--- title: How to perform a diagnostic test on a UPAS v2.0 using an external flow meter description: Instructions for performing a diagnostic test on a UPAS v2.0 device, using an external flow meter, to evaluate pump performance and flow control calibration image: https://www.accsensors.com/hubfs/Images%20-%20Blog%20Posts/Blog_DIAG_v2_Header.jpg --- [Skip to content](https://www.accsensors.com/blog/diag-upas-v2#main-content) [![AST](https://www.accsensors.com/hs-fs/hubfs/AST.jpg?width=2303&height=774&name=AST.jpg)](https://www.accsensors.com/) - [Products](https://www.accsensors.com/products) Show submenu for Products - [UPAS v2.1](https://www.accsensors.com/upasv2.1) - [UPAS v2.1 PLUS](https://www.accsensors.com/upasv2.1plus) - [UPAS v2.0](https://www.accsensors.com/upasv2.0) - [Home Health Box](https://www.accsensors.com/indoor_sampling) - [Inlets and Accessories](https://www.accsensors.com/accessories) - [UPAS Outdoor Enclosure](https://www.accsensors.com/upas_outdoor_enclosure) - [Sample Analysis Services](https://www.accsensors.com/sample_analysis) - Technical Resources Show submenu for Technical Resources - [Applications Blog](https://www.accsensors.com/blog) - [R Shiny Application](https://accsensors.shinyapps.io/shinyAST/) - [astr R Package](https://github.com/accsensors/astr) - [YouTube](https://www.youtube.com/channel/UCbbSB_ja8JY-xX90D94qyKA) - Contact Us Show submenu for Contact Us - [Request Free Demo](https://www.accsensors.com/freetrial) - [Request a Quote](https://www.accsensors.com/quote) - [Request Support](https://www.accsensors.com/support-request-form) - [Our Team](https://www.accsensors.com/about) - [Distributors](https://www.accsensors.com/distributors) Open main navigation Close main navigation - [Products](https://www.accsensors.com/products) Show submenu for Products - [UPAS v2.1](https://www.accsensors.com/upasv2.1) - [UPAS v2.1 PLUS](https://www.accsensors.com/upasv2.1plus) - [UPAS v2.0](https://www.accsensors.com/upasv2.0) - [Home Health Box](https://www.accsensors.com/indoor_sampling) - [Inlets and Accessories](https://www.accsensors.com/accessories) - [UPAS Outdoor Enclosure](https://www.accsensors.com/upas_outdoor_enclosure) - [Sample Analysis Services](https://www.accsensors.com/sample_analysis) - Technical Resources Show submenu for Technical Resources - [Applications Blog](https://www.accsensors.com/blog) - [R Shiny Application](https://accsensors.shinyapps.io/shinyAST/) - [astr R Package](https://github.com/accsensors/astr) - [YouTube](https://www.youtube.com/channel/UCbbSB_ja8JY-xX90D94qyKA) - Contact Us Show submenu for Contact Us - [Request Free Demo](https://www.accsensors.com/freetrial) - [Request a Quote](https://www.accsensors.com/quote) - [Request Support](https://www.accsensors.com/support-request-form) - [Our Team](https://www.accsensors.com/about) - [Distributors](https://www.accsensors.com/distributors) - [Try for Free](https://www.accsensors.com/freetrial) [Try for Free](https://www.accsensors.com/freetrial) Oct 24, 2026, 6:56:58 PM # How to perform a diagnostic test on a UPAS v2.0 using an external flow meter ![Picture of Jessica Tryner](https://www.accsensors.com/hs-fs/hubfs/JT_20250309_square.jpeg?width=50&name=JT_20250309_square.jpeg) [Jessica Tryner](https://www.accsensors.com/blog/author/jessica-tryner) Share: [facebook-f icon](http://www.facebook.com/share.php?u=https://www.accsensors.com/blog/diag-upas-v2) [linkedin-in icon](http://www.linkedin.com/shareArticle?mini=true&url=https://www.accsensors.com/blog/diag-upas-v2) [Twitter icon](https://twitter.com/intent/tweet?url=https://www.accsensors.com/blog/diag-upas-v2) [pinterest-p icon](http://pinterest.com/pin/create/link/?url=https://www.accsensors.com/blog/diag-upas-v2) [envelope icon](mailto:?body=https://www.accsensors.com/blog/diag-upas-v2) Do you want to check the pump performance and flow control calibration on an older [UPAS v2.0](https://www.accsensors.com/upasv2.0) to determine whether the UPAS is working well or would benefit from being sent in for [service](https://www.accsensors.com/blog/upas-service)? First, confirm that your device is a UPAS v2.0 by consulting this blog post: [Which UPAS model do I have?](https://www.accsensors.com/blog/which-upas) > **Tip:** If the UPAS serial ID starts with "PS" instead of "PSP," it’s a UPAS v2.0. Once you’ve confirmed that the device is a UPAS v2.0, follow the steps below to perform a diagnostic test using an external flow meter. # What you’ll need You’ll need the following supplies to complete the diagnostic test: - **UPAS v2.0:** Check the 35 x 1 mm O-ring in the bottom of the inlet socket. If the O-ring is missing or damaged, replace the O-ring before performing the diagnostic test. Refer to the "Physical Setup" section of our [UPAS v2.1 and v2.1 PLUS User Guide](https://www.accsensors.com/hubfs/User%20Guides/AST_UPAS%20v2.1%20and%20UPAS%20v2.1%20PLUS_UserGuide_FirmwareRev2xx.pdf?hsLang=en) for more information on this O-ring. - **Filter cartridge:** Check the O-ring in the upper half of the cartridge. If the O-ring is missing or damaged, replace the O-ring before performing the diagnostic test. Refer to the "O-ring Replacement" section of our [Size-Selective Inlet User Guide](https://www.accsensors.com/hubfs/User%20Guides/AST_SizeSelectiveInlets_UserGuide.pdf?hsLang=en) for more information on the O-ring used in each type of filter cartridge. - A **filter** of the same type as the filters that you are using to collect actual samples - **Flow check adapter:** Check the O-ring on the bottom side. If the O-ring is missing or damaged, replace the O-ring before performing the diagnostic test. Refer to the "O-ring Replacement" section of our [Size-Selective Inlet User Guide](https://www.accsensors.com/hubfs/User%20Guides/AST_SizeSelectiveInlets_UserGuide.pdf?hsLang=en) for more information on the O-ring used in each type of flow check adapter. - If you’re using our Generation 2 (G2) inlet system, you’ll also need the same type of size-selective inlet that you are using to collect actual samples. If you’re using our Generation 1 (G1) inlet system, you’ll only need the filter cartridge, filter, and flow check adapter. See Figure 1 in our [Size-Selective Inlet User Guide](https://www.accsensors.com/hubfs/User%20Guides/AST_SizeSelectiveInlets_UserGuide.pdf?hsLang=en) for more information on the G1 and G2 inlets. If you're using a G2 inlet, make sure all of the necessary O-rings are installed in the inlet and in good condition. Refer to the "O-ring Replacement" section of our [Size-Selective Inlet User Guide](https://9154461.hubspotpreview-na1.com/hubfs/User%20Guides/AST_SizeSelectiveInlets_UserGuide.pdf?hsLang=en) for more information on the O-rings in each inlet. - An [Alicat MW-5SLPM-D or MWB-5SLPM-D](https://www.alicat.com/products/gas-flow/mass-flow-meter/low-pressure-drop-mass-flow-meters/) flow meter (or another UPAS-compatible flow meter). See page 24 of our [UPAS v2.0 User Guide](https://www.accsensors.com/hubfs/User%20Guides/UPASv2.0_UserGuide_Edition1_June2018.pdf?hsLang=en) or pages 20-21 of our [UPAS v2.1 and v2.1 PLUS User Guide](https://www.accsensors.com/hubfs/User%20Guides/AST_UPAS%20v2.1%20and%20UPAS%20v2.1%20PLUS_UserGuide_FirmwareRev2xx.pdf?hsLang=en) for more information on which flow meters are compatible with the UPAS. - A piece of flexible **tubing** (e.g., silicone, Tygon®, Viton™) with a 1/4" (6.35 mm) ID and a 1/16" to 3/32" (1.6 to 2.4 mm) wall thickness. It will be most convenient if this piece of tubing is approximately 12" (300 mm) long. - A table with the format shown below, where you can record the data collected during each test. You can download and use [this spreadsheet](https://www.accsensors.com/hubfs/Other%20Technical%20Support%20Files/UPAS%20v2.0%20Diagnostic%20Test%20Results.csv). | **UPAS serial ID** | **Dead head pressure (kPaG)** | **Maximum flow (LPM)** | **Target = 1.0 LPM** | **Target = 2.0 LPM** | | --- | --- | --- | --- | --- | | | | | | | # Performing the test 1. Install the filter, filter cartridge, and flow check adapter on the UPAS. - If you’re using the G1 inlet system, install the filter cartridge and flow check adapter on the UPAS as described on pages 24-25 of our [UPAS v2.0 User Guide](https://www.accsensors.com/hubfs/User%20Guides/UPASv2.0_UserGuide_Edition1_June2018.pdf?hsLang=en) and in the "Using the Flow Check Adapter" section of our [Size-Selective Inlet User Guide](https://www.accsensors.com/hubfs/User%20Guides/AST_SizeSelectiveInlets_UserGuide.pdf?hsLang=en). - If you’re using the G2 inlet system, install the filter cartridge, size-selective inlet, and flow check adapter on the UPAS as described in the "Using the Flow Check Adapter" section of our [Size-Selective Inlet User Guide](https://www.accsensors.com/hubfs/User%20Guides/AST_SizeSelectiveInlets_UserGuide.pdf?hsLang=en). 2. Connect one end of the flexible tubing to the *outlet* of the flow meter and connect the other end to the inlet of the flow check adapter. 3. Turn the flow meter on. If you’re using an Alicat MW- or MWB-series flow meter, make sure the meter is displaying the *volumetric flow rate* in LPM (bottom left unit on screen) and the gauge pressure in kPaG (top left unit on screen). 4. Turn the UPAS on and connect to it with the mobile app. 5. In the Sample Name field, enter **DIAG#** 6. Block the inlet of the flow meter so that no air can flow through the UPAS. 7. Hit the "Start" button in the app to start the test. 8. When the test starts, the sample pump will turn on to maximum power for a few seconds. If your flow meter measures and displays the gauge pressure, record the maximum gauge pressure (preferably in units of kPaG) measured with the pump at maximum power and the flow blocked. Record this value in the spreadsheet column labeled "Dead head pressure." 9. When you hear the pump turn off, unblock the flow. 10. Soon, the pump will turn on to maximum power again, and you should record the maximum flow rate displayed on your flow meter (preferably in units of LPM). Record this value in the spreadsheet column labeled "Maximum flow." 11. After that, the pump will be set to the minimum power level. You don't need to record the flow rate displayed on the flow meter during this step. 12. Next, the UPAS will try to control the sample flow rate to 1.0 LPM for 3 minutes. When the UPAS thinks the sample flow rate has reached 1.0 LPM, the LED should turn green. Record the flow rate displayed on the flow meter (preferably in units of LPM). Record this value in the spreadsheet column labeled "Target = 1.0 LPM." 13. After 3 minutes, the UPAS will transition automatically to trying to control the sample flow rate to 1.5 LPM for another 3 minutes. When the UPAS thinks the sample flow rate has reached 1.5 LPM, the LED should turn blue. You don't need to record the flow rate displayed on the flow meter during this step. 14. After 3 minutes, the UPAS will transition automatically to trying to control the sample flow rate to 2.0 LPM for another 3 minutes. When the UPAS thinks the sample flow rate has reached 2.0 LPM, the LED will turn blue, but it should be a slightly lighter blue than in Step 13. Record the flow rate displayed on the flow meter (preferably in units of LPM). Record this value in the spreadsheet column labeled "Target = 2.0 LPM." 15. After trying to control the sample flow rate to 2 LPM for 3 minutes, the UPAS should return to Step 12. You can stop the test at this point by holding down the power button until the UPAS turns off. # Interpreting the results The acceptable range for each metric recorded during the test is shown in [Table 1](https://www.accsensors.com/blog/diag-upas-v2#Table1). If your measurements are within these ranges, the pump is performing acceptably and the flow control calibration is good. If any of your measurements are outside of these ranges, your UPAS might need to be recalibrated or repaired. **Table 1.** Acceptable ranges for each metric measured and recorded during the UPAS v2.0 diagnostic test. | **UPAS serial ID** | **Dead head pressure (kPaG)** | **Maximum flow (LPM)** | **Target = 1.0 LPM** | **Target = 2.0 LPM** | | --- | --- | --- | --- | --- | | PSXXXX | 3.0 to 4.0 | ≥2.65 | 0.96 to 1.04 | 1.92 to 2.08 | Note that we expect the maximum flow rate to be ≥2.65 LPM when a [Measurement Technology Laboratories](https://www.mtlcorp.com) (MTL) PT37P-PF03 PTFE (Teflon™) membrane filter is installed in the UPAS filter cartridge. If a different type of filter is installed, the maximum flow rate could be lower.  Please [contact us](https://www.accsensors.com/support-request-form?hsLang=en) if you have any questions; for example, if you need help interpreting measurements from a flow meter that does not display the volumetric flow rate in LPM. When contacting us, please send the following information: - Some background on the UPAS condition; - The filter type, filter size, size-selective inlet (if applicable), flow check adapter, and flow meter type used for the diagnostic test; - The diagnostic log file from the UPAS microSD card; and - The UPAS serial ID, dead head pressure, and flow rate data recorded in the spreadsheet. 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