The situation when a household refrigerator stops turning off and works in continuous mode causes reasonable concern for any owner. A unit that hums without interruption not only creates a constant background noise, but also consumes a colossal amount of electricity, which will inevitably affect utility bills. Moreover, such non-stop operation often indicates a serious technical failure, which, if ignored, can lead to complete failure of expensive equipment.
The reasons why compressor does not receive a stop signal can be many: from a trivially loose door to a complex refrigerant leak or failure of electronics. It is important to understand that modern cooling systems are more complex than their predecessors and require competent diagnostics. In this material, we will analyze in detail the main factors that influence the cyclical operation of equipment, and will help you determine when you can handle it yourself, and when you need to call a specialist.
Improper operation and external factors
Before panicking and looking for breakdowns of internal components, it is necessary to exclude the human factor and environmental conditions. Often the reason lies in a simple violation of operating rules, which the user may not notice. For example, if you have just loaded a large amount of warm food into the chamber after cooking or defrosting, the system will take a significant amount of time to reach the set temperature.
Another critical point is the location of the unit. If the refrigerator is located close to the wall, the radiator on the back wall cannot effectively transfer heat to the environment. It is also worth checking whether the body is not exposed to direct sunlight or heat from a working stove and battery. Thermostat will record high temperatures and prevent the compressor from stopping.
⚠️ Attention: Installing the refrigerator closer than 5-7 centimeters from the wall or in a niche without proper ventilation leads to overheating of the motor and reducing its service life.
In some cases, the problem is solved by simply rearranging the furniture or changing the mode of use. Check that the doors close tightly and that there are no hanging dishes or overcrowded shelves in the way. The sealing rubber must fit around the entire perimeter, ensuring tightness.
☑️ Checking operating conditions
Faults of the thermostat and temperature sensors
One of the most common reasons for continuous operation is the failure of the thermostat. This small element is responsible for controlling the temperature inside the chambers and sends a command to turn the compressor on or off. If the thermostat contacts are stuck in the “on” position or the sensor has stopped reading readings correctly, the refrigerator will work indefinitely.
In models with electronic control, instead of a mechanical thermostat, an air sensors control module is used. If one of the sensors malfunctions, the control board may receive erroneous data that the chamber is too warm and keep the motor running. Diagnostics of such systems requires the use of a multimeter to check the resistance of the sensors at different temperatures.
Symptoms of a thermostat failure often manifest themselves in the fact that the refrigerator either does not turn on at all, or, as in our case, does not turn off. In older models with mechanical control, you can try to gently tap the regulator knob or temporarily disconnect the contacts to check the reaction of the motor, but these are only temporary measures.
How to check the 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 there is no click when it cools down and the resistance does not change (open or short circuit), the part must be replaced. It is important to choose an analogue with identical temperature characteristics.
Refrigerant leak and clogged capillary tube
If the refrigerator hums, but does not produce cold (or produces very little), and does not turn off, there is a high probability of a freon leak. A refrigerant circulates in the system, which takes heat from the chambers. As the amount of gas decreases, the cooling efficiency drops, the sensors detect “heat” and force the compressor to work hard, trying to reach the target temperature.
A similar situation occurs when the capillary tube through which freon moves is clogged. A blockage can form due to moisture entering the system or oxidation products. The pressure in the system is disrupted, the circulation of the coolant stops, and the engine idles. This is one of the most difficult and expensive malfunctions.
It is almost impossible to detect a leak visually, since freon is a colorless and odorless gas. An indirect sign may be swelling of the side walls (where the heating circuit passes) or the appearance of rust in the places where the tubes are soldered. Also, uneven formation of frost may be observed on the evaporator (“snow coat” only in one corner).
| Symptom | Probable cause | Necessary actions |
|---|---|---|
| The refrigerator works, but does not cool | Freon leak | Searching for leaks, evacuation, refilling |
| Hot condenser, no cold | Clogged capillary system | Purge the system, replacement filter-drier |
| Weak cold, long temperature rise | Insufficient amount of refrigerant | Refilling the system with freon |
Problems with the compressor and start relay
The heart of the refrigerator - the compressor - can also be the culprit of the problem. If the motor has exhausted its service life, its power may drop. It will work constantly, but will not be able to create sufficient pressure for normal circulation of freon. In such cases, strong heating of the compressor housing is often observed.
The starting relay deserves special attention. This element is responsible for starting the engine. If the relay is faulty, it may not open the starting winding circuit, causing the motor to continue running when it should have stopped. Often, when a relay breaks down, you can hear a characteristic click, after which the refrigerator either does not turn on or works intermittently.
It is important to distinguish between the operation of an inverter and a conventional compressor. Inverter models (for example, Liebherr or Bosch) can indeed operate constantly, but at low speeds, maintaining the temperature. This is their normal mode, not a breakdown. Conventional compressors must turn on and off cyclically.
⚠️ Attention: If the compressor hums, but does not start, or immediately knocks out the machine in the panel, under no circumstances try to turn it on again many times - this can lead to an inter-turn short circuit of the windings.
Failure in the electronic control module
In modern models of refrigerators (for example, Samsung with a system No Frost or LG), the entire process is controlled by an electronic “brain”. A failure in the firmware or failure of the control board elements can lead to the fact that the signal to turn off the compressor simply will not be generated.
Often such failures occur due to voltage surges in the electrical network or moisture getting on the contacts. Visually, traces of burning or swollen capacitors may be visible on the board. However, in 80% of cases, the board appears to be in good condition, and only a specialist with an oscilloscope can diagnose the problem.
Sometimes a simple restart of the system helps: disconnecting the refrigerator from the network for 15-20 minutes. This allows you to reset errors in the controller memory. If after turning on the situation repeats, the problem lies deeper and requires replacing the module or resoldering the elements.
Impact of fast freezing mode
Don't forget about the Super Freeze function, which is available in many models. When activated, this mode forces the refrigerator to run continuously for a certain period of time (usually 6 to 24 hours) to quickly freeze food.
If you accidentally enable this feature by pressing the appropriate button on the control panel, the refrigerator will run continuously until the timer expires or you manually turn off the mode. Check the indication on the display: a lit snowflake indicator or the inscription “Super” indicate the active accelerated freezing mode.
In older models with mechanical control, the analogue is forced activation, which also needs to be turned off manually. Carefully read the instructions for your model to understand the logic of the control panel.
Diagnostics and elimination methods
To accurately determine the cause, it is necessary to carry out consistent diagnostics. Start with a visual inspection and checking the operating conditions. If no external causes are found, proceed to checking the electrical part. It is important to follow safety precautions when working with electrical appliances.
If you do not have the skills to work with electrical equipment and refrigerants, it is better not to take risks. Repairing the cooling system requires special equipment (vacuum pump, pressure gauge station) and knowledge. An independent attempt to replace freon or solder tubes can permanently damage the unit.
The table below shows the main actions for various symptoms:
| Symptom | Possible cause | Action |
|---|---|---|
| Works without stopping, there is cold | Thermostat/sensor is faulty | Replacing the thermostat |
| Works, there is no cold, the condenser is cold | Freon leak | Call a technician to find a leak |
| Works, no cold, condenser is hot | System clogged | Cleaning the capillary tube |
⚠️ Attention: Freon used in refrigerators, may be flammable or toxic under certain conditions. Work on the sealed circuit should only be carried out by a certified specialist.
Frequently asked questions (FAQ)
How long should the refrigerator work and how long should it rest?
In normal mode, the operating cycle is approximately 15-20 minutes of work and 10-15 minutes of rest. The working time ratio is usually around 40-50%. If the refrigerator runs for 40 minutes and rests for 2 minutes, this is a sign of a malfunction.
Can an old refrigerator start working constantly?
Yes, with age, the compressor wears out, the door seal dries out (the seal is lost) and the thermal conductivity of the insulation is impaired. The old unit is forced to work longer to compensate for the loss of cold.
Is it dangerous to leave a refrigerator running without stopping?
Yes, it is dangerous. The compressor may overheat and burn out, the wiring may melt, and if freon leaks, poisoning or fire may occur (if the freon is flammable). In addition, food can spoil due to a violation of the temperature regime.
Why does the refrigerator not turn off for a long time after defrosting?
After defrosting, the temperature and humidity in the chambers are high. The motor takes time (sometimes up to 10-12 hours) to freeze the chamber and enter the operating cycle. If after a day it does not turn off, look for a malfunction.