The situation when the refrigerator works without interruption is familiar to many owners of household appliances. Unlike the normal mode, where periods of cooling alternate with rest, here the unit hums for days on end. It's not just annoying noise that disturbs your sleep or watching TV. This is a direct signal that the control or cooling system has failed and requires immediate intervention.
Such a problem absolutely cannot be ignored. Constant wear and tear leads to rapid failure of expensive components, in particular compressor. If the malfunction is not corrected in time, simply replacing the part will no longer be enough; major repairs or the purchase of new equipment will be required. In this article we will look in detail at why this happens.
You will learn how to distinguish a software failure from a serious breakdown, what parts to pay attention to first and whether you can handle the repair yourself. We will look at the mechanical, electrical and physical reasons that cause equipment to work in emergency mode. Understanding these processes will help you save time and money.
Malfunctions of the thermostat and temperature sensors
One of the most common reasons for continuous operation is the failure of the thermostat. It is this element that is responsible for monitoring the temperature inside the chambers and sending a signal to turn off the motor. If the contacts inside the thermostat stick in the closed position or the bellows tube bursts, the sensor “thinks” that it is warm in the refrigerator and causes the compressor to work without stopping.
In modern models with the system No Frost or Full No Frost electronic sensors are responsible for the temperature regime. Their readings are read by the control module, which makes the decision to start or stop the cycle. If the sensor transmits incorrect data (for example, it shows +10°C instead of the real -18°C), the electronics will drive the motor, trying to achieve an unattainable ideal.
⚠️ Attention: Before replacing the thermostat, make sure that its sensitive element (capillary tube) has not moved and is tightly adjacent to the evaporator. If the tube has come off, the sensor does not sense real cold.
Diagnostics of the thermostat often requires testing with a multimeter. In normal condition, at room temperature, the contacts should be closed, and when cooled (for example, if you put the thermostat in the freezer for 15 minutes), they should open with a characteristic click. The absence of a click or ringing at any temperature indicates a breakdown.
How to check an electronic sensor without replacement?
Checking an electronic temperature sensor (thermistor) is only possible by measuring its resistance at different temperatures and comparing it with a table of ratings for a specific refrigerator model. A simple test “for contact” is not enough here.
Problems with sealing rubber and tightness
Often the reason lies not in internal parts, but in a banal loss of chamber tightness. The rubber seals on the doors dry out over time, crack or become deformed. Warm air from the room enters through the resulting cracks. The refrigerator tries to compensate for this heat influx and operates continuously, but the temperature still does not drop to the set values.
You can check the tightness using a simple test with paper. Press a piece of paper between the door and the cabinet all the way around. If the sheet pulls out too easily or falls out without resistance, the seal does not fit tightly. It is also worth carefully inspecting the rubber for cracks, tears and dirt that interfere with a tight fit.
Another reason for loss of tightness may be door misalignment. If the refrigerator is not level or the hinges are loose, the door warps and the tight contact with the body is broken. In this case, even a new seal will not help until the door position is adjusted.
Refrigerant (freon) leak
If the refrigerator does not turn off, but at the same time it freezes slightly or has stopped cooling altogether, there is a high probability of a refrigerant leak. Freon circulates through the system, taking heat from the chambers. When its quantity drops below a critical level, the pressure in the system drops, and the compressor is forced to work around the clock to try to reach the desired temperature, but it fails.
Leaks can occur in different places: in the foamed part of the housing (where the circuit is laid), in the evaporator (especially if it was cleaned with a knife during defrosting) or in places where the tubes are soldered. It is rarely possible to determine the location of a leak visually; it is often necessary to use a leak detector or a nitrogen pressure test method.
It is almost impossible to repair the leak and refill the system yourself without special equipment and skills. Attempts to simply add freon without finding and fixing the hole will only give a temporary effect, after which the problem will return in a few days or weeks.
Faults of the compressor and start relay
The compressor is the heart of the refrigerator. If its motor-compressor is worn out, it may lose performance. The piston group wears out, the valves leak gas, and the unit cannot create the necessary pressure for effective cooling. As a result, it hums continuously, but does not produce cold.
It is also worth paying attention to the start-up relay. This small block is responsible for starting the engine and protecting it from overloads. If the relay is faulty, it may not turn off the motor windings in a timely manner or may not respond correctly to current, resulting in constant operation or frequent attempts to start followed by an overload shutdown.
A sign of problems with the compressor is often excessive heating. If you touch the motor housing and it burns your hand, but the refrigerator is barely warm inside, this is an alarming signal. A sound should also alert you: knocking, clanging or humming, different from the usual smooth hum.
Clogged capillary tube
There is a narrow section in the refrigerant circulation system - the capillary tube. It serves as a throttle, creating a pressure difference between the high pressure at the compressor outlet and the low pressure in the evaporator. Over time, a blockage may form in this tube due to oil oxidation products, moisture or debris introduced during poor-quality repairs.
When clogged, freon cannot circulate normally. The pressure on the suction side drops, the compressor idles, trying to pump gas, but cannot. This leads to the fact that the motor runs without interruption, but there is no cold in the chamber. Often, the condenser (grid at the back) remains only partially cold or warm.
To eliminate this problem, it is necessary to purge the system with high pressure nitrogen, replace the filter drier and vacuum. The procedure is complex and requires a compressor, a pressure gauge station and a vacuum pump.
Is it possible to break through the blockage yourself?
There is a method of “bleeding” the system through the Schrader valve, but it is dangerous. Without proper knowledge, you can damage the compressor or depressurize the system even more. It is better to entrust this to professionals.
The influence of external temperature and operating conditions
Sometimes the refrigerator does not turn off not because of a breakdown, but because of improper operating conditions. If the unit is installed next to a radiator, stove or in direct sunlight, heat exchange is disrupted. The compressor has to work harder to remove heat, and it may not have time to turn off, especially in the summer.
It is also important to consider the minimum ambient temperature. Most refrigerators are not designed to operate in unheated rooms at temperatures below +10...+15°C. The oil in the compressor thickens, and the equipment may behave incorrectly, or may not start at all, or work without stopping.
Incorrect installation also plays a role. If the refrigerator is moved close to the wall, the rear grille is not blown by air and heat is not dissipated. This forces the cooling system to work harder. It is necessary to maintain a gap of 5-10 cm from the back wall to the furniture or wall.
☑️ Checking the operating conditions
Failures in the electronic control module
In modern models, the entire process is controlled by an electronic module. If there is a failure in its control board, a triac or other element that controls the compressor “burns out,” the shutdown signal may simply not be received. The motor will receive power constantly, regardless of the sensor readings.
Such a breakdown often occurs after power surges. Symptoms may also include erratic blinking of lights, failure of other functions, or complete inoperability of the control panel. In some cases, a reboot helps (disconnect from the network for 15-20 minutes), but more often a repair or replacement of the board is required.
⚠️ Attention: If you notice a burning smell or melted wires in the area of the control module, immediately disconnect the refrigerator from the network. The operation of such equipment is a fire hazard.
Table: Comparison of symptoms and probable causes
To quickly navigate the problem, use the table below. It will help to compare the observed symptoms with the most likely malfunctions.
| Symptom | Probable cause | Difficulty of repair |
|---|---|---|
| Works without stopping, warm inside | Leakage freon, clogged capillary | High (requires a technician) |
| Works constantly, freezes normally | Thermostat or sensor is faulty | Medium (you can do it yourself) |
| Buzzes, but does not start or stops immediately | Problem with the start relay or compressor | Medium/High |
| Works non-stop, ice freezes | Loss tightness (door), malfunction of the defrost heating element | Low/Medium |
| Indicators blink, modes go wrong | Electronic module failure | High (board replacement) |
To summarize, we can say that continuous operation of the refrigerator is always an emergency mode. The longer you delay diagnosis, the higher the risk of permanent breakdown of expensive components. If simple methods like defrosting and checking the seal did not help, it is better to contact a specialist.
Can the refrigerator not turn off because I put too many warm products?
Yes, if you have loaded a large amount of food at room temperature or, worse, warm, the refrigerator will work in increased mode for a long time to cool the volume. However, once the set temperature is reached, it should turn off. If this does not happen even after 10-12 hours of operation, look for a malfunction.
Is it true that the "Super Freeze" mode does not allow the refrigerator to turn off?
In the Super Freeze or "Super Freeze" mode, the refrigerator can actually work without interruption. On some models, this mode turns off the thermostat, forcing the compressor to run continuously. Check to see if the indicator for this mode is on the panel and turn it off if the function is activated accidentally.
What to do if the refrigerator is old and repairs are expensive?
If your refrigerator is more than 10-12 years old and requires a compressor replacement or complex system repairs with freon charging, it is often more economically feasible to buy a new model. Old refrigerators are less energy efficient, and a new unit will pay for itself due to energy savings in 2-3 years.
How often should you defrost the refrigerator to avoid problems?
Refrigerators with manual defrosting need to be defrosted as ice forms (usually 1-2 times a year). Models with No Frost do not need defrosting, but it is recommended to wash them and unplug them for preventive maintenance once a year. Excessive accumulation of ice impairs heat transfer and makes the equipment work longer.