General Tools and Instruments DCFM8901 - Manual (Page 13)

Fig.14
AREA
2 ft
H. AUTO POWER OFF
Air Velocity measurement is calculated
by multiplying the air velocity readings
by the free area dimensions. Free area
is published by the grill and register
manufacturer you are servicing. You must
first determine the free area of the air
source before entering it into the meter.
1. Power unit on
2. Press MODE once (you will hear one
beep). Meter will display"AREA" in
upper case lettering and "1.111" will
appear (See Fig.14) .
The first digit will be flashing.
3. Press the HOLD key to increase the
number.
4. Press the SEL/AVG key to advance
to next number. Follow Step 3 and
repeat.
5. Press the MODE key once all digits
have been entered. The word "flow"
will appear.
I. DIRECT MEASURING OF AIR
FLOW (SINGLE POINT) CFM
The unit will turn off automatically
after 20 minutes to save the battery.
Press ON/OFF and HOLD button to
disable Auto Power Off function.
12
The meter is now ready to measure air
flow(CFM).