General DCFM8906 User manual

Please read this manual carefully and thoroughly before using this product.
DIGITAL ONE PIECE
AIRFLOW METER WITH
CFM DI PLAY
USER’S MANUAL
DCFM8906

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TABLE OF CONTENTS
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Key Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
What’s in the Case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Product Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 4 –8
Setup Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Install Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Operating Instructions . . . . . . . . . . . . . . . . . . . . . . 9 – 23
Making Basic Air Speed Measurements . . . . . . 9 – 11
ecording Air Speeds at a Single Point . . . . . . 11 – 13
Displaying the Average Air Speed at
Multiple Points . . . . . . . . . . . . . . . . . . . . . . . 13 – 16
Converting to Airflow Volume Measurements 16 – 19
Switching Between Imperial and Metric Units 20 – 22
Disabling Auto Power Off . . . . . . . . . . . . . . . . . 22 – 23
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Maintenance Tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Warranty Information . . . . . . . . . . . . . . . . . . . . . 25 – 26
eturn for epair Policy . . . . . . . . . . . . . . . . . . . . . . . 26

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INTRODUCTION
Thank you for purchasing General Tools & Instruments’
DCF 8906 Digital One Piece Airflow eter with CF Display.
Please read this user’s manual carefully and thoroughly before
using the instrument.
The DCF 8906 is a professional-grade vane anemometer that
can not only measure air speeds exiting an HVAC/R system’s or
blower’s grille or register, but also convert those readings to
airflow volume measurements. The conversions are possible
because the meter makes it easy for an installer or repairman to
enter the free area dimensions of his system’s output ductwork.
The meter can record air speed readings at one point or multiple
points for up to two hours and convert those readings into
displays of average, minimum and maximum air speed or airflow
volume. The unit can hold measurements made in the dark for
later viewing in a brighter area. It also measures ambient air
temperature and displays it simultaneously with air speed or
airflow volume on a large front-panel LCD.
The DCF 8906 can display its air speed and airflow volume
measurements in Imperial or metric units and its temperature
measurements in degrees Fahrenheit or Celsius. A 20-minute
auto power off function (which can be disabled to enable long-
term recordings of air speed) helps extend battery life.
The DCF 8906 is powered by one 9V battery (included).

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KEY FEATURE
• easures and displays air speed and airflow volume in
Imperial or metric units
• Simultaneously displays temperature in °F or °C
• One-handed operation
• Records average, minimum and maximum air speed at
a single point or multiple points
• Data hold
• Auto power off
• CE and RoHS approved
WHAT’ IN THE CA E
The DCF 8906 comes fully assembled in a custom molded
plastic case along with a “9V” battery and this user’s manual.
PRODUCT OVERVIEW
Figure 1 shows the labels and positions of the six control
buttons on the front of the DCF 8906. The figure also shows
all possible indications on the LCD below the control panel.
Familiarize yourself with the buttons’ functions and the
meanings of the display indications before moving on to the
Setup Instructions.

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Fig. 1. The DCFM8906’s controls and indicators
CONTROL BUTTONS
ON-OFF ESET
Turns meter on and off
When pressed with AVE AGE button, resets default air
speed and temperature units
When pressed with HOLD button, disables auto power
off function

MODE VELOCITY F EE A EA FLOW
When pressed, places meter in airflow volume
measurement mode
Used with HOLD and AVE AGE buttons to enter free
area dimensions
AVE AGE MULTI-POINT
When pressed, calculates and displays average of
stored air speed measurements for up to eight points
Used with HOLD and MODE buttons to enter free area
dimensions in airflow volume measurement mode
When pressed with ON-OFF ESET button, resets default
air speed and temperature units
HOLD
When pressed, holds (freezes) upper display reading
Used with MODE and AVE AGE buttons to enter free
area dimensions in airflow measurement mode
When pressed with ON-OFF ESET button, disables auto
power off function
SEL: MPH KNOTS
In Imperial units mode, cycles through mil/h (mph), knots
and ft/m default settings
In metric units mode, cycles through km/h, knots, and
m/s default settings
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MIN/MAX EC SINGLE-POINT
When pressed once, meter begins recording air speed at
a single point. Default display is average air speed
since recording began
Next press changes display to real-time air speed
Next two presses change display to minimum and
maximum air speeds since recording began
Next press returns display to average air speed
All possible display indications and their meanings
vel Upper reading is an air speed measurement
FLOW Upper reading is an airflow volume measurement
A EA Lit during entry of free area dimensions
Hold Upper and lower readouts are locked (frozen)
PH Reserved for future use
Knots Air speed unit equal to 1.85 km/hr (kmph) or 1.15
miles/hr (mph). An upper display unit option in both
Imperial and metric modes
ft/m Feet per minute. An upper display air speed unit in
Imperial mode
m/s eters per second. An upper display air speed unit in
metric mode
mil/h iles per hour (mph). An upper display air speed unit in
Imperial mode
km/h Kilometers per hour (kmph). An upper display air speed in
metric mode
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ft2 Square feet. Lit during entry of free area dimensions in
Imperial mode
m2 Square meters. Lit during entry of free area dimensions
in metric mode
cfm Cubic feet per minute. Unit of airflow volume readings in
Imperial mode
cms Cubic meters per second. Unit of airflow volume readings
in metric mode
°C Degrees Celsius. Temperature unit in metric mode
°F Degrees Fahrenheit. Temperature unit in Imperial mode
EC eter is recording air speeds at a single point
AVG Upper reading is average air speed recorded during
session
MIN Upper reading is minimum air speed recorded during
session
MAX Upper reading is maximum air speed recorded during
session
– Temperature reading on lower display is a negative
number
8888 Digits of air speed, airflow volume or free area value
(upper reading)
1888 Digits of temperature value. When recording air
(lower reading) speeds at multiple points, indicates point number
(from 1 to 8)
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ETUP IN TRUCTION
INSTALL BATTERY
The meter’s battery compartment is accessible from the back
of the unit. Use a Philips-head screwdriver to remove the one
screw holding the battery compartment cover in place.
Remove the cover and set it aside. Then plug the included 9V
battery into the wired socket inside the compartment. The
terminals of the battery and the socket mate in only one way,
with the smaller male terminal plugging into the larger female
terminal. Replace the battery compartment cover and secure
it with the Philips-head screw.
OPERATING IN TRUCTION
MAKING BASIC AIR SPEED MEASUREMENTS
To power on the meter, press the ON-OFF ESET button. The
beeper (which cannot be disabled) will sound once and all
display indications will appear briefly. After a few seconds,
the readings on the upper and lower displays will stabilize.
By default, the upper display reads out air speed in ft/m and
the lower display reads out temperature in degrees
Fahrenheit. These Imperial system defaults are reflected by
three indications (Fig. 2): vel (at upper left), ft/m (to the right
of the air speed digits) and °F (to the right of the temperature
digits).
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DIRECTION OF AIRFLOW
Fig. 2. The meter’s default initial display after being
powered on
To make an air speed measurement, place the meter in the
airstream leaving the HVAC system duct or register. Be sure to
orient the meter so its vanes are centered in the stream and
its axes are as perpendicular to the stream as possible
(Fig.3).
Fig. 3. How to orient the meter
The upper display will read out the real-time air speed in
units of ft/m.
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