Thermo Scientific thermoscientific Vanquish Pumps C, Operating Manual

Page: 180 / 296

7 • Maintenance and Service
Page 180 Pumps C, Pumps F ( VC-Pxx, VF-Pxx)
Operating Manual
Pump Flow
VC‑P21, VC‑P33 4 µL/min
VF‑pump 1 µL/min
8. Observe the pressure.
The pressure should increase or remain constant for a minimum of
1 minute. A drop in pressure indicates possible leakage.
9. Find and eliminate the cause for the leak.
Take remedial action only when the system pressure is down to
zero.
Possible Source Remedial Action
Capillary connections Inspect the capillary connections for signs of
leakage. Tighten or replace leaky connections
when the system pressure is down to zero.
Piston seals • Test the piston seals for leakage. Replace
leaky piston seals.
• If leakage is observed with new piston seals,
run in the seals. Using the solvent of your
application or water, operate the pump for
2 hours or longer at 35 MPa.
Check valves • If leakage is observed on the connection
port, turn off the pump flow. When the
system pressure is down to zero, tighten
the check valve a little more.
• Remove the valve cartridge. Clean the
cartridge in an ultrasonic bath. If cleaning is
not sufficient, replace the cartridge.
Purge valve knob Inspect the purge valve knob and purge
outlet for indications of leakage.
10. After taking a remedial action, test the pump.
Testing the Pump
1. Pressure up the pump.
This is the best way to identify whether a connection is leaky.
2. Allow 5 minutes for the pressure to stabilize.
This is important. The pressure drops faster during the first 5
minutes until the seals and other components have adjusted to the
pressure.
3. After the stabilization time, monitor the pressure drop.
4. Tighten the connection that you want to test a little more. The
pressure will suddenly increase a little.