied to the motor contacts: to the common and working terminals constantly, and to the starting terminal - briefly, at the time of startup. If the engine jerks, makes a sound and starts, then the problem was in the relay. If you can only hear a hum and the motor stands still, most likely it is jammed.
⚠️ Attention: Direct activation of the compressor without a start relay can only be carried out for a few seconds! Keeping the starting winding energized for a long time will lead to its burning.
There is also a “wedging” method, when increased voltage is applied to a jammed motor or an attempt is made to rotate the shaft mechanically, but it is not recommended to do this at home without experience. Often, a jammed engine Atlant can only be revived at a service center using special equipment that creates vibration, or by replacing it with a new one. Attempts to loosen the shaft on your own can lead to permanent breakdown of the compressor.
Another sign of a mechanical problem is the nature of the sound when trying to start. If the motor emits a dull, low-frequency hum and immediately knocks out the machine in the panel or the fuse burns out, this is a sure sign that the rotor does not physically have enough strength to turn. Unlike electrical breakdown, with a mechanical wedge, the resistance of the windings may remain normal, but the starting torque is not enough.
Analysis of performance and pressure
Even if the engine starts and runs, this does not guarantee its full serviceability. The compressor can drive freon, but not create enough pressure for effective circulation. This often happens when the valve group wears out. You can check this by disconnecting the capillary tube from the compressor discharge pipe (depressurization of the system is required). When the engine is turned on, a powerful flow of gas should flow from the tube. If the flow is weak or intermittent, the valves do not hold pressure.
For accurate diagnostics, workshops connect a pressure gauge station. Normal discharge pressure for household refrigerators Atlant using R134a freon should be about 8-10 atmospheres (depending on the ambient temperature). If the compressor can barely pump 3-4 atmospheres and cannot raise the pressure higher, its efficiency has dropped critically. Such a motor will work constantly, consume a lot of electricity, but will not provide the required temperature in the freezer.
An indirect sign of a drop in performance is the temperature of the compressor housing. A working unit heats up to 70-90 degrees Celsius. If the engine is barely warm, although it runs for hours, it means that the freon is not compressed, but is simply rolling around inside without doing any work. In this case, replacing the engine is necessary, since further operation does not make economic sense.
Why can the compressor run idle?
The reason may lie in a burst plate valve inside the compressor head. The gas, instead of being pushed out into the condenser, flows back into the suction tube. This reduces efficiency to zero, although electrically the motor is fully operational.
Frequent errors in diagnostics
When independently checking the refrigerator engine Atlant beginners often make mistakes that lead to false conclusions. One of the most common is trying to check the motor without turning off the thermostat. If the thermostat is open, the motor will not start and the user will assume that it has burned out. Always check the power circuit to the compressor, making sure that the signal to turn on actually arrives.
Another mistake is ignoring the wiring condition. Oxidized or broken wires leading to the compressor can create high contact resistance. As a result, the engine receives low voltage, it cannot start and hums. Before replacing an expensive unit, be sure to “ring” all the way from the socket to the terminal box.
Also, do not forget about the capacitor (if it is in your relay circuit). Some starting circuits use a starting capacitor to help create a phase shift. If it is dry or swollen, the motor will not receive the necessary starting impulse. The capacitor is checked with a multimeter in capacitance measurement mode or visually (swelling, drips).
When a compressor replacement is necessary
Replacing an engine is a complex process that requires not only technical skills, but also special equipment for working with refrigerants. If diagnostics show that the motor is faulty (turn-to-turn short circuit, breakdown to the housing, jamming, loss of performance), it must be replaced. Refrigerators Atlant most often have compressors of the same brand or their analogues from Danfoss (Secop) and Embraco.
The replacement process includes: removing the old refrigerant, cutting off the old compressor, soldering a new one, evacuation of the system (removing air and moisture) and refilling with new freon in a strictly defined quantity. It is impossible to carry out this procedure on your own without a vacuum pump and scales for refilling freon - the system will quickly fail due to moisture or incorrect dosage.
When choosing a new engine, pay attention to the refrigerant with which it works (R134a or R600a). Compressors for different types of freon are not interchangeable without changing the system design and changing the oil. It is also important to choose a motor of similar or greater performance (power) so that the refrigerator can reach operating mode in a reasonable time.
Is it possible to run a three-phase compressor in a single-phase network?
Domestic refrigerators Atlant use single-phase motors. Three-phase motors are found in industrial equipment. Starting a three-phase motor in a 220V household network is possible only using a capacitor circuit, but for refrigerators this is not applicable due to the specific load and starting torque requirements.
Why does a new compressor burn out after a week?
This happens if there was no replacement when replacing The cause of the breakdown of the old motor has been eliminated. Often, contaminants (acid, oil breakdown products) remain in the system, which clogs the capillary tube or destroys the new motor. It is mandatory to flush the system with nitrogen and replace the filter-drier.
How much does it cost to replace the engine in an Atlant refrigerator?
The cost consists of the price of the compressor itself (about 30-50% of the cost of a new refrigerator) and the work of the technician. Taking into account materials and refilling with freon, repairs can cost 50-70% of the price of a new unit, which often makes the purchase of new equipment a more rational decision.
The compressor hums, but does not start - is this dangerous?
Yes, it is dangerous. A long hum means that current is flowing through the windings, but there is no rotation. This causes rapid and intense heat, which can cause the insulation to melt, fire, or explode the start relay. If this symptom occurs, the refrigerator must be immediately de-energized.
Is it possible to lubricate a jammed compressor?
In theory, you can try to inject special oil through the process pipe, but in practice, in sealed housings of household refrigerators, this is extremely difficult and ineffective. Mechanical wear of friction pairs is usually irreversible without opening the case, which cannot be done at home.