Waters Autospec Premier Operator's Manual page 194

The source lock pump valve is open when its handle is in line with
Tip:
the associated pipework.
7. Wait a few seconds to allow the interlock to roughly pump-down
(evacuate).
8. On the MassLynx Vacuum Monitor window, ensure that the Source
display is < 1.00e-2.
9. Hold the source handle in the retracted position and open the source
isolation valve (on the left-hand side of the source).
The source isolation valve is open when its handle is in the
Tip:
horizontal position.
10. Close the source lock pump valve.
11. Rotate the source handle so that its slot is correctly oriented with the
security lock thumbscrew.
7-36 Routine maintenance