General Tools and Instruments DCFM8906 v.1 - Manual (Page 17)

Fig. 7. The initial display produced by pressing the MODE
button
The value you need to enter is the area of the grille or
register. Inspect the grille or register to determine whether the
manufacturer stamped its area somewhere on it. If you do not
see a number followed by the unit ft
2 , measure the area
yourself.
Enter the free area one digit at a time. The largest value you
can enter is 9.999 ft
2 , and the smallest is 0.001 ft 2 .
To enter the first digit, press the HOLD as many times as
needed until the first (flashing) digit on the display matches
the first digit of the free area. Then press the AVERAGE
MULTI-POINT button to move on to the next digit, which will
begin flashing. Press the HOLD button repeatedly until the
second digit matches, and then store that digit by pressing
the AVERAGE MULTI-POINT button. Repeat the sequence
twice more to finish entering the free area.
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