The situation when it is required pumping out freon from the refrigeration circuit occurs infrequently, but is always a critical point in the repair process. Most often, the need for this appears when replacing compressor, removing a blockage in the capillary tube, or completely recharging the system with new refrigerant. Many amateur craftsmen mistakenly believe that they can simply release the gas into the atmosphere, however, modern environmental standards and technical regulations categorically prohibit the release of R600a or R134a freon into the air.
The process of evacuation and collection of refrigerant does not require only special equipment, but also a clear understanding of the physical properties of gases under pressure. Safety here comes first, since some types of refrigerants when mixed with air form explosive compounds. In addition, the entry of moisture or air into the system due to improper pumping will lead to failure of the new compressor in a matter of months.
In this article we will analyze a professional approach to degassing the circuit, consider the necessary tools and describe in detail the technological sequence of actions. You will learn why isobutane (R600a) requires special care due to its flammability and how to properly organize the work process so as not to harm either equipment or health.
Safety precautions and workplace preparation
Before Before taking up a tool, you need to understand the risks. If your refrigerator uses isobutane, any sparks can be fatal. Work should be carried out in a well-ventilated area, away from open fire and operating electrical equipment that creates sparks. Ventilation is not just a recommendation, but a prerequisite, since freon is heavier than air and can accumulate in the lower part of the room.
⚠️ Attention: When working with R600a, smoke or use welding machines within a radius of 3 meters without first purging the area. Gas concentration in air from 1.3% to 8.4% creates an explosive mixture.
Preparation of the workplace also includes checking the integrity of the hoses and pressure gauge station. Old, cracked hoses can leak, causing air to leak into the system or leak toxic gas. Make sure you have access to electricity to connect the vacuum pump, and that the outlet is grounded.
It is important to prepare a container to collect the gas. For professional pumping, cylinders with shut-off valves designed for a certain pressure are used. The use of ordinary household cylinders or, even worse, plastic containers is unacceptable. The pressure in the system can increase sharply when heated, which will lead to depressurization.
Necessary equipment and tools
High-quality pumping out of freon is impossible without a specialized tool. The master's basic set includes a pressure gauge station (manifold), which allows you to control the pressure in the low and high pressure circuit. For household refrigerators, a blue hose (low pressure) and a yellow hose are most often used to connect to a pump or cylinder.
The key element is vacuum pump. Its task is to create a deep vacuum in the system after removing the main volume of freon, and also to help pump gas into the collection cylinder due to the pressure difference. The pump power must correspond to the volume of the system, but for household refrigerators a single-stage model with a capacity of 60 liters per minute is sufficient.
You will also need:
- 🔧 Pipe cutter —for carefully opening copper tubes without forming chips.
- 🔥 Gas torch —for soldering connections and installing nipples.
- ⚖️ Electronic scales — for precise control of the amount of refrigerant pumped in or pumped out.
- 🧤 Safety glasses and gloves —for protection against cold burns and chemical exposure.
Worth separately mention about filter drier. If there is any depressurization of the circuit, it must be changed. Do not try to calcine the old filter in the oven - this will not fully restore its properties, and moisture will remain in the system.
Types of refrigerants and their pumping features
Different types of freons require an individual approach. The most common in modern refrigerators is R134a. It is a safe, non-flammable gas that is easier to remove from the system. However, it also requires collection, since it is a greenhouse gas.
The situation with R600a (isobutane) is radically different. It is a hydrocarbon compound that burns. When pumping out such freon, you cannot use conventional compressor units, which can spark. R600a is often collected in a special cylinder, creating a vacuum in it or using pressure in the circuit to allow gas to flow.
What is dangerous about freon R12?
Freon R12 (difluorodichloromethane) was used in old refrigerators. Upon contact with an open flame, it splits to form phosgene, a chemical warfare agent. Therefore, soldering of the circuit with R12 can only be carried out after thoroughly purging the system with nitrogen or completely removing freon.
The table below will help compare the main characteristics of refrigerants:
| Type of freon | Chemical name | Flammability | Boiling pressure |
|---|---|---|---|
| R134a | Tetrafluoroethane | Non-flammable | Low |
| R600a | Isobutane | Highly flammable | Very low |
| R12 | Dichlorodifluoromethane | Not flammable | Average |
| R404a | Mixture (R125/R143a/R134a) | Non-flammable | High |
Understanding the type of gas determines the choice of equipment. For R600a, explosion-proof pumps are often used or operate in a natural flow mode, avoiding electrical sparks in the work area.
Step-by-step instructions: how to properly bleed and collect freon
The process begins with preparation. The refrigerator must be unplugged at least 10-15 minutes before starting work to allow the oil to drain into the compressor. Locate the process connection on the compressor. This is usually a sealed copper tube, often marked or located next to the suction tube.
Carefully use a pipe cutter to open the process pipe. Do not use a metal saw as metal shavings will inevitably enter the system. Immediately after opening, connect the pressure gauge station. If the pressure in the system is positive, you will hear a characteristic hissing sound of escaping gas.
☑️ Algorithm of actions during pumping
To collect freon into the cylinder, the overflow method is used. The cylinder must be empty and cooled (you can place it in a container with ice or use a special cooling jacket) to create a difference in temperature and pressure. Gas will flow from the warmer refrigerator system to the colder cylinder until the pressure equalizes.
When the pressure in the system and cylinder is equal, the bulk of the freon will be collected. However, work is required to completely remove the residue and prepare for repairs vacuum pump. Connect the pump to the yellow manifold hose and turn it on. Evacuation allows you to remove not only residual gas, but also moisture that could get into the circuit.
Evacuating the system and controlling humidity
Evacuating is a critical step. Residual freon mixed with air and moisture must be completely removed. Moisture in the system is the main enemy of the refrigerator. Freezing in the capillary tube, it forms an ice plug that blocks the circulation of the refrigerant. In addition, moisture reacts with oil and freon, forming acid, which destroys the compressor windings from the inside.
The vacuum process should last at least 30-40 minutes. The pressure in the system should drop to values close to absolute vacuum (on the pressure gauge the needle should go into the negative zone, usually to -1 bar or lower, depending on the scale). If the arrow begins to creep up after turning off the pump, it means that there is a leak in the system or it is saturated with moisture, which evaporates at low pressure. Leakage leakage (leakage) or it is saturated with moisture, which evaporates at low pressure.
⚠️ Attention: Never turn on the compressor if the system is in a deep vacuum without pumped Freon. This can lead to breakdown of the winding insulation and an electric arc inside the housing, since electrical breakdown occurs more easily in a vacuum.
To speed up the process of removing moisture, you can use the “warm-up” method. During the vacuum process, you can gently (without overheating!) warm up the condenser or compressor housing with a hairdryer. This will help evaporate the moisture accumulated on the walls of the tubes and remove it with a pump. However, with R600a this method must be used extremely carefully.
Frequent errors and troubleshooting
One of the most common mistakes is an attempt to speed up the pumping process by increasing the pressure with nitrogen. You can only blow nitrogen into the system to “push out” freon if you are confident that all solder joints are strong. In older refrigerators, this can lead to a rupture of the thin-walled aluminum evaporator, which will turn a simple repair into a complex replacement of the entire refrigerator. Another mistake is ignoring the replacement of the filter drier. Many people believe that if the system has not been open for long, then the old filter will do the job. This is a misconception. Zeolite or silica gel in the filter have a limited resource and upon contact with the atmosphere they are instantly saturated with moisture. Installing a new filter is a mandatory rule. aluminum evaporator, which will turn a simple repair into a complex replacement of the entire refrigeration cabinet.
Another mistake is ignoring the replacement of the filter drier. Many people believe that if the system has not been open for long, then the old filter will do the job. This is a misconception. Zeolite or silica gel in the filter have a limited resource and upon contact with the atmosphere they are instantly saturated with moisture. Installing a new filter is a must.
Blowing out the hoses is also often forgotten. Before connecting the yellow hose to the pump or cylinder, it is worth briefly running a little freon (if it is still in the system) or nitrogen through it to expel the air inside the hose itself. This will prevent the system from airing at the last moment.
List of typical problems:
- ❄️ Ice plug —a consequence of poor evacuation or wet freon.
- 🔥 Overheating of the compressor —can be caused by residual air in the system, which increases pressure condensation.
- 📉 Low performance - if there is air left in the system, it takes up volume without participating in the cooling cycle, which reduces efficiency.
If after evacuation the pressure in the system increases, use the leak detection method. Coat the connections with soapy water or use an electronic leak detector. For R600a, the leak detector must be sensitive to hydrocarbons.
Completion of work and disposal
After successful pumping out of freon and carrying out repair work (compressor replacement, soldering), the system is vacuumed again. Only after reaching a deep vacuum is charging with new refrigerant carried out. Scales play a key role here - you need to refill strictly according to the grams indicated on the refrigerator nameplate.
Collected freon cannot simply be released into the atmosphere. Hand over waste gas cylinders to specialized collection points or dispose of them through companies licensed to work with ozone-depleting substances. This is an issue not only of ecology, but also of legislation.
Remember that proper pumping and preparation of the system is 90% of the success of the repair. Haste and neglect of technology at this stage inevitably lead to repeated breakdowns. If you are not confident in your abilities or you do not have the necessary equipment, it is better to entrust this work to professionals.
Is it possible to use a car pump for pumping?
A car compressor is designed to build up pressure, and not to create a vacuum. Although some models can "pull" a little in the opposite direction, they are not able to create the necessary deep vacuum for refrigeration equipment. The use of such equipment is pointless.
Is it possible to simply release freon into the room?
It is strictly not recommended. In addition to harm to the environment, a high concentration of freon in a closed room can cause suffocation, as the gas displaces oxygen. In the case of R600a, this creates a direct threat of explosion.
How long does it take to vacuum the refrigerator?
The minimum operating time of the vacuum pump should be 30 minutes. For systems with R600a or after a long period of inactivity of an open system, it is better to increase the time to 45-60 minutes to ensure the removal of moisture.
Is it necessary to heat the compressor during pumping?
Warming up the compressor (up to 50-60 degrees) during the evacuation process helps evaporate the moisture dissolved in the oil. This is a useful procedure, but it requires temperature control so as not to damage the varnish insulation of the windings.
What to do if the pressure gauge does not show vacuum?
Check the connections for leaks, make sure that there is oil in the pump (if it is oil-based) and that it is not dirty. Also check the integrity of the hoses of the pressure gauge station.