The situation when the refrigerator compressor hums continuously and the cooling cycle is not interrupted is familiar to many owners of household appliances. Normally, the unit should operate cyclically: turn on to set the temperature and turn off to rest. If the motor does not stop for hours, this is a signal of a serious failure in the thermoregulation or thermal insulation system. Ignoring the problem leads to overload of the compressor, increased energy consumption and, ultimately, expensive repairs.
Before calling a technician, you should try to understand the nature of the problem. Often the reason lies in trivial things that can be fixed on your own, for example, a door that is not tightly closed or an incorrectly set operating mode. However, there are also technical breakdowns that require specialist intervention. It is important to distinguish between these conditions so as not to aggravate the situation and keep food fresh.
In this article we will examine in detail the main reasons for the continuous operation of refrigeration equipment, diagnostic algorithms and methods for solving problems. You'll learn how to check the circuit for leaks, assess the condition of the thermostat, and determine whether a refrigerant charge is needed. Understanding the operating principles of your model Indesit, Bosch or LG will help you make the right decision on further actions.
Incorrect installation and violation of the temperature regime
One of the most common reasons why the refrigerator does not go into standby mode is a violation of the operating rules. If the unit is installed close to (batteries, stoves) or in direct sunlight, the cooling system is forced to work at its limit to compensate for external heating. Heat inflows do not allow the temperature inside the chambers to drop to the set value, and the compressor continues to hum without interruption.
It is also critically important to maintain distances from walls and furniture. The rear radiator grille must be freely washed by air for effective heat dissipation. If the refrigerator is moved close to the wall, hot air stagnates, heat transfer efficiency drops, and the motor does not receive a signal to cool the condenser. The minimum distance to the back wall should be at least 5-7 cm.
Another factor is the room temperature. Most household refrigerators are designed to operate in climate class SN-N-ST, which implies a range of ambient temperatures from +10°C to +38°C. If the room is too hot or, conversely, cold, the automation may not work correctly.
⚠️ Attention: Do not install the refrigerator on an unheated balcony or garage in winter. The oil in the compressor will thicken, which will lead to its breakdown when trying to start, and the thermostat may simply not “understand” that the chamber is already cold enough due to the low temperature outside.
Problems with the door seal and tightness
The rubber seal (cuff) on the door is the first barrier that keeps the cold inside the chamber. Over time, rubber loses elasticity, cracks or deforms, forming gaps. Warm air constantly flows inside through these cracks; sensors record the temperature increase and give the command to the compressor not to stop. It can be difficult to visually notice small defects, so a thorough check is required.
The easiest way to diagnose is to use a sheet of paper. Clamp the sheet between the door and the body around the entire perimeter. If the paper comes out easily, without resistance, it means that the seal in this place is broken. It is also worth inspecting the rubber itself for cracks, tears or dirt that may interfere with a tight fit.
Sometimes the problem is solved by simply cleaning or restoring the shape of the seal. If the rubber has simply moved away from the groove, it can be carefully reset. In case of deformation over time, treatment with hot water or using a hair dryer (with caution) helps to restore the elasticity of the material. However, if the seal is mechanically damaged, it will need to be replaced.
☑️ Checking the door tightness
It is also worth checking the door hinges. If they are loose or warped, the door may not fit tightly even with a good seal. Adjusting the hinges often solves the problem of “escaping” cold. In models with a system No Frost leakage is especially critical, as it leads to increased ice formation on the evaporator and an even greater load on the system.
Malfunctions of the thermostat and temperature sensors
The thermostat (thermostat) is the “brain” that makes decisions about turning on and off compressor. It measures the temperature in the evaporator or chamber and opens the electrical circuit when the target is reached. If the contacts inside the thermostat are stuck in the “on” position or the sensor has failed and is transmitting incorrect data, the refrigerator will operate continuously.
In modern models with electronic control, the role of a thermostat is performed by air sensors and defrost sensors. Their readings are read by the electronic control module. If one of the sensors is “lying,” the system may assume that the chamber is warm and not give a command to stop the engine. Diagnosis of such faults requires a multimeter and knowledge of electrical circuits.
| Type of fault | Symptoms | Check method |
|---|---|---|
| Sticking thermostat contacts | The refrigerator does not turn off even with severe hypothermia | Testing the contacts with a multimeter |
| Freon leakage from the bellows tube | Thermostat does not sense temperature changes | Visual inspection of the tube, checking the pressure |
| Malfunction air sensor | Error on display, incorrect temperature | Measurement of sensor resistance at different temperatures |
| Control module failure | Chaotic operation, lack of response to settings | Board diagnostics specialist |
Mechanical thermostats are characterized by loss of sensitivity of the bellows tube. If the filler gas has left it, the membrane will not shrink and the contacts will not open. In this case, only replacing the entire assembly helps.
How to replace the thermostat yourself?
Replacing the thermostat requires disassembling the refrigerator. You need to remove the top cover, find the thermostat, photograph the wiring diagram, disconnect them, remove the old device and install the new one. Pay special attention to installing the sensitive tube in the evaporator.
Refrigerant leakage and problems with the compressor
If the refrigerator runs non-stop, but there is no cold inside or it is insufficient, there is a high probability of a freon leak. The refrigerant circulates in a closed circuit, and if its tightness is compromised (corrosion, breakdown), the cooling efficiency drops. The compressor tries to compensate for the lack of cold, working 24/7, but cannot achieve the set parameters.
Signs of a leak are often hot sides of the refrigerator (in places where they should be warm) or, conversely, cold ones if the freon has completely come out. You may also notice swelling of the back wall inside the freezer. Prolonged idle operation quickly wears out the compressor, which is not designed for continuous operation.
In some cases, the compressor itself loses its performance due to wear of the valves or piston group. The motor hums and creates pressure, but it is not enough for normal circulation of freon. You can check the performance of the compressor by measuring the current or output pressure, which only a technician with the equipment can do.
⚠️ Attention: If you hear gurgling or hissing inside the refrigerator when the compressor is turned off, or see oily spots under the unit, these are signs of serious depressurization. You cannot operate such a refrigerator; you need to call a technician to find a leak and refill it.
Refilling a refrigerator is a technically complex process that requires evacuation of the system and precise dosage of the refrigerant. The type of freon (R134a, R600a) and its quantity are strictly regulated by the manufacturer for each model. Self-refueling “by eye” will lead to incorrect operation or breakdown of the compressor.
Freezing of the defrost system (for No Frost)
In refrigerators with a system No Frost continuous operation of the compressor is often associated with a malfunction of the defrost system. The evaporator, hidden behind a plastic panel, periodically becomes overgrown with frost, which must be removed by a heating element (heating element). If the heating element, defrost timer or defrost sensor fails, the ice does not melt.
The growing ice coat blocks the air circulation channels. The cold stops flowing into the chambers, the sensors record the heat and force the compressor to work continuously. At the same time, the freezer may be colder than normal, and the refrigerator compartment may be warm. This can be seen visually if you remove the back panel in the freezer - the evaporator will be completely covered with ice.
For diagnostics, you need to check the defrost circuit: test the heating element for resistance, check the defrost sensor (defrost thermostat) and the fuse. Often it is the sensor that fails because it “does not see” that the evaporator is frozen and does not turn on the heating. Or the defrost timer is stuck in cooling mode.
The influence of the “Super Freeze” mode and other functions
Sometimes the reason for continuous operation is trivial and lies in the settings. The “Super Freeze” mode forces the compressor to run continuously, ignoring the thermostat readings. This is necessary for quick freezing of large volumes of food. If the user accidentally activated this function, the refrigerator will hum until the mode is turned off manually or automatically (usually after 24-48 hours).
The “Vacation” functions have a similar effect (if it involves the operation of only the freezer with the main chamber turned off, but with a sensor error) or intensive cooling. In modern smart refrigerators with Wi-Fi, a failure in the software or server can also cause the controller to freeze in active mode.
Check the control panel. Is the snowflake indicator or inscription lit? Super? Try resetting the settings to factory defaults or simply unplugging the refrigerator for 10-15 minutes to reboot the electronic module. This often helps eliminate software glitches.
Frequently asked questions (FAQ)
How long can a refrigerator operate without a break normally?
In normal mode, the refrigerator operates cyclically: the operating time ranges from 5 to 20 minutes, followed by a pause of 15 to 40 minutes. The working time coefficient (WFC) is normally about 0.3-0.5 (30-50% of the time he works, the rest he rests). If the motor hums for more than 20-30 minutes without stopping under normal conditions, this is a cause for concern.
Is it dangerous if the refrigerator does not turn off for a day?
Yes, it is dangerous. Long-term operation without stopping leads to overheating of the compressor windings, oil burnout and jamming of the piston group. In addition, this is a huge energy consumption. If the refrigerator does not turn off for more than 2-3 hours, it is better to disconnect it from the network and carry out diagnostics.
Can the refrigerator not turn off due to the heat in the summer?
Yes, in extreme heat (above +30°C in the room) the operating cycles are lengthened and pauses are shortened. The compressor runs longer to compensate for heat gain. However, it should still turn off periodically. If there are no pauses at all, the problem is not only in the heat, but also in the equipment.
What to do if after defrosting the refrigerator does not stop working?
If complete defrosting (for 24 hours with the doors open) did not help, then the problem is technical. Most likely, the thermostat is faulty, there is a freon leak, or the capillary tube is clogged. It is necessary to call a technician for diagnostics.
Does the amount of food affect the operating time?
Yes, a full refrigerator holds the cold better, and the compressor can turn on less often, but longer. An empty refrigerator heats up faster when the door is opened. However, neither a full nor an empty load should lead to continuous operation without stopping.