Retrotec Commercial 441 and 451 DucTester - Manual (Page 43)

Page 43 of 56
©Retrotec Inc. 2015
Step 1 - Prepare the gauge - first time only
Once the Gauge has been set up, all settings are restored when the gauge is turned back on.
□ Home screen must
show Model 450 on
Range 47
If not, tap picture, then [Change Device].
Tap ... until “Retrotec DucTester” page appears.
Tap “450”.
Tap the number below to get Range 47
□ Home screen must show pressure
units of CFM at a pressure in WC
per 100 square feet.
If not, tap [Settings] and [Results to be displayed].
Tap pressure units until you see inches of Water Column:
Then tap flow units until you see:
Tap On button to return Home.
Once set, you’ll never have to change it again.
□ Home screen must time average
as 5 seconds.
If not, tap [Settings] and [Time Averaging] until “ 5 s avg”
is displayed. Tap On button to return Home.
This will create a running average that will smooth out
results, making them easier to read. If the result
fluctuates, increase up to 30 seconds. Refer to manual for
more information.
The Gauge is set up now and you’re ready for your first test.
Step 2 – Determine test criteria and prepare the ducts
□ Determine the Leakage
Class
Determine the specified Leakage Class from design Engineer or
determine using Table 4-1.
See section on Leakage Class.
□ Determine the Pressure
Class
Use specified value. If not specified, use a Pressure Class of 1 in
WC except upstream of VAV boxes, use 2 in WC. Use a positive
test pressure unless specified otherwise. Test pressure shall not
exceed the Pressure Class according to SMACNA “HVAC Air Duct
Leakage Test Manual”.
□ Measure duct area Select a limited section of duct for which the estimated leakage
will not exceed the capacity of the test apparatus. Measure the
duct surface area in square feet. See Table 8 Duct Surface area
that can be tested with one Model 400.
□ Ensure sealing is complete Ensure sealing materials have cured for the prescribed time or at
least 24 hours OR follow manufacturer’s directions.
□ Blank off ductwork Blank off and seal the tested ductwork by inserting temporary
plugs plates, sheets, balloons, bags into intentional openings.