We start at the highest pressure and work downward for two reasons. 

1. It helps the fans reach the target pressures faster. The speed control algorithm works faster going from a higher pressure to a lower pressure.
2. It helps you properly select your Range Ring for the test. By starting with the largest possible range (highest flow) to test at your highest pressure you ensure the minimum possible range changes while testing. Ideally, you don't want to change ranges in mid test because it wastes time. 

You need to consider that there is a fundamental issue of uncertainty with using 4 Pa as a reference pressure. Just imagine, if there is even a 1 Pa fluctuation, due to so many possible sources that can cause pressure fluctuations as you know, the pressure measurement already has an uncertainty of +/- 25% error. Consider that for almost all airtightness testing standards across the world, the reference pressure for Flow results are either 50 Pa or 75 Pa.

You need to consider that there is a fundamental issue of uncertainty with using 4 Pa as a reference pressure. Just imagine, if there is even a 1 Pa fluctuation, due to so many possible sources that can cause pressure fluctuations as you know, the pressure measurement already has an uncertainty of +/- 25% error. Consider that for almost all airtightness testing standards across the world, the reference pressure for Flow results are either 50 Pa or 75 Pa.

How does FanTestic calculate the pressures and flows that appear in the FanTestic UI and in the generated Word reports?

The table in the report (and the onscreen data entry fields) containing data for each Set shows:

• the “Induced pressure” and this is the pressure measured by the gauge (read automatically or entered by user) without correction for bias pressure.
• the “Fan Pressure” for each Fan, and this is the pressure measured by the gauge. (read automatically or entered by user)
• the “Flow” for each Fan, which is calculated using the Fan Pressure 
• the “Total Flow” which is all the Flows added up, for all the Fans used, at that target point (will be the same as Flow if only one fan is used)
• the “Corrected Flow” which is the Total Flow adjusted as required in the chosen Standard to account for air density 
  (air density corrections generally

Uninstalling FanTestic will NOT remove any of your test files or reports, it will only uninstall the program files. 

It is generally a good practice to regularly back your test and report data to a different location.

Uninstalling FanTestic will also NOT uninstall the DM-2 USB driver.  You should still be able to see it listed as installed in your Control Panel after you restart the computer.

When I try to start an Auto Test or click Find Gauges button, I get a message saying no gauges were found.  Part of the error message says "Error 5: Access denied".

Your computer is limiting access to the USB ports by programs.  In order for FanTestic to access the USB ports on your computer, you may have to "Run as Administrator".  You will need to follow the procedure outlined in the attached document, regardless of whether you have Administrator privileges on your computer. 

This problem can be avoided if you have a DM32 by connecting the DM32 gauge using an Ethernet cable to connect the computer to the Network port on the gauge instead of using the USB cable.

For reference to equations for calculating results from a Blower Door test, you can refer to the ASTM E-779-10 standard.

In engineering (fluid dynamics) terms, Bernoulli's equation is an energy balance equation that assumes incompressible fluid (e.g. air) at steady state through two points (e.g. through a building); The equation can be simplified to an orifice plate equation and applied to a Blower Door test.  We can calculate point #1 - the total leakage (EqLA or ELA) of a building, and point #2 - a known area (size of fan hole: Range configuration) by measuring via Blower Door system the airflow rate through these points at a specific induced building pressure (the reference pressure). 

Induced building pressure is directly proportional to airflow rate through a building, and EqLA is directly proportional to airflow rate; so that a higher induced

If you have a DM-2 and want to connect to it using software such as FanTestic or the Retrotec Data Logger, you need to install a USB Driver. 

Check your Windows operating system version to determine if you need a 32 bit installer or a 64 bit installer, and download and install from the website.

If you have a DM32, you should use the WiFi or Wired Ethernet connection to the computer for controlling the gauge.  The only time you need to connect the DM32 to the computer using the USB is when updating the gauge firmware using the DM32Configurator software .  You can use the USB for gauge control but it is not recommended.  In any case, the DM32 USB driver is automatically installed by FanTestic.

If you look in your Control Panel - Programs and Features section, you will see the USB drivers that are installed on your computer, listed under Retrotec as the publisher.

Checking with Microsoft Windows Click Once  Installer information, the error message you are receiving tells us the following: 

"These are generic error messages that occur when the application cannot be started, and no other specific reason can be found. Frequently this means that the application is somehow corrupted during download, or that the ClickOnce store is corrupted."

So it would seem that some of the files did not download correctly or that your ClickOnce user store may be corrupted.

Go to your Control Panel and Uninstall FanTestic.  If you get a message box asking if you want to roll back to a previous state or to Uninstall, choose the Uninstall option.  Then restart your computer.  If there are any FanTestic shortcuts left on your desktop, you will need to delete them.

Install the latest version from the website:

https://retrotec.com/software.html

Restart your computer.

If after the install you

Uncertainties of results are affected by how "stable" or reproducible your measurements are, when all your data are analyzed collectively. They are determined through statistical analysis. If you would like to see these equations, you can look up the Standard you are testing to.

What FanTestic software does, is it graphs your measurements (technically speaking: on a Flow vs Induced Pressure, log-log axis) and a bestfit trendline is generated between these multiple points. The closer your measurements are to this trendline, the lower your uncertainties. The further away your measurements are from this trendline, the higher your uncertainties.

To minimize uncertainty, it is best to take more measurement points (both target and baseline points), minimize Baseline/Bias pressures (e.g. by dampening wind, etc), take target measurement points over a larger range of induced pressures, and take measurements on each target point for longer time.