How the No Frost refrigerator works after defrosting: start and errors

Complete defrosting of the refrigeration equipment of the system No Frost often becomes a stress test for equipment, especially if the procedure was not carried out according to instructions or after a long period of inactivity. Unlike older models with a “crying” wall, where defrosting occurred naturally, here we are dealing with a complex system of air dampers, sensors and forced circulation. That is why the question of how the unit behaves in the first hours after switching on worries many owners who are faced with cooling delays or strange sounds.

Immediately after you connect the power cord to the network, smart electronics are in no hurry to start the compressor at full power. The system performs initial self-diagnosis, checks the condition of the temperature sensors and makes sure that there is no excess moisture left in the evaporator, which could instantly turn into an ice plug. First start can take from 30 minutes to several hours, and this is an absolutely normal situation that does not require panic or repeated manipulation of the buttons.

It is important to understand that cold air circulation will begin only after the main heat exchanger reaches a certain negative temperature. Until this moment, the fan may be silent, creating the illusion of a breakdown. Let's look in detail at what processes occur inside the chamber, why the freezer can start working before the refrigerator compartment and what time intervals are considered the norm for different manufacturers.

First start-up algorithm and system self-diagnosis

Modern refrigerators such as LG, Samsung or Bosch, are equipped with microprocessor control modules that control every stage of work. After applying voltage to the control board, a polling cycle of all connected sensors begins. If the system detects that the temperature inside the chambers is higher than the set one (and after defrosting it is always room temperature), it gives a command to start the compressor, but often in a gentle mode.

The key element here is defrost timer and the evaporator defrost sensor. Even if you defrosted the unit manually, the electronics may “think” that the defrost cycle has not yet completed if the error code has not been reset or if the sensor still shows positive temperatures characteristic of the defrost mode. Some models require forced entry into the service menu or a long wait (up to 24 hours) to reset the controller logic.

⚠️ Attention: If after turning on the refrigerator hums, but the cold does not appear for more than 6-8 hours, this may indicate a malfunction of the start relay or a refrigerant leak, and not a feature of the operation of electronics.

The initial cooling process always begins with the freezer. This is dictated by the design of the system No Frostwhere the main evaporator is located there. Only after the freezer reaches a temperature of about -18°C will the refrigerator door begin to open, letting in cold air. Therefore, you should not be surprised if it is still warm in the upper compartment in the first hours.

Time intervals: when to expect cold

Owners often mistakenly believe that cooling should begin instantly, as in old Soviet refrigerators. However, equipment with a system No Frost is characterized by a longer primary cycle. The standard time to reach the operating mode varies depending on the volume of the chambers, the number of loaded products and the temperature in the room.

Usually the first cycle of operation of the compressor lasts longer than usual. The unit can operate continuously for 2-4 hours, trying to “catch up” the temperature. During this period, it is not recommended to frequently open the doors or load a large amount of warm food, as this will upset the thermostat settings and increase the stabilization time.

Below is a table of the approximate time to enter the mode for various types of equipment:

It is worth considering that if defrosting was carried out in winter in an unheated room, the initial start-up time may increase. The oils in the compressor thicken in the cold, and it takes time to warm up and reach operating viscosity. In such conditions inverter compressor it may be quieter and start up smoother, but the cooling process will take longer.

Why the freezer works, but the refrigerator is warm

This is the most common situation that causes concern among users immediately after defrosting. As already mentioned, the design No Frost implies cooling of the fridge compartment with air from the freezer. If you hear the compressor running and feel cold at the bottom, but it’s still warm at the top, it means the process is going according to plan.

The air damper (damper) is responsible for the distribution of air flows. It opens only upon command from the electronic module, when the sensor in the freezer detects that the target temperature has been reached. Until this moment, the damper is closed so as not to “rob” the freezer and prevent warm air from the upper compartment from entering there.

Sometimes you can hear a characteristic click or hum of the opening damper. If this does not happen within 4-5 hours of operation, the damper may be mechanically jammed or the drive motor may have failed. Also, the cause may be freezing of the air duct if, during defrosting, moisture got into the channels and froze at the first start.

⚠️ Attention: Do not try to forcefully open the damper or pick the air ducts with sharp objects - this will lead to depressurization of the system and expensive repairs.

In models with Dual Cooling or similar double circuit systems, where each chamber is responsible for its own evaporator, the situation may be different. Here, a cold delay in one of the compartments may indicate a problem with one of the circuits or the solenoid valve that switches the refrigerant flow.

Sound effects: what is normal and what is not

After a long defrost, the refrigerator may make sounds that were not previously noticeable. This is due to the fact that all plastic and metal structural elements undergo a sharp temperature difference. The expansion and contraction of materials cause cracking and clicking noises, which are absolutely normal for the first hours of operation.

However, you should be wary if you hear:

• 🔊 Loud gurgling or fluid overflow - perhaps air has entered the system or oil has moved, which requires the attention of a technician.
• 🔊 Metallic knocking or vibration is a sign that the condenser tubes or the compressor itself are touching the housing or each other due to displacement during washing.
• 🔊 An intermittent humming sound followed by silence - may indicate an attempt to start the compressor, which is prevented by a faulty start relay.

A running motor and periodic hissing of freon in the tubes are considered normal. Also in the system monotonous hum running motor and periodic hissing of freon in the pipes. Also in the system No Frost the fan runs constantly (or cyclically). Its sound should be smooth, without whistling or beating of the blades. If the fan is noisy, there may be a layer of ice or dirt left on its axis after defrosting.

Why does the refrigerator crack after defrosting?

Crackling occurs due to the difference in the coefficients of thermal expansion of the plastic inner box and the metal evaporator. When rapidly cooled after defrosting, materials contract at different rates, producing sounds similar to gunshots or crackling sounds. This goes away on its own after 1-2 cycles of operation.

Typical errors during manual defrosting and their consequences

Many problems with starting after defrosting are not associated with equipment failure, but with violations of the rules of the procedure. The biggest mistake is using a hairdryer or other heating devices to speed up the thawing of ice. Sudden heating can deform the plastic parts of the evaporator or damage sensitive thermal sensors. The second common mistake is turning on the refrigerator immediately after the last piece of ice has melted. Any moisture that gets on the electrical contacts, control board or in the compressor niche must dry completely. Turning on a wet device is fraught with a short circuit or oxidation of the contacts, which will lead to failures in the electronics. temperature sensors.

The second common mistake is turning on the refrigerator immediately after the last piece of ice has melted. Any moisture that gets on the electrical contacts, control board or in the compressor niche must dry completely. Turning on a wet device can result in a short circuit or oxidation of the contacts, which will lead to failures in the electronics.

The third mistake is horizontal transportation or strong tilting during washing. If the refrigerator is lying on its side, it takes time for the oil from the compressor (at least 2-4 hours in a vertical position) to drain back into the crankcase. Starting the compressor without oil will lead to jamming and major breakdown.

To avoid problems, follow this algorithm:

• 💧 Leave the doors open for at least 24 hours after the ice melts to completely evaporate the moisture.
• ⏳ Let the equipment stand turned off in a vertical position for at least 4-6 hours before turning on.
• 🧹 Gently wipe all accessible electrical contacts and the back wall with a dry rag.
• 🔌 Use a separate outlet without extension cords for the first turn on to avoid power surges.

⚠️ Attention: If you used aggressive chemicals to wash the chambers, be sure to ventilate the refrigerator before starting, otherwise the fumes may damage the plastic seals and sensors.

Fault indications and error codes

Modern models such as Indesit, Atlant or Haier, if anomalies are detected in operation immediately after switching on, they can display an error code on the display or signal it by flashing indicators. After defrosting, errors associated with the defrosting system most often appear, even if you defrosted the unit manually.

The electronics “see” that the defrost sensor did not show the expected resistance, or the timer did not count down the allotted time. As a result, the control unit may block the start of the compressor or, conversely, not give a command to turn on the defrost heating element in the future, which will lead to ice accumulation. Often it is necessary to reset the error by turning off the power for 15-20 minutes.

If after resetting the errors return and no cold appears, one of the components was probably damaged during the defrosting process:

1. The defrosting heating element has burnt out (if it was touched when the ice was chipped).
2. The contact has come off the sensor temperature.
3. The drainage holes are clogged, and water goes inside the case, damaging the wiring.

Checklist: has everything been done correctly

Before sounding the alarm and looking for a service center, go through the points to make sure that you have given the equipment a chance to work correctly. Often the problem can be resolved by simply waiting or turning it on again.

Make sure the refrigerator is level, the doors close tightly, and there is clearance around the cabinet for ventilation. If all the conditions are met, and the cold does not appear for more than a day, professional diagnostics are most likely required.

FAQ: Frequently asked questions

How long does the No Frost refrigerator take to get cold after complete defrosting?

Usually the primary cooling process takes from 4 to 8 hours until operating temperatures are reached. Complete stabilization and freezing of food may take up to 24 hours, especially in large volume models or at high room temperatures.

Is it possible to load food immediately after switching on?

Strongly not recommended. You should load food only after the refrigerator reaches operating mode (after 6-8 hours). Warm foods will increase the load on the compressor and can lead to spoilage of already cooled supplies.

Why did an unpleasant odor appear after defrosting?

This could be the smell of stagnant water from the drainage system, which evaporated when heated, or the smell of new plastic elements if cleaning was carried out. The source could also be a forgotten piece of food that has thawed. It is recommended to wash the chambers with a soda solution and ventilate.

Do you need to reset the settings after defrosting?

In most cases, no. However, if the refrigerator behaves inappropriately (does not turn on, errors are on), resetting the settings to factory settings or completely de-energizing for 15-20 minutes can help the electronics restart the operating cycles correctly.

What to do if the compressor turns on and immediately turns off?

This is a sign that the thermal protection relay has tripped. Causes: motor overheating, faulty start relay or electrical problem. Allow the equipment to cool completely (2-3 hours). If the situation repeats, call a technician, operating in this mode will kill the compressor.