Retrotec DucTester 200 Series Residential Applications - Manual (Page 30)

Page 30 of 91
©Retrotec Inc. 2015
3.11 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.
3.11.1. Setting up for depressurization
1. Install the “Mid” Range Ring, since most systems can be tested on this Range Configuration. For
more information about selecting and changing Range Configurations, refer to section 3.10.
2. Install the Flex Duct over the fan inlet, covering the Range Rings and tighten the strap.
Figure 29: Install Flex Duct over the fan inlet, covering the Range Rings, for depressurization.
3.11.2. Setting up for pressurization
The only advantage of pressurizing is that it makes changing Range Rings on the fan easier. If a
pressurization test is needed, simply install the Flex Duct on the outlet side of the fan.
Figure 30: Install Flex Duct over the fan exhaust, for pressurization.