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© Retrotec 2017
The “n value” is a number set between 0.5 and 1.0 that is used in the calculation when extrapolating
[Channel B] results to a pressure that is not the pressure read on [Channel A]. It can be changed by tapping
[Settings]
[…]
[Ducts=0.6, House=0.65]. Set it to 0.65 for houses, and 0.60 for ductwork. Set to 0.5 for
tests using the Retrotec House or duct simulator, air handler flow and any large hole that is not composed
of long thin cracks.
Technical details about the “n value”
2.6.6.
Capture and apply a Baseline using [Settings]
Some buildings have an initial pressure imbalance between the indoors and outdoors, prior to any testing.
This pressure imbalance is called the Baseline pressure, bias pressure, or static pressure. The Baseline
function allows the user to capture the Baseline pressure under the existing test conditions. See Section
4.1 for illustrations of how to capture a Baseline. Once captured, the gauge will automatically subtract the
Baseline pressure from all subsequently measured pressure readings, and will display only the adjusted
pressures on the screen. The gauge averages Baseline pressure for a user-defined duration.
Tip: A 30 second Baseline acquisition is typically enough to establish an accurate baseline measurement. If the
building conditions change during the test, the baseline should be cleared and a new measurement should be taken.
2.7
Gauge compensates for sensor drift with Auto Zero
Over time, the pressure readings on [Channel A] and [Channel B] can start to drift away slowly from the
true pressure value. The longer the gauge remains on, the larger this error could become. The
“
Auto Zero
”
is a feature on the gauge that will automatically correct these errors at regular intervals. By default, Auto
Zero occurs every 30 seconds. When using set speed or set pressure, the AutoZero interval is three
minutes. This interval (seconds)
can be changed using the “
DM32 Configurator
” software on a PC.
See
Retrotec’s
Manual-Software-DM32 Configurator
for details.
