LC Packings SWITCHOS II, User Manual

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Maintenance and Troubleshooting
User’s Manual Switchos II
D850R3
6-11
6.4 Troubleshooting
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 Probable Cause Solution
Flow delivery stops after 1
minute during purging, error
message ”M inimum pressure
... “ is displayed
System pressure dropped
below the minimum pressure
(Pmin) set in SETUP menu
PRESSURE LIMITS
Set “min” value to 0 MPa
to disable checking
System pressure exceeded
the maximum pressure
(Pmax) set in SETUP menu
PRESSURE LIMITS
or in
monitor screen
Open the purge valve knob
Flow delivery stops during
purging, error message
„M aximum pressure
exceeded nn MPa “ is
displayed
Note: The pressure during
purging is limited to 0.5 MPa.
Air in solvent/pump head
Purge pump and check
degassing
Clogged solvent inlet filter Replace solvent inlet filter
No solvent delivery, pump
motor is running
Leakage in the pump head Check for any leakage
Loose inlet/ outlet fitting Tighten the fittings
Loose check valve(s) Tighten the check valves
Leaking pump head
Defective piston seals Replace seals
Flow restriction in the solvent
inlet fluid path Check tubing, filters,
proportioning valves, etc.
Air in solvent inlet fluid path
Purge pump, check
degassing
Flow fluctuation
Defective valves Clean/replace check valves
Air in solvent inlet fluid path Purge pump, check
degassing
Flow rate too high or too
low (deviation >10%)
Pump out of calibration Contact LC Packings