Vacuum pumps are component of one of the final processes in the repair procedure. After you’ve diagnosed and repaired any leaks or additional issues in the system it is time to recharge. Before recharging you wish to make sure the system is free from any undesired gasses, air, or drinking water. If these 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 broken down into its “CFM,” or Cubic Feet per Minute. To estimate what your CFM requirements, consider the tonnage of the systems you work on. Take 
the sq . root of that Ac Vacuum Pump number and you’ll obtain the approximate CFM you need to have to work with that system. Typical home systems need 4-5 CFM, while commercial and rooftop systems generally need as much as 6-8 CFM.