The situation when the refrigerator turns on and immediately turns off.often finds owners by surprise, causing panic about the safety of food. Usually this symptom manifests itself as follows: you hear a characteristic click or hum, lasting only 3-10 seconds, after which the unit becomes silent again and the defrost light comes on (if there is one) or there is simply silence. After 15-30 minutes, the cycle may be repeated, but to no avail.
This behavior of the equipment indicates that starting mechanism starts the engine, but the protection system instantly breaks the power circuit. This can be caused either by a simple power surge in the network or by a serious malfunction of the compressor motor. It is important not to ignore the problem, since constant attempts to start can finally “finish off” a motor that is still working.
In this article we will analyze in detail the mechanics of the process, consider typical breakdowns starting relay and windings, and also give an algorithm of actions for diagnostics. You will find out in which cases you can get by with replacing a cheap part, and when you need to call a technician for complex repairs.
Mechanics of the process: why the protection works
To understand the essence of the problem, you need to briefly consider the principle of operation of the compressor. At the moment of switching on, a powerful current pulse is supplied to the motor windings, which is necessary to create a starting magnetic field. This process is controlled starting relay, which physically opens the starting winding after a set of revolutions. If this does not happen or the current exceeds the norm, thermal relay (protection) comes into play.
When the refrigerator turns on for a few seconds and turns off, this means that the current in the circuit exceeds the permissible values, or the motor rotor is blocked mechanically. The thermal relay, which is a bimetallic plate, heats up from the passing current and unbends, opening the contacts. After cooling (the same 15-40 minutes of inactivity), the record returns to its original state, and the cycle repeats.
There are three main scenarios developments of events in the event of such a malfunction:
- ⚡ A short start with a characteristic click and subsequent silence is the classic operation of a thermal relay.
- 🔊 A loud hum or hum for 5-10 seconds before shutting down is a sign of mechanical jamming or problems with the windings.
- 💡 Flashing light in the room when trying to start the refrigerator indicates the consumption of a huge current (short circuit in the turns).
Problems with the starting and thermal relay
The most common and "cheapest" reason that the refrigerator clicks and does not startis failure start protection relay. This device is hung directly on the compressor housing and is responsible for supplying voltage to the starting winding and protecting against overloads. Inside the relay housing there is an inductance coil and contacts that can burn or oxidize over time.
If the contacts of the starting relay are “stuck” or covered with carbon deposits, the current does not flow correctly, or the starting winding does not turn off in time. As a result, the engine cannot reach the required speed, the current increases, and the thermal protection is triggered, turning off the unit. In older models with relay starting, the nichrome heating tablet, which is responsible for switching contacts, often burns out.
How to check the relay without instruments?
Carefully remove the relay from the compressor (after unplugging the refrigerator from the mains!) and shake it near your ear. If you hear a ringing or knocking noise from scattered parts inside, the relay is definitely faulty and requires replacement.
Diagnostics of this unit is usually carried out by exclusion or visual inspection. It is necessary:
- 🔌 Remove the relay and inspect the contacts for black carbon deposits or melting of the plastic.
- 🧪 "Ring" the windings with a multimeter (the resistance should be within the normal range specified in the instructions).
- 🔄 Check the operation of the mechanism: in a vertical position contacts should close, and in horizontal contacts should open (for certain types of relays).
Replacing a relay is a simple procedure if you have the skill to work with electricians. However, it is important to choose an analogue with identical characteristics, since there are no universal solutions for all models Indesit, Atlant or LG .
Malfunctions of the motor-compressor
The most unpleasant diagnosis that can be heard from the master is turn-to-turn short circuit motor windings or mechanical wedge of the piston group. In this case, the refrigerator turns on, hums for 5-10 seconds and turns off because the rotor physically cannot turn. Attempts to start such a compressor using external devices (for example, a starting capacitor) often lead to final combustion of the windings.
A mechanical wedge occurs due to wear of rubbing parts, metal shavings getting into the cylinder, or oil solidification during severe frosts (if the refrigerator was transported incorrectly). In this case, the motor shaft is tightly clamped, and the starting torque cannot dislodge it. The current in the windings instantly increases to critical values, which triggers the protection.
⚠️ Attention: If you feel a persistent burning smell or see sparking in the compressor area, immediately stop trying to turn it on! Operating a refrigerator with an interturn short circuit is a fire hazard.
To diagnose the condition of the compressor, professionals use the method of “testing” the windings and checking the current consumption. At home, you can only indirectly assess the condition:
- Check whether the compressor housing has become excessively hot after several attempts to start.
- Listen: a steady hum that turns into a crackling noise often indicates a water hammer or a wedge.
- Try (carefully!) to turn the motor shaft by hand if the design allows access to it (only when the power is turned off!).
Problems with electrical wiring and mains voltage
Do not discount external factors. Sometimes the reason the refrigerator turns off after a few secondslies not in the unit itself, but in the state of the electrical network. Voltage surges, dips below 190 Volts or, conversely, surges above 240 Volts can trigger the built-in protection or unstable operation of the electronics.
Particular attention should be paid to the socket and plug. Poor contact in the socket (oxidation, weakening of springs) leads to heating and voltage drop. At the moment of startup, the compressor consumes a large current, and if the contact is bad, the voltage at the input to the refrigerator drops critically, the motor does not start, and the protection is triggered.
To check this aspect, follow these steps:
- 🔌 Plug in the refrigerator into another outlet, preferably in another room, to eliminate the problem with wiring.
- 🔦 Inspect the power cord plug: there are no traces of melting, blackening or the smell of burning plastic.
- 📉 If you have a multimeter, measure the voltage in the network while powerful consumers are operating (washing machine, microwave).
Malfunctions of the thermostat and electronics
In models with electronic control, the cause of cyclic switching on and off may be a failure in the control module or a malfunction of the sensors. If thermostat (thermostat) is “stuck” in the “on” position or, conversely, does not close the contacts, the compressor may behave inappropriately. However, more often, if the thermostat breaks down, the refrigerator simply does not turn on at all or works without stopping.
In modern inverter models the situation is more complicated. The electronic control unit constantly monitors the condition of the compressor. If the Hall sensor (located inside the compressor) does not send a signal to rotate the rotor, the control module emergency cuts off the power to prevent breakdown. In this case, the refrigerator may turn on for a split second and immediately stall.
Diagnostics of electronics requires special knowledge:
- 🔍 Visual inspection of the board for swollen capacitors or burnt tracks.
- 🌡 Checking the resistance of temperature sensors (it varies depending on temperature).
- 📟 Reading error codes from the display (if the model allows).
⚠️ Attention: In modern refrigerators with a No Frost system and electronic control, independent replacement of the thermostat or sensors may require entering the service menu for calibration. Without this, the unit may not work correctly.
Diagnostic table: symptoms and probable causes
For convenience, we will systematize the data obtained. Below is a table that helps to compare symptoms with the most likely malfunctions.
| Symptom | Probable cause | Difficulty of repair |
|---|---|---|
| Clicking, buzzing for 3-5 seconds, silence | Faulty start relay | Low (part replacement) |
| Strong hum, case heating, shutdown | Compressor wedge or interturn short circuit | High (motor replacement) |
| Flashing lights, sparks, burning smell | Short circuit in wiring or windings | Critical (fire hazard) |
| Power on 1 sec and shutdown (inverter) | Error in Hall sensor or control module | Medium (electronic diagnostics) |
☑️ Primary diagnostic checklist
Algorithm of actions and prevention
If you encounter the problem described, do not rush to call a specialist right away. Sometimes basic defrosting helps. If an ice plug has formed in the system (for example, due to moisture in the freon or a defrost malfunction), the compressor cannot push the refrigerant. Let the refrigerator stand turned off at least 24 hours with the doors open. If after this it works normally, the problem was in the ice.
If defrosting did not help, follow the algorithm:
- De-energize the device.
- Remove the back cover at the bottom (where compressor).
- Remove the start relay and check it visually and soundly.
- If the relay is working properly, the problem is most likely in the compressor.
Prevention of such breakdowns is simple: do not place the refrigerator close to the wall (a gap is needed for ventilation), defrost it regularly (it is advisable to wash even the No Frost system once a year) and use a voltage stabilizer if there are surges in your network.
⚠️ Attention: The characteristics of refrigerators and error codes may vary depending on the manufacturer and year of manufacture. Always check the technical documentation (manual) of your specific model Bosch, Samsung or Liebherr before starting disassembly.
Frequently asked questions (FAQ)
Is it possible continue to use the refrigerator if it constantly turns off?
Strongly not recommended. Frequent switching on and off (cycling) leads to overheating of the compressor windings and can permanently damage it. In addition, the food in the chamber will begin to deteriorate due to the lack of cold.
How much does it cost to replace the start relay?
The part itself is inexpensive (usually from 500 to 1500 rubles, depending on the model). However, if you do not have the skills to work with electricians, it is better to entrust the replacement to a specialist, since incorrect installation can lead to the burning of the new relay or compressor.
Why does the refrigerator hum, but does not start after defrosting?
If after 24 hours of defrosting the situation has not changed, then the problem is not in the ice jam. Most likely, the starting mechanism has failed or the compressor itself has lost compression (valve wear).
Could the cause be a faulty thermostat?
Yes, if the thermostat contacts are burnt and do not close completely, the current may be insufficient for a reliable start, or the thermostat may randomly open the circuit. But more often, if the thermostat breaks down, the refrigerator simply does not turn on at all.