Yes, it is important to pull a vacuum on the recovery tank. This helps to ensure all of the moisture and other contaminants are removed from the system prior to recharging with fresh refrigerant. Pulling a vacuum can also help identify any leaks in the system before adding new refrigerant. Here are some tips for pulling a successful vacuum:
-Evacuate until pressure is below 500 microns or lower
-Monitor temperature and pressure readings during evacuation process
-Use appropriate size hoses and connections when working with recovery tanks
-Check valve operation during evacuation process