Diagnostic Tests
54
4
Procedure
1.
Disconnect the outlet tube of the system at the reference (or vent) valve and install a
compression plug in its place.
2.
Purge the pumps with 100% methanol. If your eluent is not miscible with methanol,
use an intermediate eluent.
3.
Disconnect pump B from the tee by removing the outlet tube of the pulse dampener
and install a compression plug in its place.
4.
Disconnect the left pump head outlet tube of Pump A from the draw-off valve and
install a compression plug in its place.
5.
Place tissues under the disconnected pump head outlet tube and the disconnected
pulse dampener tube to catch drips.
6.
Ensure that the draw-off valves are closed and the reference valve is closed to
waste.
7.
Set the following pump parameter values:
•
Flow parameter:
1525µ Pump:
0.2
mL/min
1525EF Pump:
0.5
mL/min
•
High-pressure limit:
1525µ Pump:
5000
psi (41,370 kPa, 401 bar)
1525EF Pump:
5000
psi (34,475 kPa, 334 bar)
8.
With the 100% methanol reservoir still connected to the pump inlet, click
Load
Method
in the Inlet Method window to start the pump. Observe pump pressure in
the MassLynx Main window or
in the Status window of the Inlet Method window:
•
If the check valves are operating properly, pressure continually rises with each
plunger stroke on the connected head, holding as the plunger recedes.
•
If there is a bad inlet check valve, pressure may stop at a certain point, or may not
rise at all.
•
If there is a bad outlet check valve, pressure may increase, then immediately
decrease as the plunger recedes.
•
If the pressure does not rise to the high-pressure limit, try repriming the pump or
increasing the Flow parameter setting.
9.
Allow the pump to reach the high-pressure limit. The pump will stop flow
automatically.
STOP
Attention:
Before starting this procedure, move the eluent reservoir below
the pump head levels. This eliminates gravity flow of the eluent.
