Troubleshooting - LC Packings SWITCHOS II User Manual

6.4
Troubleshooting refers to the determination of the cause of a problem. Since the
Switchos Advanced Microcolumn Switching Unit is incorporated into an HPLC
system, the first step to determine if the problem is due to this instrument is to
remove the unit from the system, then perform an injection and compare the
results from the two runs. If the results are fine, the problem is due to the
switching unit.
In addition, the typical system parameters (e.g. flow rates and pressure) of a pre-
concentration setup with trap column and separation column are presented in
TABLE 6-3
TABLE 6-1 Troubleshooting the Loading Pump
Problem
Flow delivery stops after 1
minute during purging, error
message "Minimum pressure
..." is displayed
Flow delivery stops during
purging, error message
„Maximum pressure
exceeded nn MPa" is
displayed
No solvent delivery, pump
motor is running
Leaking pump head
Flow fluctuation
Flow rate too high or too
low (deviation >10%)
User's Manual Switchos II

Troubleshooting

Probable Cause
System pressure dropped
below the minimum pressure
(Pmin) set in SETUP menu
PRESSURE LIMITS
System pressure exceeded
the maximum pressure
(Pmax) set in SETUP menu
PRESSURE LIMITS or in
monitor screen
Note: The pressure during
purging is limited to 0.5 MPa.
Air in solvent/pump head
Clogged solvent inlet filter
Leakage in the pump head
Loose inlet/ outlet fitting
Loose check valve(s)
Defective piston seals
Flow restriction in the solvent
inlet fluid path
Air in solvent inlet fluid path
Defective valves
Air in solvent inlet fluid path
Pump out of calibration
D850R3
Maintenance and Troubleshooting
Solution
Set "min" value to 0 MPa
to disable checking
Open the purge valve knob
Purge pump and check
degassing
Replace solvent inlet filter
Check for any leakage
Tighten the fittings
Tighten the check valves
Replace seals
Check tubing, filters,
proportioning valves, etc.
Purge pump, check
degassing
Clean/replace check valves
Purge pump, check
degassing
Contact LC Packings
6-11