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13 Maintaining the NPD
To Replace the NPD Bead Assembly
Maintaining Your GC
219
17
Close the NPD cover, install the GC detector top cover, and install the electronics top cover.
All covers must be closed to get a stable NPD baseline.
18
Exit maintenance mode. Select
Maintenance > Instrument > Perform Maintenance >
Maintenance Mode > Finished.
19
Restore normal NPD operating gas flows.
20
With all gases on, heat the detector to 150 °C and hold for about 15 minutes, then increase
the temperature to 250 °C and hold for 15 minutes.
21
Increase the temperature to operating value (310 to 320 °C recommended). Allow
15 minutes for equilibration.
22
Check the NPD leakage current. See
“To Check the NPD Leakage Current”
> 2.0 pA, verify bead installation or see the
Troubleshooting
manual.
23
If using an Agilent data system, connect to the instrument.
24
Restore the analytical method. Confirm the detector hydrogen, air, makeup gas flow rates.
25
Start the
Adjust offset
process. Enter the desired offset in the
Target offset
field. The
default offset is 20 pA for Blos beads. An offset of 25 to 30 pA is sufficient for most
applications. The bead life may be shortened at a higher offset.
26
Reset the bead counter.
1
2
Summary of Contents for 8890
Page 1: ...Agilent 8890 Gas Chromatograph Maintaining Your Gas Chromatograph GC ...
Page 8: ...8 Maintaining Your GC ...
Page 22: ...2 Removing Covers To Remove the Electronics Cover 22 Maintaining Your GC ...
Page 142: ...8 Maintaining the MMI To Bakeout Contaminants from the MMI 142 Maintaining Your GC ...
Page 178: ...10 Maintaining the VI To Bakeout Contaminants from the VI Inlet 178 Maintaining Your GC ...
Page 208: ...12 Maintaining the TCD To Bakeout Contaminants from the TCD 208 Maintaining Your GC ...
Page 240: ...14 Maintaining the ECD To Bakeout the ECD 240 Maintaining Your GC ...
Page 264: ...16 Maintaining EPC Modules Installing or Replacing Frits in the PCM 264 Maintaining Your GC ...
Page 276: ...17 Maintaining a Valve To Install the Upper Valve Box 276 Maintaining Your GC ...