Operating the GBC 902
Atomic Absorption Spectrometer

Part 4: Shutting Down the Instrument

When you are through running all of your samples make sure to aspirate plenty of distilled water through the nebulizer to remove all traces of your samples from the instrument before shutting it down.
To turn the flame off, just turn off the FUEL by turning the FUEL valve clockwise until it seats. The flame will go out quietly. You can then turn off the Air using the oxidizer master control as shown.
Turn off the acetylene at the main tank valve. Even though the acetylene is now off, some gas still remains in the regulator and the lines. We will now purge that gas from the system.
Turn the oxidizer control back to AIR. Then turn up the FUEL control to allow the acetylene to bleed from the lines. The hood must remain on during these procedures.
Watch the tank gauge and the output regulator gauge until they both read zero. The lines are now purged.
Turn the regulator valve counter-clockwise (screwing it OUT) until you feel it become loose. It is now in the zero pressure position.
Turn the master oxidizer control from AIR to OFF. Turn the FUEL control clockwise until it gently seats. The gases are now all off.
Finally, turn off power to the instrument. If you have correctly followed all of these shutdown procedures, you will not have left any nasty surprises for the next person to use the instrument. Please turn off the hood (unless someone else is using it) and clean up the area before you leave.