Preparing to Traverse a Round Duct
Preparing the Duct
To do a proper airflow measurement (CFM) you should do traverse
readings to obtain the true average airflow through the duct. You will
need to drill 2 holes at 90 degrees to each other, similar to the draw-
ing below.
1. Take your measurements by inserting the hotwire probe into the
drilled hole. and use the insertion depth chart to determine how far in
the duct you will go for each point. Then you will repeat for the other
hole.
2. Be sure you have the tip of the hotwire pointed into the flow of air,
there is a white dot on the tip, this should be inline with the flow.
HINT: If you turn the probe you will see the readings change up or
down, when the reading is at the highest you are in the proper posi-
tion.
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