How does Jigao Air Conditioning perform vacuum testing on centrifugal chillers? Article Source: Beijing Jigao Air Conditioning Repair http://blog.tianya.cn/blogger/blog_main.asp?BlogID=3774707. After the chiller is installed or has not been used for a long time, before using it again, the sealing performance of the chiller needs to be checked. This check can be carried out according to the method of vacuum reduction rate.
Vacuum Reduction Rate = Increase in vacuum value / Inspection start and end time
The vacuum inside the machine should be drawn down to 93325Pa (700mmHg). Within the inspection period, if the vacuum reduction rate is 166Pa per day (1.25mmHg) or less (for 24 hours), the sealing performance of the chiller can be considered good. If the vacuum reduction rate exceeds 166Pa per day (1.25mmHg), the sealing performance of the chiller is poor, and a small amount of refrigerant needs to be injected into the machine for a pressure test to find leaks and carry out repairs. Then repeat the above work until it is qualified. When checking the sealing performance, it is essential to use a U-tube vacuum gauge or a rotary vacuum gauge, as this will ensure that the calculated values are accurate.