Troubleshooting Tasks 8
Agilent 7890 Series Troubleshooting 189
To Run the Inlet Trap Check
From the GC keypad:
1 Press [Service Mode], scroll to Front inlet trap check or Back inlet
trap check, then press [Enter]. The display will be similar to
Figure 5:
Figure 5 Example front inlet trap check display. Example assumes a
test has been previously run. Scroll to see all lines of the
display.
2 Scroll to Te st flow r at e and enter a flow rate. A typical flow
rate for this test is 400 mL/min for helium and hydrogen
carrier gas, or 150 ml/min for nitrogen carrier gas, but you
may find other values more appropriate for your setup.
3 Scroll to Test Inlet and press [On/Yes] to start the test.
4 Wait while the pressure stabilizes. When stable, the Test Inlet
line of the display changes to Test pressure OK x.xx, where
x.xx is the current pressure.
If the inlet cannot achieve the test setpoint, check for a leak
(at the inlet, split vent trap, or split vent line) or low supply
gas pressure.
5 Note the resulting Inlet Pressure. If the measured pressure
exceeds any limits you have set up, the GC will respond
accordingly. See “To Check or Monitor Split Vent Line
Backpressure”.
Typical pressures for a clean split flow path are:
• 1–2 psi (7–14 kPa) at 400 mL/min for a split liner
• 3–10 psi (21–69 kPa) at 400 mL/min for a splitless liner
FRONT INLET TRAP CHECK
Inlet Pressure 5.471 psi<
Test Inlet (ON to Start)
Test flow rate 400mL/min
Warning if pressure check OFF
Fault if pressure check OFF
Last test results
Tue Oct 20 16:07 2009
Test pressure OK: 4.8
Reset the test results? (yes)
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