Alnor Airflow Proood PH730, Owner'S Manual, Page: 65 / 80

Chapter 6: Flow Measurements Using the Capture Hood 57
Note
It is important that the capture hood see the same flow for both parts of the backpressure
compensated flow measurement. It is best to keep the Capture Hood in place for both
measurements, but it is alright to remove and replace the Capture Hood between the two
readings. However, if the flow is changed or changing between the two measurements, the
measurement results will be inaccurate.
“ERROR” Display
For the backpressure compensation measurement to be meaningful, the measurement in the flap
“
OPEN
” position must be higher than the measurement in the flap “
CLOSED
” position. If this is not true,
the ProHood meter will display an error: backpressure open greater than closed.