After purchasing and delivering new household appliances, owners are often faced with incomprehensible behavior of the unit: it hums for hours without stopping, and this causes panic. First power-up - this is a critical stage on which the further durability of the entire cooling system depends. Many users mistakenly believe that if the motor does not turn off after 30 minutes, then the device is faulty, and they rush to call a technician or issue a return.
In fact, the standard cooling cycle at start is fundamentally different from the usual operation, since the system must cool not only the air, but also the massive walls of the chambers, shelves, as well as products that you put it there. Understanding the physics of this process will allow you to avoid unnecessary stress and unreasonable expenses for diagnosing faulty equipment.
In this article we will analyze in detail the time frame for normal operation of the compressor, factors influencing the cycle duration, and situations when it is really worth sounding the alarm. You will learn why modern inverter models behave differently than the good old Atlanteans, and how to properly prepare the equipment for the first start.
Physics of the process: why the refrigerator does not stop immediately
When you first connect refrigerator to the power supply, the thermostat or electronic control module gives the command to start the compressor. At this point, the inside of the chambers is at room temperature, usually around +20...+25°C, and the target temperature should be +4°C in the main compartment and -18°C in the freezer. A difference of 40 degrees for air is one thing, but plastic, metal shelves, and glass partitions also need to be cooled.
Thermal capacity materials play a decisive role here. The air cools quickly, but temperature sensors are often located deep in the evaporator or in special niches where the cold flow does not reach immediately. The compressor operates at full power, the refrigerant circulates through the system, taking heat from the internal volume and releasing it through the condenser (the grille at the back or on the sides). Until the target temperature is reached at all control points, cooling cycle it will not be interrupted.
This process takes especially long if you loaded the chamber with products immediately after turning it on. The water contained in food has a huge heat capacity, and cooling it requires a significant amount of energy and time. That is why manufacturers recommend carrying out the initial startup with empty chambers.
⚠️ Attention: If you turn on a refrigerator full of food, the first cycle time may increase by 1.5–2 times. This is not a breakdown, but an increased load on the system.
It is also important to consider that in modern models with the system No Frost part of the time may be taken up by preliminary diagnostics of the system or the operation of fans, which also consume energy and create noise, simulating the active operation of the compressor.
Standard operating time at first startup
The answer to the question of exactly how long the motor should run depends on the type of compressor, the volume of the chambers and the room temperature. However, there are average technical standards that service engineers rely on during initial diagnostics. For most standard models with a volume of up to 350 liters, continuous operation for 6–12 hours is considered normal.
If we are talking about large two-chamber units or Side-by-Side models, the first cycle time can reach 24 hours. This is due to the large volume of air and a complex system of air ducts that need to be filled with cold. Inverter compressors, unlike classic start-stop ones, they can work even longer, but with less intensity, smoothly reducing speed as they approach the set temperature.
⚠️ Attention: Specifications may vary depending on model. Always check the "First Start" section of your device's official user manual.
The key point is not so much the time as the final result. If after 12 hours of operation the refrigerator does not turn off (or does not go into quiet mode), check the temperature inside. If the food is being cooled and cold appears in the freezer, it means that the process is going normally, it’s just that the system has not yet gained “thermoinertia”.
Below is a table showing the dependence of the first cycle time on the type of equipment:
| Refrigerator type | Volume of chambers | Expected time of the first cycle | Features |
|---|---|---|---|
| Single-chamber | up to 150 l | 4–8 hours | Quick temperature set |
| Two-chamber (standard) | 200–300 l | 8–14 hours | Freezing time required |
| Side-by-Side | 400+ l | 12–24 hours | Complex circulation system |
| Built-in | Any | +20% of the norm | Deteriorated heat transfer in the niche |
Factors influencing cooling duration
Why did your neighbor’s refrigerator turn off after 5 hours, but yours has been humming for the 10th hour? This setting is affected by many variables. The first and most important factor is ambient temperature. If you install equipment in a hot room (above +25°C), the compressor has to work harder and longer to remove heat through the condenser.
The second factor is the correct installation. If the refrigerator is standing close to the wall or the sides are jammed by furniture, heat transfer is disrupted. Hot air remains around the radiator, cooling efficiency decreases, and motor-compressor is forced to work without interruption. It is also important to consider whether the “transport settling” has been observed. If the oil in the compressor does not flow into the crankcase after transportation, the device may be overloaded or fail altogether.
- 🌡️ Room temperature: the hotter it is, the longer the cycle.
- 📦 Loading: an empty refrigerator cools down faster full.
- 🔌 Network voltage: low voltage increases operating time.
- 🚪 Tightness: frequent opening of doors during the first start resets progress.
Differences between a conventional and inverter compressor
Behavior when first turned on strongly depends on the type of motor. In classic models with a conventional compressor, you will hear a characteristic start-up, a hum, and then a relay click and complete silence when the temperature is reached. The work cycles here are clear: on - work - off - rest.
With inverter models (for example, from LG, Samsung, Hitachi) the situation is different. These compressors rarely stop completely. After the first powerful jerk to set the temperature, they do not turn off, but switch to low speed mode, maintaining the cold. Therefore, owners of such devices may think that the refrigerator “does not turn off,” although in fact it simply works in an economical maintenance mode.
When first started, the inverter can operate at high speeds for up to 12 hours, after which you will notice that the noise has become almost inaudible. This is a normal situation. Trying to find the moment when the engine stops completely in such models may be useless.
Typical errors during first start-up
Many problems with “long” operation of the compressor are created by the users themselves due to ignorance of basic operating rules. The most common mistake is ignoring the settling time after delivery. If the refrigerator was transported lying down or simply tilted strongly, the oil needs time (from 2 to 8 hours) to return to the compressor crankcase. Starting "dry" or with oil in the circuit leads to water hammer and long-term incorrect operation.
The second mistake is setting the “Super Freeze” mode immediately when you turn it on for the first time. This mode causes the compressor to run continuously, ignoring standard cycles. If you accidentally activate this function, the refrigerator may hum for days. Be sure to check the settings on the control panel or in the application.
☑️ Correct first start
Also a common placement error. Installing the refrigerator next to a radiator, stove, or in direct sunlight forces the cooling system to work in extreme mode. In such conditions, the first cycle can last more than 24 hours, and the service life of the equipment is reduced.
When to sound the alarm: signs of malfunction
Despite the long cycles of the first start, there are clear boundaries, exceeding which indicates a breakdown. If your refrigerator runs for more than 24 hours and the inside remains at room temperature, there is cause for concern. Also an alarming signal is the lack of cold when the compressor is running - this may indicate a leak refrigerant or compressor malfunction.
Pay attention to the nature of the unit’s operation. If the compressor turns on, runs for 1-2 minutes, then a click is heard and it tries to start again (the cycle is repeated often) - this is a sign of a malfunction of the start relay or the motor itself. In the normal first start-up mode, such frequent starts should not occur.
A critical sign is heating of the compressor housing to a state where it is impossible to touch it with your hand (above 80-90°C), combined with a lack of cooling in the chambers.If you observe the following symptoms, operation should be stopped and contact service:
- ❄️ It is warm inside or the temperature drops very slowly after 12 hours of operation.
- 🔥 The rear grille (condenser) remains cold when the motor is running.
- 💧 The appearance of puddles of water under the refrigerator or inside the chambers (not to be confused with condensation).
- 🔊 The appearance of knocking, grinding or whistling noises during operation.
Frequently asked questions (FAQ)
Is it possible to load food into the refrigerator during the first cooling cycle?
It is highly not recommended. Products have their own temperature and humidity, which will significantly increase the first cycle time and create extra load on the compressor. It is better to wait until it stops completely (or goes into quiet mode), and then load food in small batches.
Is it normal for the side walls of the refrigerator to get very hot when you first start it up?
Yes, this is absolutely normal. The side walls in modern models often serve as a condenser that removes heat. During the first long cycle they can heat up to 50-60°C. Over time, when the mode stabilizes, the heating will become less noticeable.
The refrigerator turned off after 2 hours, but it was still warm inside. Is this a breakdown?
Most likely not. The sensor could react to local cooling of the air, although the walls and food are still warm. Allow the refrigerator to operate for a total of 6-8 hours. If after this the temperature does not drop to normal, then it is worth checking the thermostat settings.
Does the time of year affect the duration of the first turn on?
Of course. In winter, in a cold room, the refrigerator will gain temperature faster. In the summer, when it’s hot, the process may take longer. If the room is +30°C, the first cycle may last longer than standard.