78 5975/5977 Series MSD Operation Manual
3 Operating in Electron Ionization (EI) Mode
2 When prompted, turn the vent valve knob counterclockwise only 3/4 turns
or until you hear the hissing sound of air flowing into the analyzer
chamber.
WARNING
If you are using hydrogen as a carrier gas, the carrier gas flow must be off before
turning off the MSD power. If the foreline pump is off, hydrogen will accumulate in
the MSD and an explosion may occur. Read “Hydrogen Safety”on page 18 before
operating the MSD with hydrogen carrier gas.
CAUTION
Be sure the GC oven and the GC/MSD interface are cool before turning off carrier gas
flow to prevent damage to the column.