The situation when the refrigerator does not turn off and buzzes around the clock is familiar to many owners of household appliances. Instead of the usual cycle of work and rest, the compressor continues to pump refrigerant, trying to reach the set temperature, but it never stops. This is not just an annoying noise that interferes with sleep, but also a signal of a serious malfunction in the thermoregulation system or the tightness of the circuit.
Constant operation of the motor leads to accelerated wear of parts, a significant increase in electricity bills and, ultimately, to complete breakdown of the unit. Inverter models in this regard, they are more stable, since they do not turn off completely, but only reduce the speed, however, if you hear the continuous hum of an old refrigerator, this is a reason for immediate diagnosis. Ignoring the problem can lead to defrosting of food and expensive repairs.
In this article we will look in detail at why equipment behaves this way, how to distinguish banal overheating from a serious freon leak, and in what cases you can handle it yourself. Understanding the principles of operation thermostat and compressor will help you quickly identify the malfunction and make the right decision about calling a technician.
Violation of the chamber seal and problems with the seal
The most commonplace, but often ignored reason that the refrigerator does not turn offis a violation of the tightness of the internal chamber. If warm air from the room constantly enters the system, sensors detect an increase in temperature and command the compressor to work harder. As a result, the unit tries to cool the incoming heat, entering an endless operation mode.
First of all, you need to check the condition of sealing rubber (cuffs) on the doors. Over time, the rubber dries out, becomes deformed, or becomes covered with a sticky coating, causing the door to not fit tightly. Even a microscopic gap allows warm air to penetrate inside, throwing off the thermostat settings. The cause may also be a skewed door or loose hinges, which often happens due to improper use or after transportation.
To check the tightness of the seal, you can use the method with a sheet of paper or visual inspection under a bright light placed inside a closed chamber. If light breaks through the cracks, it means the cold is escaping. In some cases, careful use of warm water and soap to remove grease helps, but if the rubber has lost its elasticity, it will need to be replaced or restored with special means. wiping the seal warm water and soap to remove grease, but if the rubber has lost its elasticity, it will need to be replaced or restored with special means.
☑️ Diagnosis of tightness
Malfunction of the thermostat (thermostat)
The thermostat is the “brain” of the refrigerator, which is responsible for turning the compressor on and off depending on the temperature inside the chamber. If thermostat fails, it can “stick” in the “on” position, constantly sending an electrical signal to the motor. In this case, the refrigerator will work until it is forcibly turned off from the outlet, ignoring the fact that the desired cold has been achieved.
Symptoms of a thermostat malfunction often appear in the form of the absence of a characteristic click when switching from cooling mode to standby mode. In mechanical models, the cause may be a freon leak from the thermostat bellows tube or a broken contact. In electronic models with control module the problem may lie in a failure of the board or temperature sensor (NTC thermistor).
⚠️ Attention: If you find that the temperature regulator scrolls endlessly or, conversely, is stuck in one position, most likely the part requires replacement. Operating with a faulty thermostat can lead to food “freezing” or, conversely, spoilage.
Replacing a thermostat is a procedure accessible to experienced DIYers, but requires caution. It is necessary not only to select a similar part with the same characteristics, but also to correctly install the capillary tube so that it correctly reads the evaporator temperature. An installation error will lead to incorrect operation of the system.
How to check a thermostat with a multimeter?
To check a mechanical thermostat, it must be removed and “ringed” with a tester. At room temperature the contacts should be closed (resistance close to zero). If you put the thermostat in the freezer for 15-20 minutes, the contacts should open (infinity resistance). If this does not happen, the part is faulty.
Freon leakage and clogged capillary system
One of the most serious reasons why the refrigerator does not turn offis a leak in the cooling circuit or a clogged capillary tube. If there is not enough refrigerant (freon) in the system, the compressor runs idle, trying to build up pressure and temperature, but physically cannot do this. The temperature sensor does not record the required values and keeps the motor on.
Signs of a leak or blockage are often accompanied by specific symptoms: the refrigerator may freeze slightly or not freeze at all, the back wall may be covered with an uneven layer of frost or, conversely, be completely dry and warm. At the same time, the compressor works continuously and often gets very hot, trying to compensate for the lack of refrigerant.
It is almost impossible to eliminate a leak or blockage on your own, since this requires special equipment: a vacuum pump, a pressure gauge station and a supply of freon. In addition, it is necessary to find the location of the damage, which in foamed housings of modern models can be extremely difficult without disassembling the thermal insulation.
| Symptom | Probable cause | Action |
|---|---|---|
| The compressor is hot, there is no cold | Freon leak | Call a technician to find the leak and refill |
| Frost only at the entrance to the evaporator | Clogged capillary tube | Purge the system or replace filter-drier |
| The refrigerator freezes, but does not turn off | Small leak or wear on the compressor | Diagnostics of pressure in the system |
| A gurgling sound is heard | Lack of freon or air in the system | Checking the tightness of the circuit |
If you suspect a leak, it is important to stop using the unit as soon as possible. Running a compressor without proper oil cooling (which circulates along with the freon) can cause it to jam and burn out the windings, turning a simple repair into an expensive motor replacement.
Problems with the compressor and start relay
Compressor are the heart of the refrigerator, and if it is running continuously, this may indicate a loss in its performance. Over time, the mechanical parts wear out, the valves lose their tightness, and the motor ceases to create the necessary pressure. It continues to hum, trying to complete the task, but its efficiency drops so much that it cannot reach the set temperature in normal mode.
Another reason for continuous operation may be a malfunction start relay. This small element is responsible for starting the engine and protecting it from overloads. If the relay contacts are stuck in the closed position, current continues to flow to the compressor windings even after the thermostat has signaled to stop.
Diagnostics of a compressor requires measuring current consumption and output pressure. If the motor consumes current above the rated value, but does not develop pressure, or operates with a metallic knock, most likely its resource has been exhausted. In modern inverter refrigerators diagnosis is more difficult, since engine starting is controlled by an electronic module, and the problem may lie in the control board itself.
⚠️ Attention: If the compressor runs continuously and gets very hot (up to 80-90 degrees), this is an emergency mode. It is urgent to disconnect the device from the network to avoid a fire or complete failure of the unit.
The influence of external factors and improper operation
The reason does not always lie in the breakdown of parts. Often the refrigerator does not turn off due to improper operating conditions. For example, if the unit is installed close to a wall, in a niche without ventilation, or next to heating devices, heat exchange is disrupted. The compressor overheats and cannot effectively cool the condenser, which causes the operation cycle to become disrupted.
It is also important to consider the temperature in the room. Most refrigerators are designed to operate in climate class SN-T (from +10 to +43 °C). If the room is too hot (above +30-35 °C) or, conversely, cold (below +10 °C), the equipment may behave inappropriately: either work without stopping, trying to cool down, or not turn on at all.
Frequent opening of the door, loading a large amount of warm food or a loosely closed door also causes the motor to work in increased mode. In this case, the system simply does not have time to restore the temperature in a standard cycle, and the operation timer shifts upward.
The myth about the “winter mode”
Many older models of refrigerators do not have a winter mode. At temperatures below +10°C, the oil in the compressor thickens, and freon cannot condense effectively, which leads to breakdown. Do not turn on a regular refrigerator in an unheated dacha in winter.
Features of operation of No Frost and inverter models
Owners of refrigerators with the system No Frost sometimes mistakenly believe that the unit is faulty when they hear the operation of fans or a defrost heater. In such models, the compressor can work longer than in old “crying” refrigerators, since the system is aimed at maintaining a stable temperature and the absence of frost. However, they must also periodically stop or reduce speed.
Inverter compressors, which are found in models LG, Samsung, Bosch and other brands, in principle do not turn off completely after entering the mode. They switch to minimum speed, maintaining the temperature. Therefore, a quiet, barely audible hum, even at night, is normal for them. You should be concerned if you hear a characteristic cyclic on/off with a click that should not be there, or if the noise has become loud and the vibration has increased.
A malfunction of the defrost sensors in the No Frost system can lead to the fact that the refrigerator “thinks” that the evaporator is frozen, and turns on the heating, and then takes a long time to restore the temperature, working without interruption. This requires checking the sensors and defrost heating elements.
When you need to call a technician
Self-diagnosis is good for identifying simple problems such as incorrect installation or a stuck door. However, if you checked the seals, made sure that the temperature in the room was normal and gave the equipment a rest, but it continues to work without interruption, a professional look is needed.
It is especially dangerous to ignore the problem if you notice oily spots under the refrigerator (a sign of freon leakage along with oil) or smell burnt wiring. Interfering with the refrigerant circulation system without a license and equipment is not only ineffective, but also dangerous for the environment.
The technician will conduct a full diagnostic: check the pressure in the system, the integrity of electrical circuits, the operation of electronics and mechanical components. Only after this will it be possible to say for sure whether the compressor needs to be replaced, refilled with freon, or the control board repaired.
How long should a refrigerator normally work?
Under normal conditions, the refrigerator operates approximately 30-40% of the time of the total cycle (about 10-15 minutes it works, 20-25 rests). In hot weather or when fully loaded, the operating time can increase to 50-60%. If the operating coefficient exceeds 80% constantly, this is a sign of malfunction.
Can an old refrigerator start working constantly?
Yes, with age, the door seal wears out, the elasticity of the rubber bands is lost, and the compressor takes more time to create pressure. In addition, moisture may accumulate in the system, causing periodic blockages, due to which the unit works longer than usual.
Is it dangerous to leave a refrigerator running without stopping?
Short-term operation (several hours) in the heat is not dangerous. But long-term operation (a day or more) without a break leads to overheating of the compressor windings, oil burnout and eventual jamming of the motor. This can cause a short circuit and fire.
Why does a new refrigerator work without interruption after switching on?
When turned on for the first time or after defrosting, the refrigerator takes time (from 2 to 12 hours) to cool the entire volume of chambers and food to the set temperature. During this period, continuous operation of the compressor is an absolutely normal “acceleration” mode.