The situation when the refrigerator stops freezing, and the food inside quickly deteriorates, always takes you by surprise. First of all, we check whether the light is on and listen to the sounds of operating equipment. If it is quiet inside, but there is light, or a characteristic click is heard, followed by a hum that lasts only a couple of seconds, there is a high probability of problems with the compressor.
Before calling a technician, it is useful to understand whether the compressor itself has really failed or the problem lies in components that are more accessible for repair. Self-checking requires accuracy and a minimal set of tools, but it saves time waiting for a specialist. In this article we will look at the main diagnostic methods. refrigerator motor or the problem lies in components that are more accessible for repair. Self-checking requires accuracy and a minimal set of tools, but it saves time waiting for a specialist. In this article we will look at the main diagnostic methods.
It is important to immediately note that any work on electrical components is carried out only with the device completely disconnected from the network. The current required for the operation of a household compressor is fatal to humans even with short-term contact. If you are not confident in your abilities, it is better to stop at a visual inspection and call a professional.
Primary diagnostics without tools
You should start checking by simply observing the behavior of the unit. In normal mode compressor it turns on according to a signal from the thermostat, works for a certain time, pumping refrigerant, and then turns off. If you hear the motor trying to start, humming, but after 3-5 seconds there is a click and there is silence, this is a classic symptom of overload or blockage.
Often the reason for this behavior is not a breakdown of the motor itself, but a malfunction of the starting relay or thermostat. If the engine does not make any sounds at all, although the light in the chamber is on, the problem may be a lack of power to the windings or an open circuit. In some cases, the motor hums continuously without turning off, which indicates a freon leak or loss of compression properties.
Pay attention to the temperature of the compressor housing. If after trying to start it remains cold, it means that electricity simply does not reach the windings. If it heats up to such an extent that it is impossible to touch it, this indicates an interturn short circuit or jamming of the piston group. Thermal relay in such a situation it should work and break the circuit.
Visual inspection and check of the starting relay
To carry out detailed diagnostics, you need to gain access to the compressor, which is usually located in the lower rear part of the refrigerator. Remove the protective cover by unscrewing the mounting bolts. You will see a view of a black barrel-shaped unit and additional elements attached to it on the side or top.
The first object to be checked is the starting relay. This is a small plastic box placed on the compressor rod. Carefully remove it, having previously photographed the wiring diagram so as not to mix up the contacts during assembly. Inside the case there is a coil and contacts that can burn or oxidize.
⚠️ Attention: If inside the start relay you see traces of burning, melted plastic or smell burnt insulation, the part requires immediate replacement. Operation with a damaged relay can lead to permanent failure of the motor windings.
Check the integrity of the wires going to the relay and thermostat. Often rodents or vibration lead to chafing of the insulation and short circuit. If no visual defects are found, a more in-depth check using measuring instruments will be required.
Necessary tools for checking the windings
To check the refrigerator motor for electrical faults, you will need a basic DIY kit. Without special equipment, diagnostics will be incomplete and may lead to erroneous conclusions. The main tool here is a multimeter.
Here is a list of necessary equipment:
- 🔌 Multimeter (digital or analog) - for measuring resistance and checking circuit integrity.
- 🔧 Set of screwdrivers - for dismantling protective panels and removing terminals.
- 🧤 Dielectric gloves - to ensure safety when working with electrical wiring.
- 🔦 Flashlight - for high-quality illumination of the rear niche of the refrigerator.
The multimeter must be switched to the resistance measurement mode (Ohms), usually indicated by the symbol Ω. Select the measurement limit in the range up to 2000 Ohm (2 kOhm). Before starting measurements, check the serviceability of the probes by connecting them to each other: the device should show zero or a value close to it.
It is also useful to have on hand a table of standard resistance values for various compressor models, although in practice the ratio of resistances between windings is more important than absolute numbers. For different brands, such as Atlant, Indesit or Bosch, these values may differ.
Measuring the resistance of motor windings
There are three terminals on the compressor housing, covered by a contact strip. They are usually designated by letters or arranged in a specific geometry (triangle). Two terminals are the ends of the working and starting windings, and the third is common. The task is to call each winding and find the common point.
The measurement process is as follows:
- 📏 Attach the probes to the first and second contacts and record the readings.
- 📏 Then measure the resistance between the first and third contacts.
- 📏 Finally, check the second and third pin pair.
As a result, you will get three values. The sum of the two smaller resistances must be equal to the largest. The highest resistance is the sum of the resistances of the starting and operating windings, measured between their free ends. The common wire is located at the point of connection of these two windings.
Table of typical resistance values
Working winding: 10-30 Ohm|Starting winding: 20-50 Ohm|Between housing: Infinity
If the multimeter shows one (infinity) on any of the sections between the terminals, this indicates a winding break. In this case, it is almost impossible to restore the engine; it needs to be replaced. If the resistance is close to zero, then a short circuit of the turns has occurred.
Checking for insulation breakdown (short circuit to housing)
One of the most dangerous malfunctions is breakdown of winding insulation on the metal body of the compressor. In this case, voltage may appear on the housing, which creates a risk of electric shock if you touch the refrigerator. You can check this using the same multimeter.
Switch the device to the dialing mode (with a sound signal) or measuring resistance to the maximum limit. Press one probe to the cleaned area on the compressor housing (where there is no paint or rust), and with the second touch all three motor contacts in turn.
⚠️ Attention: With a working motor, the multimeter should show infinite resistance (one on the screen). If the device beeps or shows any resistance values, it means the insulation is broken. Using such a refrigerator is strictly prohibited!
Often a breakdown occurs due to aging of the varnish coating of the wires inside the motor or moisture ingress. If a breakdown is detected, the only correct solution is to replace the compressor. Attempts to isolate the windings from the outside will not yield results, since the damage is located inside the sealed casing.
Analysis of mechanical faults of the compressor
If the electrical part is in order, the windings are intact and there is no breakdown in the housing, but the engine does not start or does not work, the problem may be mechanical in nature. Inside the sealed casing there is a piston group, which wears out or jams over time.
Main mechanical problems:
- 🔩 Piston group jamming - often happens after a long period of inactivity or due to oil burnout.
- 🔩 Breakage or weakening of the internal suspension —the motor begins to knock heavily and vibrate during operation.
- 🔩 Valve wear —the compressor hums, but does not create the necessary pressure in the system.
It is difficult to check the mechanics without opening the casing, but you can try to “unwedge” the motor. To do this, there is a method of applying voltage directly to the working winding, bypassing the starting relay. This is a risky method that requires experience. If, after a short period of switching on, the motor hums, but does not spin, and the shaft does not turn, most likely it is jammed.
☑️ Diagnostics of mechanics
There is an opinion that a jammed motor can be revived by applying increased voltage or hitting the housing. However, in modern hermetic compressors this rarely has a long-term effect. If you hear a metallic knock inside the case during operation, this is a sure sign of destruction of the internal mechanisms.
Comparative table of symptoms and malfunctions
For the convenience of systematizing the data obtained, use the following table. It will help compare the measurement results with the probable cause of the malfunction.
| Symptom | Multimeter readings | Probable cause | Actions |
|---|---|---|---|
| The motor does not hum, silence | Infinity between terminals | Open winding or circuit | Replacing the compressor |
| Buzzing and clicking | Resistance in normal | Faulty starting relay | Replace the relay |
| The machine is triggered | Resistance is close to 0 | Interturn short circuit | Replacing the compressor |
| The housing is receiving an electric current | There is conductivity to the housing | Insulation breakdown | Urgent replacement |
By analyzing the data in the table, you can accurately determine the vector of further actions. Remember that replacing a compressor is a complex process that requires evacuation of the system and charging with freon. Without special equipment, it is impossible to perform this procedure efficiently.
Questions and answers (FAQ)
Is it possible to check the compressor without a multimeter?
Full diagnostics cannot be carried out without instruments. However, you can indirectly assess the condition: if, when plugged into the network, the circuit breaker knocks out or the fuse burns out, it means there is a short circuit in the circuit. If the engine hums and is hot, but does not start, it may be jammed. Only a tester will provide accurate data.
What resistance is considered normal for windings?
Normal values vary depending on the power and model. Typically, the resistance of the working winding is 10-30 Ohms, and the starting winding is 20-50 Ohms. The main rule: the resistance between the common wire and the other two should add up to the resistance between the two extreme terminals. What is more important is the absence of a short circuit to the housing.
Why is the compressor hot, but the refrigerator does not freeze?
This may indicate several problems: freon leakage (the motor is idling), jamming of the piston group, or loss of compression properties. It is also possible that the refrigerant circulation is impaired due to a blockage. A comprehensive diagnosis of the system is required.
Is it worth changing the compressor yourself?
Replacing the compressor requires soldering copper tubes, using nitrogen for purging, a vacuum pump and scales for charging freon. Without experience and equipment, there is a high risk of damaging the new motor or not achieving the desired temperature. This is a job for the service center.