The situation when the refrigerator works and does not turn offoften takes owners by surprise, causing concern for the safety of products and the safety of electrical wiring. During normal operation, the compressor must turn on and off at certain intervals, depending on the thermostat settings and the temperature inside the chambers. However, if the motor hums continuously for several hours or even a day, this is a clear signal of a failure in the cooling system or a violation of the tightness of the circuit.
Constant operation of the engine leads to its overheating and accelerated wear of the moving mechanisms, which ultimately may require an expensive replacement of the unit. In addition, a continuous refrigeration cycle often results in the formation of excess ice in the evaporator, further impeding heat transfer. It is important not to ignore the first signs of a malfunction, since timely diagnosis helps to avoid critical breakdowns.
In this material we will analyze in detail the mechanical and electrical reasons why refrigeration equipment stops turning off, and we will describe action algorithms for eliminating problems. Some faults can be corrected independently, while others will require the intervention of a qualified technician using specialized equipment to diagnose pressure and find leaks.
Tightness failure and refrigerant leakage
One of the most common reasons why the refrigerator does not turn off, is a banal freon leak. The refrigerant circulates in a closed circuit, and if its quantity decreases, the system loses its ability to effectively remove heat. The compressor is forced to work non-stop, trying to compensate for the lack of working fluid and achieve the specified temperature parameters, but this becomes physically impossible.
Leaks can occur in various places: in sealed tube connections, in places of metal corrosion or through microcracks in the evaporator. This is often preceded by mechanical damage during defrosting with a sharp object or natural aging of the metal. As a result, the pressure in the system drops, and even with prolonged operation of the engine, the temperature in the chambers either does not drop to normal or drops very slowly.
⚠️ Attention: If you notice oily spots under the refrigerator or on the pipes at the back, this is a sure sign of depressurization of the system. Do not try to seal the tubes yourself - complete evacuation and charging of the system with professional equipment is required.
Diagnostics of a leak often requires the use of a leak detector or a soap solution to detect gas bubbles at the connections. After eliminating the leak, it is necessary to replace the filter-drier, since it could be saturated with moisture from the air that entered the circuit during the leak.
It is important to understand that working with refrigerants requires compliance with safety precautions and a license. Independent attempts to refill without eliminating the cause of the leak will only lead to temporary results and repeated failure of the compressor.
Problems with the thermostat and temperature sensors
The thermostat is the “brain” of the system, which commands the compressor to start or stop depending on the temperature in the chamber. If thermostat fails, it can “stick” in the “on” position, sending a constant signal to start the motor, even when the food is already frozen. In modern models with electronic control, this function is performed by temperature sensors (thermistors), which can also give erroneous readings.
Mechanical thermostats lose sensitivity over time, their contacts burn or oxidize, which leads to disruption of the electrical circuit. In such cases, either complete switching failure or, conversely, continuous operation is often observed. You can check a mechanical thermostat by disconnecting its contacts: if the refrigerator turns off, then the problem is in the regulator.
Electronic control modules are more difficult to diagnose, as they require checking the resistance of the sensors with a multimeter. If the sensor “lies” and shows that the chamber is warm, the control module will keep the compressor on indefinitely. Replacing the sensor usually solves the problem, but in rare cases, it may be necessary to reflash or replace the control board itself.
How to check a thermostat with a multimeter?
To check a mechanical thermostat, remove it from the refrigerator and cool it (you can put it in the freezer for 15-20 minutes). Then test the contacts with a multimeter: when cold, the circuit should be closed (resistance close to 0), and when heated to room temperature, it should be open (resistance infinity). If the circuit does not open when heating, the thermostat is faulty.
Incorrect operation No Frost systems can also be associated with defrost sensors. If the defrost sensor does not work, the evaporator becomes overgrown with ice, the air stops circulating, and the refrigerator works without stopping, trying to cool the chamber.
Wear of the sealing rubber and loss of tightness
Tight fit of the door to the body ensures preservation cold inside the cells. If sealing rubber is worn out, cracked or deformed, warm air from the room constantly enters the chamber. Sensors detect an increase in temperature and instruct the compressor to work harder, which leads to its continuous operation.
Often the problem lies not in the rubber itself, but in contamination of its surface or misalignment of the door. Grease, crumbs and sticky residue prevent a tight seal. The door may also warp due to loose hinges or overloading the shelves with heavy products. Visual inspection and checking the tight fit of a sheet of paper around the perimeter of the door will help identify problem areas.
| Type of malfunction | Symptoms | Solution method |
|---|---|---|
| Dirty rubber band | Door does not stick, plaque is visible | Wash with soapy water, dry |
| Rubber deformation | Cracks, creases, loss of elasticity | Replacing the seal with a new one |
| Disk doors | Uneven gaps, creaking | Adjusting hinges, overhanging |
| Loose fasteners | The door is wobbly | Tightening screws and bolts |
To restore the elasticity of the rubber, you can use a hairdryer, gently heating the deformed areas, but this is a temporary measure. If the rubber has completely lost its properties, it must be replaced with an original or high-quality analogue suitable for your model refrigeration equipment.
Freezing and blocking of the defrost system
In refrigerators with a system No Frost or “Crying evaporator” is critical Proper operation of defrost cycles is important. If the defrost timer, heating element (heating element) or defrost sensor fails, a “coat of ice” begins to grow on the evaporator. This ice blocks the circulation of cold air, and the sensors in the chamber do not detect a decrease in temperature, forcing the compressor to work non-stop.
Visually this can manifest itself in the form of a hum (the fan running against the ice) or a complete absence of cold when the engine is running. In some cases, ice can completely block the air channels, and cold simply does not enter the main chamber, although it may be very cold in the freezer.
☑️ Diagnostics of the defrost system
Defrosting the refrigerator for 24 hours with the doors open often helps to temporarily solve the problem if the ice plug has not damaged other elements. However, if after defrosting the situation repeats after a few days, replacement of faulty elements of the defrosting system is required.
⚠️ Attention: Do not try to break off the ice with a knife or other sharp objects! You may damage the evaporator tubes or puncture the heating element, which will lead to expensive repairs.
Improper installation and external factors
Sometimes the reason for continuous operation lies not in a breakdown, but in incorrect operating conditions. If refrigerator is installed too close to the wall, the radiator on the rear wall does not have time to release heat, and cooling efficiency decreases. Direct sunlight or proximity to heat sources such as radiators or ovens are also detrimental.
Loading the refrigerator with hot foods is another common mistake. The thermostat will “see” the high temperature and keep the compressor on until the food has cooled completely. This creates an extreme load on the equipment.
In addition, it is worth checking the temperature settings. If you accidentally set the “Super Freeze” mode or set the minimum possible temperature, the refrigerator will work without interruption, following your command. In winter, if the refrigerator is on an uninsulated balcony, the oil in the compressor may thicken, which will also disrupt its normal operating cycle.
Wear of the compressor and electrical problems
The most serious and expensive option is wear of the compressor itself. compressor. Over time, the piston group wears out, compression drops, and the engine physically cannot create enough pressure to achieve the desired temperature. It hums, heats up, but does not turn off, since the goal has not been achieved.
The problem may also lie in the start-up relay. If it is stuck or faulty, it may not break the power supply to the motor windings. In some cases, the fault lies in the wiring or oxidation of the contacts, which leads to direct current to the windings.
Diagnostics of the compressor requires measuring current consumption and discharge pressure. If the current is below the rated current and the pressure does not increase, the compressor “does not pump” and must be replaced. Repairing a compressor in a domestic environment is practically impossible and economically unfeasible.
Frequently asked questions (FAQ)
How long can a refrigerator operate without interruption normally?
In normal operation, modern refrigerators can operate from 15 to 40 minutes, followed by a pause (off-period) approximately the same duration. However, when loading food for the first time, after defrosting or in super-freezing mode, continuous operation for 6-12 hours is considered acceptable.
Is it possible to operate a refrigerator if it does not turn off?
Short-term - yes, but long-term operation without breaks leads to overheating of the motor windings, drying out of the oil and rapid compressor failure. If the equipment works non-stop for more than a day, it must be disconnected from the network and diagnosed.
Why does a new refrigerator work constantly?
When turned on for the first time, a new refrigerator can work for up to 24 hours without interruptions. This is necessary for the initial cooling of the entire volume of the chambers and freezer to the specified temperatures. After reaching the norm, it should begin to turn on and off cyclically.
Does the temperature in the room affect the operation of the refrigerator?
Yes, if the room is too hot (above +30°C), it is more difficult for the refrigerator to give off heat, and its operating time increases. If it is too cold (below +10°C), the thermostat may not turn on, or, conversely, due to thickened oil, the compressor will work intermittently or continuously.
What to do if after defrosting the refrigerator does not turn off again?
If complete defrosting (at least 24 hours) did not help, then the problem is not in the ice traffic jam There may be a freon leak, a thermostat malfunction, or compressor wear. In this case, professional diagnostics using a manometric manifold are necessary.