Remove the service valve covers from both of the refrigerant lines with an adjustable wrench. The refrigerant service valves, found between the condensing unit and the copper line set, provide a means to access the system's refrigerant.
Connect a refrigerant manifold gauge set to the service valves. The hose on the left side of the manifold connects to the service valve on the large copper tube. The hose on the right side of the manifold connects to the service valve on the little copper tube.
Connect the middle hose of the manifold gauge set to a drier filter. The arrow on the filter must face the recovery unit. A drier filter prevents contaminates from entering the recovery machine.
Connect the yellow hose from a refrigerant recovery unit to the drier filter. The yellow hose should connect to the intake port on the recovery machine.
Connect the red hose from the recovery unit to a refrigerant recovery tank. The red hose should connect to the liquid discharge port.
Open the recovery tank's valve. Turn the handle counter-clockwise.
Close the intake port valve on the recovery machine. Labels will point to the "Open" and "Close" positions.
Open the discharge port valve on the recovery machine. Labels will point to the "Open" and "Close" positions.
Turn the recovery machine function switch to "Recovery." This switch has two settings, "Recovery" and "Purge."
Open the valve on the right (liquid) side of the refrigerant manifold. Discharging liquid refrigerant first speeds the recovery process.
Plug the recovery machine into a 110 volt electrical outlet. Turn the machine on.
Open the recovery machine's intake port valve to the half open position. Check the refrigerant pressure gauge on the recovery machine. If the pressure goes above the acceptable range, as marked on the gauge, close the intake port valve until the meter reaches a safe level. As the liquid level in the HVAC system depletes, the pressure reading on the gauge will start to drop. Open the intake port valve to full open.
Open the left (vapor) valve on the refrigerant manifold.
Run the recovery machine until the manifold gauge set reads a vacuum on the vapor gauge. Turn the recovery machine off. Close the intake port valve and the manifold valves.
Wait five minutes. Check the manifold gauges. If the pressures have risen above zero then restart the recovery machine.
Turn the recovery unit's function switch to "Purge." Purge the recovery unit according to the manufacturer's instructions.
Close the recovery tank's valve tightly. Disconnect all hoses and install the service port caps.