Vacuum pumps are Ac Vacuum Pump china component of among the final procedures in the repair process. After you’ve diagnosed and repaired any leaks or other issues in the machine it's time to recharge. Before recharging you need to make sure the system is free from any undesired gasses, air, or drinking water. If they were to remain in the system, it would turn the oil it runs on into sludge and leave behind damaging impurities.
The draw on a vacuum pump is usually divided into its “CFM,” or Cubic Feet per Minute. To estimate what your CFM needs, look at the tonnage of the systems you work on. Take the square root of that number and you’ll obtain the approximate 
CFM you need to have to utilize that system. Typical home systems need 4-5 CFM, while commercial and rooftop systems generally need just as much as 6-8 CFM.