Table of Contents
Advertisement
Each Retrotec DucTester includes three Range Configurations to maximize accuracy and versatility:
Open, 74, 47 and 29 as standard. The selected Range Configuration will determine the range of air flow
that the DucTester can measure. While it is easy to change the Range Configuration when pressurizing,
it is better to make your best guess at
the correct Range Configuration when
testing in the depressurization direction
since the Flex Duct must be removed to
change Range Configurations. Do NOT
try to forcefully attach the Range Rings
to the exhaust; they must always go on
the inlet of the fan.
Use a Range with a larger opening for
leakier ducts and smaller opening for
tighter ducts. Testing should always be
done at the highest possible fan speed,
which means using the most restrictive
Range Configuration possible (the one with the smallest hole
possible). Higher fan speeds lead to the highest degree of
accuracy. If the fan is running too slowly, "-----"will appear on
the DM32 gauge display indicating you must change to a more restrictive range.
6.9
Select a test direction
Duct leakage can be measured by blowing air into the ducts to pressurize the ducts, or by pulling air out
of the ducts to depressurize the ducts. Program guidelines may specify a particular test direction. Both
test directions provide similar results, however depressurization testing is faster and more consistent
because the negative pressure will pull the Grill Mask (or other sealing means) onto the registers
ensuring a tighter seal. In the absence of any other requirement, Retrotec recommends
depressurization. Some standards require pressurization.
6.9.1.
1. Install Range 47, since most systems can be tested on this Range Configuration. For more
information about selecting and changing Range Configurations, refer to section 6.8.
2.
Install the Flex Duct over the fan inlet, covering the Range Rings and tighten the strap.
Page 27 of 58
©Retrotec Inc. 2015
Setting up for depressurization
Figure 21: Inserting a range plug into the end plate.
Advertisement
Table of Contents
