Fieldpiece AAT3 User Manual
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In-Duct
Psychrometer
and Air Velocity
Head
Model AAT3
Quick Start
1. Connect AAT3 to Fieldpiece meter.
2. Select mVDC range on meter.
3. Remove vinyl slip cover from the
probe tip.
4. Select desired switch position on
AAT3 for temperature, %RH, or air
velocity.
5. Read your measurement directly on
the display of the Fieldpiece meter.
Description
Your AAT3 is a portable,
psychrometer accessory head, with a
built in hot wire anemometer.
The compact probe tip makes
directly measuring in ducts a breeze.
The 38"(96cm) telescopic probe with
laser etched ruling and flattened
edges allows you to locate proper
measurement points within a duct and
ensures that your probe is properly
aligned for air velocity measurements.
The AAT3 can measure percent
In-Duct
Psychrometer
& Air Velocity
Head
DRY BULB
WET BULB
DEW POINT
ENGLISH METRIC
RH%
Ft/min
°F
RH%
M/s
AAT3
ON
LO BATTAVG
ENGLISH
AVG
METRIC
NORMAL
°C
AUTO OFF
80
Certifications
C-Tick (N22675)
CE
WEEE
RoHS Compliant
relative humidity, dry bulb, and air
velocity and can calculate wet bulb
and dew point.
The AAT3 snaps directly onto the
Fieldpiece HS series DMMs. For other
meters, use Fieldpiece ADLS2 test
leads or AHDL1 handle adapter.
Use your AAT3 with the HVAC Guide
to easily calculate in-duct CFM or
to perform Target Evaporator Exit
Temperature tests and get accurate
Target Superheat calculations.
OPERATOR'S MANUAL
01 03 0602 0504
Go wireless with your AAT3 by
using Fieldpiece wireless transmitters
(ET2W/EH2W) to send measurements
over-the-air to Fieldpiece wireless
receivers (HG3, LT17AW, EH4W)
anywhere on the jobsite.
AAT3 w/ ET2W
transmitting
wirelessly to HG3
In-Duct
ON
Psychrometer
Head
LO BATT
ON
°F
1%RH/mVDC
1°F/mVDC
1°C/mVDC
OFF
°C
TEMP
INPUT FORM
SH Table: Standard
Refrigerant: R-22
OD Dry Bulb: 85.4°F
Return WB: 63.0°F
SL Pressure: 52.4psig
SL Temp: 45.4°F
CustomerID: __JONES123
Sync
Input
SETUP
CFM
Target
CheckMe!
Evaporator
Exit Temp
Data
Logger
Superheat
Service
Light
SubcoolingCombustion
Clear
Recall
HVAC Guide
HG3
Fieldpiece
Output
Enter
Display
Save
WET BULB
DEW POINT
SEND
SYNC
RECEIVE
%RH
ARH5
ET2W
AC
DC
Wireless
Transmitter
AUTO OFF
ON
LO BATT
How to Use
General Instructions
1. Remove sensor cap from the telescoping
probe tip.
2. Connect directly onto any Fieldpiece
HS multimeter, data logget or the HG3 HVAC
guide. For most Fieldpiece SC and LT meters,
use Fieldpiece ADLS2 test leads plugged into
the COM and VΩ jacks.
3. Select mVDC range on multimeter.
4. Set switch position of AAT3 to °F and°C,
Ft/min and M/s, or %RH.
a.) For temperature set temp type switch
to DRY BULB, WET BULB or DEW POINT.
b.) For velocity measurements wait for 10
seconds as the AAT3 warms up.
5. Read the measurement directly on
the multimeter display.
What is Free Area?
How Do I Get It?
Free Area is the total area through
which air can ow on either a supply
outlet or a return grille. Free area
is also some times referred to as
"eective area" or "see through area."
If there is no grille or restriction on
the area through which air is owing
then the free area is equal to the actual
area. This would be the case if you are
performing an in-duct measurement
or if you were to remove the grille
from a supply or return.
If you are measuring airow where
there is an obstruction present then
the free area is the total area minus
area covered by the ns or grating.
Free Area is published by grille
manufacturers and is the most
accurate representation of the Free
Area of a duct. Use manufacturer's
data whenever available.
Specifications
Operating environment:
Air Velocity: -4°F to 140°F (-20°C to 60°C)
Temperature: -4°F to 140°F (-20°C to 60°C)
Relative humidity: 32°F to 131°F (0 to 55°C)
Storage temp: -4°F to 140°F (-20°C to 60°C) <80%
R.H. (Batteries removed)
Output impedance: approx. 1KΩ
Temperature coecient: 0.1 x (specied accuracy)
per °C (<18°C or >28°C) (<64°F or >82°F)
AIR VELOCITY
Range: 40-3940 ft/min (0.20-20.00 m/s)
Note 1: To use full range AAT3 must be connected to a
DMM with a 4000 mVDC range or greater.
Note 2: For m/s, divide the reading on the display by
10 for actual measurement. Tip: Move the decimal
point one place to the left.
Accuracy: ± (5%+1 dgt) reading or ± (1%+1dgt)
full scale.
RELATIVE HUMIDITY
Range: 0% to 100% RH
Accuracy:
±2.5% @ 73.4°F (23°C), 10% to 90% RH
±5% @ 73.4°F (23°C), <10% RH, >90% RH
Sensor Response Time: 60 seconds typical for 90%
of total range.
Sensor Hysteresis: ±1%RH typical
TEMPERATURE
Range: -4°F to 140°F (-20°C to 60°C)
Accuracy: ±1°F 32°F to 113°F
±2°F -4°F to 32°F, 113°F to 140°F
±0.5°C 0°C to 45°C
±1°C -20°C to 0°C, 45°C to 60°C
Sensor type:
Air velocity: Tiny glass bead thermistor.
Relative Humidity: Capacitance polymer lm.
Temperature: Precision thermistor.
Battery: 9V
Battery life: 20 -35 hours typical
Battery indication: Red Lo Batt LED
Auto Power o: after 15 minutes of inactivity if APO
is active.
Dimensions: 144mm(H) x 67mm(W) x 32mm(D).
Weight: approx. 240g including battery.
Maintenance
Clean the exterior with a dry cloth.
Do not use liquid.
Battery Replacement
When Lo Batt LED lights up replace
old battery with new 9V battery.
Sensor Care
When not in use it is best to protect
this sensors with the vinyl slip cover
included with the AAT3.
Extreme conditions or exposure to
solvent vapors may oset the RH%
sensor. If this happens, place the
sensor in a controlled envrionment of
75%RH and between 68°F - 86°F for a
period of 24 hours.
To create a 75%RH environment
moisten a small amout of table salt,
in an open container such as a clean
2 liter bottle cap.
Place the container with the salt
solution and the AAT3 probe in a
sealable plastic bag, and leave the bag
in a room temperature location where
it will not be disturbed for 24 hours.
Note: It is important that the salt
solution does not come in direct
contact with the sensor, as this may
permenantly damage the sensor.
Optional accessories
In-Duct
ON
Psychrometer
& Air Velocity
LO BATTAVG
Head
ENGLISH
AVG
DRY BULB
WET BULB
DEW POINT
METRIC
NORMAL
ENGLISH METRIC
RH%
RH%
Ft/min
M/s
°F
°C
INPUT FORM
SH Table: Standard
Refrigerant: R-22
OD Dry Bulb: 85.4°F
Return WB: 63.0°F
SL Pressure: 52.4psig
SL Temp: 45.4°F
CustomerID: __JONES123
Output
Sync
Input
Enter
SETUP
CFM
Target
CheckMe!
Evaporator
Exit Temp
Display
Data
Logger
Superheat
Service
Light
SubcoolingCombustion
Clear
Save
Recall
HVAC Guide
HG3
Fieldpiece
RCONE1 and AAT3 working with
ET2W and HG3 to wirelessly log
Wetbulb for target superheat testing.
AUTO OFF
AAT3
ET2W
AC
DC
SEND
ON
Wireless
SYNC
Transmitter
RECEIVE
LO BATT
Limited Warranty
This meter is warranted against
defects in material or workmanship
for one year from date of purchase.
Fieldpiece will replace or repair the
defective unit, at its option, subject
to verication of the defect.
This warranty does not apply to
defects resulting from abuse, neglect,
accident, unauthorized repair,
alteration, or unreasonable use of
the instrument.
Any implied warranties arising
from the sale of a Fieldpiece product,
including but not limited to implied
warranties of merchantability and
tness for a particular purpose, are
limited to the above. Fieldpiece shall
not be liable for loss of use of the
instrument or other incidental or
consequential damages, expenses, or
economic loss, or for any claim of such
damage, expenses, or economic loss.
State laws vary. The above
limitations or exclusions may not
apply to you.
For Service
In the USA, call Fieldpiece
Instruments for one-price-x-all out of
warranty service pricing. Send check or
money order for the amount quoted.
Send the meter freight prepaid to
Fieldpiece Instruments. Send proof
of date and location of purchase for
in-warranty service. The meter will be
repaired or replaced, at the option of
Fieldpiece, and returned via least cost
transportation. Outside of the USA,
please visit www.eldpiece.com for
service contact information.
www.eldpiece.com
©Fieldpiece Instruments, Inc 2015;v13
07 09 1208 1110
90°
D (<10”)
D (>10”)
0.032D
0.135D
0.321D
0.679D
0.865D
0.968D
0.019D
0.077D
0.153D
0.217D
0.361D
0.639D
0.783D
0.847D
0.923D
0.981D
D (<10”)
0.032D
0.135D
0.321D
0.679D
0.865D
0.968D
90°
D (<10”)
D (>10”)
0.032D
0.135D
0.321D
0.679D
0.865D
0.968D
0.019D
0.077D
0.153D
0.217D
0.361D
0.639D
0.783D
0.847D
0.923D
0.981D
90°
90°
90
85
80
Diagnostic Tests
Wireless Return Wet Bulb
for Target Superheat
The AAT3 with a wireless transmitter
(ET2W, EH4W, or LT17AW) allows to
you monitor the return wet bulb while
you are at the condensor. Send this
real-time WB measurement wirelessly
to the INPUT FORM of the HVAC Guide
(HG3) to calculate a real-time target
superheat.
1. Sync your transmitter with AAT3 to
2. Punch or drill a small 3/8" hole in
3. Input an outdoor dry bulb manually
4. Press OUTPUT on HG3 to see your
the Return WB INPUT line in Super-
heat Test of the HG3.
the return plenum to insert AAT3
probe. Press ENTER on the HG3 to
lock reading.
or with an ATH4 at the consdensor
into the OD Dry Bulb INPUT line in
the Superheat Test of the HG3.
target superheat calculations.
Target Evaporator Exit
Temp with the HVACGuide
The AAT3 with Fieldpiece HVAC
Guide, allows you to easily perform
a Target Evaporator Exit Temperature
(TEET) test to determine if the
evaporator is getting the optimum
airow.
1. Slide AAT3 onto the top of the HVAC
Guide. Select TEET switch position.
2. In the INPUT FORM, highlight Return
DB. Set the AAT3 to the Temperature
switch position and select dry bulb.
Press ENTER to measure air tem-
perature going into the evaporator
Drill a small 3/8" hole in the return
plenum and insert the AAT3 probe.
Press ENTER to lock reading. Take
measurements as close to the air
handler as possible. Seal any holes
before leaving the jobsite.
3. In the INPUT FORM, highlight Re-
turn WB. Press ENTER to measure
wet bulb temperature going into
the evaporator by inserting AAT3
return and selecting the appropriate
switch position on the AAT3. Press
ENTER to lock reading.
4. In the INPUT FORM, highlight Supply DB. Press ENTER to measure
air temperature coming out of the
evaporator. Punch or drill a small
3/8" hole in the supply plenum and
insert ARH5 wand in the center of
the plenum to take measurement.
Press ENTER to lock reading.
5. Press OUTPUT to view results.
probe through the same hole at the
13 15 1814 1716
Measuring Accurate
Airow
Find a Suitable Location
for a Traverse
1. The cross sectional area at, before and after the
traverse location should be a either rectangular
or round.
2. Make sure you have sucient access around
the traverse location so that the duct may be
traversed at multiple angles.
3. The traverse location should be chosen so as to
minimize the eects of leaks in the portion of
the system between the fan and the traverse
location.
4. The traverse location should be located far
enough downstream of the fan to allow the
airow to come to a uniform distribution.
To determine an eective length, assume a
minimum of 2.5 duct diameters for 2500 ft/
min or less and add 1 duct diameter for each
additional 1000 ft/min measured. (For a
rectangular duct the equivalent diameter can
be calculated as D=√(4hw/π) where “h” is the
height of the duct and “w” is the width.)
5. Locations directly downstream from
obstructions, bends or sudden changes in the
duct are not good locations for a traverse.
Ex. 8” round duct
D=8”
2.5D=20“
2.5D+1D=28”
Traverse here if
velocity is 3500ft/min
Traverse here if
velocity is 2500ft/min
*Not to Scale
1 D
Ex. 24”x 8” duct
H=24
W=8
D=√(4HW/π)
D=16” (approx.)
2.5D= 40” (approx.)
Traverse here if
velocity is
2500ft/min
2.5 D
2.5 D
*Not to Scale
FAN
Execute the Traverse
1. Determine the appropriate measurement
2. Set the average switch on the AAT3 to AVG to
3. Insert the probe tip of the AAT3 into the duct
4. Use the laser etched ruler on the side of the
5. Record a point measurement (Either manually or
6. Use the recorded velocity measuremtents
19 21 2420 2322
points by measuring either the diameter of
the duct or the width and height. Then use the
appropriate table (See table 1 and 2) to calculate
the insertion depth where each of the point
measurements should be recorded.
display a 16 second running average.
and use the at edges of the probe to align the
sensor with the airow direction. Check that
the direction of airow is at 90° to the probe by
making sure that the probe is at a right angle to
the side of the duct.
probe probe to measure the insertion depth and
nd the locations you determined in step 1.
by using the Fieldpiece HG3, or DL3) at each of
the locations determined in step 1.
to calculate the airow by rst detemining
the average velocity of the traverse and then
multiplying by the free area of the duct.
Proper Measurement
Points for Rectangular/
Square Ducts
W
H
0.061W
0.235W
Traverse locations using log-Tchebyche rule in a rectangular duct
Length of Side # of Traverse Lines Distance from Inner Wall in % of Length of Side
< 30 in (76 cm) 5 7.4%, 28.8%, 50%, 71.2%, 92.6%
30-63in (76-160cm) 6 6.1%, 23.5%, 43.7%, 56.3%, 76.5%, 93.9%
>63in (160cm) 7 5.3%, 20.3%, 36.6%, 50%, 63.4%, 79.9%, 94.7%
0.437W
0.563W
TABLE 1
Proper Measurement
Points for Round Ducts
0.926H
0.712H
0.500H
0.288H
0.074H
0.765W
0.939W
TABLE 2
Log linear rule for traverse points on two diameter for a round duct
Diameter # of points per diameter Distance from inner wall in % of diameter
<10in (25.4cm) 6 3.2%, 13.5%, 32.1%, 67.9%, 86.5%, 96.8%
≥ 10in (25.4cm) 10 1.9%, 7.7%, 15.3%, 21.7%, 36.1%, 63.9%
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