Many owners of refrigeration equipment have noticed a small plastic pin or tube protruding from the back wall inside the main chamber. This item is often perceived as a random part, fastener, or even a manufacturing defect that interferes with product placement. However, this plastic tube is a critical component that ensures the automatic operation of the defrosting system.
In modern models with a system No Frost or “Crying Evaporator”, this element serves as a channel for removing condensate. It is through this hollow rod that the water generated on the rear wall flows into a special tray located above the compressor. If this element is damaged or clogged, the refrigerator will no longer cope with moisture.
In older models or devices with manual defrosting, this plastic element acts as a sensor. There is thermostatlocated inside or around it, which reads the temperature of the evaporator. As soon as the ice melts and the temperature reaches a certain value, the system receives a signal to turn off the heating or turn on the compressor.
Principle of operation of the moisture removal system
The functioning of the refrigerator is based on a constant cycle of evaporation and condensation of the refrigerant. During operation, moisture from the air of the products settles on the internal surfaces of the evaporator, turning into frost. To prevent this ice from turning into a block, blocking airflow, the system must remove it regularly. The plastic tube you see is the final link in the chain of removing this moisture.
When the compressor stops or the defrost mode is turned on, the ice on the back wall begins to melt. Water droplets collect in a groove at the base of the rear panel. From there, the liquid flows by gravity into drainage hole, which is often covered or framed by that same plastic structure. Next, the water flows down the tube into a container, where it evaporates due to the heat of the running motor.
Important understand that the material used was not chosen by chance. Plastic has low thermal conductivity, which prevents water from re-freezing inside the drainage channel itself. If the tube were metal, it would freeze through, forming an ice plug, and the water would stop leaving, flowing onto the shelves of the refrigerator.
The role of the defrost sensor in a plastic case
In a number of designs, especially in “Crying Wall” type refrigerators, the plastic pin is the housing for thermostat. It protrudes deep into the chamber in order to come into contact with the air or the surface of the evaporator through a thin wall. This allows the electronics to know exactly when the evaporator has warmed up enough to remove ice.
The system works according to the following algorithm: the timer gives the command to turn on the heating element (heating element), the ice melts, the water leaves through the drainage. A sensor located inside or at the base of the plastic tube detects the increase in temperature. As soon as the ice has completely melted and the temperature has reached, for example, +10°C, the thermostat opens the circuit, turning off the heating, so as not to waste energy.
⚠️ Attention: It is strictly forbidden to pierce or pierce the plastic tube with sharp objects when trying to tear off the ice. There may be freon inside (in older models) or sensitive electronics, and failure of the drainage seal will lead to leaks.
If this sensor fails, the refrigerator may behave incorrectly: either not turn on for cooling, believing that the chamber is too warm, or, conversely, constantly freeze without starting the defrost cycle. It is difficult to visually check the serviceability of this part; usually problems are indicated by incorrect temperature or constant freezing of the rear wall.
Why does freezing occur around the tube
A frequent problem for users is the formation of a “fur coat” or ice build-up directly around the plastic element. This phenomenon indicates a violation of heat exchange or problems with moisture removal. If the drainage hole located in the center or at the base of this structure becomes clogged with debris, the water has nowhere to go and freezes to form a cone of ice.
Another reason is a faulty door seal. If warm air from outside enters the chamber, the humidity increases sharply. The defrost system does not have time to process such volumes of water, and it freezes around the drainage channel. In this case, the plastic tube becomes overgrown with ice, blocking further drainage.
- 🧊 Clogged drainage: Crumbs, lettuce leaves or mold create a plug, the water stands and freezes.
- 🚪 Loose fit of the door: The constant flow of moist air accelerates the formation of ice.
- ❄️ Sensor malfunction: The system “does not see” the ice and does not turn on the heating to remove it.
It is also worth considering that in some models the plastic element may freeze slightly around the edges in winter if the refrigerator is placed on an unheated veranda. However, under normal operating conditions (room temperature from +16°C to +32°C), this area should remain free from a thick layer of ice.
Instructions for safe drainage cleaning
If you notice that water is standing in the groove under the plastic tube or an ice crust has formed around it, it is necessary to carry out preventive cleaning. This procedure is simple, but requires care so as not to damage the thin walls of the canal. To work, you will need warm water, a syringe or a small syringe, and a soft brush.
First you need to completely defrost the refrigerator. Unplug the appliance, remove all food and leave the doors open for at least 12 hours. The ice should melt naturally. Using a hairdryer or knife to speed up the process strongly not recommendedas a sharp temperature change can damage the plastic or evaporator.
☑️ Cleaning the drainage system
After defrosting, take a syringe with warm water and rinse the hole under pressure. If the water drains slowly, carefully insert a soft wire (for example, a cleaned headphone wire) or a special brush into the channel. The movements should be progressive, without strong pressure, so as not to pierce the wall of the tube.
Table: Main causes of drainage system malfunctions
To quickly diagnose a problem related to the plastic tube and moisture removal, use the following table. It will help determine whether you can solve the problem yourself or whether you need to call a specialist.
| Symptom | Probable cause | Solution method |
|---|---|---|
| Water standing in the groove | Clogged with debris | Cleaning with a brush and rinsing with water |
| Ice cone around the tube | Frequent opening of the door / Sensor malfunction | Checking the seal, diagnosing the thermostat |
| Water flows onto the floor | Displacement or dislocation of the drainage tube | Access from behind the refrigerator, putting the tube in place |
| Unpleasant odor from the hole | Growth of bacteria and mold | Antiseptic treatment and thorough rinsing |
It is worth noting that in models with a full system No Frost the drainage tube is often hidden inside the case and is not visible to the user. In such cases, access to it is possible only by partially disassembling the rear panel of the freezer, which is best left to a specialist.
Features of operation and care of the element
In order for the plastic tube and the entire moisture removal system to serve for a long time, you must follow simple operating rules. First of all, watch the packaging of the products. Liquid products must be tightly closed, otherwise moisture will actively evaporate and settle on the walls, overloading the system.
Regularly, at least once every six months, conduct a visual inspection of the drainage hole area. Make sure there are no green leaves, crumbs or signs of mold. For prevention, you can wipe the hole with a cotton swab dipped in a weak solution of soda or a special product for cleaning refrigerators.
⚠️ Attention: Do not use aggressive chemicals, bleach or boiling water to clean the drainage tube. Plastic can be deformed from high temperature, and chemistry can destroy the rubber seals inside the system.
Is it possible to lubricate the tube with oil?
It is strictly forbidden to lubricate the inside of the tube with oil or grease. This will cause the grease to harden, mix with dust and create an impenetrable plug that will be extremely difficult to remove without disassembling the system.
If you notice that the plastic element is cracked or broken, this requires replacing the part. Operating a refrigerator with a damaged moisture drainage channel will lead to constant humidity inside the chamber and spoilage of food.
When professional repairs are required
In most cases, you can deal with the plastic tube and drainage yourself. However, there are situations when the intervention of a specialist is necessary. If, after thorough cleaning and defrosting, water continues to accumulate, perhaps the problem lies deeper - in the freezing of the channel inside the housing or a malfunction of the defrosting system.
A specialist will be needed if:
- 🛠️ Replacement of the sensor is required: If the thermostat built into the tube is faulty, it needs to be diagnosed with a multimeter and replaced.
- 🔧 Disassembly of the case is required: To access hidden drainage areas in systems No Frost often it is necessary to remove the back panel and evaporator.
- 💧 There is a freon leak: If the cooling system was damaged during manipulation, professional refilling will be required.
Ignoring problems with moisture drainage can lead to more serious consequences, such as corrosion of metal parts housing, the appearance of mold in hard-to-reach places and failure of the compressor due to abnormal operation.
Frequently asked questions (FAQ)
Is it possible to seal a cracked plastic tube?
Using ordinary glue or tape inside the refrigerator is not recommended due to toxicity and low temperatures. If the crack is small and located on the outside, you can use food grade silicone. However, in case of serious damage, it is better to replace the part, since warm air can enter the chamber through the crack.
Why does cold air blow from the tube?
This is normal for some models of refrigerators. Through the drainage hole, air can circulate between the chamber and the space behind the rear wall. The main thing is that water does not flow from there and clearly warm air does not blow.
How to understand that the defrost sensor is faulty?
The main symptom is that the refrigerator freezes too much, turning food into ice, or, conversely, does not gain temperature. Also, a thick layer of ice may form on the back wall, which does not melt even after a long defrosting (if the problem is in the electronic control).
Does the tube need to be lubricated for better water drainage?
No, nothing needs to be lubricated. The water should drain by gravity. Any greasy substances will create a film on which dirt will stick, which will ultimately lead to a clog. It is enough to keep the hole clean.