HP 5973 - To Vent the MSD Without the Chemstation

64
2 Operating the MSD
To vent the MSD without the ChemStation
To vent the MSD without the ChemStation
If the MSD ChemStation is functioning, use the procedure on page 52. This proce-
dure should only be used if it is absolutely necessary.
1 If your system is equipped with a gauge controller, switch off the triode
gauge tube and gauge controller.
2 From the GC keypad, turn off the GC zone controlling the GC/MSD
interface heater and set the GC oven to 30°C (see page 49).
3 Disconnect the
HIVAC POWER cable from the back panel.
This turns off the MS heaters and the diffusion pump heater or turbo pump, but
the cooling fans and foreline pump stay on.
4 After 45 minutes, turn off the MSD power switch.
5 Unplug the MSD power cord.
6 Reconnect the
HIVAC POWER cable.
7 Remove the upper MSD cover (page 50).
8 Turn the vent valve knob counterclockwise to admit air into the vacuum
manifold.
Do not remove the knob. Be sure to retighten the knob before pumping down.
See Also To open the vacuum manifold, page 54
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Be sure the GC oven and the GC/MSD interface are cool before turning off carrier gas flow.