Vacuum pumps are component of among the final processes in the repair process. After you’ve diagnosed and repaired any leaks or various other issues in the machine it’s time to recharge. Before recharging you need to make sure the system is free of any unwanted gasses, air, or water. If these were to remain in the system, it could turn the oil it runs on into sludge and leave behind damaging 
impurities.
The draw on a vacuum pump is usually broken down into its “CFM,” or Cubic Feet per Minute. To estimate what your CFM requirements, look at the tonnage of the systems you focus on. Take the sq . root of that quantity and you’ll get the approximate CFM you must have to work with that system. Typical Ac Vacuum Pump china residential systems need 4-5 CFM, while commercial and rooftop systems generally require as much as 6-8 CFM.