Air Monitor VOLU-flo/OAM II User manual

VOLU-o/OAM II Transmitter
Version 1.2
Di󰀨erential Pressure Airow & Temperature
Measurement System
www.airmonitor.com • 1-800-AIRFLOW
Installation, Operation and Maintenance Manual

P.O. Box 6358 •Santa Rosa, CA •USA • 1-800-AIRFLOW • www.airmonitor.com • [e-mail]
OAM II Transmitter Dierential Pressure Airow & Temperature Measurement System 1017-1 - 12/17 2
Regarding this Manual
• This manual should be passed on to the end user.
• Before use, read this manual thoroughly to comprehend its contents.
• The contents of this manual may be changed without prior notice.
• All rights reserved. No part of this manual may be reproduced in any form without Air
Monitor’s written permission.
• Air Monitor makes no warranty of any kind with regard to this material, including, but not
limited to, implied warranties of merchantability and suitability for a particular purpose.
• All reasonable effort has been made to ensure the accuracy of the contents of this manual.
However, if any errors are found, please inform Air Monitor.
• Air Monitor assumes no responsibilities for this product except as stated in the warranty. If
the customer or any third party is harmed by the use of this product, Air Monitor assumes
no responsibility for any such harm owing to any defects in the product which were not
predictable, or for any indirect damages.
Safety Precautions
The following general safety precautions must be observed during all phases of installation, operation,
service, and repair of this product. Failure to comply with these precautions or with specic
WARNINGS given elsewhere in this manual violates safety standards of design, manufacture, and
intended use of the product. Air Monitor Corporation assumes no liability for the customer’s failure to
comply with these requirements. If this product is used in a manner not specied in this manual, the
protection provided by this product may be impaired.
The following symbols are used in this manual:
!
!
WARNING
Messages identied as “Warning” contain information regarding the personal safety of individuals
involved in the installation, operation or service of this product.
CAUTION
Messages identied as “Caution” contain information regarding potential damage to the product or
other ancillary products.
IMPORTANT NOTE
Messages identied as “Important Note” contain information critical to the proper operation of the
product.
i

P.O. Box 6358 •Santa Rosa, CA •USA • 1-800-AIRFLOW • www.airmonitor.com • [e-mail]
OAM II Transmitter Dierential Pressure Airow & Temperature Measurement System 1017-1 - 12/17 3
TABLE OF CONTENTS
1.0 GENERAL INFORMATION ...................................................................................4
1.1 PURPOSE OF THIS GUIDE........................................................................4
1.2 TYPICAL METER INSTALLATION ...........................................................4
1.3 SPECIFICATIONS.......................................................................................6
1.4 CHECKING THAT YOU RECEIVED EVERYTHING .................................7
1.5 WORKING ENVIRONMENT......................................................................7
1.6 SERIAL NUMBER.......................................................................................7
2.0 INSTALLATION .....................................................................................................8
2.1 SITE SELECTION........................................................................................8
2.2 ENCLOSURE INSTALLATION...................................................................9
2.3 AIRFLOW SENSORS..................................................................................10
2.4 AIRFLOW SENSOR INSTALLATION .......................................................11
2.5 AIRFLOW SENSOR INSTALLATION DETAIL .........................................12
2.6 AIRFLOW SENSOR PROCESS CONNECTIONS ......................................14
2.7 POWER/SIGNAL CONNECTIONS.............................................................15
3.0 OPERATION .........................................................................................................16
3.1 OPERATING MODES .................................................................................16
3.2 DISPLAY OPTIONS BASED ON OPERATING MODE..............................16
3.3 STATUS BAR ..............................................................................................17
4.0 PROGRAMMING MENU .......................................................................................17
4.1 MAIN MENU...............................................................................................18
4.2 FLOW SETTINGS (LOW/EXT/SPLIT/DUAL) ............................................18
4.3 FLOW CONFIGURATION (LOW/EXT)......................................................19
4.4 DISPLAY CONFIGURATIN (LOW/EXT/SPLIT/DUAL).............................21
4.5 ANALOG OUTPUT CONFIGURATION ....................................................21
4.6 FILTER AND LOCKDOWN SETTINGS .....................................................22
4.7 TRANSDUCER CONFIGURATION ...........................................................23
4.8 NETWORK CONFIGURATION..................................................................23
4.9 FIELD CHARACTERIZATION ...................................................................24
5.0 SERVICE MENU..........................................................................................25
5.1 PASSWORD.................................................................................................25
5.2 AUTOZERO INTERVAL.............................................................................25
5.3 CALIBRATE TRANSDUCERS....................................................................25
5.4 ANALOG OUTPUT CALIBRATION ..........................................................26
5.5 SET CUSTOM ID.........................................................................................26
5.6 FACTORY SETTINGS.................................................................................27
5.7 PRODUCT INFORMATION .......................................................................27
5.8 AUTOZERO AND ANALOG OUTPUT TEST............................................27
6.0 COMMUNICATIONS .............................................................................................28
7.0 MAINTENANCE.....................................................................................................32
8.0 TROUBLESHOOTING ...........................................................................................32
9.0 WARRANTY INFORMATION...............................................................................33

P.O. Box 6358 •Santa Rosa, CA •USA • 1-800-AIRFLOW • www.airmonitor.com • [e-mail]
OAM II Transmitter Dierential Pressure Airow & Temperature Measurement System 1017-1 - 12/17 4
SECTION 1.0 GENERAL INFORMATION
Thank you for purchasing the OAM II Outdoor Airow Measurement System. As our valued
customer, Air Monitor’s commitment to you is to provide quality service and support while
continuing to offer you accurate, reliable products to meet your ow measurement needs.
1.1 PURPOSE OF THIS MANUAL
This manual provides information regarding the installation, operation and maintenance of
your differential pressure airow measurement system. This is not an electrical or HVAC
trade manual. This manual is the basic reference tool for the OAM II transmitter, including
its mains power connection and associated signal inputs and outputs. The complete system
consists of the transmitter and associated airow and temperature sensors. Please refer to
supplemental documents for additional information.
1.2 TYPICAL AIRFLOW MEASUREMENT SYSTEM INSTALLATIONS
Air Monitor’s OAM II Outdoor Airow Measurement system has been specically designed to
accurately measure airow by measuring the pressure drop across a xed inlet resistance such
as a set of louvers or a layer of expanded metal. Temperature is also measured via a separate
sensor. The measured pressure drop and temperature are converted to actual air ow readings
utilizing proprietary algorithms that provide density compensation and signal conditioning.
The OAM II can be used with most single, dual, and split inlets found on air handlers and
built-up systems. Depicted below are the most commonly encountered inlet congurations.
For clarity, the examples below are only shown with only one airow sensor at each location.
With larger inlets or multiple inlets to one air handler, multiple sensors would be connected
in parallel using manifolds.
The example above illustrates a single OA inlet. The OAM II would be congured for low ow
or extended mode operation for this application.

P.O. Box 6358 •Santa Rosa, CA •USA • 1-800-AIRFLOW • www.airmonitor.com • [e-mail]
OAM II Transmitter Dierential Pressure Airow & Temperature Measurement System 1017-1 - 12/17 5
The example above illustrates a dual OA inlet (two inlets providing outside air to separate
air handlers). In this application, the VOLU-o/OAM II would be congured for dual mode
operation. Separate ow readings will be reported for each channel in this mode.
The example above illustrates a split OA inlet. Two inlets separately provide minimum and
economizer outside air ow to a single air handler. In this application, the VOLU-o/OAM
II would be congured for split min/max mode operation. Separate ow readings will be
reported for each channel in this mode.

P.O. Box 6358 •Santa Rosa, CA •USA • 1-800-AIRFLOW • www.airmonitor.com • [e-mail]
OAM II Transmitter Dierential Pressure Airow & Temperature Measurement System 1017-1 - 12/17 6
1.3 SPECIFICATIONS
Channel 2 transducer: 316 stainless steel ¼” NPT
compression ttings for channel 2 Dual mode or as the
maximum pressure port Split Min/Max mode
Temperature: 3-wire RTD terminal block connections
TEMPERATURE LIMITS
Standard operating range: +32 to 120 ºF
Extended operating range: -40 to 120 ºF (requires
optional NEMA4 enclosure heater)
Storage temperature range: -20 to 180 ºF
POWER SUPPLY REQUIREMENTS
24VAC (20-32VAC RMS) or 24VDC (20-40VDC)
Power Consumption
Standard:18VA @ 24VAC; 13W @ 24VDC
With heater: 40VA @ 24VAC; 35W @ 24VDC
DISPLAY
3.5” diagonal color graphic LCD with eld programmable
menu driven user interface accessed via four button
membrane keypad.
PROGRAMMING
Factory programmed for specic application. Field
programming available through the user interface/display.
MEMORY
Nonvolatile FLASH memory retains all program
parameters in the event of power loss.
ANALOG OUTPUTS
Three analog outputs are provided: Depending on the
operating mode, they can report ow, temperature and/or
differential pressure.
Field congurable via user interface/display as: 4-20mA,
0-10 VDC or 0-5VDC
COMMUNICATION PROTOCOLS (Field congurable via
user interface/display)
BACnet MS/TP (Default)
MODBUS RTU
NETWORK CONFIGURATION & ADDRESSING
RS485 unit load: ⅓
Recommended maximum number of devices per segment: 32
Baud Rates: 9600, 19200, 38400, 57600, 76800, or 115200
(Default: 38400)
Device Address Range: 1 – 255 (1 - 247 MODBUS)
(Default: 1)
BACnet Device Instance Range: 1 – 4,194,303 (Default 1)
BACnet Max Master Range: 1 – 127 (Default 127)
MODBUS Parity: None, Even, Odd (Default: Even)
APPROVALS
FCC Part 15 Subpart B, Class A Device
SENSING METHOD
Differential pressure is measured across a xed inlet
resistance along with temperature. Sensor readings are
used to calculate and report velocity, volumetric ow and
temperature data. The xed inlet resistance must produce at
least 0.06” w.c. pressure drop at 600 FPM face velocity.
MEASUREMENT MODES
Low Flow Mode: provides a single differential pressure
signal connection
Extended Mode: provides a single differential pressure
signal connection operating over an extended ow range
Min/Max (Split) Mode: provides two differential pressure
signal connections, one for the minimum OA inlet, and
the other for the maximum OA inlet.
Dual Mode: provides separate air ow measurement
channels for OA feeding two separate air handlers.
ACCURACY
Airow
±5% of actual airow over the specied operating
range above 150 FPM. Requires an optional enclosure
heater to maintain accuracy when operating at ambient
temperatures below 32 °F.
Temperature
±2° F from -50 to 120 °F
OVERALL FLOW RANGE (≥ 100 FPM)
Low ow operating mode: 6:1 turn-down
Extended operating mode: up to 24:1 turn-down
Min/Max (Split) operating mode: 6:1 turn-down for each
channel
Dual operating mode: 4:1 turn-down for each channel
AVAILABLE TRANSDUCERS (max. pressure in inches
w.c.) 0.1, 0.25, 0.5, 1.0. 2.0, 5.0 and 10
AVAILABLE SENSOR TYPES
Uni-sensor
316 stainless steel combination reference and inlet
airow pressure sensors.
Temperature
316 stainless steel 3-wire 100 Ohm Platinum RTD with
¼” NPT mounting hardware
ENCLOSURE
Standard: NEMA 1 aluminum with hinged cover
Optional: NEMA 4 with display window and heater
AIRFLOW SENSOR CONNECTIONS
Channel 1 transducer: 316 stainless steel ¼” NPT
compression ttings used for low ow, Extended or
channel 1 Dual mode or as the minimum pressure port for
Min/Max (Split) mode

P.O. Box 6358 •Santa Rosa, CA •USA • 1-800-AIRFLOW • www.airmonitor.com • [e-mail]
OAM II Transmitter Dierential Pressure Airow & Temperature Measurement System 1017-1 - 12/17 7
1.4 CHECKING THAT YOU RECEIVED EVERYTHING
Carefully open the VOLU-o/OAM II shipping container(s) and remove all equipment. Inspect
equipment for any damage. If damaged, contact Air Monitor and your freight company. Verify
that the following items have been shipped:
• 1 OAM transmitter
• 1 temperature probe with mounting hardware
(Packed inside enclosure or part of OAM II Station)
• 1 VOLU-o/OAM II I/O & M manual
• 1 Factory Set-Up Information Sheet
Additional items included with the shipment may contain the following:
• 1 or more pre-fabricated OAM Airow Stations
• 1 or more uni-sensors, including mounting hardware
1.5 WORKING ENVIRONMENT
The OAM II with transmitter NEMA 1 enclosure was designed for installation and use in
indoor commercial/residential environments that are free of condensing moisture, temperature
extremes and excessive vibration. Do not expose to direct sunlight. The operating ambient air
temperature range is 32° to 120° F.
The OAM II transmitter with optional NEMA 4 enclosure was designed for installation and
use indoors or outdoors in commercial/residential environments, that are free of excessive
vibration. Avoid exposure to direct sunlight. The operating ambient air temperature range is 32°
to 120° F. When provided with an optional heater, the operating ambient air temperature range
is -40° to 120° F.
The electrical supply should be relatively clean, free of high frequency noise, large voltage
transients, and protected from power surges and brown outs. Avoid installation locations that
are in close proximity to strong sources of electrical interference.
1.6 SERIAL NUMBER
The serial number of your OAM II transmitter is located outside of the enclosure. The serial
number is a unique identier for your product. Please have it available when contacting Air
Monitor for assistance regarding your product.

P.O. Box 6358 •Santa Rosa, CA •USA • 1-800-AIRFLOW • www.airmonitor.com • [e-mail]
OAM II Transmitter Dierential Pressure Airow & Temperature Measurement System 1017-1 - 12/17 8
SECTION 2.0: INSTALLATION
The OAM II Airow Measurement System should be installed by experienced HVAC technicians
and others with related knowledge and experience with air ow systems. Air Monitor support
personnel are available to assist with technical recommendations and to provide guidance by
telephone and/or e-mail. On-site eld engineering, installation, and service are also available at an
additional cost.
The installer should use good trade practices and must adhere to all state and local building codes.
Each OAM II is individually calibrated, congured and programmed using customer specic
application data. Conguration and programming parameters are recorded on the Factory Set-Up
Information Sheet, provided with the unit. Review this information and verify that the OAM II
setup is correct for your application. If any problems or discrepancies are detected, contact Air
Monitor’s Customer Service Department at 1-800-AIRFLOW prior to proceeding.
2.1 SITE SELECTION
• Careful attention to the site selection for the system components will help the installers
with the initial installation, reduce start-up problems, and make future maintenance easier.
For example, do not install the OAM II transmitter where it will be difcult for personnel to
perform periodic maintenance. When selecting a site for mounting the system components,
consider the criteria under Section 1.5: WORKING ENVIRONMENT, as well as the following:
• OAM II enclosure
The standard NEMA1 transmitter enclosure is intended for indoor installations in non-
condensing environments.
The optional NEMA4 transmitter is suitable for outdoor installations. Avoid mounting the
enclosure in direct sunlight.
Find an easily accessible mounting location near the air handler to minimize sensor tubing
lengths. Mounting the enclosure slightly higher than the sensors will reduce the risk of any
water (from condensation) migrating into the enclosure. If this cannot be done, provisions for
drip legs should be installed at the lowest point in the sensing lines.
• Airow sensors
Each OAM II is factory congured for one of four operating modes. Each mode is intended
for use in specic applications. In all cases, uni-sensors should be installed at or near the
center of the inlet. When using multiple sensors on a single inlet, equidistant spacing is
required.
• Temperature sensors
A single RTD temperature sensor is installed with each OAM II. This sensor provides
ambient air temperature for density correction calculations. When the OAM II is provided
with a NEMA1 enclosure, the sensor may be installed in the air ow stream or outside the
air handler in a shaded area. When provided with the NEMA4 enclosure, the temperature
sensor is mounted to the bottom of the enclosure in a shaded area. When ordered with an
OAM II Station, the sensor will be installed on the station. In all cases, do not mount this
sensor in direct sunlight.

P.O. Box 6358 •Santa Rosa, CA •USA • 1-800-AIRFLOW • www.airmonitor.com • [e-mail]
OAM II Transmitter Dierential Pressure Airow & Temperature Measurement System 1017-1 - 12/17 9
2.2 ENCLOSURE INSTALLATION
Find an easily accessible location where electrical connections can be made and display
readings can be taken from the oor level.
Use four screws for mounting the enclosure. The mounting surface must be structurally sound
and capable of withstanding a minimum weight of 40lbs (18kg). Use the following screws for
mounting.
For NEMA1 enclosure:
• (4) Machine screws - #8-32 x 1.5”
• (4) Wood screws - #8 x 1.5”
• (4) Concrete screws - 3/16” x 1.5”
For NEMA4 enclosure:
• (4) Machine screws - HHMS .25-20 x 1.5”
• (4) Wood screws - FHLS .25 x 1.5”
• (4) Concrete screws - HHCS .25 x 1.5”
SUBMITTAL SHEET
Outside Air Monitor
VOLU-flo/OAM II
ENT DN
ESC UP
8.16
10.25
3.00 4.29
NEMA 1 NEMA 4
7.00
9.10
4X Ø.188
A
C
E F B
D
E
A
C
B
D
F
ESC
ENT
UP
DN
Outside Air Monitor
VOLU-flo/OAM II
10.30
8.20
6.00
10.77
4X Ø.312
RTD
2.75
OPT.
WINDOW
VOLU-flo/OAM ll

P.O. Box 6358 •Santa Rosa, CA •USA • 1-800-AIRFLOW • www.airmonitor.com • [e-mail]
OAM II Transmitter Dierential Pressure Airow & Temperature Measurement System 1017-1 - 12/17 10
2.3 AIRFLOW SENSORS
Air Monitor provides airow sensors in pre-fabricated airow stations and as separate
Uni-sensors as shown below.
OAM II Airow Station (shown with a single Uni-sensor)
OUTS IDE AIR MONITOR
VOL U- f l o/O AM ll
OAM Airflow Station
OAM II stations are built to order and provided fully assembled. The number of sensors
provided varies based on the size and shape of the station. When multiple OAM II
stations are provided for a single system, only one RTD will be included.
Uni-sensor
Uni-sensors combine the outside reference (high pressure) sensor and the inlet airow
(low pressure) sensor into one assembly. They are provided with probe lengths that
match the clearance requirements of the inlet where they will be installed.
DIMENSIONAL SPECIFICATIONS - UNI-SENSOR
VOLU-flo/OAM ll
OUTSIDE AIR MONITOR
12X
Ø.218
Ø4.00 LENGTH
1/8" FPT Fitting
1.50
Ø.25
12X
Ø.218
Ø4.00
LENGTH1.50
Ø.25
High Pressure Port,
1/4" Compression
Low Pressure Port,
1/4" Compression
AIR MONITOR CORPORATION
VOLU-flo/OAM ll
(800)-AIRFLOW
SANTA ROSA CA. 95406
OUTSIDE AIR MONITOR
OAM II Airow Station

P.O. Box 6358 •Santa Rosa, CA •USA • 1-800-AIRFLOW • www.airmonitor.com • [e-mail]
OAM II Transmitter Dierential Pressure Airow & Temperature Measurement System 1017-1 - 12/17 11
2.4 AIRFLOW SENSOR INSTALLATION
The following information details the installation requirements for the airow sensors.
Depending on what was ordered with your OAM II system, it will be necessary to install one or
more pre-fabricated OAM II airow stations or uni-sensors.
When installing a single uni-sensor at each inlet, it should be located as close to the center of
the opening as possible.
Air Monitor recommends that signal tubing between the transmitter enclosure and all sensors
be 1/4” OD stainless steel or copper. Use tees or manifolds when combining multiple sensor
signals at the transmitter input. UV resistant exible plastic tubing specically designed for
outdoor use, such as Tygon R-3400 or equivalent, may also be used.
i
IMPORTANT NOTE
Built-up systems should always use attened galvanized or stainless steel expanded metal
with the follow dimensions that follow: 63% open area, 0.05” thickness, 0.50” SWD x 1.25”
LWD x 0.096” strand width.
!
CAUTION
Flexible plastic signal tubing used in outdoor applications must be resistant to weathering and the
effects of UV exposure.
The following restrictions must be observed to ensure an accurate air ow measurement.
Louvered inlets:
• There must be a minimum clearance of 4” between the louver and the edge of the
damper blades when damper is wide open.
• The recommended distance between tip of the OAM uni-sensor and the edge of the
100% open damper blade should be at least 2”.
• The louver depth will dictate the length of the uni-sensor probe (louver depth +2”).
Rain Hood Inlets:
• In order to use an existing screem, it must meet the specied pressure drop requirement
of 0.06 inches w.c. at 600 FPM.
Plenum Inlets:
• When installing an OAM station directly on an AHU’s OA inlet that has damper blades
extending outside the damper casing, there must be a minimum clearance of 4” between
the screen and the edge of the damper blades when damper is wide open.
• The distance between tip of the OAM uni-sensor and the edge of the 100% open damper
blade should be at least 2”.
Ducted Inlets:
• Airow stations installed in ducts should be located such that there is no interference
upstream or downstream of the station that would intrude into the OAM station casing
or into the area where the Uni-sensor is installed.
Multiple Inlets: (OAM II transmitter in standard or extended mode)
• The area of each inlet must be the same and inlet dampers must operate in unison.
• Uni-sensors must be installed on each inlet and then connected via manifolds to
provide averaged sensor signals to the transmitter.

P.O. Box 6358 •Santa Rosa, CA •USA • 1-800-AIRFLOW • www.airmonitor.com • [e-mail]
OAM II Transmitter Dierential Pressure Airow & Temperature Measurement System 1017-1 - 12/17 12
Inlets with an Aspect Ratio > 6:1
• Inlets with an aspect ratio > 6:1 require the use of multiple uni-sensors spaced at
equidistant intervals. For example: A 2’ x 30’ louvered inlet has aspect ratio of 15:1. Use
three equally spaced sensors serving 2’ x 10’ areas, to reduce the aspect ratio to 5:1 for each
sensor.
• Uni-sensors must be connected via manifolds to provide averaged sensor signals to the
transmitter.
Very Large Inlets:
• Inlets with an area > 30 ft2 require the use of multiple uni-sensors spaced at equidistant
intervals. For example: A 7’ x 12’ inlet would require three sensors with each sensor
covering a 7’ x 4’ area. Uni-sensors must be connected via manifolds to provide averaged
sensor signals to the transmitter.
2.5 AIRFLOW SENSOR INSTALLATION DETAIL
OAM II Airow Station
AIR
FLOW
OAM II Station
Pre-fabricated OAM airow stations are built to order and delivered ready for installation in
ductwork or attached to an inlet using hardware provided by the installer.
NOTE: A temperature sensor is built into one of the OAM stations.

P.O. Box 6358 •Santa Rosa, CA •USA • 1-800-AIRFLOW • www.airmonitor.com • [e-mail]
OAM II Transmitter Dierential Pressure Airow & Temperature Measurement System 1017-1 - 12/17 13
Uni-sensors
Uni-sensors are installed in ductwork or attached to an inlet using the hardware provided. Air
Monitor recommends that signal tubing between the transmitter enclosure and all sensors be
1/4” OD stainless steel or copper. UV resistant exible plastic tubing specically designed for
outdoor use, such as Tygon R-3400 or equivalent, may also be used.
AIR
FLOW
AIR
FLOW
i
IMPORTANT NOTE
Built-up systems should always use attened galvanized or stainless steel expanded
metal with the dimensions that follow: 63% open area, 0.05” thickness, 0.50” SWD
x 1.25” LWD x 0.096” strand width.
!
CAUTION
Flexible plastic signal tubing used in outdoor applications must be resistant to weathering and the
effects of UV exposure.

P.O. Box 6358 •Santa Rosa, CA •USA • 1-800-AIRFLOW • www.airmonitor.com • [e-mail]
OAM II Transmitter Dierential Pressure Airow & Temperature Measurement System 1017-1 - 12/17 14
Temperature sensor
Installation with the NEMA1 OAM II enclosure.
• Remove the RTD temperature probe from the enclosure (taped in bag at bottom).
• Locate a convenient mounting location inside the air handler to mount the probe.
• Use the two supplied sheet metal screws to mount the probe.
Installation with the NEMA4 OAM II enclosure.
• Remove the RTD temperature probe from the enclosure (taped in bag at bottom).
• Remove the compression nut from the unmarked bulkhead tting at the bottom of the
enclosure.
• From outside the enclosure, slip the probe, wires rst, into the tting until it bottoms out.
• Slip compression nut over the probe and thread onto tting.
• Tighten nut one-half turn past nger tight.
2.6 AIRFLOW SENSOR PROCESS CONNECTIONS
Air Monitor recommends that signal tubing between the transmitter enclosure and all sensors
be 1/4” OD stainless steel or copper. Use tees or manifolds when combining multiple sensor
signals at the transmitter input. UV resistant exible plastic tubing specically designed for
outdoor use, such as Tygon R-3400 or equivalent, may also be used.
!
CAUTION
When installing or removing signal tubing from either the enclosure or the sensors, a wrench
should be used on the bulkhead nut to prevent turning.
Sensor 1 transducer: Pair 316 stainless steel ⅛”FPT ttings used for low ow, Extended or
sensor 1 Dual mode or as the minimum pressure port for Split Min/Max mode
Sensor 2 transducer: Pair 316 stainless steel ⅛”FPT ttings for sensor 2 Dual mode or as the
maximum pressure port Split Min/Max mode
!
CAUTION
Flexible plastic signal tubing used in outdoor applications must be resistant to weathering and the
effects of UV exposure.

P.O. Box 6358 •Santa Rosa, CA •USA • 1-800-AIRFLOW • www.airmonitor.com • [e-mail]
OAM II Transmitter Dierential Pressure Airow & Temperature Measurement System 1017-1 - 12/17 15
2.7 POWER/SIGNAL CONNECTIONS
Power and signal connections are made at the terminal blocks shown below. Input power wiring
should be 14 to 18 AWG. Signal wiring should be 18 to 22 AWG. The maximum wire gauge that
the terminal strips can accommodate is 14AWG. No more than two wires should be connected to
any one terminal. 18 AWG is the maximum gauge wire that can be doubled up in one terminal.
!
CAUTION
The OAM II transmitter is a low voltage device (24V AC/DC). Connecting the
transmitter to high voltage power (e.g. 110 VAC) may cause damage and will void the
warranty.
Mini USB Connector: Provided for eld service. See gure above for details.
I/O: AO1 (+) and (-), AO2 (+) and (-), AO3 (+) and (-). See gure above for details.
NETWORK: RS485 BACnet or MODBUS. (+) and (-) are for the RS485 signal. (G) is RS485
common. (S) is for the shield. See gure above for details.
ON/OFF Switch: There is an ON/OFF switch located in the lower left hand corner
of the front cover of this transmitter. Briey press the switch twice to turn on. Press
the switch once to turn off. If power fails while the transmitter is ON, it will restart
automatically.
!
CAUTION
PWR: (L +) for Line, (N -) for Neutral and (G) for Ground. See gure above for details.
The OAM II can be powered by either 20-32VAC 50/60 Hz or 20-40VDC.
!
CAUTION
The earth ground is required on all OAM II transmitter installations. Omitting the
connection to earth ground could result in poor performance and may void the warranty.

P.O. Box 6358 •Santa Rosa, CA •USA • 1-800-AIRFLOW • www.airmonitor.com • [e-mail]
OAM II Transmitter Dierential Pressure Airow & Temperature Measurement System 1017-1 - 12/17 16
SECTION 3.0: OPERATION
Start-up
Press the power button located in the lower left hand
corner of the cover. The pushbutton must be pressed
twice to power on. At power-up, you will see the current
version of the software and the company logo displayed.
This will disappear after a brief pause, and the normal
display will appear.
Information shown on this screen (ow, temperature,
velocity, etc.) will vary based on the OAM II operating
mode. In addition, system status data provided at
the top of the display window and the user dened
User
interface for
programming
Power Switch
Press twice for
On and once for
OFF.
locations tag is displayed at the bottom. Default display settings based on the operating mode are
provided below.
The user interface consists of 4 pushbuttons. These are only used to access the programming mode.
3.1 OPERATING MODES
The displayed information is dependent on the conguration of the OAM II (operating mode).
The operating modes for the VOLU-o/OAM II is are Low Flow (Std.), Extended (Ext), Split Min/
Max and Dual.
Low Flow – Single transducer (100-600 FPM)
Extended – Two transducers in series (stacked) to extend the range
Split Min/Max – Two transducers in parallel to allow for two different ranges to be blended to
a single ow
Dual – Two transducers which are physically in the same transmitter, but monitor separate ducts
and work autonomously from each other
3.2 DISPLAY OPTIONS BASED ON OPERATING MODE
For Low Flow/Extended Mode:
- Line 1 is for Flow
- Line 2 can display Velocity/Temperature/DP/None
- Line 3 can display Velocity/Temperature/DP/None
- Line 4 can display Velocity/Temperature/DP/None
For Split Min/Max mode:
- Line 1 is for Flow
- Line 2 can display Velocity Min/Flow Min/DP Min/None
- Line 3 can display Velocity Max/Flow Max/DP Max/None
- Line 4 can display Temperature or None
For Dual Mode:
- Line 1 is for channel 1 Flow
- Line 2 can display Velocity Velocity/Temperature/DP/None
- Line 3 is for channel 2 Flow
- Line 4 can display Velocity Velocity/Temperature/DP/None

P.O. Box 6358 •Santa Rosa, CA •USA • 1-800-AIRFLOW • www.airmonitor.com • [e-mail]
OAM II Transmitter Dierential Pressure Airow & Temperature Measurement System 1017-1 - 12/17 17
The Main System Display for Split/Ext/Low The Main System Display for Dual
3.3 STATUS BAR
An upper status bar is always displayed indicating the general operational status of the unit.
The following status’ are indicated on the upper left hand corner of the display:
Message Blue on Blue Normal Operation
Out Of Range - High Yellow on Blue If the ow exceeds the design ow max setting
Monitor Temp Low Yellow on Blue Transducer temperature too low (<-50 °F)
Monitor Temp High Yellow on Blue Transducer temperature too high (>120°F)
SECTION 4.0: PROGRAMMING MENUS
Press ENT at any time to access the programming menus.
Pushbutton Denitions
Four pushbuttons control the OAM II:
Button In an Editable Field In a Selectable Field
ENT Press once to select next character
Press twice to enter the value and go to the
next eld
To select the value and go to the next
eld
ESC Press once to delete the character to the left Exits the menu, discards change
UP Selects the next character
(note: some elds support alpha or numeric
or both)
Selects the next item in the list
(note: once at the top of the list, this
button has no effect)
DN Selects the next character
(note: some elds support alpha or numeric
or both)
Selects the next item in the list
(note: once at the bottom of the list,
this button has no effect)

P.O. Box 6358 •Santa Rosa, CA •USA • 1-800-AIRFLOW • www.airmonitor.com • [e-mail]
OAM II Transmitter Dierential Pressure Airow & Temperature Measurement System 1017-1 - 12/17 18
Password Menu
If the password has been set previously, the
following screen will be displayed:
Enter the password and you will be brought
to the menus selection screen. Infomation
regarding the password settings can be found
in the Service Menu and is discussed later in
this manual.
4.1 MAIN MENU
In this screen select Main Menu or Service
Menu, depending on the function you wish to
carry out.
4.2 FLOW SETTINGS (LOW/EXT/SPLIT/DUAL)
Flow settings will set the engineering units for the
whole system. You cannot individually change
units on other menu pages; for example, if you set
the units to be in US and the velocity to be in FPM,
the lockdown (low ow cutoff) settings will be in
FPM.

P.O. Box 6358 •Santa Rosa, CA •USA • 1-800-AIRFLOW • www.airmonitor.com • [e-mail]
OAM II Transmitter Dierential Pressure Airow & Temperature Measurement System 1017-1 - 12/17 19
Units System - Select between SI or US. The dropdowns for ow and
velocity will present the units for the system selected.
Conditions - Select between actual and standard ow conditions. This affects the ow results, so
make sure you select the correct conditions for your application. Standard ow normalizes data to
68 °F and 29.92” Hg.
Site Elevation - Enter site elevation. This is a static value which is used to calculate actual ow.
This eld should represent the altitude where the system is installed.
Velocity - Select velocity units. Units of velocity are FPM or FPS for US and MPM or MPS for SI.
Flow - Select ow units. Units for ow are CFM or CFH for US and LPS, LPM or CMH for SI.
4.3 FLOW CONFIGURATION (LOW/EXT)
This menu shows the items which allow a user to
congure the OAM for installation.
Inlet Type - The inlet type is selected by the user
based on the installation. The options are:
• Ducted OAM
• Ducted 63%
• Inlet OAM
• Inlet 63%
• Other
Each selection corresponds to a default gain and exponent, used to calculate ow. If the user
selects “Other” a default gain of 1600 and an exponent of 0.5 is used. This can be changed
based on the eld characterization which is discussed later in this document.

P.O. Box 6358 •Santa Rosa, CA •USA • 1-800-AIRFLOW • www.airmonitor.com • [e-mail]
OAM II Transmitter Dierential Pressure Airow & Temperature Measurement System 1017-1 - 12/17 20
Design Flow Max
This is the upper ow limit based on the selected transducers. The value entered
cannot exceed corresponding DP span of the installed transducer. The transducers
DP span controls the maximum ow which can be achieved. The user should set this
value to a range which they expect represents the duct or inlet they are monitoring.
Based on the user set value, the analog outputs will represent the ow. Therefore, if
the design ow max is set to 2000, and the ow hits 1000, the analog output will be at
50% of its scale.
Area
This is an editable eld which controls the ow value. It is important for the user to
make sure this is accurately entered so the system ow value is also accurate.
Gain and Exponent
These are read-only elds to indicate what the gain and exponent is in the system.
These values will change if eld characterization is turned on and the calculation
modied these values.
Flow Conguration (Split and Dual)
The following two dialogs are identical, but one refers to the two separate inlets of a Dual
mode system and the other to the inlets of a Split Mode one. The inlets are both congurable
and all the other values are the same as the previous screen. The main difference is how the
analog outputs work with the two different Equipment Types. For Dual mode, the AO1 output
represents the System 1 and AO2 represents the System 2. In Split mode, the Total Flow is
represented on AO1 only, AO2 can represent Minimum ow or Temperature, and AO3 can
represent ECON ow or Temperature.