If the Basic Tightness Test is not available in the chromatography data system for your Vanquish system configuration, test the pump manually. Manual testing requires user interaction.

TIP

With the dual pump, test each pump separately.

Parts and additional items required

  • Fitting plug, Viper

  • Solvent suitable for your application

Follow these steps

  1. Disconnect the capillary on the pump outlet.

  2. Close the pump outlet with the fitting plug.

  3. In the chromatography data system, set the upper pressure limit to the appropriate value:

Pump

Upper Pressure Limit

VC‑pump

60 MPa

VF‑pump

80 MPa

  1. Apply a flow of 50 µL/min and use the solvent for the application.

  2. Observe the pressure. When the pressure reading is as indicated in the table, change the flow rate to a lower value.

Pump

Pressure

VC‑pump

Between 30 MPa and 40 MPa

VF‑pump

Between 60 MPa and 70 MPa

  1. Have the pump deliver until the following pressure has built up:

Pump

Pressure

VC‑pump

55 MPa

VF‑pump

75 MPa

  1. When the pressure has built up, apply the following flow:

Pump

Flow

Standard pump

VC‑P10, VC‑P20, VC‑P32, VC‑P40

1 µL/min

VC‑P21, VC‑P33

4 µL/min

VF‑pump

1 µL/min

Pump modified for NP applications

VC-P20, VC-P21,
VC-P32, VC-P32, VC‑P40

4 µL/min

VC-P10

6 µL/min

  1. Observe the pressure.

    The pressure should increase or remain constant for a minimum of 1 minute. A drop in pressure indicates possible leakage.

  2. 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.

  1. 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.

  5. Monitor if the pressure drops at the same rate as before. If the pressure drops significantly slower, the connection was leaky.

  6. When testing the pump for leakage is complete, reset the upper pressure limit to the value used before the leakage test.