Diagnostics (UltiMate 3000 Series)
Detailed Leak Test (NCP-3200RS/NCS-3500RS – NC Pump)

The following information applies to NC pumps equipped with either a Classic or a ProFlow flowmeter.

Run this test to check the valves, seals and capillary connections of the NC pump for leakage and to identify the source of the leak. When this test is run, a Viper fitting plug is installed on the pump outlet. The pump then measures the leak rate at two different pressures. During this measurement, the working and the equilibration pistons are moved in turns. The pump passes the test when the leak rate is in the correct range.

 Note: 

This test changes the defined upper and lower pressure limits. After the test has been finished, the limits are reset to the user-defined values.

Do not run this test if a leak is visible. In this case, reduce the flow rate to 0 µl/min and follow the instructions in the troubleshooting section in the operating instructions for the pump.

Tip:

(NC pump with ProFlow only) It is also recommended to run the Detailed Leak test if a leak is detected during solvent calibration (also see Calibrating Solvents (NCP-3200RS/NCS-3500RS) – ProFlow Flowmeter).

How to

The test procedure consists of up to two stages: in the first stage, the pump unit is tested as a whole (system test). In the second stage, each pump head is tested separately. The second test stage is only required if the source of a detected leak could not be located during the first test stage.

  1. In the Chromeleon Client, open and connect a control panel to your timebase.

  2. On the Control menu, select Diagnostics. The Diagnostics dialog box lists the installed instruments and available diagnostic tests. Select a line on the list to view details about the test type and purpose, as well as the required materials and estimated duration.

  3. Double-click the Detailed Leak test for the NC pump. (As an alternative, select the test and confirm with OK.) A wizard will guide you through the test steps.

  4. On the introductory page of the test wizard, click Next to proceed with the pump preparation that is required for the test.

 Tip: 

If the Next button is not active on the page, the pump is not connected in Chromeleon or is in Standby mode. Connect the pump to Chromeleon before you continue by selecting the Connected check box. If the pump is in Standby mode, clear the Standby check box.

  1. Optional: Enter a descriptive text in the Comments field of the Prepare Pump page, for example, the reason why the test was performed.

  2. Prepare the pump. (Grayed test steps can be ignored.) After each completed step, click the Done button:

    1. Stop the pump flow by clicking the Stop button.

    2. Close the two purge screws of the flowmeter.

    3. Close the pump outlet by installing the Viper fitting plug (provided with the accessories kit of the pump).

    4. In the Left and Right edit boxes, verify that the viscosity of the used eluents is correct. This information is required to match the limits with the allowed leak rate. The viscosities of the most common eluents and solutions are preset in Chromeleon: Water, Acetonitrile (ACN), Methanol (MeOH) and Isopropyl alcohol (IPA). To select a preset viscosity, click the button of the appropriate eluent. To select a preset solution (e.g., Water and Acetonitrile 50:50 (V/V) or 20:80 (V/V)) click the appropriate percent value. If you use a different eluent, you can determine its viscosity in Chromeleon and then enter the value manually in the Left or Right box. For detailed information on how to determine the viscosity of an eluent, refer to Viscosity Measurement (NCP-3200RS/NCS-3500RS).

  3. Click Next to start the test. On the subsequent test page (System Leak Test), you can view the progress of the test run. When the test has finished, click Next again to display the test results on the View Results page.

  4. If the test result indicates that the source of a detected leak could not be located, proceed to the second stage of the test to check each pump head individually:

    1. On the View Results page, click Continue.

    2. Prepare the pump for the second test: Remove the capillary connections between the flowmeter and the right and/or left pump head. Then close the outlet of the respective pump head with a Viper fitting plug. Click the Done button to confirm that you have completed the preparation steps, then click Next to start the test. On the Pump Head Test page, you can view the progress of the test run.

    3. When the test has finished, make sure to remove the Viper fitting plug(s) from the pump's outlet(s) again. Click the Done button to confirm that the plugs are removed.

      Warning: Make sure that the Viper fitting plugs are removed from the pump's outlets at the end of the test. Otherwise, serious hardware damage will occur.

    1. Click Next to display the test results on the View Results page. To view the results, do one of the following:

    2. To view the results in full detail, click the Detailed Results button.

    3. To view the print version of the report, click Finish and Preview Report.

    4. To quit the test panel without viewing the report click Finish.

    5. For troubleshooting information, click Open Troubleshooting Guide.

    5.  Tips: 

    The Detailed Leak Test is a very sensitive test. Even if the pump fails the test, the pump's performance can be considered sufficient for operation under usual conditions.

    If this test is performed for new piston seals, allow the seals to run in for several hours before you perform the test. Without this, the test result may not be accurate.

     

    For general information, refer to

     Diagnostics (UltiMate 3000 Series) and

    Diagnostic Tests for UltiMate 3000 Instruments

    Also refer to the Operating Instructions of the NC pump / NCS system shipped with the instrument.