UEi DAFM3B Instruction Manual

O

P

E

N

C

L

O

S

E

CFM

VOL

LW

MODE

HOLD

START
STOP

EXIT

[HOLD TO EXIT

AVG MODE]

LW-D-AREA

ON / OFF

(SET)

MAX / MIN

AVG

DAFM3B

INSTRUCTION MANUAL

ENGLISH

Digital Air Flow Meter

DAFM3B

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TABLE OF CONTENTS

Introduction ................................................................................................3

Safety ..........................................................................................................3

Controls and Indicators ..............................................................................4

Figures and Components ............................................................................5

Operating Instructions

Disable Auto Power Off ....................................................................5

Selecting Units..................................................................................5

Basic Measurement ...................................................................... 5-6

Measuring Air Volume (CFM or CMM)

Entering Duct Information ................................................................6

Timed Average Air Volume ...............................................................7

Estimating FREE AREA (Effective area) of a Grill ......................................8

Maintenance

Low Battery ......................................................................................9

Cleaning ............................................................................................9

Battery Replacement ........................................................................9

Specifications ...........................................................................................10

Warranty and Service Information ..........................................................11

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3

INTRODUCTION

The DAFM3B Anemometer/Psychrometer is designed with 6 HVAC/R
parameters in one instrument. These are included in a portable, battery­operated instrument for measuring humidity, air temperature, dew point,
wet bulb, air velocity and air volume. The vane probe includes
sensors for velocity, temperature and humidity.

FEATURES

• Measures Air Velocity, Temperature, and Relative Humidity (RH%)

• Calculates Wet-bulb temperature, dew point, and air volume
(CFM, CMM)

• 3” diameter air vane

• Timed accumulative average for air volume with one hour maximum

• Min/Max and Hold

• English/Metric Scales

• Fast response

• Auto-power off (can be disabled)

• Low battery indicator

INCLUDED

• DAFM3B Meter

• Air vane probe

• Battery (1 x 9V)

• User manual

• Hard carrying case

SAFETY NOTES

Before using this meter, read all safety information carefully. In this
manual the word “WARNING” is used to indicate conditions or actions
that may pose physical hazards to the user. The word “CAUTION” is
used to indicate conditions or actions that may damage the instrument.

CAUTION! Do not strike the fan portion of the probe.

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CONTROLS AND INDICATORS

1. On/Off (Setup): Press briefly to power meter on. Press and hold

to turn the meter off.

• Note: When the meter is OFF, press more than two seconds

to enter SETUP mode.

2. HOLD: Freezes display reading for current parameter

3. MODE: Press to scroll through available measurements of
velocity, air flow, ambient temperature, relative humidity,
wet-bulb temperature, and dew point temperature.

4. EXIT: Use to exit setup.

• Note: Press and hold to exit timed average display

5. START/STOP: Press to begin air volume timed average. Press a
second time to pause timed average.

6. LW-D-AREA: Press when setting up area for calculation of air
volume. Pressing repeatedly scrolls through the three options.

(LW-Length/Width, D-Diameter, A – Area)

7. MIN/MAX AVG ( ): Press to display minimum or maximum
values for any measurement. Press when in timed average air
volume to display average, minimum or maximum air volume.

[HOLD TO EXIT

AVG MODE]

START/

STOP

HOLDMODE

EXIT LW-D-AREA

ON / OFF

(SET)

MAX / MIN

AVG

7

3

4

5

6

2

1

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5

FIGURES AND COMPONENTS

OPERATING INSTRUCTIONS

DISABLE AUTO POWER OFF

With the meter off, press and hold ON/OFF and HOLD for more than two
seconds. The display will show an “n” indicating that auto power off is
disabled.

SELECTING UNITS

• With the meter off press and hold ON/OFF (Set) button for more
than two seconds.

• Press MIN/MAX AVG ( ) to select unit (P10)

• Press or to switch units

• Press MIN/MAX AVG ( ) to select choice

• Press EXIT to return to normal operation

BASIC MEASUREMENT

When the DAFM3B is first powered on, air velocity is the default display.
To view other parameters press “MODE” key. Each parameter will be
displayed in turn.

• VEL – Air Velocity

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OPERATING INSTRUCTIONS CONT.

• VOL – Air volume in CFM or CMM, based on dimensions entered

Note: Icon at bottom of screen will indicate the method used to
calculate volume (LW-Length/Width, D-Diameter, A – Area).

• TA – Ambient Temperature measured at the probe tip

• RH – Relative Humidity measured at the probe tip

• WBT – Wet Bulb Temperature calculated from measured
temperature and RH%

• DP – Dew Point Temperature calculated from measured
temperature and humidity

MEASURING AIR VOLUME (CFM OR CMM)

Measuring air volume with the DAFM3B has two steps. The first step is
to enter the characteristics of the area being measured. There are three
methods to enter this and depend on the location of your measurement.
If measuring square duct work you would enter Length and Width
(LW). For round duct you would enter Diameter (D). If measuring the
exit with a grill it is recommended to use the effective area or free
area (A) from the grill manufacture. If this is not known, the air volume
measurement will be an estimate.

Note: Grill manufacturers often provide engineering data on
effective or free area. This is indicated as the Ak value.

ENTERING DUCT INFORMATION

1. Press MODE until VOL is showing in the upper right corner of the
display

2. Press LW-D-AREA until the desired method is showing in the
lower left corner of the display

3. Press MIN/MAX AVG ( ) to select this mode
a. Press (HOLD) to increase the value
b. Press (LW-D-AREA) to decrease the value
c. Press MIN/MAX AVG ( ) to accept the displayed value

Note: Press and hold to scroll through the values quickly.

Release and then press briefly to increase or decrease one
digit at a time.

After entering the duct characteristics you will be taken back to the
display for Air Volume. Hold the probe in the area to be measured for a
direct display of air volume.

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MEASURING AIR VOLUME (CFM OR CMM) CONT.

TIMED AVERAGE AIR VOLUME

1. Press MODE until VOL is showing in the upper right corner of
the display

2. Enter duct dimensions using the method described prior section

3. Place the probe at the face of the opening, or on the grill surface

4. Press “START” to begin timed average
a. Slowly move the probe across the entire surface of the grill or

duct opening

5. Press “STOP” to end timed average.
a. The cumulative timer will stop when the DAFM3B is not

capturing data

6. Press MIN/MAX AVG ( ) after capturing data to view
average volume

a. AVG flashing and elapsed time will show when displaying
average

b. AVG flashing, elapsed time and MIN will show minimum
measured volume

c. AVG flashing, elapsed time, and MAX will show maximum
measured volume

7. Press and hold EXIT to end test

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ESTIMATING FREE AREA (EFFECTIVE AREA) OF A GRILL

To obtain air volume on a grill with unknown effective or free area you
must estimate the free area. This is difficult, but can be used to provide
an estimate of the volume for comparison testing. If multiple grills of the
same design are compared using this method, you will have an accurate
relative comparison, although the actual value may not be exact.

Method 1

• Measure length and width in inches.

• Obtain overall area in square inches by multiplying length

times width.

• Divide square inches by 144 to convert to square feet.

• Multiply the result by 0.70 (70%) to estimate the actual

open area.

Note: For return registers that are more open, increase the factor to

0.9 (90% open). For louvered registers with much more covered area
decrease to 0.5 or 0.6 (50~60% open).

Example – 4”x10” residential floor register

• Step 1 – 4” and 10”

• Step 2 – 4 x 10 = 40 square inches

• Step 3 – 40 ÷ 144 = 0.2777 square feet

• Step 4 – 0.277 x 0.70 = 0.194 square feet
(use this when entering free area “A” on the DAFM3B)

Method 2

Measure the grill area inside the frame of the register, calculate area in
square inches and convert to square feet using the method 1 steps. You
do not need to perform step 4.

Example – 4”x10” floor register

• Step 1 – actual louver area dimensions are 9” x 3.5”

• Step 2 – 9 x 3.5 = 31.5 square inches

• Step 3 – 31.5 ÷ 144 = .219 square feet

Note: This method may result in a slightly elevated result as it does not
fully remove the louvers that are in the air path.

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MAINTENANCE

LOW BATTERY

When the low battery “ ” icon appears on the display, all readings will
change to “ “ to prevent inaccurate results. Change the 9V battery
located in the inner compartment on the rear of the instrument.

CLEANING

Periodically clean your meters case using a damp cloth (not wet) only.
DO NOT use abrasive, flammable liquids, cleaning solvents, or strong
detergents as they may damage the finish, impair safety, or affect the
reliability of the structural components.

BATTERY REPLACEMENT:

Remove screw from the battery compartment cover on the back of your
meter and remove cover. Replace battery with a fresh 9 Volt battery
paying attention to polarity. Replace cover and secure with screw.

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SPECIFICATIONS:

English Metric

Air velocity range 99 ~ 3937 ft/min 0.5 ~ 20 m/s

Air velocity resolution 0.1 ft/min 0.1 m/s

Air velocity accuracy ±5% ±5%

Temperature range -4 ~ 140°F -20 ~ 60°C

Temperature resolution 0.1°F 0.1°C

Temperature accuracy ±1˚F ±0.6˚C

RH% range 0.1 ~ 99.9% RH

RH% resolution 0.1% RH

RH% accuracy ±3% (10 ~ 60% RH);

±5% at others

Wet bulb range -7.6 ~ 158 °F -22 ~ 70°C

Wet bulb resolution 0.1°F 0.1°C

Air volume display 0 ~ 99999 CFM (m

3

/s)

Air volume resolution 0.1 (0 ~ 9999.9), 1 (10000 ~ 99999)

Dew point range -90˚ ~ 158˚F (-68˚ ~ 70˚C)

Dew point resolution 0.1˚F (0.1˚C)

Dew point accuracy ±3% (-10 ~ 60% RH);

±5% at other range

LCD Size (HxW) 1.38 x 2.13 inches 35.2 x 54 mm

Operating temperature
range

32 ~ 122°F 0 ~ 50°C

Operating RH% Less than 80% (handset)

Storage temperature
range

-4 ~ 122°F -20 ~ 50°C

Storage RH% Less than 90%

Dimension 7.1 x 2.9 x .5 inches 180 x 73 x 38 mm

Weight .37 lbs 170g

Battery 9V battery (1)

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