Agilent Technologies 8860 Maintaining page 195

12 Maintaining the NPD
To Replace the NPD Bead Assembly
16 Close the NPD cover, install the GC detector top cover, and install the electronics top cover.
17 Exit maintenance mode. Select Maintenance > Instrument > Perform Maintenance >
18 Restore normal NPD operating gas flows.
19 With all gases on, heat the detector to 150 °C and hold for about 15 minutes, then increase
20 Increase the temperature to operating value (310 to 320 °C recommended). Allow
21 Check the NPD leakage current. See
22 If using an Agilent data system, connect to the instrument.
23 Restore the analytical method. Confirm the detector hydrogen, air, makeup gas flow rates.
24 Start the Adjust offset process. Enter the desired offset in the Target offset field.An offset
25 Reset the bead counter.
Maintaining Your GC
All covers must be closed to get a stable NPD baseline.
Maintenance Mode > Finished.
the temperature to 250 °C and hold for 15 minutes.
15 minutes for equilibration.
> 2.0 pA, verify bead installation or see the Troubleshooting manual.
of 25 to 30 pA is sufficient for most applications. The bead life may be shortened at a
higher offset.
2
1
"To Check the NPD Leakage Current" on page 201. If
195