The situation when the refrigerator stops cooling due to a freon leak or blockage, it often takes you by surprise. Ideally, high-quality repairs require vacuum pumpthat allows you to remove air and moisture from the circuit in a matter of minutes. However, in conditions of remoteness from service centers or when there is an urgent need to revive the unit, craftsmen often look for ways to do without specialized equipment.
There is a myth that the necessary vacuum can be created only with a pump, but physics offers alternative solutions based on the law Boyle-Mariot and the thermodynamic properties of gases. Of course, full vacuuming without a pump is technically impossible in the classical sense, but it is possible to create deep vacuum conditions, sufficient for the operation of a household refrigerator, using the compressor of the unit itself.
In this material We will look at two main methods: using a standard refrigerator compressor and using a modified car compressor. It is important to understand that such actions require caution, since improper sealing or the presence of moisture in the system can lead to repeated failure of the equipment in a short time.
Physics of the process and why it even works
To understand the essence of the method, you need to realize that a vacuum is not “sucking out” air, but creating conditions under which the pressure inside the system becomes below atmospheric. In factory conditions, a vacuum pump is used that mechanically pumps out gases. At home, we can use the refrigerator compressor itself, which by its design is a piston pump.
The operating principle of the standard motor allows it not only to compress the refrigerant for condensation, but also to rarefy the medium at the inlet. When you start the compressor with the suction tube open, it begins to intensively suck air from the circuit. If a check valve is installed at the outlet of the discharge tube or the valves are manipulated correctly, a pressure of several torr can be achieved, which is acceptable for starting the system.
Key point here is the removal of moisture. The air always contains water vapor, which at low temperatures in the evaporator turns into ice and clogs the capillary tube. That is why the process must be long, and best of all, accompanied by heating of the compressor in order to evaporate moisture from the windings and oil.
⚠️ Attention: Using a standard compressor to pump out air creates a risk of atmospheric moisture getting inside the motor. This can lead to oxidation of the windings and the formation of an acidic environment in the oil, which will shorten the service life of the unit.
Do not forget about safety. Working with live electrical appliances requires compliance with electrical safety rules. All manipulations with tubes and soldering should be carried out only after disconnecting the device from the network, and starting the compressor for vacuuming should be under strict control.
Method one: Vacuuming with a standard compressor
This is the most common method among single craftsmen who do not have a vacuum pump at hand. It requires a minimum set of tools: a torch, solder, flux and, preferably, a pressure gauge station to control the process, although experienced craftsmen focus on time and temperature.
The essence of the method is to repeatedly start the compressor cyclically with the service tube closed. First, the system is purged with freon (if there is a supply) or simply with pressurized air to displace the bulk of contaminants. Then the compressor starts, and during its operation the discharge tube is pinched or the valve is closed, after which the unit turns off.
To implement this method you will need:
- ⚡ Soldering torch (gas or oxygen) and a set of copper tubes.
- ⚡ Sealant or special a clamp for temporarily blocking the tubes.
- ⚡ Freon for subsequent charging of the system.
- ⚡ A multimeter for checking the compressor windings before starting.
The process is as follows: after soldering all connections and eliminating leaks, a service tube (usually a process tube on the body compressor) remains open. The compressor is connected to the network. Air begins to come out of the open tube noisily. After 2-3 minutes, when the flow weakens, the tube is sharply pinched with pliers (if it is soft) or sealed, and only then the power is turned off.
Repeating the cycle 3-5 times can significantly reduce the pressure inside the circuit. It is important to allow the motor to cool between cycles so as not to overheat the protection thermostat. Case temperature should not exceed 80-90 degrees Celsius, otherwise insulation breakdown may occur.
Method two: Using a car compressor
If fiddling with the starting cycles of a standard engine is scary or impossible, you can use a car compressor to inflate tires. However, a standard compressor pumps air v the system, but we need to pump it out. The solution lies in modifying the device or using the Venturi effect, but the easiest way is to remake the compressor itself.
Most automobile compressors have a piston group similar to a refrigeration group, but smaller in size. If you disassemble the housing, find the inlet (where the air filter is located) and hermetically attach the hose coming from the refrigerator to it, the device will begin to work as a vacuum degasser. At the outlet (where the hose for the wheel is usually) you need to leave a free outlet for air.
Algorithm of actions when using a modified auto compressor:
- Disassemble the body of the automobile pump and find the inlet pipe of the cylinder.
- Connect the hose from the refrigeration circuit to the inlet, ensuring tightness (you can use adapters or clamps).
- Connect the compressor to the car network or via a 12V power supply.
- Monitor the process using a pressure gauge, if installed at the outlet, or by operating time.
The efficiency of this method is lower than that of a specialized pump, but higher than that of a standard compressor refrigerator, since the car unit is not afraid of moisture and air to the same extent. However, productivity will be low, and the process may take 40-60 minutes to achieve an acceptable result.
Risks of using a car compressor
Car compressors are not designed for long-term continuous operation. They can overheat after 15-20 minutes, so be sure to take breaks to cool down. In addition, the rubber seals of such pumps may not provide ideal tightness under deep vacuum.
Step-by-step instructions: from soldering to startup
Regardless of the chosen method, preparing the system is the same. Errors at the soldering stage will negate all efforts to vacuum. First you need to find and fix the leak. This is done by visual inspection, soap emulsion or nitrogen pressure testing.
After eliminating the defect, soldering is performed. It is critical here not to overheat the tubes and to choose the right solder. For copper pipes, solder containing silver is used, for steel pipes, a special refractory solder is used. Flux must be completely removed after soldering, as its remains cause corrosion.
☑️ Checklist for preparing for vacuuming
The vacuuming process itself with a standard compressor looks like like this:
- Open the service tube (usually it is sealed in a seal).
- Plug in the refrigerator for 3-5 minutes. You will feel the flow of air.
- Carefully bend the service copper tube with pliers near the compressor body itself, blocking the outlet.
- Only after pinching, turn off the refrigerator from the outlet.
- Roll up (solder) the bent tube.
It is recommended to repeat this procedure 3-4 times at intervals of 10-15 minutes. Between cycles, you can lightly tap the condenser and evaporator tubes to help release air bubbles stuck in the bends.
Comparison table for vacuuming methods
So that you can choose the best option for your situation, we have prepared a comparison table. It will help assess the time costs and risks of each method.
| Parameter | Standard compressor | Car pump | Specialized pump |
|---|---|---|---|
| Residual pressure | High (insufficient) | Average | Low (ideal) |
| Risk for the motor | High (moisture in the oil) | Low | Absent |
| Process time | 40-60 minutes | 30-40 minutes | 10-15 minutes |
| Required equipment | Minimum | Average (modification) | Professional |
As can be seen from the table, standard compressor is the least desirable option in terms of durability of repairs, but the most affordable. A specialized pump provides a guarantee of quality, but purchasing it for a one-time repair is not economically feasible.
Typical errors and possible consequences
The most common mistake is insufficient vacuuming time. Owners often think that 5 minutes of compressor operation is enough. This is wrong. Microbubbles of air and moisture vapor remain in the system, which after a week form an ice plug in the capillary.
The second mistake is a violation of the sequence of actions. Some craftsmen first seal the tube and then turn off the compressor. This leads to the fact that when the motor cools down, a vacuum is created inside, and air can be sucked back through a poor-quality seam or seals, nullifying the work.
⚠️ Attention: Never leave the system with open pipes for a long time unattended. Air humidity will quickly saturate the internal walls, and instead of repair, you will get deep humidification of the system, requiring replacement of the filter-drier and repeated blowing.
The condition of the oil is also often ignored. If water gets into the compressor, the oil becomes cloudy and loses its properties. In such cases, after “vacuuming” without a pump, the refrigerator may work for a season, but then the compressor will jam. Therefore, if possible, after vacuuming it is worth replacing the oil in the compressor, although this is a labor-intensive procedure.
FAQ: Frequently asked questions
Is it possible to use a vacuum cleaner to vacuum a refrigerator?
Theoretically, it is possible if the vacuum cleaner has a blowing function and the ability to tightly connect the hose to inlet. However, the power of household vacuum cleaners to create a deep vacuum is usually insufficient. They can reduce the pressure, but not to the level necessary for reliable operation of the refrigeration circuit. The risk of dust and moisture getting from the vacuum cleaner into the system is very high.
How many times should the compressor turn on cycle be repeated?
3-5 cycles are considered optimal. The first cycle removes the main volume of air, the subsequent ones draw out residues and moisture through evaporation. There is usually no point in repeating the procedure more than 5 times, since efficiency decreases and the risk of motor overheating increases. Between cycles, be sure to let the compressor cool for at least 10-15 minutes.
Is it necessary to change the filter drier during such repairs?
Yes, this is critically important. The filter drier (trunnion) is a disposable element. When the system depressurizes, it becomes saturated with moisture from the air. If you evacuate the system without replacing the filter, it will quickly release accumulated moisture back into the circuit, leading to ice blockage and acid corrosion. Always change the filter whenever the circuit is opened.
How to understand that the vacuum is sufficient without a pressure gauge?
Without a pressure gauge it is impossible to determine the exact pressure. An indirect sign can be the nature of the sound of the escaping air (it should become a barely audible hiss) and the operating time. However, relying on these signs is risky. If you are doing repairs by eye, increase the number of pumping cycles and the compressor operating time in each cycle to 5-7 minutes.
In conclusion, it is worth noting that repairing a refrigerator is a set of measures where vacuuming is only one of the stages. The quality of soldering, the correct dosage of freon and the condition of the filter-drier play an equally important role. If you are not confident in your abilities, it is better to turn to professionals, since the cost of a mistake may exceed the cost of a new unit.