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.

Why is there a reference pressure for EqLA results?
(Or Flow, Permeability, ACH results?)

The results are all referenced to a single pressure, the reference pressure.  The reference pressure is dictated by the standard with which the test is trying to comply.

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 building pressure would be a higher EqLA. Hence, there needs to be a reference pressure when referring to a leakage or flow result.

For the ASTM standard, the leakage result is required to be at a reference pressure of 50 Pa, whereas it is 75 Pa for the USACE standard. Reference pressure also applies to permeability (e.g. CFM/ft2) and air change (ACH) results.

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

What is an extrapolated result? (e.g. Q4)

Why is an extrapolated result different in FanTestic than on a DM32?

Q4 is a Flow result that is extrapolated to 4 Pa. For extrapolation of what the result would be at 4 Pa, a best-fit line on a graph (with a known slope) is needed.

The slope value is different for different enclosures, since the slope is dependent on enclosure leakage. To generate a line on a graph, you will either need to:

1. Measure multiple points of data to compute a slope ('n' value), or you
2. Guess a slope ('n' value)

FanTestic performs #1, whereas your DM32 performs #2. 

In other words, FanTestic software records multiple measurements to create a graph

Yes. The LEED standard references test procedures from the ASTM E779-10 standard, so we have included the "LEED Permeability" result (in units of in2/100 ft2) in the user interface of the ASTM standard.

In other words:

1. Download FanTestic, if you haven't already
2. Go to Choose Tools-->Options section of the software, and select the standard "ASTM E-779-10"
3. Click File--> New Test
4. Perform your Door Fan test, and once you have all your data, and it will calculate a "LEED Permeability" result for you at the bottom of your test set.

Consider the following:

1. Connection range lowers when the DM32 gauge is under low battery power. The voltage goes from 4.2V down to 3.3V and the signal strength output is slightly reduced. If you are having connection troubles and can only connect within a few feet, you should first check if the battery level is in the ‘red’; if so, charge the DM32.
2. You may have an older version of GaugeRemote installed  – make sure your Andriod or iOS device is updated to the latest. There have been improvements in the most recent versions to improve reconnection.
3. Some mobile platforms’ ROMS have issues with their WiFi connection (something Retrotec cannot control). For example, the recent iOS 8.0 had WiFi issues and Apple had to  push a fix out for 8.1, and then subsequently 8.1.1 for further patching. Go into the Settings of their mobile device, check its version number, and make sure it’s running

I updated FanTestic software and now it cannot not find my DM-2 gauge anymore.

If you previously had to use the "ADMIN" shortcut to allow FanTestic to find your DM-2 then you need to make sure that the previous version of FanTestic and all shortcuts to it are removed from your computer.  Check here to find out if you need to use the ADMIN shortcut.

Uninstall FanTestic completely from your computer  using the Control Panel (choose the Remove from computer option, not the Revert to a previous version option if you are presented with a choice).  Uninstalling FanTestic will NOT uninstall the DM-2 USB driver.  You should still be able to see the Driver listed as installed

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.

One question we get a lot is about leaking flex duct that connects the ducTester to the return. We have tested the most ripped up flex available in our warehouse; it had way bigger pinholes and it measured 0.68 CFM at 25 Pa. When you measure a typical leakage of 100 CFM at 25 Pa or more, this is not even 1%.  So we believe it is not worth spending money on replacing.