The situation when the refrigerator stops cooling, and the motor is silent or makes only a short click, can catch take any home appliance owner by surprise. This is not just an inconvenience, it is a direct threat to the safety of products, which at room temperature begin to deteriorate literally in a matter of hours. Absence of a characteristic hum a working unit is the first and most alarming signal that a failure has occurred in the refrigerant circulation system.
Before To panic and call a technician, it is worth carrying out an initial diagnosis, which often allows you to identify trivial faults that can be eliminated without a special tool. Compressor is the heart of the refrigeration unit, and if it does not start, this may indicate both electrical problems and mechanical damage to internal components. Understanding the physics of the process will help you make the right decision on further actions.
In this article we will analyze in detail the main scenarios of engine failure, methods for checking them and precautions that must be observed when working with electrical appliances under voltage. Safety in this case comes first, since inept handling of refrigerator components may lead to electric shock or complete failure of the device.
⚠️ Attention: Carry out any manipulations with the electrical components of the refrigerator only after completely disconnecting the device from the network! The residual voltage in the capacitors can persist for several minutes.
Primary diagnostics and checking the power supply
The most obvious, but often ignored reason for the motor not working is a simple lack of voltage in the outlet or a broken contact in the power circuit. Sometimes the problem lies not in the refrigerator itself, but in home electrical network. Check whether the indicator lamp inside the chamber lights up when the door is opened. If there is light, it means that power is being supplied to the device, and the problem should be looked for deeper in the electrical circuit.
Visually inspect the power cord for mechanical damage, kinks or traces of melting. Insulation the wires should not have cracks, especially at the base of the plug and at the entrance to the refrigerator body. Frequent movement of the unit or careless cleaning could damage the cable, which led to an open circuit.
If you use an extension cord or surge protector, try connecting the refrigerator directly to the wall. Cheap extension cords often cannot withstand the starting currents of powerful motors, which is why their internal protection is triggered or the contacts burn out. Starting current the compressor at the moment of switching on can be several times higher than the rated operating current.
- 🔌 Check the voltage in the outlet using multimeter or by connecting another working device.
- 👀 Inspect the refrigerator plug for blackening of the contacts or melting of the plastic.
- ⚡ Avoid using tees and extension cords for direct connection of powerful equipment.
Faults in the starting relay and thermostat
If the power is normal, but the motor does not start, the most likely culprit is starting relay. This small unit is responsible for sending an impulse to the motor winding and starting it. Modern refrigerators often use posistor relays, while older ones use electromagnetic ones. If the posistor fails, the circuit opens and the compressor does not receive a signal to start, although voltage is supplied to it.
The second important element of the control circuit is thermostat (or electronic temperature sensor). It is he who gives the command to turn on the motor when the temperature in the chamber rises. If the thermostat contacts are oxidized or the mechanism is jammed, the control circuit remains open. In some models with electronic control, the control moduleitself, which does not send a signal to start, could fail.
To check the relay, it must be removed and shaken: if a ringing is heard inside, it means the mechanical part is destroyed. Burning of the contacts inside the relay housing is also often observed, which can be seen when opened. In 70% of cases of engine failure, the problem lies precisely in the starting relay or thermostat.
How to check the thermostat with a multimeter?
To check the thermostat, put the multimeter in dial mode. Connect the probes to the thermostat contacts. If the device beeps, the circuit is intact. Cool the sensor (for example, by putting it in the freezer for 10 minutes) and check again: the circuit should break (the sound will disappear). If the circuit does not close even in a warm state, the thermostat is faulty.
⚠️ Attention: When replacing the start relay, make sure that the new part has exactly the same markings as the original. Installing an unsuitable relay can lead to burnout of the compressor windings.
Problems with the compressor: interturn short circuit and wedge
The most unpleasant scenario is failure of the compressor itself compressor. The engine may not start due to an interturn short circuit in the windings. In this case, when trying to start, the current increases sharply, and the thermal protection relay instantly opens the circuit, making a characteristic click. Repeated attempts to turn on will lead to the same result after short intervals.
Another serious problem is mechanical wedge piston group. This occurs during long-term operation when oil leaks from the compressor or moisture enters, causing corrosion. The pistons get stuck in the cylinders and the engine is physically unable to turn over. Attempts to start such a unit only lead to humming and rapid heating of the motor housing.
You can diagnose the condition of the windings using an ohmmeter by measuring the resistance between the contacts on the compressor connector. Normal values usually range from 10 to 30 ohms for the operating winding and slightly higher for the starting winding. If the device shows zero (short circuit) or infinity (break), the compressor requires replacement.
| Symptom | Probable cause | Necessary actions |
|---|---|---|
| A click is heard, silence | Faulty starting relay | Replace the relay |
| Humming for 5-10 seconds, then click | Compressor wedge or short circuit | Replacement compressor |
| Complete silence, light is on | Open circuit (thermostat) | Checking the thermostat |
| Motor is hot, does not start | Thermal protection | Cooling, winding diagnostics |
☑️ Compressor diagnostics
The role of the thermal protection relay in stopping the motor
The design of the refrigeration unit includes an overheating protection system, presented thermal relay. It is installed directly on the compressor housing or built into the starting unit. The main task of this element is to break the electrical circuit if the current consumption exceeds the norm or if the temperature of the motor housing becomes critical.
It often happens that the motor does not start immediately after trying to turn it on precisely because the thermal relay has not yet cooled down. The bimetallic plate inside the relay must cool down and return to its original position in order to close the contacts again. This process can take from 5 to 20 minutes depending on the degree of heating.
If the relay operates instantly every time a cold engine is turned on, this is a sure sign of a malfunction of the relay itself or serious problems with the compressor (short circuit, wedge). Replacing the thermal relay is a simple procedure, but it requires the selection of an element with exactly the same current parameters cutoff.
The influence of temperature conditions and the No Frost system
In refrigerators with the system No Frost starting the compressor is closely related to the operation of the defrost system. If the defrost heating element is burnt out or the defrost sensor is faulty, the evaporator becomes covered with ice. The fan, which is supposed to drive cold air, can become jammed with ice, which creates additional load on the system or blocks startup according to the electronic algorithm.
It is also worth considering the ambient temperature (room temperature). If the room is too cold (below +10°C), the oil in the compressor becomes thick and it may not start on the first try. Some refrigerator models have climate classthat does not allow operation at low ambient temperatures.
The electronic control module can block the motor from starting if it receives incorrect data from the sensors. For example, if the temperature sensor in the freezer shows abnormally low values due to a malfunction, the controller “thinks” that refrigeration is not required and does not give a start command.
⚠️ Attention: The design and operating algorithms of the No Frost system depend on the manufacturer. Parts may vary in different models, so check the diagrams in the official service manual for your specific brand.
When a call to a professional technician is necessary
There are a number of situations when independent repair is not only impractical, but also dangerous. If the diagnostics showed interturn short circuit or a mechanical compressor wedge, the unit needs to be replaced. This procedure involves working with refrigerant, requires evacuation of the system and charging with freon, which cannot be done without specialized equipment.
Also, the help of a specialist is necessary if you find a freon leak (oily spots around the tubes, lack of cold when the engine is running). Finding leaks and soldering copper tubing requires skills and tools that the average user does not have. An attempt to simply “add gas” without eliminating leaks will lead to a repeat breakdown in a short time.
If after replacing the starting relay and thermostat the situation has not changed, most likely the problem is deeper. Professional diagnostics using an ammeter (to measure the starting current) will allow you to accurately determine the condition of the compressor windings without dismantling it.
- 🛠️ To replace the compressor, a vacuum pump and a pressure gauge station are required.
- 🧪 Working with refrigerants requires a license and compliance with environmental standards.
- 🔍 Sophisticated electronics of control modules can only be diagnosed by the programmer.
Is it possible to restore a jammed compressor?
There is a method of “wedging” by applying increased voltage to the starting winding, but it helps only in 10% of cases and temporarily. Most often, such a compressor soon completely fails, so replacement is more reliable.
Why does the refrigerator click but does not turn on?
The click indicates that the starting relay is trying to start the motor, but the current increases sharply, and the protection opens the circuit. This is a typical sign of a malfunction of the relay itself, the compressor wedge, or an interturn short circuit.
Is it possible to temporarily use the refrigerator if the motor does not start?
No, you cannot operate the refrigerator with the motor not running. Products will begin to deteriorate, and mold and an unpleasant odor will develop in the chambers. In addition, frequent attempts to start can finally finish off a compressor that is still working.
How much does it cost to replace the start relay?
The relay itself is inexpensive (usually in the range of 500-1500 rubles depending on the model), but if you do not have the skills, you will have to pay for the work of a specialist. Replacement takes about 30-40 minutes.
Does unstable voltage in the network affect the starting of the motor?
Yes, with low voltage in the network (less than 190-200V), the engine may hum, but not start, which will lead to its overheating and protection activation. It is recommended to use a voltage stabilizer.