Troubleshooting
6850
6850
Released: April 2004 6850 Series Gas Chromatograph Service Procedures 285
Case 3: Chromatographic performance
problems suggest a possible leak
This section contains procedures for two differ-
ent inlet system leak tests.
Noninvasive leak check
The first leak test is performed without removing
the customer's column, septum or liner. It is
called the non-invasive leak check. This test does
not prove that the inlet is absolutely leak free,
but is a good first pass or remote diagnostic to
see if complete inlet pressure testing is needed.
1. Confirm that the installed column is config-
ured correctly to the capillary inlet.
2. Put the inlet into splitless mode.
3. Set the purge flow to 50 mL/min; purge time
to 1.0 minute.
4. Set the column flow to 2 mL/min. The
system will try to establish the pneumatic
conditions shown in the following diagram.
The inlet pressure will be a function of the
column dimensions and oven temp. This
example shows 20 psi.
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