The situation when the refrigerator hums for days on end is familiar to many owners of household appliances. Constant operation of the motor not only increases electricity bills, but also creates discomfort due to noise. Most often, users begin to panic when they notice that the device has stopped pausing its work. This is truly an alarming signal indicating a violation of the thermodynamic cycle.
Modern models are equipped with complex electronics that must control the temperature regime. However, even inverter compressors can fail or operate in emergency mode. Understanding why your refrigerator does not turn off will help you make the right decision: call a technician or try to fix the situation yourself.
In this article we will analyze mechanical and electrical faults in detail. You will learn how to distinguish a trivial operating error from a serious breakdown of the unit. It is important not to ignore the first symptoms, since long-term work without a break leads to rapid wear of the components.
The influence of external factors and operating errors
Before disassembling the equipment, it is worth excluding simple causes. Often the unit is operational, but its operating conditions are violated. Room temperature plays a critical role. If the refrigerator is located near the radiator or in direct sunlight, it physically cannot reach the desired temperature inside the chambers. Heat inflows force the motor to work non-stop.
Another common reason is a tight fit of the door to the body. Rubber seal over time it dries out or becomes dirty. Through microscopic cracks, warm air constantly enters, sensors record the temperature rise and give a command to cool. Check whether the door closes tightly using a simple test with a piece of paper.
⚠️ Attention: If you have just loaded a large amount of warm food into the chambers, continuous operation for 6-12 hours is normal. The device is simply trying to cool the new thermal mass.
Incorrect installation also affects the efficiency of heat transfer. The rear radiator grille must have free air access. If the equipment is built into a niche without gaps or is moved close to the wall, condenser does not have time to cool down. This leads to overheating of the refrigerant and a decrease in the efficiency of the entire system.
Malfunctions of the thermostat and temperature sensors
One of the most common reasons for endless operation is failure thermostat. In mechanical models, it is this unit that is responsible for opening the compressor power circuit when the set temperature is reached. If the contacts inside the thermostat are “stuck” in the closed position, the motor will work until it burns out or is de-energized from the outside.
In refrigerators with a system No Frost and electronic control, temperature sensors are used instead of a thermostat. Their readings are read by the control module. If the sensor “lies” and shows that it is warm in the chamber, although in fact it is already frosty there, the control board will not give the command to stop. Replacing such an element often requires disassembling the internal panel.
How to check a thermostat with a multimeter?
To check, you need to remove the thermostat, immerse its sensitive tube in cold water with ice and ring the contacts. If during cooling the circuit does not open (the resistance does not go to infinity), the part is faulty and requires replacement.
Diagnostics of the electronic unit requires special knowledge. Often the problem lies not in the sensor itself, but in oxidation of the contacts or broken wiring. In such cases, error codes may appear on the display, but not always. Some models Liebherr or Bosch can continue to operate in emergency mode without indicating a malfunction.
Problems with the compressor and motor
The heart of the refrigerator is the compressor. If it is worn out, its performance decreases. The motor tries to compensate for the lack of power by increasing operating time. As a result, it hums constantly, but does not provide the required cold. This is a classic symptom of interturn short circuit windings or deterioration of the mechanical parts of the piston group.
The starting relay also plays an important role. If it is faulty, the compressor may hum, click, but not start, or vice versa - work without stopping. In older models, relays often fail due to power surges. Checking this element takes little time and does not require complex equipment.
Inverter compressors are designed differently. They do not turn off completely, but only reduce the speed. However, if the inverter control board is faulty, the motor may run at maximum speed continuously. This is typical for modern models Samsung and LG. Diagnostics of such systems requires calling a specialist with an oscilloscope.
Refrigerant leak and system blockage
The most unpleasant and costly reason is a freon leak. The refrigerant circulates in a closed circuit. If a hole forms in the tubes (due to corrosion or mechanical damage), the gas escapes. The pressure in the system drops and the compressor runs non-stop, trying to build up pressure that it physically cannot reach. In this case, the refrigerator may hum for days, but it will be warm inside.
A clogged capillary tube has a similar effect. Oil or decomposition products clog the narrow channel, preventing the circulation of freon. The compressor wears out, creating excess pressure before the blockage and vacuum after it. This can be determined by the characteristic sound of gurgling or its absence, as well as by the temperature of the condenser tubes.
⚠️ Attention: Self-filling the refrigerator with freon is dangerous and requires a license. The wrong dose or type of refrigerant can lead to a compressor explosion or fire.
Visually, a leak can sometimes be detected by swelling of the wall of the refrigerator compartment or the appearance of oily stains on the floor under the equipment. However, in 80% of cases, the location of the leak is hidden in the foamed casing, which makes repairs difficult and often economically impractical.
Malfunctions of the defrost system (for No Frost)
In systems No Frost the serviceability of the evaporator and defrost system is critically important. If the defrost heating element, timer or defrost sensor is faulty, a coat of ice will build up on the evaporator. It blocks the circulation of cold air. The fan is moving air, but it is not cooling properly. Sensors record the high temperature and keep the compressor on.
A symptom of such a breakdown is often that the refrigerator freezes, but weakly, or the freezer works normally, but it is warm in the refrigerator compartment. Over time, ice can block the fan completely, and then extraneous noise or humming will appear.
☑️ Diagnostics of the defrost system
To eliminate this problem, complete defrosting of the unit is required (at least 24 hours with the doors open) and subsequent replacement of burnt elements of the defrost system. Ignoring the problem will lead to ice reaching the compressor or damaging plastic parts.
Table of symptoms and probable breakdowns
To systematize knowledge, let's turn to the summary table. It will help you navigate the initial diagnosis based on external signs.
| Symptom | Probable cause | Difficulty of repair | Necessary tools |
|---|---|---|---|
| It buzzes, but no cold | Freon leak | High | Leak detector, vacuum sealer, freon |
| Works without stopping, very cold inside | Thermostat is faulty | Average | Multimeter, screwdriver |
| Humming, hot condenser, little cold | Clogged capillary tube | High | Compressor for purge, nitrogen |
| Noisy, works non-stop, ice on the back wall | Failure of the defrost system | Medium | Tester, hair dryer |
| Buzzes intermittently, clicks | Faulty starting relay | Low | Multimeter, new relay |
Analysis of this table shows that some problems are solved by replacing a cheap part, while others require the intervention of professionals with gas. It is important to understand: if the cause is a leak inside the foamed circuit, the repair is often equivalent to buying a new refrigerator.
Algorithm of actions when a problem is detected
If you notice that the refrigerator does not turn off, do not immediately take it apart. Be consistent. First, rule out external factors: check the tightness of the door, the temperature in the room and the presence of warm foods inside. Try defrosting the unit manually during the day. If after turning on the problem returns after a few hours, it’s a technical issue.
Next, listen to the sounds. A uniform hum indicates the engine is working, an intermittent hum indicates attempts to start. Feel the back of the grill: it should feel warm (or hot at the top) but evenly. If the tube is hot only at the entrance to the compressor, and then cold, this is a sign of blockage.
For owners of complex electronic models, the best solution would be diagnostics through the service menu (if there is access) or calling a specialist. Attempts to “treat” electronics at random can lead to the burning of an expensive control module.
Frequently asked questions (FAQ)
How long should the refrigerator work before the first shutdown?
When turned on for the first time or after complete defrosting, the refrigerator can work without stopping for 6 to 12 hours. This is necessary to reach operating temperature conditions. If it does not turn off for more than a day, this is a malfunction.
Can the refrigerator not turn off in the summer due to the heat?
Yes, in extreme heat (above +30°C) the operating cycle changes. The device works longer, the pauses become shorter. However, it should still turn off periodically. If there are no pauses at all, check the ventilation around the case.
Is it dangerous to leave a refrigerator running without stopping?
For a short time - no. But long-term operation without breaks (a day or more) leads to overheating of the compressor windings, oil burnout and eventual motor breakdown. It is better to turn off the power to the appliance before the technician arrives.
Why does a new refrigerator constantly work?
New models often have more powerful compressors for quick freezing. Also check that the transport locks have been removed and that the door is not pressed down during transport. If after 24 hours the mode has not returned to normal, this is a defect.