Electronic Pressure Control - HP 5890 Series II Plus Reference Manual

Chromatographic Troubleshooting

Electronic pressure control

Electronic pressure control
The electronic pressure control option provides very accurate and precise
control of column head pressure, resulting in retention time
reproducibility of better than 0.02% RSD when there are no column
effects. The inlet pressure can be set constant, programmed, or set to
maintain a desired column flow rate. This mass flow control can be
maintained even at vacuum column outlet pressures. A safety shutdown
feature stops the run and can trigger an alarm if the column breaks or
pressure otherwise falls. In addition, a bypass flow maintains a small
positive column pressure in the event of power failure, protecting the
analytical column.
Electronic Pressure Control Problems
Symptom
Not enough pressure
(Safety shutdown activated)
Pressure goes to O or max.
Not Ready light flickers
(oscillating pressure)
Pressure not controllable
If you have checked these possible causes and still have a problem, call
HP Service.
218
Possible Cause
1. Septum leaks or is missing
2. Column is broken
3. Column ferrule seal leaks
4. Gas supply is off
5. Supply pressure is inadequate
6. Desired pressure may not be achieveable with
the column in use.
1. Configuration is wrong. See the section Proper
configuration.
1. Septum and/or column connection leaks.
2. Pressure set higher than the operating limit
1. Configuration is wrong. See the section Proper
configuration.