Sudden appearance of an ice crust on external or internal pipes of the refrigeration unit - this is not just a cosmetic defect, but a serious signal about a malfunction of the system. When the refrigerator tube becomes covered with ice, this indicates that the refrigerant is not circulating correctly or there is an abnormal change in pressure in the circuit. Ignoring this symptom can lead to failure of an expensive compressor, since liquid freon can cause water hammer.
Owners often notice that a thin copper tube on the back wall freezes over or, even worse, a panel inside the chamber swells. This is due to differences in temperature and humidity, but the root of the problem lies deeper. In this article, we will analyze in detail the mechanics of the process so that you understand the physical essence of what is happening before you start troubleshooting.
There are several main scenarios for the development of events, from banal leaks to complex problems with automation. No Frost System drip refrigerators may behave differently, but the principle of ice formation is the same. Understanding these nuances will help you save time and money by avoiding unnecessary calls to the technician for simple cases.
Physics of the process: why icing occurs
To understand how to fix the problem, you need to understand why the refrigerator tube is covered with ice under normal conditions and during breakdowns. In a working unit, the refrigerant boils in the evaporator, taking away heat, and then is compressed in the compressor, heating up. If you see ice in an area where it should not be, it means that there is a sharp expansion of gas or the surface temperature is below the dew point of the surrounding air.
Often the cause is a violation of the tightness of the circuit. When the pressure drops, the boiling point of freon decreases, and the tube begins to “take away” heat even from the air in the room, instantly condensing moisture and turning it into frost. This is a classic sign that freon leak has already happened or is happening right now.
Another aspect is the operation of the thermostat. If it does not turn off the compressor in time, the system wears out, freezing all accessible surfaces. In models with Low Frost or partial automatic defrosting, this can lead to fouling of the return line running from the evaporator to the compressor.
Refrigerant leakage: the most common culprit
If you find that the refrigerator tube is covered with ice uneven or an ice “coat” grows in one specific place, most likely depressurization has occurred. Freon comes out, the pressure in the system drops, and abnormal cooling begins at the leak point or immediately after it. Most often this happens in solder areas or in corroded areas of shut-off valves.
It is difficult to determine a leak visually, but indirect signs are obvious. The refrigerator starts working longer, the compressor almost never turns off, and the temperature in the chambers rises, although everything outside is covered with frost. In such cases refilling the refrigerator without finding and fixing the hole is only a temporary measure that will not solve the problem.
⚠️ Attention: Independent search for leaks using soapy water is possible only on accessible external tubes. If the problem is inside the foam housing or in the sealed evaporator, professional equipment is required and the panels are opened.
The process of restoring the tightness includes finding the place where the gas is escaping, vacuuming the system to remove moisture and air, and then charging with a new portion of refrigerant. It is important to use exactly the type of freon that is indicated on the tag: R600a (isobutane) or R134a. Mixing different types of refrigerants is strictly prohibited and will lead to compressor failure.
Malfunctions of the defrost system (No Frost)
In refrigerators with the system No Frost the situation looks different. Here the tubes are hidden behind a plastic panel, but ice may bleed through or accumulate at the bottom of the freezer. If Defrost heating element the fuse blows or burns out, the evaporator becomes overgrown with ice, which blocks the air circulation channels. As a result, cold stops flowing into the chamber, and frost may appear on the return tube due to a violation of heat exchange.
Diagnosis of this problem requires disassembling the freezer chamber. You need to check the integrity of the defrost heater and defrost sensor. Often the one that fails is the one that “does not see” that the evaporator is frozen and does not give the command to turn on the heating element. As a result, the refrigerator operates in cooling mode constantly, building up an ice block. defrost sensor, which “does not see” that the evaporator is frozen and does not give the command to turn on the heating element. As a result, the refrigerator operates in cooling mode constantly, building up an ice lump.
It is also worth checking the defrost timer or electronic control module. If they do not switch modes, the system will only work for freezing. Visually this manifests itself as a huge snowdrift inside, although externally the refrigerator may look normal, except for the whistling of the fan that hits the ice.
☑️ Diagnostics of the No Frost system
Problems with the thermostat and sensors
Incorrect operation thermostat is another reason, through which the refrigerator tube is covered with ice. If the thermostat contacts are “stuck” in the “on” position, the compressor will thresh without interruption. This leads to deep freezing. In drip systems, this causes freezing of the back wall and the tubes underneath it, and in No Frost it causes clogging of the evaporator.
In modern models, the role of a thermostat is performed by electronic temperature sensors. They may give incorrect readings if they become dirty or damaged. For example, the sensor may “think” that the chamber is +10°C, although it is already -5°C, and continue cooling. Replacing thermostat or calibrating the sensors often solves the problem.
It is worth noting that in some models the temperature is controlled by an electronic control unit. A malfunction may be caused by a power surge. In this case, a complete diagnosis of the electronics is required, and not just a mechanical replacement of parts.
How to check the thermostat?
To check a mechanical thermostat, you can close its contacts directly. If the compressor starts, then the problem is in the thermostat itself. However, this method requires caution and an understanding of electrical circuits.
Clogged capillary tube
One of the hidden and complex problems is clogged capillary tube. This is a thin tube in which throttling (a sharp drop in pressure) of freon occurs. If there is moisture in the system, it freezes at the narrowest point of the capillary, forming an ice plug. This blocks the circulation of the refrigerant.
Symptoms of a blockage are similar to a leak: the refrigerator does not freeze well, the compressor is hot, and frost may appear in the area in front of the blockage (often on the filter drier or the evaporator inlet pipe). In this case, the compressor itself may work with overload, trying to pump freon through the plug.
Removing the blockage requires purging the system with nitrogen under high pressure and replacing the filter-drier. At home, this operation is almost impossible to perform without special equipment. Attempts to simply defrost the refrigerator will give a temporary effect - after a few days the moisture will freeze again in the capillary.
| Symptom | Probable cause | Nature of ice | Necessary actions |
|---|---|---|---|
| Ice on the outer tube of the compressor | Thermostat malfunction | Uniform layer | Replacing the thermostat |
| Ice crust in one place | Freon leak | Local build-up | Searching for leaks and refilling |
| Snowdrift inside the freezer | Failure of the defrost system | Dense snow/ice | Checking the heating element and timer |
| Frost on the filter drier | Clogged capillary | Spot icing | Purge the system with nitrogen |
Mechanical damage and human factor
Sometimes the answer to the question why the refrigerator tube becomes covered with icelies in simple carelessness. When defrosting, many people use sharp objects (knives, screwdrivers) to chip the ice. One awkward movement - and the blade pierces the thin wall of the evaporator or the tube suitable for it.
In this case, depressurization occurs instantly. You may hear the hissing of gas escaping. If this happens, you must immediately unplug the device from the outlet and ensure the room is ventilated (especially if it is used R600a, which is explosive in concentration with air).
Also the cause may be a loose door seal or a damaged seal. Warm, humid air constantly enters the chamber, and the system does not have time to dry it. Moisture settles on the coldest elements - the evaporator tubes, turning into ice. Regularly checking the seal and replacing the magnetic tape will help avoid this problem.
⚠️ Attention: If you pierced the tube with a knife during defrosting, under no circumstances turn on the refrigerator again! This will lead to moisture and air getting inside the system, which will make repairs much more expensive and difficult.
Diagnostic and restoration methods
If you decide to act on your own, start with a visual inspection and defrosting. Defrosting the refrigerator completely within 24 hours may help if the problem was a temporary glitch or a small amount of moisture in the system. After defrosting, turn on the device and observe: if ice appears again after a few hours, the problem is technical.
For deeper diagnostics, you will need a multimeter. With its help, you can check the resistance of the defrost heating element, the integrity of the fuses and the operation of the thermostat. The normal resistance of the heating element is usually several hundred ohms; if the device shows infinity, the heater has burned out.
If a leak or capillary blockage is confirmed, the best solution would be to call a specialist with evacuation and charging equipment. Repairing the cooling circuit requires not only skills, but also licensing when working with fluorinated gases. Independent experiments with freon cylinders are dangerous to health and life.
Prevention and proper care
In order the refrigerator tube is not covered with ice, it is important to follow the operating rules. Do not place hot foods in the chamber - this will dramatically increase the humidity and load on the system. Keep the drainage hole clean; if it becomes clogged, the water will not flow into the pan, but will freeze at the bottom of the chamber, disrupting the operation of the sensors.
Regularly, at least once a year, completely defrost the refrigerator, even if you have a No Frost system. This will help remove plaque that cannot be removed automatically and check the condition of the seals. Cleaning the condenser (grid at the back) from dust will also improve heat transfer and reduce the load on the compressor.
Compliance with temperature conditions and chamber loading rules will extend the life of your refrigerator. Don't overcrowd the freezer, leave room for air circulation. Proper care is the best prevention of costly breakdowns.
How often should you wash the condenser?
If you have pets, hair can clog the condenser grille every 3-4 months. Under normal conditions, cleaning once a year with a vacuum cleaner or soft brush is sufficient.
Frequently asked questions (FAQ)
Is it possible to operate the refrigerator if the tube is covered with ice?
Short-term operation is acceptable for diagnostics, but long-term operation is prohibited. Ice can damage seals, cause metal corrosion, and in the event of a freon leak, lead to combustion of the compressor due to overheating or water hammer.
Why does the thin tube freeze, while the thick one remains dry?
The thin tube is a capillary or outlet from the evaporator, where the pressure and temperature minimal. The thick tube is the discharge line after the compressor, where the freon is hot and under high pressure, so ice cannot form on it in principle.
How much does the repair cost if a leak is detected?
The cost consists of the work of finding the leak, replacing the filter-drier, evacuation and refilling with freon. The price may vary depending on the difficulty of access to the leak site (repairs are more expensive in a foamed casing).
Is it dangerous to touch an icy tube?
You can touch it, but you should not hold your hand for long if very cold freon circulates there - a slight cold burn is possible. The main thing is not to try to pick out the ice with a knife or sharp objects, so as not to damage the metal.