Problems to be considered when replacing R22 refrigerant with R404a refrigerant

In our display life, no matter what product is used to replace another product, there are many problems in it, and the refrigerant is no exception. Today, FRIOFLOR will introduce the problems that need to be considered when replacing R22 refrigerant with R404a refrigerant, and friends who want to know more about it, please follow the introduction of FRIOFLOR to see the related articles below.

 1. The big problem of using R404a refrigerant to replace R22 is the lubricating oil problem. 

It is necessary to use PVE ester oil instead of mineral lubricating oil for R22. Ester lubricating oil has high affinity with water and poor dehydration, so try to avoid contact with the outside air during use. After opening the container, it should be used as soon as possible, and it must be sealed and stored after use; Store in a well-ventilated place; avoid contact with skin and eyes during use, and avoid inhalation of its vapors and sprays.

 2. The exhaust pressure of R404a refrigerant is about 1.2 times that of R22, and the mass flow is about 1.5 times that of R22. 

The exhaust flow rate increases and the resistance becomes larger. Generally speaking, the heat exchange capacity of the condenser is 20% to 30% larger than that of R22.

 3. At the same temperature, the saturation pressure of R404a refrigerant and R22 is different, so the action mechanism of R404a refrigerant thermal expansion valve is different from that of R22. At the same time, due to the different compatibility of R404a refrigerant and lubricating oil with sealing materials, the sealing material of expansion valve should be changed accordingly. Therefore, R404A special expansion valve should be selected in the selection of thermal expansion valve.

 4. For the same compressor, the current of R404a refrigerant is larger than that of R22, so the diameter of the AC contactor, thermal relay and cable of the compressor should be adjusted. In terms of system protection, the setting value of the high pressure pressure switch is adjusted from the original 2.45MPa to 2.7MPa.

 5. Since the saturation pressure of R404a refrigerant is different from that of R22, the air tightness test pressure is higher than that of R22. At the same time, the vacuum degree of the system should be higher than R22, and the water content should be lower than R22. When charging the refrigerant, it should be charged in liquid form to prevent the configuration of R404A from changing.

 6. R404a refrigerant is a non-azeotropic mixed working medium, and the composition concentration of the non-azeotropic mixture varies with temperature and pressure, which brings certain difficulties to the production, debugging and maintenance of the refrigeration system, and also affects the thermal conductivity of the system. It will have a certain impact, especially when the refrigerant leaks, the system refrigerant needs to be completely emptied and replaced, so as to ensure the proportion of each mixed component and achieve the designed cooling effect, otherwise it will get worse.

 Since R404A refrigerant and lubricating oil have good compatibility with water, the system's requirements for moisture, residues, cleanliness, etc. are improved compared with R22 refrigerant. R404A system moisture control and impurity control are one of the For more important indicators, the corresponding filtering devices in the system should be changed.