UEi Test Instruments DAFM3 - Manual (Page 3)

Basic Measurement
When you first turn the unit on the air temperature is the default value
to show on the LCD. To review the other basic parameters, just press the
“MODE” key. Each parameter will be displayed in turn.
Parameters Measured will cycle through the following in order
• Dry Bulb Temperature
• Dew Point Temperature (DP)
• Wet Bulb Temperature (WB)
• Relative Humidity (RH%)
• Air Velocity
MIN/MAX/AVG
All modes will capture the average (AVG), minimum (MIN) and
maximum (MAX) value since the meter was powered on. Select
AVG/MIN/MAX by pressing this button. Pressing “MODE” while
displaying “MIN/MAX” or “AVG” will scroll through available readings.
Each mode will also provide a choice of MIN/MAX or AVG.
Velocity with Average
The DAFM3 has the ability to capture up to eight values for velocity, and
then display the minimum, maximum and average of these readings.
The maximum number of records is 8 points.
1. Store readings while in the measurement mode by pressing
“RECORD” (up to 8 points of data).
2. Press “ENTER” to view results.
NOTE: “REC H” will display in the lower left of the display.
3. Press “MIN/MAX/AVG” to cycle through the calculated values.
Air Volume Note
The DAFM3 will also calculate air volume for supply or return air flow.
The meter will measure velocity and then utilize the area entered to
calculate volume.
The critical aspect of this function is to have the correct area. There are
three methods used to enter area, but consider the following.
Dimensional outlet size can only be used on ductwork that does not
have a grill over the opening. The louvers and frame on the grill reduce
the effective open area so that the space available for airflow is less
than what the outside dimensions would calculate.
DAFM3-MAN P. 2
Operating Instructions
Disable Auto Power Off
With the meter off, press and hold “MIN/MAX” then press and hold
“ON/OFF”“ until the meter beeps.
Selecting Units
With the meter off press and hold the “ON/OFF” button for more than
two seconds. The display will show only the units portion.
Use the “UP” or “NEXT Dgt” buttons to alternate between the avail-
able scales. When the scale desired is showing press the “ENTER” but-
ton to save. The units available are Ft, in, cm.
Ft Range
Select these units to enter free area specification from grill manufacture.
Free Area is not a calculated area based on grill dimensions, but
accounts for the space between louvers. It is often referred to as Ak, or
effective area. The following figure represents these units.
INCH
Select these units if measuring open ductwork and you wish to enter the
length and width or diameter in inches. It can also be used to enter
specified grill free area provided by manufacture in square inches for
the Ak number.
CM
Select these units for metric scales. The temperature is ˚C, and velocity
and volume are in meters per second and cubic meters per minute.