The situation when the refrigerator hums continuously is familiar to many owners of household appliances. You may notice that the unit has stopped pausing in operation, and the inside of the chamber has become too cold or, conversely, the products have begun to deteriorate due to insufficient cooling at maximum motor load. Continuous operation of the compressor - this is an alarm indicating that the system cannot reach the set temperature or that one of the key control units has broken down.
Ignoring this problem can lead to serious consequences, including engine failure and the need for an expensive replacement of the entire assembly. In some cases, the reason lies in a banal violation of operating rules, but most often the intervention of a specialist or serious diagnostics is required. Let's look at the main scenarios why refrigerator went into non-stop mode.
The first thing to do when a problem is detected is to check the tightness of the door closure and the presence of foreign objects that interfere with the tight fit of the seals. If there are no visual obstacles, and the unit continues to hum, it means there is a technical malfunction. Continuous operation of the compressor for more than 24 hours without rest cycles is guaranteed to lead to overheating and melting of the windings.
Faults in the thermostat and temperature sensors
One of the most common reasons continuous operation is the failure of the thermostat (thermostat) or electronic control module. It is this element that “tells” the compressor when to turn on for cooling and when to stop. If the thermostat contacts are stuck in the “on” position or the electronic sensor ATN transmits incorrect data about the high temperature, the motor will run indefinitely.
In mechanical models, the thermostat is a device with a bellows that responds to changes in refrigerant pressure in the capillary tube. Over time, the mechanism wears out and the spring stops opening the contacts when the desired temperature is reached. In modern models with the system No Frost or Full No Frost air sensors are responsible for control, which can oxidize or fail.
⚠️ Attention: Attempting to independently replace the thermostat in refrigerators running on isobutane (R600a) requires special care. Opening the system without evacuation can lead to ignition of the gas.
To diagnose a mechanical thermostat, you can try disconnecting its contacts and closing them directly (for experienced users only). If the compressor starts, then the problem is in the regulator itself. In the case of electronics, you will need to test the sensors with a multimeter and check their resistance with a table of values for a specific model.
How to check a thermostat with a multimeter?
To check, remove the thermostat and put the multimeter in testing mode. At room temperature the contacts should be closed (there is sound). Place the thermostat sensing part in the freezer for 10-15 minutes. If after cooling the contacts do not open (the sound does not disappear), the thermostat is faulty and requires replacement.
Freon leakage and circuit leakage
If the refrigerator operates constantly, but there is not enough cold inside, or only partial frost forms on the evaporator, there is a high probability of a refrigerant leak. Freon circulates in a closed circuit, and if there is a shortage of it, the system cannot create the necessary pressure for effective cooling. The compressor tries to compensate for the lack of refrigerant by working 24/7.
Leaks often occur at the soldering points of the tubes, in the foamed part of the housing (where the door perimeter heating circuit runs) or in the evaporator due to corrosion or mechanical damage. It is rarely possible to determine the location of a leak visually, since the gas evaporates quickly and has no color. The main symptom is that condenser grid the back of the unit remains cold or warm only partially.
The process of eliminating leaks is complex and requires special equipment: a leak detector, nitrogen for pressure testing and a vacuum pump. The technician must find the place of damage, solder it, replace the filter-drier and fill the system with new gas in a strictly defined quantity.
- 🔍 The refrigerator is humming, but inside it is warm or the temperature is higher than normal.
- 🔍 The rear wall (condenser) does not heat up over the entire area.
- 🔍 The evaporator tubes show traces of oil or frost in only one corner.
- 🔍 The compressor is hot to the touch, but there are no shutdown cycles.
Problems with the compressor and start relay
The very “heart” of the refrigerator - the compressor - can also cause uninterrupted operation. If the piston group is worn out, the valves have lost their tightness or the compression has dropped, the unit will not be able to gain the required pressure in the system. As a result, the refrigerator will work constantly, trying to achieve the set parameters, but will not turn off.
Another common problem is a malfunction of the start-up relay. This small element is responsible for starting the engine and protecting its windings from overheating. If the relay is “stuck” or the contacts are burnt, it can constantly supply current to the windings, preventing the motor from stopping. In some cases, the relay simply does not open the circuit after starting.
Diagnostics of the compressor requires measuring the outlet pressure and current. If the current is below the rated current and the pressure does not increase, it means that the compressor is “not working” and requires replacement. Replacing a compressor is a complex procedure, including resoldering the tubes, evacuating the system and accurately filling with freon.
| Symptom | Probable cause | Necessary actions |
|---|---|---|
| Humming, does not turn off, cold yes | Thermostat or sensor is faulty | Replacing the thermostat |
| Humming, does not turn off, no cold | Freon leak or blockage | Search for leaks, refueling |
| Gets very hot, buzzes | Compressor wear | Replacing the compressor |
| Clicks, buzzes, does not turn off | Problem with starting relay | Replacing the relay |
Faults in the No Frost system
In refrigerators with an automatic defrosting system No Frost the reason for constant operation is often a violation of air circulation. If the fan driving cold air through the chambers has stopped or is working weakly, the temperature sensor in the main chamber does not detect cooling. As a result, the “brain” of the refrigerator gives a command to the compressor to continue working.
Another common problem is freezing of the evaporator due to a malfunction of the defrost heating element, timer or defrost sensor. An ice coat on the evaporator is blocking the air flow. The compressor works hard, trying to cool the chamber, but the air simply does not reach the food. Visually, this can manifest itself in the form of ice on the back wall of the freezer.
To fix the problem, you need to defrost the refrigerator (completely, for at least 12-24 hours with the doors open). If after defrosting the unit started working normally, and after a few days the problem returned, it means that one of the elements of the defrosting system is faulty. Most often, the evaporator heating element burns out or the defrost sensor fails.
⚠️ Attention: When defrosting the No Frost refrigerator, it is strictly forbidden to use hair dryers, hot water or sharp objects to chip ice. Mechanical damage to the evaporator tubes will lead to an immediate leak of freon.
External factors and operating errors
Before sounding the alarm and calling a technician, it is worth eliminating factors not related to equipment breakdown. Often, users themselves create conditions under which the refrigerator is forced to work in increased mode. Check the following points to ensure correct operation.
One of the main mistakes is installing the refrigerator too close to heating devices, radiators or in direct sunlight. It is also important to provide clearance between the back of the unit and the wall to allow proper air circulation around the condenser. If (heat dissipation) is impaired, the refrigerator will not be able to cool effectively.
- 🍲 Loading Hot Food: Placing warm food will dramatically raise the temperature inside, causing the motor to run longer.
- 🚪 The door is not tightly closed: door distortion or contamination of the seal leads to a constant influx of warm air.
- ❄️ “Super Freeze” mode: the intensive freezing function, forgotten when turned on, blocks the compressor from turning off.
- 🧊 Large layer of ice: in drip models, a layer of snow of more than 5-7 mm impairs heat transfer.
☑️ Checking operating conditions
Frequently asked questions (FAQ)
How long can a refrigerator operate without stopping before breaking down?
Modern compressors can withstand long-term operation, but 24/7 mode is not standard. If the refrigerator operates without stopping for more than a day, the risk of overheating and melting of the windings increases significantly. It is recommended to turn off the device and call a technician if the cause is not eliminated within 12-24 hours.
Why does the new refrigerator work constantly?
In the first 24-48 hours after the first turn on, the new refrigerator can work without interruption. This is a normal process of primary cooling of a large volume of air and the walls of the chamber. If after two days the cyclicity has not been restored, the thermostat may be defective or a leak occurred during transportation.
Is it possible to use the refrigerator if it does not turn off?
For a short time, it is possible, but this is an emergency mode. Products may freeze or, conversely, deteriorate due to unstable temperatures. The main thing is not to leave such a refrigerator unattended for a long time, since there is a high probability of a wiring fire or failure of an expensive compressor.
Does the room temperature affect the operation of the refrigerator?
Yes, it does significantly. If the room is hot (above +30°C), it is more difficult for the refrigerator to remove heat, and the compressor operating time increases. However, even in the heat he must take breaks. Working in an unheated room at temperatures below +5°C is also harmful: the oil in the compressor thickens, and the refrigerant may not evaporate correctly.