The situation when the refrigerator begins to emit a characteristic hum, and then suddenly stops after 3-5 seconds, is a classic sign of an emergency system start-up. At this moment, the motor-compressor tries to start working, consumes the maximum starting current, but due to resistance or mechanical jamming, it cannot turn the shaft. As a result, thermal protection is triggered, and the unit stalls so as not to burn out completely.
For the owner, this mode of operation means a complete absence of cold in the chambers and a potentially high cost of future repairs if operation is not stopped immediately. Cyclic startup attempts create a colossal load on the motor windings and starting equipment. If you hear a click, a hum, and then silence again, this is a signal that there is a failure in the system that will not go away on its own.
In most cases, the problem lies in one of three components: the start relay, the compressor itself, or the electrical wiring system. Diagnostics requires consistent elimination of causes, starting with the simplest and cheapest to eliminate. Understanding the physics of the process will help you avoid unnecessary expenses on calling a technician to replace a small part or, conversely, will tell you that the equipment requires serious intervention.
⚠️ Attention: At the first signs of cyclic on-off (clocking), immediately disconnect the device from the power supply. Continuing operation in this mode with a 90% probability will lead to burnout of the compressor windings, after which repairs will become economically unfeasible.
The principle of operation of the starting mechanism and thermal protection
To understand why the refrigerator clicks and turns off, you need to understand device starting relay. This small element is responsible for supplying voltage to the starting winding of the engine only at the moment of start. As soon as the rotor reaches the required speed, the relay should break the starting winding circuit. If this mechanism is faulty, the engine does not receive the required impulse or cannot enter the operating mode.
Works in parallel with the starting relay thermal protection relay. Its task is to open the power circuit in case of critical overheating or excess current. When the compressor hums for several seconds and turns off, this means that the current in the circuit has increased to emergency values. The protection is activated by opening the contacts and allowing the system to cool down. After cooling, the cycle repeats.
Modern models, such as Indesit or Beko, often use posistor starting devices that do not have moving parts, unlike old electromagnetic relays. Atlantov or Saratov. The principle of their operation is based on a change in the resistance of the ceramic element when heated. If the posistor is “broken” or has lost its properties, the compressor will hum, but will not start until the protection turns off the power.
Starting relay malfunctions: symptoms and replacement
The most common reason why the refrigerator turns on for a few seconds and turns off is the failure of the start relay. This is a consumable item that is subject to wear and tear. Inside the housing, the coil may burn out, the contacts may oxidize, or the core may collapse. Visually, traces of burning, melting of plastic, or a characteristic odor may be visible on the relay.
The replacement process usually does not require complex equipment. After disconnecting the device from the network, it is necessary to remove the casing at the bottom of the rear wall. The relay fits onto three contact pins of the compressor. It is important to remember or photograph its correct position, as installing it upside down may result in a short circuit or malfunction.
When choosing a new part, it is critical to consider the compressor model, and not just the brand of the refrigerator. On the motor housings LG, Whirlpool or Danfoss there are specific markings stamped on them, according to which a compatible relay is selected. The use of universal analogues is allowed, but requires an exact match of the electrical parameters.
It is worth noting that even a new relay may not start the engine if the problem is deeper. However, if the compressor is working, replacing the relay solves the problem in 70% of cases. This is the most favorable scenario, since the cost of the part is not comparable to the cost of replacing the motor.
Problems with the compressor: interturn short circuit and jamming
If replacing the start relay does not produce results, a serious malfunction of the start relay itself is likely. motor-compressor. One option is an interturn short circuit in the windings. In this case, the circuit resistance drops, the current increases sharply, and thermal protection instantly turns off the device. You can check this using a multimeter by measuring the resistance between the contacts.
Another common reason is mechanical compressor wedge. This occurs when the rubbing parts inside the hermetic block jam due to lack of lubrication, metal shavings, or deformation. In this condition, the motor shaft is physically unable to rotate. The motor hums, trying to move the pistons, but after a few seconds the protection turns it off.
⚠️ Attention: There is a “folk” method of resuscitating a jammed compressor by applying voltage directly bypassing the relay. We strongly do not recommend using this method at home without professional equipment. This can lead to the final destruction of the compressor components, fire or electric shock.
Diagnostics of the compressor requires skills in working with electrical measuring instruments. Normal winding resistance is usually from 20 to 40 Ohms, but the exact values depend on the specific model Samsung or Bosch. If the multimeter shows zero (short circuit) or infinity (break), the compressor must be replaced.
Is it possible to start a jammed compressor forever?
There is a theory that a powerful current pulse can “unjam” the mechanism. However, even if this is successful, the resource of such a compressor will be calculated in hours. Metal production has already begun inside, and a second wedge is a matter of time.
The influence of low voltage and wiring quality
Often the problem lies not in the refrigerator, but in the parameters of the electrical network. If the voltage in the outlet drops below 190-200 Volts, the current power may not be enough to reliably start the engine. The compressor begins to hum, trying to start, the current increases, but there is not enough inertia. As a result, the protection works. This is often found in holiday villages or old houses with worn-out communications.
It is also worth checking the condition sockets and extension cords. Using cheap surge protectors or long, low-gauge wires creates additional resistance. At the moment of start-up, when energy consumption is maximum, a voltage drop occurs on the wires, and a “non-working” current reaches the refrigerator.
For diagnostics, you can connect the device directly to another outlet, preferably in the kitchen or in the hallway, where the wiring is more modern. If the problem goes away, it means the problem was with the room's electrical system. In such cases, the installation voltage stabilizer is a prerequisite for the safety of the equipment.
Diagnostic table of the main ones malfunctions
To systematize symptoms and possible causes, it is convenient to use a summary table. It will help you quickly determine the troubleshooting vector, based on sound and visual signs.
| Symptom | Probable cause | Required actions | Difficulty of repair |
|---|---|---|---|
| Buzzing 3-5 seconds, click, silence | Faulty starting relay | Replace the relay | Low |
| Buzzing, clicking, burning smell | Interturn short circuit | Replacing the compressor | High |
| Quiet humming, no click | Compressor jammed | Replacing the compressor | High |
| Clicks without buzzing | Open circuit or thermostat | Check wiring | Medium |
| Works jerkily at low light | Low voltage in the network | Voltage stabilizer | Average |
Analysis of the table shows that external manifestations may be similar, but the reasons are radically different. For example, the absence of a click may indicate that the current is not even reaching the starting device, which narrows the search to a thermostat or wiring.
The role of the thermostat and starting capacitor
Although the main symptom of “on and off” more often points to a relay or motor, one cannot exclude data-i="132">. If the thermostat contacts are burnt or oxidized, they may not make a reliable connection. When voltage is applied, the contact may appear and disappear, causing chaotic switching on. thermostat. If the thermostat contacts are burnt or oxidized, they may not make a reliable connection. When voltage is applied, the contact may appear and disappear, causing chaotic switching.
In some models of refrigerators, especially old or industrial ones, starting capacitoris involved in the start-up circuit. It creates the phase shift necessary to create torque. If the capacitor has lost capacity or is swollen, there will not be enough starting torque, and the motor will only hum without starting.
Checking the thermostat is carried out by testing the contacts. When the temperature drops, the contacts should close. Checking the capacitor requires a special device or careful replacement with a known-good analogue with the same capacity and voltage.
☑️ Diagnostics before calling a technician
Algorithm of actions when a malfunction is detected
If you encounter the problem described, act consistently. First, unplug the appliance and let it cool completely for 2-3 hours. This is necessary to defrost the evaporator (if the problem is in the No Frost system) and cool down the thermal protection.
After turning on, listen carefully. If the cycle repeats after 10-15 minutes, proceed with a visual inspection of the rear wall. Remove the plastic cover and inspect the start relay. The presence of black spots, cracks or odor is a sure sign of its failure.
If there are no external signs of failure, and you do not have enough skills to work with a multimeter, it is better not to risk it. Attempts to “revive” the compressor with hammer blows or artisanal methods often finish off the equipment completely.
Why does the refrigerator turn off immediately after turning it on in the heat?
In hot weather, heat transfer worsens, the compressor works with increased load. If this is combined with poor ventilation of the condenser (dust, proximity to the wall), the motor overheats faster. Thermal protection is triggered earlier than usual, preventing the engine from even starting properly. Clean the condenser grid from dust.
Is it possible to temporarily use the refrigerator if it constantly turns off?
Absolutely not. Each such cycle is an extreme load. The compressor does not have time to create pressure, the oil does not circulate normally, and the windings become hot. Operation in this mode will lead to irreversible changes in the structure of the metal and insulation, making repairs impossible.
How much does it cost to replace a starting relay compared to a compressor?
The cost of a starting relay usually ranges from 500 to 2000 rubles, depending on the model, plus the work of a master. Replacing a compressor costs from 6,000 to 15,000 rubles and more, as it requires evacuation of the system and refilling with freon. Therefore, early diagnosis of the relay is so important.
Does the amount of freon affect frequent switching on?
Yes, it does. When freon leaks, the pressure in the system drops. It becomes “easier” for the compressor to spin, but pressure sensors (if any) or indirect signs of overheating can cause an emergency shutdown. However, more often, if there is a lack of freon, the refrigerator simply works non-stop, trying to gain temperature.
What to do if after replacing the relay the situation has not changed?
This means that the problem is not in the relay, but in what it protected. Most likely, the compressor itself is faulty (turn-to-turn short or wedge) or there are wiring/voltage problems. Professional diagnostics are required with measurement of current consumption and winding resistance.