Measurement Modes in the Main Menu
30
6.4
Option „Airflow
(k value)
“
Select the submenu "Airflow (k-value)" to measure
the airflow at apertures or similar measuring open-
ings of air pipes or vents. This method is simple
and precise and therefore suitable for the adjust-
ment of air pipe systems and vents.
6.4.1 Theoretical Backround
In this menu, the air flow measurement is based
on the k value. The k value is a factor which de-
scribes the relation between the decrease in pres-
sure and the air flow.
NOTE!
The k-value is always entered into the meter re-
lated to l/s.
The k-value is entered into the meter related to l/s.
The air flow will be indicated by the Wöhler DC
410
FLOW
in l/s and in m
3
/h.
The DC 410
Flow
will calculate the airflow according to the following formula:
Formula 4
Explanation:
= airflow
K value (Enter the K-value, indicated in the
data sheet, into the DC 410
Flow
.
= measured pressure
= air density, calculated on the basis of temper-
ature and pressure
By default, the exponent will be 0.5 as indicated in the formula. Some fan manufactur-
ers inform explicitly in the data sheet that a special exponent has to be used for the
airflow calculation.
In this case, go to the setup menu and enter the exponent indicated in the data-
sheet in the Wöhler DC 410
FLOW
. (see chapter 6.12
, „exponent“).
