Routine Maintenance: Inlets
Maintaining a PTV
Released: March 2004 6850 Series II GC User Information page 163 of 256
9. Configure the inlet for the test using a control module or data system.
a. Set the inlet to “Split Mode.”
b. Configure the column as 0 length.
c. Set the inlet’s Total Flow to 60 mL/min.
d. Set the pressure to 25 psi.
e. Set the inlet temperature to its normal operating temperature.
10. Wait approximately 15 seconds for equilibration.
If pressure cannot be achieved, either a very large leak is present in the
system, or the supply pressure is not high enough.
11. Turn the inlet pressure “Off” using your control module or data system.
Both the flow controller and the back pressure valves will close.
12. Note the “Actual” reading on the control module or data system and
monitor the pressure for 10 minutes.
• If there is less than 0.5 psi pressure loss, the system is leak tight.
• If pressure loss is much greater than 0.5 psi, there is a leak that must
be found and corrected. Note, however, that you may want to slightly
decrease the leak test time based on the internal inlet volume which
changes with the liner type used (smaller volumes = shorter
acceptable leak test times). See “Correcting leaks” on page 163.
13. When the system is considered leak tight, the caps may be removed, the
column reinstalled, its dimensions configured at keyboard, and the desired
pressure and flow rate set.
Correcting leaks
Materials needed:
• Electronic leak detector suitable for the gas type
• Tools to tighten parts of the inlet that leak (if leaks are detected)
1. Use an electronic leak detector to check all areas of the inlet that are
potential sources of a leak.
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