Retrotec DucTester 341 - Manual (Page 33)

Page 33 of 83
©Retrotec Inc. 2014
7. Set up the gauge to display Duct Leakage Results
Read the Total Duct Leakage results directly from the gauge. Change units by tapping on Channel B. In
order to compare duct systems in different homes/buildings, it is necessary to normalize the leakage
results for the size of the HVAC system and the size of the building. The two most common variables
used to normalize duct leakage are total HVAC flow rate and the floor area of the building.
Figure 24: Some of the most common results that can be read directly off the gauge.
7.1 Mode setup for duct testing in the US
The Table below shows what settings will directly calculate the results required for testing compliance
with the codes adopted in the various states.
Table 3: Gauge Mode Setup for US state Codes and programs for Duct Testing
Code
2009
IECC
ENERGY
STAR
Northwest
ENERGY STAR
Homes
Title-24
Code
WA State
Code
Region:
VT GA CT DE
GA ID IL IO
MA NC NH NJ
NY OH TX
MD
USA ID MO OR WA CA WA
Pressure
Pa Pa Pa Pa Pa
Flow
CFM CFM CFM CFM CFM
(Flow) @ Pressure
@25 Pa @25 Pa @50 Pa @25 Pa @25 Pa
Flow per Area of
Conditioned floor area
CFM/100 ft 2 CFM/100 ft
2 CFM/ft 2 Off CFM/100 ft 2
(Flow per Area) @
Pressure
@25 Pa @25 Pa @50 Pa Off @25 Pa
Grey areas in the table indicate those results are not needed for those programs but can be turned on or
off any time they may be needed. The “@ Pressure” value for Flow measurement is set at the value
required for duct testing.