The high-precision constant temperature and humidity air conditioning compressor is a precision component, and the requirements for the cleanliness of the system and lubricating oil are very high. When the compressor fails, such as the insulation breakdown of the compressor coil, the short circuit between turns or the burning of the winding, a large amount of acidic oxides will be generated during the burning process, which will pollute the system. Therefore, in addition to replacing the compressor and the dry filter, the entire refrigeration system must be thoroughly treated. Specifically, the lubricating oil and the cleanliness of the system should be checked and treated. In addition, if the compressor fails due to impurities blocking the system, the system should also be cleaned or blown before replacing the compressor.
    Before replacing the high-precision constant temperature and humidity air conditioning compressor, it is necessary to check whether the lubricating oil has deteriorated. The degree of deterioration of the lubricating oil can be divided into mild and severe. When it is mild, the refrigeration system is not completely polluted, and the color of the oil is transparent. If the litmus paper test is light yellow (normal is white), the compressor can be replaced directly without treatment because the system is lightly polluted. If the lubricating oil is seriously polluted, you can smell the tar smell and the color is black. Use litmus paper to immerse in the oil. After 5 minutes, the color of the paper turns reddish brown. At this time, the lubricating oil has seriously deteriorated. The following treatment must be performed before replacing the new compressor:
1. Remove the dirt in the relevant parts
    . The schematic diagram of the outdoor unit system of the high-precision constant temperature and humidity air conditioner is shown in the figure. Weld the gas-liquid separator (① and ② welding points in the figure), the throttling components such as the capillary (⑤ and ⑧ welding points in the figure) and the compressor suction and exhaust ports (⑦ and ⑨ welding points in the figure), and blow high-pressure nitrogen from 7 points and 2 points respectively until there is no dirt at the outlet.
    Use high-pressure nitrogen to blow from both ends of the capillary until there is no dirt at the outlet. If it cannot be blown clean, it is recommended to replace it with a capillary of the same specification. In addition, the dry filter needs to be replaced, and the ordinary filter can be cleaned with F113 cleaning fluid.
2. If the lubricating oil in the gas-liquid separator
    cannot be poured out completely, you can drill a small hole in the gas-liquid separation part to release the lubricating oil, wash it with F113, blow it clean with high-pressure nitrogen, and finally weld it. If there are gas-liquid separator accessories, it is recommended to replace them with new ones after the above treatment, and then replace them with a new compressor. All parts can be evacuated and fluorinated.
    If the lubricating oil has not deteriorated or is slightly contaminated, and there are no impurities or dirt in it, you can evacuate and add fluorine after replacing the new compressor.