Chromatographic Troubleshooting
Electronic pressure control
Safety shutdown
Systems equipped with electronic pressure programming have a safety shutdown feature to prevent gas leaks from creating a safety hazard. If the system cannot reach a pressure setpoint it beeps. After about 45 seconds the beep will stop and the message:
ACTUAL SETPOINT
EPPB: SAFETY SHUTDOWN
will appear on the display, and the system will shut down by turning off all electronic pressure and heated zones, and locking the keyboard.
A safety shutdown can occur when:
1.There is a leak in the system (see Pressure control problems). This includes missing septa or columns!
2.The column is not restrictive enough to reach desired pressure (i.e., 530 ¿ columns will not go to 100 psi with available flow). Note: When using pressure programming, this may occur during a pressure ramp to too high a pressure.
3.There is insufficient supply pressure.
4.Configuration is set wrong. Check the mode switch on the inlet controller board (see Proper configuration).
To recover from a safety shutdown, turn the GC power off, then on. Then reset temperature and pressure zones to desired values. (After safety shutdown, pressure setpoint is automatically reset to zero.)
219