Vacuum pumps are part of one of the final procedures in the Ac Vacuum Pump china repair procedure. After you’ve diagnosed and repaired any leaks or additional issues in the machine it is time to recharge. Before recharging you need to make sure the system is free from any undesirable gasses, air, or drinking water. If they were to stay in the system, it would turn the essential oil it operates on into sludge and leave behind damaging impurities.
The draw on a vacuum pump is usually divided into its “CFM,” or Cubic Feet each and every minute. To estimate what your CFM requirements, look at the tonnage of the systems you focus on. Take the square root of that number and you’ll get the approximate CFM you must have to work with that system. Typical home systems need 4-5 CFM, while industrial and rooftop systems 
generally need just as much as 6-8 CFM.