The situation when a household appliance ceases to maintain a stable temperature mode always causes concern for the owner. If you notice that the refrigerator often turns off, and then immediately starts again, this indicates a failure in one of the cooling system components. A short operating cycle does not allow the compressor to gain the required pressure, which leads to food spoilage and overheating of the motor.
In normal mode, the unit should operate approximately 30-40% of the total time of the day, taking breaks for cooling. However, in case of breakdowns, rest intervals are reduced to several minutes or even seconds. Understanding the nature of this phenomenon is the first step to eliminating the problem without calling a technician.
There are many factors that influence the frequency of switching on: from simple overheating of the case to failure of the electronics. In this article, we will analyze in detail the main reasons why the device operates in emergency mode and how to fix them yourself.
Symptoms of a short operating cycle
Before disassembling the case, it is necessary to accurately determine the nature of the malfunction. Users often confuse normal operation with signs of failure. If the motor hums for 2-3 minutes, then silence follows for 5 minutes, and the cycle repeats - this is a clear sign that thermostat incorrectly reads the temperature inside the chambers.
Pay attention to the sounds accompanying the start-up. A heavy, buzzing hum that ends abruptly with a click indicates that starting relay tries to start the compressor, but the protection is tripped due to overload. In this case, the device may turn off every 20-40 seconds.
It is also worth checking the temperature conditions of the products. If the milk turns sour in half a day, and the ice melts in the freezer, it means that the compressor does not physically have time to catch up with the cold. This occurs when the operating time is too short to achieve the specified parameters.
⚠️ Attention: If you smell burning wiring or see sparking in the compressor area, immediately unplug the appliance. Further operation may lead to a fire.
It is important to distinguish between normal shutdown and emergency shutdown. The normal operation occurs smoothly, without sharp sounds, when the desired temperature is reached. An emergency is always accompanied by clicks, buzzing or chaotic behavior of indicators on the control panel.
Faults of the thermostat and sensors
One of the most common reasons why the refrigerator often turns off is the failure of the thermostat. This mechanical or electronic component is responsible for closing and opening the compressor power circuit depending on the evaporator temperature.
Older mechanically controlled models use a capillary tube filled with freon. If there is a depressurization in the system or the tube has moved, the sensor will “think” that it is already cold in the chamber and turn off the motor ahead of time. In this case, the temperature in the chamber does not have time to drop, and after a couple of minutes the cycle repeats.
In modern models with a system No Frost and electronic control, air sensors are responsible for the temperature. Their readings may be distorted due to oxidation of contacts or moisture. The electronic module receives incorrect data and gives a command to stop the engine.
How to check the thermostat with a multimeter?
To check the mechanical thermostat, you need to remove it and close the contacts directly. If the refrigerator starts working and does not turn off (be careful not to overcool!), then the problem is in the sensor. When testing with a multimeter in a cold state, the contacts must be closed.
Replacing a component often requires partial disassembly of the internal panel or removal of the back cover. It is important to choose an analogue with identical characteristics, since different models of thermostats have different response ranges.
Problems with the start relay and compressor
If the refrigerator turns on for a few seconds and immediately turns off with a characteristic click, the problem lies in the electrical part of the motor. Starting relay is a small unit, which provides an impulse to start the motor windings. Over time, the contacts inside it burn out or stick.
If the relay is faulty, the current cannot pass to the windings in the required volume, or the relay does not open the starting circuit after start. This causes a sharp jump in current, to which the thermal protection installed on the compressor housing reacts. The motor stalls, cools down for a couple of minutes, and the start attempt is repeated.
A more serious situation is an interturn short circuit in the windings of the compressor itself. In this case, the engine hums, but does not start, quickly heats up and is switched off by protection. Repair in this case is often not economically feasible; replacement of the unit is required.
Diagnostics of the relay can be carried out visually and using testing. If carbon deposits are visible inside the housing, or the ball in the mechanical relay does not roll freely when shaking, the part must be replaced.
| Symptom | Possible cause | Probability |
|---|---|---|
| Clicking 3-5 seconds after start | Start relay malfunction | High |
| Operation for 1-2 minutes, then shutdown | Thermostat malfunction | Medium |
| Humming without starting the compressor | Compressor jamming | Medium |
| Chaotic switching on | Problems with the electronic module | Low |
The influence of the No Frost system and defrosting
In units with an automatic defrosting system, frequent starts may be associated with a malfunction of the evaporator heating circuit. If Defrost heating element, the timer or defrost sensor fails, a “coat” of ice grows on the evaporator.
Ice blocks the circulation of cold air. The temperature sensor in the chamber does not detect a decrease in degrees and does not give a command to stop the compressor. However, if the overheating protection system is working properly, it can forcefully stop the motor, seeing that the temperature does not drop, or, conversely, short the circuit.
It is also worth checking the drainage system. If the meltwater drain hole is clogged, the water freezes at the bottom of the chamber, creating an ice plug. This disrupts heat exchange and forces the system to work in an enhanced, but ineffective mode.
To defrost such a unit, a complete disconnection from the network is required for at least 24 hours. Only complete melting of the ice inside the hidden cavities will allow the system to return to the normal operating cycle.
☑️ Diagnostics of the No Frost system
Refrigerant leak and pressure problems
When a leak occurs in the freon circulation system, the pressure drops. The compressor tries to compensate for the lack of refrigerant and works longer than usual, but due to low pressure the coolant does not have time to cool the chambers.
In some cases, when the freon level is critically low, the pressure at the outlet of the compressor may be insufficient for the system to operate correctly, which leads to chaotic stops. However, more often, when there is a leak, the refrigerator, on the contrary, works continuouslywithout turning off at all.
Frequent switching on during a leak can be observed if the temperature sensor is installed incorrectly or if the system tries to compensate for the loss of cold with short powerful jerks, although this is a less typical scenario.
It is difficult to determine a leak visually, since freon is colorless and odorless. An indicator may be swelling of the wall of the refrigerator compartment or oily spots in the area of the compressor or condenser.
⚠️ Attention: Filling the refrigerator with freon requires special equipment and qualifications. Independently adding refrigerant “by eye” will lead to compressor failure.
External factors and operating conditions
The reason does not always lie within the equipment. Sometimes the refrigerator switches off frequently due to improper operating conditions. For example, if the device is installed close to a wall or in a niche without gaps for ventilation, the condenser (grid at the back) does not have time to release heat.
Overheating of the housing leads to the fact that the thermal protection of the compressor is triggered more often than usual. It is also worth checking the voltage in the network. If it fluctuates or is too low, the starting relay may not be able to start the engine.
Dense loading of chambers with warm products or frequent opening of doors also affects the operating cycle. In this case, frequent switching on is an attempt by the system to quickly restore the temperature, which is a normal reaction and not a breakdown.
Check the rubber seals on the doors. If they do not fit tightly, warm air constantly enters the chamber, causing the motor to work with overload.
When you need to call a technician
Independent repair is possible by replacing the thermostat, starting relay or defrosting the system. However, there are situations when specialist intervention is inevitable. If you hear a knock inside the compressor or see that the main pipes are damaged, it is better not to risk it.
A technician is also needed to look for freon leaks and evacuate the system. These procedures require professional tools: a pressure gauge station, a vacuum pump and a scale for refrigerant dosing.
If the situation has not changed after replacing the thermostat or relay, the problem may be in the electronic control module. Diagnostics of the board requires deep knowledge of electronics and circuit design.
Remember that timely repairs are cheaper than replacing a compressor or buying a new refrigerator. Ignoring frequent switching on can lead to complete burnout of the motor windings.
Is it possible to operate a refrigerator if it turns off frequently?
Short-term - yes, but this will lead to food spoilage and overheating of the compressor. Long-term operation in this mode reduces the life of the motor and can cause a fire hazard.
How much does it cost to replace the starting relay?
The relay itself is inexpensive (usually from 500 to 1500 rubles depending on the model), but calling a technician and the work can cost more than the part itself.
Why does the refrigerator click but does not turn on?
This is a classic sign of a faulty start relay or a jammed compressor. The mechanism tries to start the motor, but the protection immediately opens the circuit.
How often should a working refrigerator turn on?
In normal mode, the operating coefficient is about 0.3-0.4. This means that for 10 minutes of work there should be 15-20 minutes of rest. The exact figures depend on the model and load.