The situation when the refrigerator suddenly stops humming and turns on only after a few hours often takes owners by surprise. In some cases, this is the normal operation of smart electronics that have switched to energy saving or defrosting mode. In others, this is an alarming signal that compressor it is overheating or there is a failure in the control system.
You should not panic ahead of time, but you cannot leave the problem unattended. Prolonged downtime of equipment can lead to spoilage of products, and in the worst case, to complete failure of expensive equipment. Understanding the nature of this phenomenon will help you save time and money when calling a technician. unit. Understanding the nature of this phenomenon will help you save time and money when calling a specialist.
Before disassembling the back wall, it is necessary to exclude trivial causes. Often the answer lies in voltage drops in the network or improper installation of the device. Let's figure out how to distinguish normal operation from a breakdown.
Natural causes of shutdowns and operating modes
Modern models, such as Bosch or Liebherr, are equipped with complex electronics that themselves regulate operating cycles. If you notice that the device is silent for 10-15 minutes and then starts again, this is absolutely normal. This is how the cooling cycle works However, there are long pauses that can be confusing. For example, the “Vacation” or “Eco Mode” function specifically increases the intervals between engine starts. At this time, the temperature in the chamber is maintained at a limit level, which saves energy..
However, there are long pauses that can be confusing. For example, the “Vacation” or “Eco Mode” function specifically increases the intervals between engine starts. At this time, the temperature in the chamber is maintained at a limit level, which saves energy.
⚠️ Attention: If the refrigerator turns off for 20-30 minutes or more, while the temperature inside the chamber manages to rise above normal, we are no longer talking about savings, but about a malfunction of the thermoregulation system.
It is also worth considering thermal inertia. After loading a large amount of warm food, the compressor can work continuously for several hours and then go into a long rest. This is an attempt by the system to restore the set temperature. temperature regime.
Problems with the thermostat and temperature sensors
One of the most A common cause of chaotic shutdowns is thermostat failure. This unit is responsible for sending a signal to start and stop the engine. If the contacts inside it are “stuck” or oxidized, the circuit can break randomly.
In models with the system No Frost air sensors are responsible for climate control. They are located inside the cameras and transmit data to the electronic module. If such a sensor becomes dirty or fails, the “brains” of the refrigerator receive false data that the cold has been reached and turn off the compressor. Diagnostics of a mechanical type thermostat is simple: it can be temporarily closed by removing it from the circuit. If the engine starts and does not stall, the problem has been found. Electronic sensors are checked with a multimeter for changes in resistance with temperature changes. compressor.
Diagnostics of a mechanical type thermostat is simple: it can be temporarily closed by removing it from the circuit. If the engine starts and does not stall, the problem has been found. Electronic sensors are checked with a multimeter for changes in resistance with temperature changes.
- 🔍 Oxidation of contacts in the thermostat terminal box.
- 🌡️ Displacement of the capillary tube of the sensor from the back wall.
- ⚡ Voltage surges that damaged the electronic board controls.
- 🧊 Freezing of the defrost sensor in the No Frost system.
How to check the thermostat with a multimeter?
Set the device in dial mode. At room temperature the contacts should ring. If you put the sensor in the freezer, after a while the circuit should break (stop ringing).
Starting relay malfunctions and compressor protection
The starting relay is a small but critical element that is located next to the motor. It is this that supplies the impulse to start and keeps the windings running. If the relay is faulty, the engine may try to start, hum, and then click and turn off.
A common situation is when the thermal protection is triggered. This happens if compressor overheats. The reasons may be different: wear of the bearings, interturn short circuit of the windings or a banal lack of refrigerant, which is why the motor runs “idle”.
A visually faulty relay often has traces of carbon deposits or a melted housing. There may be a burnt-out spiral or a deformed bimetallic plate inside. Replacing this element is one of the most accessible procedures in repair with your own hands.
Freon leak and problems with the circulation system
If the refrigerant in the system becomes less than normal, the pressure drops. The compressor works, trying to gain temperature, overheats and turns off due to thermal protection. After cooling, the cycle repeats. This is a classic symptom of freon leak.
It is difficult to determine the leak visually, since the gas is colorless and odorless. However, indirect signs are: poor cooling, hot side walls (in some models) or, conversely, cold only at the evaporator. Oil may also appear under the device.
A clogged capillary tube gives similar symptoms. Oil or decomposition products clog a narrow channel, circulation stops, and the pressure at the outlet of the compressor rises sharply, causing an emergency shutdown.
| Symptom | Probable cause | Nature of motor operation |
|---|---|---|
| Short cycle (5 min operation / 20 min rest) | Freon leak | Hums smoothly, but does not cool |
| Clicks and buzzing before turning off | Faulty starting relay | Attempts to start, then silence |
| Long work, then a long rest | Thermostat is faulty | Works all the way, then stops |
| Spontaneous shutdowns during the day | Problems with wiring | Unstable operation |
⚠️ Attention: Self-filling the refrigerator with freon is prohibited without a license and special equipment. If a leak is detected, you must call a technician to find the fistula and evacuate the system.
The influence of network voltage and wiring
Unstable power supply is the enemy of any equipment. If the voltage in your network fluctuates, the built-in protection can turn off the device to save the electronics. Inverter compressors are especially sensitive to this compressors.
Check the outlet into which the refrigerator is plugged in. Loose contacts can overheat, causing a voltage drop. It is also worth inspecting the power cord: if it has creases or melting, it must be replaced immediately.
☑️ Power supply diagnostics
Using cheap extension cords or low-quality surge protectors can also cause problems. For expensive equipment, it is recommended to use a voltage stabilizer or at least a high-quality surge protector with overload protection.
Errors in operation and installation
Sometimes the user himself creates the conditions for frequent shutdowns. For example, installing a refrigerator close to a wall disrupts air circulation. The radiator on the rear wall overheats and the thermal protection is triggered.
Loading hot products or a door that is not tightly closed causes the unit to wear out. At some point, the system may go into protective mode. It is also worth checking whether the door is sticking due to contamination of the seal.
Incorrectly set temperature is another reason. If you set the minimum possible value in the summer, the refrigerator may simply not cope with the heat influx and go into long pauses or, conversely, work without a break until it burns out.
Frequently asked questions and answers (FAQ)
Why does the refrigerator turn on and immediately turn off after a couple of seconds?
Most likely the problem is in the start relay or the compressor itself. The motor tries to start, the current increases sharply, and the thermal protection opens the circuit. A relay replacement or diagnostics of the motor windings is required.
Is it normal for the refrigerator to be silent for 40 minutes?
In modern energy-efficient models with inverter control, such pauses are possible if the door was not opened and warm food was not placed in the chamber. If the temperature inside has increased, this is a breakdown.
Can the refrigerator turn off due to the defrost timer?
Yes, in systems No Frost the defrost heating element is periodically turned on. At this moment the compressor and fan are switched off. The process can last from 20 to 40 minutes, after which the cooling cycle resumes.
What to do if the refrigerator does not turn on after defrosting?
Let it stand unplugged for another 3-4 hours. Moisture may have gotten into the electrical contacts. If after complete drying the situation has not changed, check the integrity of the cord and the presence of voltage in the socket.