Vacuum pumps are component of one of the final processes 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 of any undesired gasses, air, or drinking water. If these were to remain in the machine, it would turn the oil it runs on into sludge and leave behind damaging impurities.
The draw on vacuum pressure pump is usually broken down into its “CFM,” or Cubic Feet per Minute. To estimate what your CFM needs, look at the tonnage of the systems you focus on. Take the sq . root of that amount and you’ll get 
the approximate CFM you must have to utilize that system. Typical home systems need 4-5 CFM, while Ac Vacuum Pump commercial and rooftop systems generally need just as much as 6-8 CFM.
