The moment of switching on a household refrigerator after transportation or long-term inactivity is a critical phase that determines the durability of the compressor and the quality of further freezing of products. Many users mistakenly believe that the device begins to freeze instantly, but the physics of the process requires time to stabilize the pressure in the system and distribute the refrigerant. Understanding exactly how the equipment behaves in the first minutes and hours of operation helps to avoid panic due to heating of the side walls or lack of cold in the chamber.
In this article we will analyze in detail the physical and technical processes occurring inside the cooling circuit. You will learn why you can’t load food right away, how oil is distributed in the compressor, and what the different sounds mean when starting. This knowledge will allow you to properly operate refrigeration equipment and extend its service life.
Startup physics: what happens in the first seconds
The moment you insert the plug into the socket and set the temperature on the thermostat, electric current flows on starting relay compressor. This device is necessary to create the initial impulse to move the piston of the motor, which is under high pressure. In these first seconds, a characteristic hum or click is heard, after which the engine begins to operate normally.
Simultaneously with the engine starting, the circulation of the refrigerant (freon) begins. Liquid freon under pressure is pushed out of the condenser and enters the capillary tube, where it expands sharply and boils, turning into gas. It is this process phase transition that absorbs heat from the internal space of the chambers. It is important to understand that instant cooling does not occur, since the system needs time to displace warm air from the evaporator tubes.
⚠️ Attention: If in the first 10-15 seconds of operation you hear a loud metallic clang or knock, this may indicate improper transportation (compressor hitting the casing) or an installation defect. In this case, it is better to turn off the equipment and have it checked by a specialist.
The initial start-up is also characterized by active energy consumption. The motor-compressor works at the limit of its capabilities to create the necessary pressure difference between the high and low pressure circuits. At this stage electronic control module (if it is in the model) conducts self-diagnosis of temperature sensors.
The role of the compressor and oil distribution
The heart of any refrigeration unit is the compressor. In its lower part there is oil, which is necessary to lubricate the rubbing parts. During prolonged downtime or after shaking during transportation, the oil could drain into the cooling circuit or move into one of the cylinder chambers. In the first minutes of operation, the critical process of returning oil to the compressor crankcase occurs.
If you start the unit under full load (with products) right away, the compressor may run dry, which will lead to rapid wear of the piston group. Modern models inverter compressors have a smoother start, but the lubrication principle remains unchanged. The pressure in the system must be equalized so that the oil emulsion begins to circulate together with freon, protecting the metal.
- 🛢️ Lubrication: The oil creates a thin film between the piston and the cylinder walls, preventing scuffing.
- 🌡️ Engine cooling: Circulating oil also removes excess heat from heating engine parts.
- 🔄 Water hammer: An attempt to compress liquid oil (if it has not had time to drain) can lead to valve failure.
During operation, you may notice that the compressor runs continuously in the first 30-40 minutes. This is a normal phenomenon. Thermostat has not yet detected the achievement of the set temperature, so it does not give a command to stop the engine. Only after the heat exchanger inside the chamber has cooled down, the cycle will be interrupted.
Heat exchange and heating of the housing: is this normal?
One of the most common questions that arises from users: “Why do the side walls or the space between the doors get very hot?” The answer lies in the principles of thermodynamics. The refrigerator does not create cold, it transfers heat from the inner chamber to the outside. Heat exchangers (capacitors), which in older models were located at the back in the form of a black coil, in modern devices are often built into the side walls of the case.
In the first hours of operation, when the temperature difference between the contents of the chamber (room temperature) and the required one (for example, +4°C) is maximum, the system operates at maximum efficiency. The condenser heats up to 50-60°C and even higher. This means that the heat removal process is successful. If the walls remained cold, this would indicate a malfunction or leak of freon.
| Heating zone | Cause | Is this normal? |
|---|---|---|
| Side walls | Operation of the built-in condenser | Yes, especially in the first hours |
| Jumper between the doors | Anti-condensation circuit (heated to prevent dew) | Yes, constantly in the warm season |
| Rear grill | Classic condenser | Yes, it can be hot to the touch |
| Compressor (bottom) | Heating of a running engine | Yes, but should not burn |
It is worth noting that the heating intensity depends on the room temperature. In summer, when the room is +28°C, the walls will be hotter than in winter at +20°C. This is due to the fact that heat transfer efficiency falls at a high ambient temperature, and the system has to work harder.
⚠️ Attention: If the walls heat up to a state where they cannot be touched (more than 70-80°C), or the smell of burnt wiring appears, immediately disconnect the device from the network. This may indicate a malfunction of the starting relay or a clogged capillary system.
Dynamics of chamber cooling and the appearance of frost
After starting the compressor, the cold begins to spread unevenly. In systems No Frost cold air is pumped by a fan through special channels, so the temperature equalizes faster. In drip systems (“crying evaporator”), cooling begins from the rear wall, where the evaporator is located.
The first cooling cycle can last from 2 to 6 hours depending on the volume of the chambers and the initial temperature of the products (if they are already inside). In the freezer, the process takes longer due to the need to freeze a larger volume of air and walls. At this time, “islands” of frost or condensation begin to appear on the back wall of the main chamber, which then flow into the drainage hole.
- ❄️ First 30 minutes: Cooling of the air in the immediate vicinity of the evaporator.
- ⏱️ 1-2 hours: Stabilization of the temperature in the main chamber to +10...+15°C.
- 🧊 3-4 hours: Achieving operating parameters (+4°C in the refrigerator, -18°C in the freezer).
Why is it colder in the freezer than in refrigerator?
The freezer has a smaller volume and a more powerful flow of cold air, since the main evaporator is often located there, and air is simply blown into the refrigerator compartment.
It is important to consider that temperature sensors have a certain inertia. Even if the air has already cooled, the thermostat may “think” that heat is still retained and continue to operate the compressor. That is why the first working cycle is often the longest.
Sound accompaniment: what noises are normal
A new or just turned on refrigerator is a source of various sounds. Understanding their nature will relieve unnecessary worry. Unlike old equipment, modern units can be quite noisy at the moment of start-up due to powerful compressors and active circulation systems.
Immediately after switching on, you will hear a smooth hum of the engine. After a while, you may hear the sound of bursting bubbles or shimmering water. This is refrigerant boiling in the evaporator tubes and the movement of freon through the system. The sound may persist even after the compressor stops, until the pressure in the system is completely equalized.
Periodical clicking is also considered normal. This is the work of a thermostat or protection relay, as well as thermal expansion and contraction of the plastic parts of the internal housing when the temperature changes. However, if you hear a piercing whistle, a metallic grinding sound or loud knocks, this is a reason for diagnosis.
When you can load products: rules for first launch
The most common mistake is loading products immediately after turning on. This is strictly forbidden. The compressor must work at least one full cycle (turn on, cool the chambers, turn off according to the sensor and turn on again) for the system to reach operating mode operating mode.
If you put warm food in a chamber that has not yet been cooled, you will create a critical load on the motor. He will have to work non-stop for days, trying to cool not only the air, but also heat-intensive products. This can lead to overheating of the windings and failure of the compressor in the very first days of operation.
☑️ Rules for first start-up
It is recommended to wait at least 4-6 hours before the first load. During this time, the empty chambers will have time to freeze, and the thermostat will record that the desired temperature has been reached. After this, you can start filling, but it is better to do this gradually, in small portions, so as not to disturb the already established temperature balance. temperature balance.
Frequently asked questions about turning it on for the first time
How long does the refrigerator take to reach the temperature for the first time?
Usually the process takes from 4 to 8 hours. The exact time depends on the volume of the chambers, the ambient temperature in the room and the type of refrigerant. Complete stabilization of the mode can take up to 24 hours.
Why does the refrigerator hum more than usual when first started?
When first started, the compressor works without interruption at full power until it cools the entire volume of the chambers. In addition, new parts can grind in, which creates additional noise.
Is it possible to turn on the refrigerator in the cold?
No. The oil in the compressor thickens in the cold and cannot properly lubricate the parts. Turning it on in the cold is guaranteed to cause damage. Allow the equipment to warm up to room temperature for at least 4-5 hours.
Do you need to wash the refrigerator before turning it on for the first time?
Yes, definitely. Factory dust, plastic odors, or preservatives may remain inside. Wipe the chambers with a soft cloth with a soda solution or a special product, then wipe dry and ventilate before turning on.