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Part 4. Flow and pressure problems Flow and Pressure Control
A gas exceeds the setpoint pressure or flow
A gas exceeds the setpoint pressure or flow
• The pressure sensor for that device is not operating properly. Contact your
Agilent service representative.
If you are using a split/splitless inlet, PTV inlet, or volatiles interface:
• The split ratio is too high. Decrease the split ratio.
• The proportional control valve is stuck closed. Contact your
Agilent service representative.
• The trap on the split vent line is contaminated. Contact your
Agilent service representative.
If you are using a purged packed or cool on-column inlet:
• The inlet proportional control valve is stuck open. Contact your
Agilent service representative.
The inlet pressure or flow fluctuates
A fluctuation in inlet pressure will cause variations in the flow rate and retention
times during a run.
• A small leak is present in the flow system. Use an electronic leak detector
to find leaks; correct them. You should also check for leaks in the gas supply
plumbing.
• Large restrictions, such as a blockage in a liner or the split vent trap, are
present in the split/splitless or PTV inlets. Make sure that you are using the
correct liner. Replace liners with large pressure drops caused by design or
tight packaging. If the liner does not appear to be causing the problem, the
split vent trap may be blocked. Contact your Agilent service representative.
• Extreme changes in room temperature during runs. Correct laboratory
temperature problem or move the instrument to a more suitable location.
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