112 Troubleshooting
System pressure troubleshooting is presented in a flow diagram format. Use Figure 6-1,
Figure 6-2, and Figure 6-3 to investigate pressure-problem sources.
6.2.1 System Pressure Overview
This section provides background information for troubleshooting system pressure
problems. It discusses:
• Determining your system pressure reference point
• Noting gradual versus sudden pressure increase
• Isolating high pressure locations in the 600E system
Determining Your System Pressure Reference Point
To identify a pressure change from normal operation, it is critical that you have a pressure
reference point. System pressure is affected by the column, flow rate, mobile phase, and
temperature, and can vary greatly with different methods. When running a gradient,
fluctuations in system pressure may be due to viscosity differences among eluents.
Each time you install a new column or start a new method, equilibrate the system and
record the system pressure (both with and without the column in-line) to use as a
reference.
Noting Gradual Versus Sudden Pressure Increase
When high system pressure occurs, it is important to note whether the pressure increase
was gradual or sudden. This can help you isolate the problem source.
If the pressure has risen gradually (over a series of injections), it may be due to:
• Particulates in the sample or mobile phase that have accumulated in the column frits
• Debris from failed fluid seals
If the pressure has risen suddenly, it may be due to:
• Particulates in one sample
• A system hardware problem (such as blocked tubing)
• Collapse of the column packed bed
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