The situation when the refrigerator does not turn off and continues to buzz for days all day long, is familiar to many owners of household appliances. This is not just an annoying noise that disturbs sleep, but also a serious signal that there is a failure in the cooling system. If the unit works without interruptions, the compressor experiences colossal overloads, which in the shortest possible time can lead to its complete failure and costly repairs.
In modern models with a system No Frost or drip defrosting, the operating algorithms are different, but the principle is the same: the equipment must cycle turn on and off. When this cycle is disrupted, food can begin to spoil due to excess cold or, conversely, due to insufficient cooling if the compressor hums but does not freeze. Understanding the nature of the malfunction is the first step to saving your refrigerator.
Before calling a technician, it is important to conduct an initial diagnosis to eliminate common operating errors. Often the reason lies not in a breakdown of the electronics or motor, but in improper installation or a violation of the seal of the cameras. In this article we will look in detail why the refrigerator stopped turning offhow to detect a refrigerant leak and what to do if the thermostat has burned out.
Checking tightness and operating conditions
The most common reason for continuous operation of the unit is heat coming from outside, which the cooling system cannot cope with. If warm air constantly enters the chamber, sensors detect an increase in temperature and command the compressor to work without stopping. First of all, check sealing rubber bands on the doors. Over time, they dry out, crack, or simply become dirty, which is why the door does not fit tightly.
Assess the conditions in which the equipment is located. If refrigerator is located next to a battery, oven or in direct sunlight, its performance decreases. It is also critical to have a gap between the rear wall of the unit and the wall of the room. The radiator needs a free flow of air to release heat.
⚠️ Attention: If you recently defrosted the refrigerator and immediately closed the door tightly, an air lock or vacuum may have formed inside, which prevents the seal from pressing. Open the door for a couple of minutes to equalize the pressure.
For a quick leak check, use a simple test with a sheet of paper. Clamp the sheet between the door and the body around the perimeter. If the paper pulls out easily and without resistance, the seal requires replacement or cleaning. Also pay attention to how often you open the door. Frequently looking inside makes compressor work in increased mode, especially in hot weather.
Malfunctions of the thermostat and temperature sensors
If everything is in order with the tightness, the next probable cause is failure of the thermostat. It is this element that is responsible for turning off the compressor when the set temperature is reached. Older models use a mechanical one, which wears out over time. Its contacts can “stick” in the closed position, which is why the electrical circuit does not break, and the motor continues to hum. thermostat, which wears out over time. Its contacts may “stick” in the closed position, which is why the electrical circuit does not break and the motor continues to hum.
In modern electronically controlled units, sensors (thermistors) are responsible for the temperature. If such a sensor “lies” and sends a signal to the control module that it is warm in the chamber, although in fact it is already minus 20 degrees there, the refrigerator will work endlessly. Diagnostics of the electronic unit requires special equipment, but primary signs can also be noticed visually.
Symptoms of a malfunctioning thermostat are often accompanied by the absence of a characteristic click when turned off. Mechanical regulators usually make an audible click when they open the circuit. If there is no sound for a long time, most likely the problem is in the regulator.
How to check a mechanical thermostat yourself?
To check a mechanical thermostat, it must be removed. In a cold state (after the freezer), its contacts should be closed. When warmed in your hands to room temperature, you should hear an opening click. If there is no click or the contacts are oxidized, the part must be replaced.
Refrigerant leakage and problems with the circulation system
One of the most serious problems leading to continuous operation of equipment is freon leak. The refrigerant is the working fluid of the system, which circulates through the tubes, picking up heat. If a microcrack forms in the circuit and the gas evaporates, the cooling capacity drops to zero. The sensors see that the temperature is not decreasing and force the compressor to work hard, trying to compensate for the lack of refrigerant.
Signs of a leak often manifest themselves not only in a continuous hum, but also in a change in the nature of the operation. The compressor may run very hot and the back grill (condenser) may remain lukewarm or cold. Bloating of the inner wall of the refrigerator compartment may also be observed if the leak occurred in the foamed part of the housing.
The second option for a circulation problem is clogged capillary tube. An ice or dirt plug may have formed in the system, which blocks the flow of freon. The symptoms are similar to a leak: the refrigerator hums, but does not freeze. In this case, it is necessary to clean the system and replace the filter-drier.
⚠️ Attention: You can independently search for a freon leak using soapy water only in open areas of the tubes (at the back). If the leak is in the foamed part of the housing, it is impossible to determine it without equipment. Do not try to refuel the refrigerator yourself without evacuating the system.
Wear of the compressor and start relay
The heart of the refrigerator is the compressor. If it has exhausted its resource, its productivity drops. The motor may hum, creating the appearance of work, but not create the necessary pressure in the system. As a result refrigerator it cannot reach the temperature and does not turn off. Often, when the compressor wears out, there is increased noise, vibration and strong heating of the motor housing.
Another important element is the starting relay. This device starts the motor and protects it from overloads. If the relay is faulty, it may not open the starting winding circuit, which is why the compressor will run constantly, get very hot and eventually burn out. Testing the relay takes a few minutes: you need to remove it and shake it. If you hear a clear knock on the internals, it is better to replace the relay.
It is worth noting that modern inverters compressors work on a different principle. They may not turn off completely, but only reduce speed to maintain temperature. This is normal for models such as LG Linear or Samsung Digital Inverter. However, if the temperature in the chamber is clearly below normal, and the motor does not slow down, this is a sign of a failure in the electronics.
☑️ Compressor diagnostics
Diagnostic table: Symptoms and probable causes
To systematize troubleshooting, it is convenient to use a comparison table. It will help compare the observed symptoms with the most likely breakdowns. Remember that an accurate diagnosis can only be made by a specialist after instrumental measurement of pressure and current consumption.
| Symptom | Probable cause | Difficulty of repair | Necessary action |
|---|---|---|---|
| Humming, but not freezing, the tubes are cold | Freon leak or blockage | High | Call a technician to find a leak |
| Works without stopping, the chamber is very cold | Thermostat is faulty | Medium | Replacing the thermostat |
| The engine gets very hot, hums intermittently | Wear of the compressor or relay | High | Replacement of the compressor or starter |
| Humming, slightly freezing, the “fur coat” is freezing | Problems with defrosting (No Frost) | Average | Checking the heating element and defrost timer |
Analysis of the table shows that external manifestations are often similar, but the reasons can be radically different. For example, if there is a leak or if the compressor breaks down, the refrigerator will not freeze, but the repair methods will be completely different. In the first case, soldering and refueling are needed, in the second - replacement of an expensive unit.
Specific operation of No Frost refrigerators
In units with a system No Frost another layer of possible malfunctions is added. The defrost system plays an important role here. If the defrost heating element, defrost temperature sensor or timer (module) fails, the evaporator becomes covered with ice. The fan stops driving cold air, the temperature in the chamber rises, and the compressor begins to work continuously, trying to cool the volume.
Visually, this may manifest itself in the fact that the back wall of the refrigeration chamber is covered with ice or snow, although normally it should be dry there. You may also hear the cracking of ice or the hum of a fan trying to break through the ice crust. In such cases, defrosting a refrigerator for a day (with the doors open) may temporarily solve the problem, but it will remain.
It is important to understand the difference: in drip systems, water simply flows down, and in No Frost, ice freezes on a hidden evaporator. If the defrost system does not turn on on the timer, ice blocks air exchange. The compressor at this moment is working correctly from a logical point of view (it is trying to cool), but physically cannot do this due to the ice plug.
The influence of external temperature and the "Super Freeze" mode
The human factor cannot be discounted. Many models are equipped with a Super Freeze function. When this mode is activated, refrigerator turns off the thermostat and works continuously for up to 24-72 hours to quickly freeze large volumes of food. Check to see if the corresponding icon is lit on the display panel (often a snowflake or the letter F).
The room temperature is also critical. If you install the refrigerator on an unheated balcony or in a garage, where the temperature drops below +10°C (or rises above +35°C), its operation is disrupted. The oil in the compressor thickens in the cold, and heat transfer deteriorates in the heat. In such conditions, the unit can operate without stopping or frequently turn on the protection.
⚠️ Attention: Operating the refrigerator at temperatures below +5°C (climate class SN/N/ST/T) can lead to rapid failure of the compressor and destruction of the seals. Do not use the equipment for other purposes.
Another reason is incorrect initial loading. If you put a large volume of warm food into the refrigerator that was just turned on, it will work in high mode for several hours until it reaches normal mode. This is normal, but if after a day it does not turn off, look for a breakdown.
Frequently asked questions (FAQ)
How long should a refrigerator work normally?
Under normal conditions, the operating cycle is approximately: 15-20 minutes of work and 30-40 minutes of rest. That is, operation coefficient is about 30-40%. If the refrigerator works more than 50% of the time or does not turn off at all, this is a sign of a malfunction.
Can the refrigerator not turn off due to the heat in the summer?
Yes, on hot days (above +30°C) the operating time of the compressor increases and the downtime is reduced. This is an attempt by the system to compensate for the high heat flow. However, it should still turn off periodically, at least for 5-10 minutes.
What will happen if you do not fix the malfunction and leave the refrigerator running constantly?
Long-term operation without stopping will lead to overheating of the windings compressor and melting of the insulation. As a result, an interturn short circuit will occur and the motor will burn out. Repair in this case will cost much more than timely replacement of the thermostat or eliminating the leak.
Why does a new refrigerator work without interruption for the first hours?
When turned on for the first time, the unit must cool the entire internal volume and chamber walls from room temperature to operating temperature. This process can take from 6 to 12 hours. During this period, continuous operation of the compressor is a normal situation and does not require intervention.