When problems arise with cooling or strange sounds from the back of the refrigeration unit, the first thing that comes to mind is to check compressor. It is this unit that is often called the “heart” of the system, and it is to it that all the main refrigerant lines lead. However, for a non-specialist, the back wall of a household appliance may look like a labyrinth of intertwined copper tubes, paints and wires, where it is difficult to determine at first glance which part is responsible for supplying or discharging gas.
Understanding that where is the refrigerator compressor tube locatedis necessary not only for professional repairs, but also for primary diagnosis. Knowing the location of the discharge and suction lines will help determine whether the unit is heating normally, whether there is a freon leak or a blockage in the system. In this article, we will analyze in detail the anatomy of the compressor compartment so that you can confidently navigate the technical space of your refrigerator.
It is worth noting right away that the design may vary slightly depending on the manufacturer. Models Indesit, Atlant or LG have their own layout features, but the physical principle of operation remains the same for all. The point of entry of the refrigerant into the compressor is always located at the bottom of the housing motor, while the outlet for pressurizing is located in the upper zone. This is a fundamental rule of thermodynamics that will help you not get confused during visual inspection.
General structure of the compressor unit
The compressor is a sealed metal cylinder, usually black, mounted on shock-absorbing springs or rubber feet inside a niche on the back wall of the refrigerator. Electrical wires and several copper tubes are connected to this cylinder. The main task of the unit is to compress the gaseous refrigerant and push it along the system circuit. Without this process, circulation of freon and, accordingly, cooling of the chambers is impossible.
Visually you can see that the tubes approach the unit from different sides. One of them, as a rule, is thicker and goes to the evaporator, the other is thinner and connected to the condenser. The third, sealed, is used only during factory service to charge the system. Understanding this circuit is critically important, since damage to any of them leads to depressurization of the circuit.
- 🔴 Discharge tube - removes hot compressed gas to the condenser.
- 🔵 Suction tube - supplies cold gas from the evaporator back to the motor.
- ⚪ The technological tube (plug) is a sealed outlet for service.
It is important to understand that all connections are sealed. If you see oil or signs of corrosion at the junction of the tube and the compressor housing, this is a sure sign of a microcrack. In such cases, immediate intervention by a specialist is required, since independent soldering without evacuation of the system will not give a long-term result.
Location of the suction tube
The suction line is the most visible part of the compressor unit. It connects the outlet of the evaporator (located inside the refrigerator and freezer compartments) with the inlet of the compressor. Since spent, but still cold, freon gas moves through this tube, it is often covered with frost or condensation during operation.
Finding it is quite simple: this is, as a rule, the thickest copper tube suitable for the unit. It can be covered with a thermal insulation tube made of black or gray polyethylene foam, which prevents the formation of dew and loss of cold. If the insulation is damaged or removed, you will see copper that will feel cold to the touch.
The diameter of the suction tube is always larger than that of the discharge tube. This is due to the physics of the process: gas occupies a larger volume than liquid, so a larger cross-section is required for its free circulation. In models Bosch or Siemens this tube often has a curved shape to compensate for vibrations.
⚠️ Attention: If the suction tube is covered with a thick layer of frost (“fur coat”) right up to the compressor itself, this may indicate that liquid freon has entered the motor. This situation is dangerous due to water hammer and requires adjusting the thermostat or checking the defrost system.
In some modern models with inverter compressors, this tube can be made of copper-plated steel, which makes it visually less noticeable. However, the principle of its operation and location remain unchanged: the entrance is in the lower part of the housing.
Where is the discharge tube located
The discharge tube is responsible for transporting the hot gas compressed by the compressor to the condenser (heat exchanger on the rear wall). It is through it that the refrigerant under high pressure enters the system for cooling. You can find it by its characteristic location in the upper part of the compressor.
Unlike the suction line, the discharge tube is always thinner. It does not have thermal insulation, since its task is to release heat to the environment. When the compressor is running, this tube heats up to high temperatures, so it is not recommended to touch it with your hands while the unit is operating.
Structurally, it is a copper squeegee or a straight tap, which immediately goes into the radiator grille or is connected to it through an adapter. The area where the discharge tube is soldered to the compressor housing is an area of high thermal stress, making it potentially vulnerable to cracking during long-term operation.
If you find that the thin tube is hot but the refrigerator is not cooling, this may indicate a blockage in the system (capillary tube) or a lack of freon. In normal mode, hot gas must cool effectively in the condenser.
Process pipe (muffler)
The third element that can be found on the compressor is the process pipe, often called the “muffler”. It is a short piece of copper tube, soldered at the end. Its only purpose is the ability to connect service equipment for evacuation of the system and charging with refrigerant.
The plug is usually located in the middle or on the side, separately from the two main lines. Its length varies from 2 to 5 centimeters. In the factory version, the end of this tube is securely sealed, forming a sealed cap. The presence of this element allows repairs to be carried out without cutting the main contours.
When diagnosing yourself, it is important not to damage this pipe. If you see gas escaping from it or oil coming out, it means the seal is broken. Restoring functionality in this case requires calling a specialist with soldering and refilling equipment.
Why is the plug sealed?
The process pipe is sealed at the factory after all operations on assembling and testing the refrigerator are completed. This ensures that moisture and air do not enter the system, which can destroy the compressor from the inside in a short time.
Diagnostics by temperature and sound
Understanding where each tube is located allows for effective express diagnostics of the condition of the refrigerator. The temperature regime of various parts of the compressor can tell more about problems than external signs.
During normal operation, the suction tube should be cool, but not icy. Discharge - hot. If the suction tube is at room temperature and the compressor is running, this may indicate a lack of freon circulation (the compressor pushes air) or a breakdown of the motor itself.
Sound also plays a role. Normal operation is accompanied by a steady hum. If you hear gurgling sounds, this is a sign that freon is actively moving. Complete silence while the engine is running may indicate a blockage of the capillary system.
- 🔊 A loud knock is a sign of mechanical destruction of the compressor suspension or internal valves.
- 🔊 Hissing is a probable gas leak at the soldering site.
- 🔊 An intermittent hum is a problem with the start relay or the network voltage.
Long-term operation of the compressor without shutting down (more than 20 hours) in the absence of cold is an alarming symptom. In this case, it is necessary to check the integrity of the circuit and the operation of the thermostat.
Table of symptoms of malfunctions
To systematize knowledge about the condition of the pipes and compressor, it is convenient to use a pivot table. It will help you quickly compare visual and tactile sensations with the possible cause of the malfunction.
| Observed symptom | Probable cause | Necessary actions |
|---|---|---|
| The suction tube is frozen to the compressor | Malfunction of the thermostat or defrost sensor | Check the settings, call a technician to replace the sensor |
| The discharge tube is cold | Lack of freon (leak) or compressor breakdown | Check the system for leaks, measure the current |
| The sound of flowing liquid is heard | Normal circulation or oil getting into the circuit | Observation, if there is cold, no repairs are needed |
| The compressor is hot, the tubes are cold | Clogged capillary system | The system needs to be purged and the filter-drier needs to be replaced |
Using this table allows you to weed out simple problems from complex ones. However, remember that an accurate diagnosis can only be made by a specialist using a pressure manifold.
Inspection precautions
Working with the rear end refrigerator requires compliance with certain safety rules. Despite the fact that there is no voltage on the tubes, the compressor itself is under electrical potential, and its operation is associated with high temperatures and pressure.
Before starting any inspection, be sure to disconnect the refrigerator from the electrical outlet. Even if you just want to see where the tubes are, accidentally touching live parts of the terminal box can result in an electric shock. In addition, a running fan (in No Frost models) can injure your fingers.
⚠️ Attention: Never try to bite or saw through the pipes if pressure may remain in the system. Refrigerant under pressure can cause frostbite to the skin or damage the eyes.
It is also worth considering that modern refrigerants (for example R600a isobutane) are flammable. Although its quantity in the system is negligible for an explosion, open fire near a depressurized circuit is strictly prohibited.
☑️ Safety rules during inspection
If you find oily stains, do not touch them with your bare hands. Compressor oil may contain chemical additives that irritate the skin. It is better to use disposable gloves or rags.
Frequently asked questions (FAQ)
Can I replace the compressor myself if I found where the tubes are?
Theoretically, yes, if you have the skills to solder copper pipes, a vacuum pump and a scale for refilling Freon. However, without special equipment it is impossible to properly solder the system and remove moisture. An error will lead to rapid failure of the new compressor.
Why is the tube going to the compressor covered with a “fur coat”?
This indicates that liquid freon enters the compressor instead of gaseous. Reasons: the thermostat is faulty (does not turn off the cold), there is not enough freon in the system, or the capillary tube is clogged. Diagnostics is required.
Which tube should be hot: the top or the bottom?
The thin tube coming out of the top of the compressor (supercharger) should be hot. The thick tube entering from the bottom or side (suction) should be cool.
What to do if the compressor tube breaks off?
Immediately turn off the refrigerator. If the sealed part (glushak) breaks off, that’s not so bad, it can be soldered. If the main line near the housing itself breaks off, the compressor will most likely need to be replaced, since soldering in this place is extremely difficult and often leaky.
Does the compressor housing itself get hot?
Yes, the compressor housing heats up to 60-80 degrees Celsius during operation. This is normal operating mode. However, if it is hot to such an extent that it is impossible to touch it, or if it is cold when the engine is running, this is a sign of a malfunction.