# How to check flow cell vacuum pressure on the NovaSeq 6000

**Background**

The NovaSeq Service Software (NVSS) can be used to check the vacuum pressure when the instrument or flow cell is the suspected cause of a vacuum issue.

* See also [How to resolve Vacuum Failure Phenotype and "Flow cell Vacuum is no longer engaged" on NovaSeq 6000](https://knowledge.illumina.com/instrumentation/novaseq-6000/instrumentation-novaseq-6000-troubleshooting-list/000001309).

**To check the flow cell vacuum pressure:**

* Close the NovaSeq Control Software and launch NovaSeq Service Software (NVSS).
* Once initialized, select the **Flow Cell** option on main screen.
* Load wash flow cells on Sides A and B.
* Pressure readings for the wash flow cell should be around -90 kPa and show a steady green check mark for the sensor.
* If the pressure is low or the sensor is not steady, clean the flow cell and stage, and re-check pressure values.
  * If the vacuum pressure is within the expected range, perform a power cycle on the instrument and proceed with next run. See [How to Power Cycle the NovaSeq 6000 System](https://knowledge.illumina.com/instrumentation/novaseq-6000/instrumentation-novaseq-6000-reference_material-list/000002470).
  * If vacuum pressure is not within expected range, contact [Illumina Technical Support](https://www.illumina.com/company/contact-us.html#/united-states/technical-support).

**NovaSeq 6000 Control software v1.8** introduced an option to check vacuum pressure prior to run start. This can be done through the control software.

**To check the flow cell vacuum pressure from NovaSeq control software v1.8 and above:**

* Open the NovaSeq Control Software (NVCS).
* Select **Tools** from the dropdown menu on the upper left corner.

  ![](https://761066130-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FGM9W2DuBTgEXv1ClCm8H%2Fuploads%2Fgit-blob-c27e57bf4248f6a7612f4855ec3876169046dcb9%2Fimage1.jpg?alt=media)
* Select **Flow Cell Vacuum**.

  ![](https://761066130-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FGM9W2DuBTgEXv1ClCm8H%2Fuploads%2Fgit-blob-276ddab04d899ef606e58c7d52d187dd13830ff1%2Fimage2.jpg?alt=media)
* Load wash flow cells on sides A and B.

  ![](https://761066130-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2FGM9W2DuBTgEXv1ClCm8H%2Fuploads%2Fgit-blob-8f8e142705e25cb84fc17bfffa348a226b2a1852%2Fimage3.jpg?alt=media)
* Pressure readings for the wash flow cell should be around -90 kPa and show a steady green check mark for the sensor.

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| *For any feedback or questions regarding this article (Illumina Knowledge Article #5390), contact Illumina Technical Support* [*techsupport@illumina.com*](mailto:techsupport@illumina.com?subject=Question%2FFeedback%20Regarding%20Illumina%20Knowledge%20Article%20#000002470%20-%20Instrumentation%20\&body=Dear%20Illumina%20Technical%20Support,%0D%0A%0D%0A)*.* |