The situation when a household refrigerator begins to hum without interruption, and the products on the shelves turn into ice blocks, is familiar to many equipment owners. This is not just an annoying noise that interferes with a restful sleep, but also a direct signal that the cooling system is operating in emergency mode. If the unit does not turn off, this leads to critical wear of the compressor, which can eventually burn out, requiring an expensive replacement.
Continuous operation of the motor is often associated with a violation of heat exchange or failures in the control electronics. In modern models with the system No Frost and old two-chamber “drops”, the reasons may differ, but the result is the same: inside the chamber the temperature drops below normal, and the motor continues to pump in cold. It is important to understand that ignoring the problem in the first hours or days leads to higher repair costs.
In this article we will analyze in detail the mechanical and electrical causes of such a malfunction. You will learn how to carry out initial diagnostics yourself and in what cases calling a specialist becomes inevitable. The main thing is not to panic, but to consistently check the main components in order to eliminate simple operating errors.
⚠️ Attention: Before starting any diagnostics, be sure to disconnect the refrigerator from the power supply. Working with live electrical components is life-threatening.
Violation of the tightness of the door and seal
The most commonplace, but common reason why the refrigerator does not turn off and freezes intensely, lies in a bad chamber tightness. If warm air from the room enters the system, sensors detect an increase in temperature and command the compressor to work harder. As a result, the unit tries to “supercool” the space in order to compensate for the constant flow of heat, which leads to the formation of a fur coat on the back wall.
First of all, inspect the rubber seal around the perimeter of the door. Over time, the rubber dries out, cracks or deforms, no longer fitting tightly to the body. Even a microscopic gap of 1-2 millimeters can disrupt the entire work cycle. Also check if anything is preventing it from closing tightly: swollen packaging, protrusions on the shelves, or simply fat accumulated on the magnetic tape.
- 🔍 Do a test with a sheet of paper: hold the sheet with the door and try to pull it out. If it slides out without resistance in different places, the seal is worn out.
- 🧼 Wash the seal thoroughly with warm water and soap to remove the grease film that reduces the magnetic adhesion.
- 🚪 Check the position of the door: if it is skewed, the rubber will not fit evenly, which will require adjustment loops.
If you find that the door is warped, this often happens after long-term use or transportation. The hinges could weaken, and the heavy door would move away from the body under its own weight. In this case, it is necessary to tighten the fastening bolts or, in some models, move the fastening pins to the opposite side to reposition them.
Malfunctions of the thermostat and temperature sensors
The thermostat (thermostat) is the “brain” that decides when to turn on and when to turn off the compressor. In mechanical models it is a simple “twist” with a capillary tube, in electronic models it is complex touch sensors. If the thermostat “sticks” in the “on” position or transmits incorrect data to the control board, the refrigerator will freeze indefinitely, ignoring the achieved temperature.
In mechanical thermostats, the bellows often become depressurized or the adjustment screw is displaced. The capillary tube that senses temperature may lose contact with the evaporator. In electronic systems No Frost thermistors are responsible for control. Their resistance changes depending on the heating, and if the sensor “lies”, the controller will not receive a stop signal.
How to check a thermostat with a multimeter?
To check a mechanical thermostat, it must be removed. When cold, the contacts should be closed (the multimeter shows 0 Ohm). If you put the thermostat in warm water (about 30-40 degrees), the contacts should open (infinite resistance). If this does not happen, the part is faulty.
A symptom of a thermostat failure is often not only continuous operation, but also the absence of a characteristic click when trying to manually move the knob to the “Off” position. If the refrigerator freezes down to -20 degrees and does not think to stop, and the handle rotates freely without locking, this is a sure sign of failure of the control element.
⚠️ Attention: Replacing the thermostat in modern models may require reconfiguring the controller. Not all universal analogues work correctly without calibration.
Problems with the defrost system in No Frost refrigerators
For systems No Frost the proper operation of defrost cycles is critically important. If the heating element (heating element), defrost timer or defrost sensor fails, a “coat of ice” begins to grow on the evaporator. This ice blocks the air circulation channels, and the cold stops getting into the main chamber.
Sensors in the main chamber record that the temperature has not reached the norm and force the compressor to work without stopping. At this time, a huge ice ball may form behind the back panel of the freezer, which completely blocks the fan. As a result, the refrigerator hums, the wall freezes, but the chamber is warm, or vice versa - food freezes at the back wall.
Diagnostics of the defrost system requires partial disassembly of the freezer. It is necessary to check the integrity of the heating element, the resistance of the defrost sensor and the operation of the blower fan. Often the problem lies in the blown fuse, which is in the heater circuit and trips when overheated.
☑️ Diagnostics of the No Frost system
Refrigerant leak and capillary tube clogged
When a leak occurs in the freon circulation system, the pressure drops and the compressor is forced to idle, trying to gain the required pressure to shut down. Since there is little refrigerant, it cannot effectively cool the chamber, the sensors do not give the command to stop, and the motor wears out. Often, when there is a leak, you can hear gurgling or see oily spots under the refrigerator.
A similar situation occurs when the capillary tube is clogged. The microscopic hole through which freon enters the evaporator becomes clogged with oil breakdown products or moisture. The circulation is disrupted, the compressor creates excess pressure on one side and a vacuum on the other, but does not produce cold. This is one of the most difficult breakdowns, requiring professional cleaning or replacement of the filter drier.
Signs of problems with freon or blockage are:
- 🌡️ Hot side walls (normally they should be warm, but not hot).
- ❄️ Poor cooling during continuous operation of the motor.
- 🔇 A sharp change in the sound of the compressor (quieter or, on the contrary, a strained hum).
It is important to note that it is impossible to eliminate a leak or blockage on your own. Requires evacuation of the system, charging with freon and the use of specialized equipment. Attempts to “top up” the gas without eliminating the cause will only temporarily alleviate the situation.
Failure in the electronic control module
In inverter and modern refrigerators, the entire process is controlled by an electronic module. Power surges, moisture, or manufacturing defects can cause the relay to “stick” on the control board. In this case, the relay simply does not open the compressor power circuit, and it operates continuously, even if the temperature sensors scream that the norm has long been reached.
Often the failure is of a software nature. The “brains” of the refrigerator may freeze, and rebooting (unplugging for 15-20 minutes) sometimes helps clear the error. However, if the problem lies in a burnt triac or tracks on the board, the module will need to be replaced or its complex repair in a service laboratory.
| Symptom | Probable cause | Difficulty of repair |
|---|---|---|
| The compressor does not stop, there is cold | The thermostat or sensor is faulty | Low |
| The motor hums, there is no cold | Freon leak or blockage | High |
| Ice in the freezer, warm in the chamber | Failure of the defrost system (No Frost) | Medium |
| Chaotic operation, blinking indicators | Electronic module failure | High |
Influence of the external environment and proper operation
Sometimes the reason lies not in the breakdown, but in the operating conditions. If the refrigerator is placed near the radiator, in direct sunlight or in an unheated room in winter, its operation is disrupted. In summer, high ambient temperatures cause the engine to run longer to remove heat. In winter, the oil in the compressor may thicken, and the sensors may not read readings correctly.
How you load food is also important. If you put a large pot of hot soup into the chamber or load a lot of food at room temperature at once, the refrigerator will work in intensive mode for several hours until the climate evens out. This is normal, but if this mode becomes a habit, the service life of the equipment is reduced.
⚠️ Attention: Do not install the refrigerator close to the wall. A gap of 5-10 cm is necessary for free air circulation around the condenser (grid at the back).
Check whether you have the “Super Freeze” function turned on (usually indicated by a snowflake or button Super Freeze). In this mode, the refrigerator is not forced to turn off for several hours or days (depending on the model) in order to quickly freeze food. If you accidentally activated this function, simply disable it, and the operating mode will return to normal.
What is super freezing?
This is the maximum performance mode in which the thermostat is turned off. It is not recommended to use it for longer than 24-48 hours, as this leads to excessive energy consumption and wear of the compressor.
Frequently asked questions and answers (FAQ)
How long should the refrigerator rest between operating cycles?
In normal mode, the refrigerator operates for about 15-20 minutes, and then rests for 30-40 minutes. The working time coefficient is approximately 0.3-0.4. If it works for 50 minutes and rests for 10, this is a sign of overload or malfunction.
Could the reason be due to improper defrosting?
Yes, if you defrosted the refrigerator with a knife or hair dryer and damaged the inner tube of the evaporator, freon could come out. Also, you cannot turn on the unit immediately after defrosting; you need to let it stand turned off for at least 2-3 hours.
Why does the refrigerator freeze, but does not turn off, after moving?
If the refrigerator was transported lying down, oil could leak into the cooling circuit. It should be allowed to stand upright for at least 12-24 hours before turning it on. If you turned it on right away, a water hammer or blockage could have occurred.
Is it dangerous to leave the refrigerator running without stopping?
Extremely dangerous. The compressor is designed for cyclic operation. With constant operation, it overheats, the motor windings may burn out, and the oil may lose its lubricating properties. This leads to expensive repairs or the purchase of new equipment.
How to reset an error on a refrigerator?
Try to perform a full reset: unplug the appliance for 15-20 minutes. In some models with electronic control, you need to hold down a certain combination of buttons (for example, “Defrost” and “Temperature”) for 10 seconds. Look for the exact combination in the instructions for your model Bosch, LG or Indesit.