The situation when the refrigerator begins to behave inappropriately always takes you by surprise. You open the door to take the groceries, and it’s already warm inside, or you hear a characteristic click, followed by a hum that lasts only a couple of seconds, after which there is silence again. This is a classic symptom, which in a professional environment is called “cyclic start-up” or “clocking” of the compressor.
Instead of normal operation, which lasts 15-40 minutes, the unit tries to start, but the protective mechanism instantly de-energizes the system. Start relay triggered, the engine makes a jerk, but full rotation of the shaft does not occur. If you ignore this signal, you can lead to the complete failure of an expensive motor-compressor, the replacement of which is often comparable in cost to buying a new household appliance.
In this article we will analyze in detail the mechanics of the process, explain why Samsung, LG, Indesit or Atlant behave exactly this way, and what steps need to be taken for diagnosis. Understanding the nature of the sound and operating intervals will help you save time and money by determining whether you can handle it yourself or calling a technician is inevitable.
The principle of operation of the protective system and start relay
To understand why the refrigerator turns on and off, you need to look inside its electrical circuit. The heart of the system is the compressor, which requires significant starting current to start rotating the rotor. This process is controlled by a special unit - the starting relay. It is this that supplies the impulse to the starting winding of the engine at the moment of start.
If in a split second the rotor does not gain the required speed, the thermal protective relay comes into play. It heats up from the current passing through it and opens the circuit, preventing the windings from burning out. Thermal relay This is a critical safety element that prevents the engine from operating in a short circuit or wedge mode.
⚠️ Attention: Frequent starting attempts (every 30-60 seconds) lead to rapid overheating of the stator windings. If you hear a continuous clicking sound, forcefully disconnect the device from the network for 2-3 hours to allow the thermal release and compressor to cool completely before further diagnostics.
In modern models with inverter control, the principle is different, but the essence of the problem is similar: the electronics detects the lack of correct response from the engine and goes into error, stopping power supply. In classic models with a linear compressor, you hear a physical click of the bimetallic plate.
What is the danger of the “clocking” mode for the compressor?
With frequent starts, the oil in the compressor crankcase does not have time to return to the lubrication system, which leads to “dry” operation. This causes critical wear of the piston group and scuffing on the cylinders, after which the entire compressor will have to be replaced, since repairs become economically unfeasible.
Faults in the starting relay: diagnosis and symptoms
The most common reason why the refrigerator clicks and stalls lies in the starting relay itself. This small plastic block that fits over the tail end of the compressor wears out over time. Inside it there is a coil and a movable core, which can stick or burn.
A sign of a relay malfunction is a characteristic metallic clanging or crackling sound when you try to start. If you remove the relay and shake it near your ear, you may hear a knocking sound - this means that the internal mechanism has collapsed or the core is loose. In this state, it cannot close the starting winding circuit correctly.
For owners of older models, it is important to know that relays come in different types: posistor and inductive. Posistor is a ceramic element that changes resistance when heated. If it is cracked or lost its properties, starting will become impossible. Induction relays suffer from burnt contacts, which stop conducting the required current.
- 🔌 Visual inspection: Remove the relay and check the contacts for black carbon deposits or melting.
- 🔊 Sound test: Shake the part - if the ringing of pieces inside is heard, the relay needs to be replaced.
- 🔥 Burning smell: The noticeable smell of burning plastic in the compressor area indicates overheating of the relay.
Problems with the compressor: interturn short circuit and wedge
If replacing the relay did not help, and the refrigerator still turns on for a few seconds and turns off, the situation gets worse. This may indicate problems with the engine itself. The most unpleasant Diagnosis is interturn short circuit in the stator windings.
When a short circuit occurs, the winding resistance drops, the current increases sharply, and the thermal relay is instantly activated, breaking the circuit. You can check this with a multimeter by measuring the resistance between the contacts. However, even if the resistance is normal, a mechanical wedge is possible.
A mechanical wedge occurs when the piston group gets stuck due to exhaustion, the ingress of foreign particles or oil thickening. In this case, the shaft simply cannot turn. An attempt to start creates a powerful jerk, but without rotation, which causes a protective shutdown.
There is a method of “wedging” by supplying increased voltage, but at home it is extremely dangerous and requires special equipment. Most often, when a wedge or short circuit occurs, a complete replacement of the compressor is required, which is a complex procedure that requires evacuation of the system and refilling with freon.
Malfunctions of the thermostat and temperature sensors
Sometimes the problem lies not in the power part, but in the control system. A thermostat (thermostat) is a device that gives a command to turn on when the temperature in the chamber rises. If its contacts are stuck in the “open” position or it is faulty, the compressor may not receive a signal for long-term operation.
In models with electronic control (No Frost, modern two-chamber), sensors (thermistors) are responsible for the temperature. If the sensor transmits incorrect data that the chamber is already colder than it actually is, the controller may turn off the motor prematurely. However, more often, if the sensor breaks down, the refrigerator simply does not turn on at all or works without stopping.
Let's consider the influence of various factors on the operation of the control electronics:
| Type of malfunction | Symptom | Probability | Check method |
|---|---|---|---|
| Sticking thermostat contacts | The refrigerator does not turn on or works non-stop | Medium | Close the contacts manually |
| Capillary break thermostat | The compressor does not start at all | High | Visual inspection of the tube |
| No Frost sensor malfunction | Error on the display, cycle failure | High | Measuring resistance with a multimeter |
| Control module failure | Chaotic on/off | Low | Diagnostics of codes errors |
For mechanical thermostats, there is a simple test: short-circuit the two wires coming from the thermostat, bypassing it. If after this procedure (do it carefully, with the network turned off!) the refrigerator started working normally, then the culprit has been found.
The influence of voltage in the network and wiring
Unstable voltage in the electrical network is the scourge of many areas. If the voltage drops below 190-200 Volts, the compressor may not have enough power to start confidently. It tries to start, it hums, but the protection relay turns it off due to the increased current at low voltage.
It is also worth checking the condition of the socket and plug. Loose contacts, oxidation or burning at the junction create additional resistance. This leads to a voltage drop directly at the entrance to the refrigerator, even if it is nominal in the network.
Inrush currents Compressors are large, and old wiring with a thin cross-section can “drain” the voltage at the moment of switching on. Check to see if the plug or socket gets hot after attempting to start. If yes, the problem is in the apartment's electrics, and not in the refrigerator.
⚠️ Attention: Do not use extension cords and tees for refrigerators, especially cheap ones. They often cause poor contact and a fire hazard at high starting currents.
To protect equipment in regions with an unstable network, it is recommended to install a voltage stabilizer. It will smooth out surges and provide the motor with the necessary parameters for starting.
Specifics of inverter compressors
Owners of refrigerators Liebherr, Bosch or top models LG are faced with a different picture. Inverter compressors do not have a classic starting relay in the usual sense. Their launch is controlled by an electronic module, smoothly increasing the frequency of the current.
If such a refrigerator turns on for a couple of seconds and stalls, this often means an error in the inverter module. The electronics perform a self-diagnosis, detect an anomaly (for example, a lack of rotation of the rotor or a short circuit) and block further attempts.
In such cases, an error code often lights up on the display. Decoding the code allows you to accurately determine the component: the Hall sensor, the inverter unit itself or the motor windings. Self-repair of inverter systems without an oscilloscope and knowledge of electronics is practically impossible.
☑️ Primary diagnostics before calling a technician
Algorithm of actions upon detection malfunction
If you encounter the problem described, do not panic. Be consistent. First, unplug the refrigerator. Let it sit for at least 30-40 minutes. This is necessary to equalize the pressure in the system and cool the thermal relay.
After a pause, turn on the device and listen. If the situation repeats (click - buzz - click), then the problem is systemic. If you have a multimeter and electrical skills, you can ring the compressor windings and check the relay.
However, if you are not confident in your abilities, it is better not to risk it. An attempt to independently repair a compressor or defrost system without skills can lead to a freon leak, which will require expensive evacuation and refilling. specialists.
The table below shows the approximate repair time and complexity:
| Malfunction | Repair complexity | Required tools | Average time |
|---|---|---|---|
| Replacing the start relay | Low | Screwdriver, pliers | 15-20 min |
| Replacing the thermostat | Medium | Screwdriver set, tester | 40-60 min |
| Replacement of the compressor | High | Burner, vacuum sealer, freon | 2-3 hours |
| Repair of the control module | High | Soldering iron, oscilloscope | 1-2 hours |
Remember that timely contacting professionals is often cheaper than eliminating the consequences of unqualified intervention or completely replacing a burnt-out unit.
Is it possible to temporarily use a refrigerator that often turns off?
Theoretically, products may not spoil in a couple of hours, but operation in this mode is strictly not recommended. Each start-stop cycle wears out the compressor. It is better to unload the food, defrost the chamber and wait for the technician.
Why does the refrigerator click but does not start, although it worked fine before?
Most likely, the starting relay or inter-turn short circuit in the compressor windings has failed. The relay is a consumable item that could simply burn out. If the problem is in the compressor, then it could jam due to exhaustion or lack of oil.
Is it dangerous to leave a refrigerator on that is constantly clicking?
Yes, it is a fire hazard. Overheating of the windings, melting of the insulation of the wires and the starting relay can lead to a fire. In addition, this is guaranteed to kill the compressor, turning a simple repair into an expensive replacement of the unit.
Can low voltage cause frequent switching on and off?
Absolutely. At low network voltage (below 190V), the starting torque of the engine is insufficient to overcome the inertia and freon pressure. The compressor hums, but does not start, the current increases, and the thermal protection turns it off. The cycle is repeated after the protection has cooled down.
How to distinguish a thermostat failure from a compressor failure?
If, when the thermostat contacts are closed (bypassing the regulator), the compressor starts and operates normally, the thermostat is faulty. If, even with a direct connection, you hear a click and a buzz followed by a shutdown, the problem is in the start relay, wiring or the compressor itself.