Alnor Airflow Proood PH730, Owner'S Manual, Page: 63 / 80

55
Chapter 6. Flow Measurements Using the Capture
Hood
There are two methods of making flow measurement using Capture Hood:
(1) Capture Hood (non-backpressure compensation).
(2) Capture Hood with backpressure compensation.
(S
ee “
Appendix A. Back Pressure
,” for an explanation of the implications of capture hood-induced back
pressure on the measured flow.)
Supply or return flows can be measured with both methods, and return flow is indicated as a negative
number. In addition, flow measurements can be performed by taking a single reading or running average
(continuous) reading mode.
Note
Keep the Capture Hood in place during the entire measurement; otherwise, the reading will be
in error.
C A U T I O N
W
HILE USING THE
P
RO
H
OOD CAPTURE HOOD TO TEST AIR FLOW IN DUCTS
,
YOU MAY
COME INTO CONTACT WITH OR BE EXPOSED TO DUST
,
POLLEN
,
MOLD
,
FUNGUS
,
OR
OTHER AIRBORNE CONTAMINANTS
. I
F YOU ARE OR MAY BE SENSITIVE TO DUST
,
POLLEN
,
MOLD
,
FUNGUS
,
OR OTHER AIRBORNE CONTAMINANTS
,
ALWAYS USE AN APPROPRIATE
MASK OR RESPIRATOR WHILE EMPLOYING THE
P
RO
H
OOD CAPTURE HOOD
.
Single Reading Measurements
Single reading measurements are individual flow me
asurements initiated by pressing either the “READ”
button on the meter or the red switch on the left side of the base. Depending on the flow being measured,
a single reading will take one to eight seconds to complete (lower flows take longer).
Once the measurement is complete, the flow value will be displayed. Press
SAVE to log to memory, or
press READ , or red switch, to take a new measurement.
To measure in this mode:
1. Select Capture Hood or Hood BP Comp in the Pressure Tool menu.
2. Set the Data Logging mode to Manual/Single .
3. Set the Time Constant to 5 seconds.