A vacuum pump is used to remove air and contaminants from an HVAC system after refrigerant recovery. This creates a vacuum state. The deeper and more complete the vacuum, the more contaminants trapped within the system, its components, and even the compressor oil are removed. A vacuum pump can also tell you that your system has a leak if normal vacuum pressures are not being achieved. A vacuum can help protect your system from contaminants and non-condensable gases which can damage HVAC system components, reduce system efficiency, and even cause failure. Be sure to recover any and all refrigerant before pulling a vacuum.