Greenheck Sure-Aire User manual

®
Sure-Aire™ Flow Monitoring System 1
®
Document 1021624
Sure-Aire™ Electronics
User and Service Manual
Installation, Operation and Maintenance Manual
Please read and save these instructions for future reference. Read carefully before attempting to assemble, install,
operate or maintain the product described. Protect yourself and others by observing all safety information. Failure
to comply with these instructions will result in voiding of the product warranty and may result in personal injury
and/or property damage.
Sure-Aire™ Electronics Features:
• NEMA-4 / IP56 enclosure rating
• Factory calibrated
• 24 VDC / 24 VAC or 100-240 VAC 50 / 60Hz input
voltage
• Part numbers and pressure ranges:
386719 – 0-4.15 in. wg
386720 – 0-8.30 in. wg
386721 – 0-22.14 in. wg
386722 – 0-41.52 in. wg
386723 – 0-83.14 in. wg
386724 – 0-138.40 in. wg
• Isolated output transmitter linear to differential
pressure or volume
4-20 mA
2-10 VDC
• Communication protocols
BACnet MSTP
Modbus
• LCD display with user-friendly touch panel interface
• Temperature compensation for air density
• Remote duct temperature sensor
• Programmable elevation
• English or metric readings
Hardware Required:
• Four (4) #8-32 screws
• 1/4-inch nylon tubing (length dependent on
distance between fan and Sure-Aire electronics,
maximum 75 feet (23 m) each line)
• Sensor wiring for temperature sensor (if
temperature sensor is being used)
Pressure ranges reflect differential pressures between
the fan inlet and inlet cone, not system static pressure.
Flow Accuracy +/-3.0% of actual flow
Transducer in Electronics:
• Accuracy +/- 0.5% of full scale at 77ºF (25ºC)
• Pressure limit: 70 psi (1938 in. wg)
• Thermal effects: 0.015%/°F (0.027%/°C) from -13°
thru 185°F (25° thru 85°C)
WARNING
Improper installation, adjustment, alterations,
service or maintenance may cause injury and / or
property damage, as well as possibly void the
factory warranty. No person may install, operate,
or maintain a Sure-Aire™ electronics without first
being fully trained and qualified in the installation,
operation and maintenance, and carefully reading and
understanding the contents of this manual. If you have
any questions about these instructions, contact your
local representative.
CAUTION
Risk of electrical shock! More than one disconnect
switch may be required to de-energize the equipment
before servicing.

Sure-Aire™ Flow Monitoring System2
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Table of Contents
Label Information . . . . . . . . . . . . . . . . . . . 2
General Information . . . . . . . . . . . . . . . . . . 3
Installation and Setup . . . . . . . . . . . . . . . . . 3
Menu Structure. . . . . . . . . . . . . . . . . . . . . 6
Display Setting Options and Parameter Setup . . . . 8
4-20 mA Transmitter Calibration Procedure . . . . . .12
2-10 VDC Transmitter Calibration Procedure . . . . .13
Temperature Sensor . . . . . . . . . . . . . . . . . .14
Network Protocol - Optional . . . . . . . . . . . . . .14
Analog Output Signal - Optional. . . . . . . . . . . .15
Calculation Using Manual Pressure Gauge or Third
Party Transducer . . . . . . . . . . . . . . . . . . . .15
K-Factors. . . . . . . . . . . . . . . . . . . . . . . .16
Label Information
Match the Tag Mark on the Sure-Aire electronics
tag to the Tag Mark on the fan nameplate. Sure-Aire
electronics are supplied set-up individually for a specific
model and performance. Contact factory if Sure-Aire
electronics are being used on a different Tag Mark then
specified.

Sure-Aire™ Flow Monitoring System 3
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This instruction manual provides installation, operating, maintenance, and other information for the Sure-Aire™
series differential pressure electronics.
Receiving
Upon receiving the electronics, check to ensure all items are accounted for by referencing the packing list. Inspect
each crate or carton for shipping damage before accepting delivery. Alert the carrier of any damage detected. The
customer will make notification of damage (or shortage of items) on the packing list and all copies of the bill of lading
which is countersigned by the delivering carrier. If damaged, immediately contact your local sales representative.
Any physical damage to the unit after acceptance is not the responsibility of the manufacturer.
Unpacking
Verify that all required parts and the correct quantity of each item have been received. If any items are missing,
report shortages to your local representative to arrange for obtaining missing parts.
Storage
Electronics are protected against damage during shipment. If the electronics cannot be installed and operated
immediately, precautions need to be taken to prevent deterioration during storage. The user assumes responsibility
of the electronics and any accessories while in storage. The manufacturer will not be responsible for damage during
storage. These suggestions are provided solely as a convenience to the user.
The ideal environment for the storage of electronics is indoors, above grade, in a low humidity atmosphere which
is sealed to prevent the entry of blowing dust, rain or snow. Temperatures should be evenly maintained between
30°to 110°F (-1° to 43°C). Wide temperature swings may cause condensation and “sweating” of metal parts. All
accessories must be stored indoors in a clean, dry atmosphere.
Removing from Storage
As electronics are removed from storage to be installed in their final location, they should be protected and
maintained in a similar fashion until the control goes into operation. Environmental Operation Range: -4°to 140°F
(-20° to 60°C).
1. Mount the electronics in the vertical plane using four(4) #8-32 screws, field supplied. Open the front cover by
unscrewing the two captive thumb screws to gain access to the four mounting locations.
Note: Mount the Sure-Aire™ electronics within 75feet of the termination plate on the fan.
WARNING
When wiring the electronics, you must follow industry standard practices for controls and protect against
electrostatic discharge (ESD). Failure to exercise good ESD practices may cause damage to the electronics.
General Information
Installation and Setup
Incoming power
High (H)
Low (L)
Communication
and signal
4-5/32 in.
(105.6 mm)
5-3/8 in.
(136.5 mm)
3-9/32 in.
(83.3 mm)
5 in.
(127 mm)
Dimensions and Hole Mounting Pattern 2. Use 1/4-inch nylon tubing to connect the
corresponding High (H) and Low (L), 1/4-inch quick
connect, pressure ports of the Sure-Aire electronics
to the high and low pressure ports on the fan.

Sure-Aire™ Flow Monitoring System4
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Installation and Setup (continued)
3. Remove terminal block TB1 and perform wiring for the pins if you are using AC. If using low voltage AC/DC, plug
the wires into TB2. For liquid tight applications, use only 1/2-inch liquid tight conduit.
Terminal Block TB1: AC Input Power:
Pin 1 = 100-240VAC Line
Pin 2 = 100-240VAC Neutral
Pin 3 = Earth Ground
4. Provide power to the electronics to turn it on.
5. Select the desired Output Signal of the electronics for the Building Automation System. Use the touch screen to
select the 4-20 mA or 2-10 VDC output signal via the monitor’s setup menu. (Refer to Setup Menu, Output Signal,
page 9).
6. Wire TB3 appropriately for the selected Output Signal in Step 5.
Terminal Block TB3: Transmitter/Temperature Sensor:
Pin 6 = 4-20 mA or 2-10 VDC (+) (output)
Note: 4 to 20 mA requires a load resistor 200-900 ohms
Pin 7 = 4-20 mA or 2-10 VDC (+) (output)
Pin 8 = Shield
Pin 9 = Remote Temperature Sensor (input)
Pin 10 = Remote Temperature Sensor (input)
7. Select the desire network protocol of the electronics for the Building Automation System. Use the touch screen to
select Modbus/BACnet, baud rate, and the network address of the electronics. This is done via the setup menu.
(Refer to Setup Menu, Output Signal, page 9)
Note: Signal isolator may be required when
two or more output signals share a common
connections at the PLC/electronics.
Terminal Block TB2: Low Voltage AC/DC Input Power:
Pin 1 = 24V, AC or DC (+ or -)
Pin 2 = 24V, AC or DC (+ or -)
Pin 3 = Earth Ground
Wiring Diagram

Sure-Aire™ Flow Monitoring System 5
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8. Wire TB3 appropriately if the networking features of the electronics are being used. There are two wiring options
for the network protocol: 2-Wire and 4-Wire. The currently selected option is based on the position of SW1.
Switch SW1: 2-Wire/4-Wire Select:
Left Position = 2-Wire
Right Position = 4-Wire
9. If not using temperature compensation, change Temperature Compensation to “No” via the setup menu. If
temperature compensation is desired, mount the provided temperature sensor in contact with the airstream. Wire
the temperature sensor into TB3 and confirm Temperature Comp is “Yes” via the setup menu. (Refer to Setup
Menu, Temperature Compensation, page 9).
10.When the above steps are completed, make sure the front cover is properly aligned to the housing and the two
captive thumbscrews are securely tightened.
Network Input Register Address
Object Name
Modbus BACnet
16-bit
address
16-bit
address
K Factor 0 0
Elevation 1 1
Outlet Area 3 2
Flow Temperature 2 3
Pressure 4 4
Volume 5 5
Velocity 6 6
4-Wire RS485 Wiring Diagram
ULINX
USB-to-RS485
Sure-Aire
Terminal Block
TDA(-) RX(-)B
TDB(+) RX(+)A
RDA(-) TX(-)Z
RDB(+) TX(+)Y
GND SGND
2-Wire RS485 Wiring Diagram
FTDI
USB-to-RS485
Sure-Aire
Terminal Block
A RX(-)B
B RX(+)A
GND SGND
Terminal Block TB3: 4-Wire Communication:
Pin 1: RX+ (A)
Pin 2: RX- (B)
Pin 3: TX- (Z)
Pin 4: TX+ (Y)
Pin 5: Signal Ground (SGND)
Terminal Block TB3: 2-Wire Communication:
Pin 1 or Pin 4: RX+ (A)/TX+ (Z)
Pin 2 or Pin 3: RX- (B)/TX- (Y)
Pin 5: Signal Ground (SGND)

Sure-Aire™ Flow Monitoring System6
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Menu Structure
See page 7 for parameter
Setup menu.
Up / Down
Setup
Air Density
Air Flow
Temperature Sensor
Installed
Electronics Temperature
Differential Pressure
Measurement
Pressure Sensor Range
K-Factor
Software Version
Transmitter Output Type
Units
Elevation
Main Menu

Sure-Aire™ Flow Monitoring System 7
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Prev/Next Edit
Measurement System English (Default) Metric
K-Factor
Elevation
Pressure Units
Air Flow Units
Outlet Area
Top View
Bottom View
Temperature
Compensation
Output Signal
K-Factor:
200 to 30,000
Elevation:
0 ft. (default)
0-10,000 ft
Pressure Units:
in. wg (default)
See manual for all options
0 - 10 ft²
Top View:
Flow (default)
See manual for all options
Bottom View:
Output Signal (default)
See manual for all options
Yes (default)
No
Output Signal:
4-20mA (default)
2-10 VDC
Linearize By:
Flow (default)
Pressure
Protocol
Baud Rate
Network Address
Device Instance Number
Transmitter Min/Max Value
Display Brightness
Load Factory Defaults
Load Customer Defaults
Save Customer Defaults
Protocol:
BACnet (default)
Modbus
Baud Rate
Network Address
Device Instance Number
Transmitter Calibration
See manual for details
Modbus:
2400 - 115200
See manual for all options
BACnet:
9600 - 115200
See manual for all options
Modbus:
1 - 255
BACnet:
0 - 127
BACnet:
0 - 1000
80% (default)
10 - 100%
No (default)
Yes
No (default)
Yes
No (default)
Yes
Setup
Air Flow Units:
CFM (default)
See manual for all options

Sure-Aire™ Flow Monitoring System8
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K-Factor and Elevation
K-Factor: Press “Edit“ to change K-Factor. Press “Inc“
or “Dec“ to adjust, then press “Enter“ to store the value.
• 200 to 30,000
(Factory set to fan model and size)
Elevation: Press “Edit“ to change elevation. Press “Inc“
or “Dec“ to adjust, then press “Enter“ to store the value.
• 0 - 10,000 ft
(0 ft default)
Pressure and Air Flow Units
Pressure Units: Press “Edit” to change pressure units.
Press “Prev” or “Next” to adjust, then press “Enter” to
store the value.
• In. wg (default)
• Ft wg
• mm wg
• cm wg
• PSI
• In. Hg
• mm Hg
• mBar
• Pa
• kPa - kilopascals (1kPa = 1000 Pa)
• hPa - hectopascals (1hPA = 100 Pa)
• Oz. In.
Air Flow Units: Press “Edit” to change Air Flow Units.
Press “Prev” or “Next” to adjust, then press Enter to
store the value.
• CFM (default)
• m³/hr
• m³/min
Navigation Buttons
The monitor is equipped with a touchscreen LCD
display. There are 4 navigation buttons on the bottom
of the screen. Button names will change based on the
parameter you are in (i.e. “Setup” will change to “Home”
and “Home” will change to “Edit”).
Home Screen
To view display variables, use the “Up” and “Down”
buttons to scroll through the list. To adjust parameters,
press “Setup” and scroll through the settings.
• Air density
• Flow
• Temperature sensor installed
• Electronics temperature
• Differential pressure measurement
• Pressure sensor range
• K-Factor
• Software version
• Transmitter output type
• Units
• Elevation
Press “Home” to return to the main screen.
Setup Menu
Following is information on the adjustable parameters
that can be changed in the Setup menu of the
electronics.
Measurement System
Press “Edit“ to change the measurement system units.
Press “Prev“ or “Next“ to adjust, then press “Enter“ to
store the value.
• English (default)
• Metric
Display Setting Options and Parameter Setup
Greenheck
Sure-Aire V 2.00
0.0010 CFM
3.96 mA
Setup Up Down Home
Display
variable
Buttons
Greenheck
Sure-Aire V 2.00
Measurement System:
English
Exit Prev Next Edit /
Enter
Greenheck
Sure-Aire V 2.00
K-Factor: 200
Elevation: 150
Exit Prev Next Edit /
Enter
Greenheck
Sure-Aire V 2.00
Pressure Unit: In WC
Air Flow Unit: CFM
Exit Prev Next Edit /
Enter

Sure-Aire™ Flow Monitoring System 9
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Outlet Area
Press “Edit“ to change the stack outlet area. Press “Inc“
or “Dec“ to increase or decrease the area, respectively.
Then press “Enter“ to store the value.
• 0-10 Ft²
Top and Bottom Views
Top View: Press “Edit“ to change Main Display Value.
Press “Prev“ or “Next“ to adjust what reading displays
on the Home screen, then press “Enter“ to store the
value.
• Flow (default top display)
• Pressure
• Temperature
• Air density
• Output signal (default bottom display)
• Velocity
• None
Bottom View: Press “Edit” to change Secondary
Display. Press “Prev” or “Next” to adjust, then press
“Enter” to store the value.
Temperature Compensation
Press “Edit“ to change Temperature Compensation.
Press “Prev“ or “Next“ to adjust, then press “Enter“ to
store the value.
• Yes (default)
• No
Note: If temperature compensation is set to “No“, the
air density will be a function of standard temperature
(70°F / 21°C).
Output Signal
Output Signal: Press “Edit“ to change Output Signal
type. Press “Prev“ or “Next“ to adjust, then press
“Enter“ to store the value.
• 4-20 mA (default)
• 2-10 VDC
Linearize By: Press “Edit“ to change the linearization
settings. The electronics will linearize the transmitter
output with respect to this setting.
• Flow (default)
• Pressure
Note: The maximum measurable flow rate will
automatically calculate based on the electronics
settings. The maximum flow rate is displayed on the
screen.
Greenheck
Sure-Aire V 2.00
Outlet Area: 1.00Ft²
For Outlet Velocity
Exit Prev Next Edit /
Enter
Greenheck
Sure-Aire V 2.00
Top View: Flow
Bottom View: Velocity
Exit Prev Next Edit /
Enter
Greenheck
Sure-Aire V 2.00
Temperature Comp:
No
Exit Prev Next Edit /
Enter
Greenheck
Sure-Aire V 2.00
Output Signal: 2-10V
Linearize By: Flow
Max Flow = 1400 CFM
Exit Prev Next Edit /
Enter
WARNING
Due to load resistance change from product to
product, it may be necessary to recalibrate the
4-20mA electronics. See 4-20 mA transducer
calibration procedure.

Sure-Aire™ Flow Monitoring System10
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Display Setting Options and Parameter Setup (continued)
Protocol and Baud Rate
Protocol: Press “Edit“ to change the current network
protocol. Press “Prev“ or “Next“ to adjust, then press
“Enter“ to store the value.
• BACnet (default)
• Modbus
Baud Rate: Press “Edit“ to change the protocol baud
rate. Press “Prev” or “Next” to adjust, then press “Enter”
to store the value.
Baud Rate Options (Modbus):
• 2400
• 4800
• 9600
• 19200
• 38400
• 57600
• 115200
Baud Rate Options (BACnet):
• 9600
• 19200
• 38400
• 57600
• 76800
• 115200
Network Address
Press “Edit“ to adjust the network address, then press
“Enter“ to store the value.
Network Address Options (Modbus):
• 1 – 255
Network Address Options (BACnet):
• 0 – 127
Note: The protocol and baud rate must be set before
the network address can be modified.
Device Instance Number (BACnet only):
The instance number is an unsigned decimal number
that can range from 0 to 4,194,302. Every device on
a BACnet network gets an instance number, and two
devices must not have the same number.
Press “Edit” to adjust the Device Instance Number, then
press “Enter” to store the value.
• 0 - 4,194,302
Transmitter Min/Max Value
Transmitter Min Value: Press “Edit” to change
Transmitter Min Value. Press “Inc” or “Dec” to adjust,
then press “Enter” to store the value.
Note: See Transmitter Calibration Section.
Transmitter Max Value: Press “Edit” to change
Transmitter Max Value. Press “Inc” or “Dec” to adjust,
then press “Enter” to store the value.
Note: See Transmitter Calibration Section.
Greenheck
Sure-Aire V 2.00
Protocol: Modbus
Baud Rate: 38400
Exit Prev Next Edit /
Enter
Greenheck
Sure-Aire V 2.00
Network Address:
10
Exit Prev Next Edit /
Enter
Greenheck
Sure-Aire V 2.00
Trans Min: 1858
Trans Max: 822
Exit Prev Next Edit /
Enter

Sure-Aire™ Flow Monitoring System 11
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Display Brightness
Press “Edit“ to change brightness. Press “Inc“ or “Dec“
to adjust, then press “Enter“ to store the value.
• 10 - 100%
(80% default)
Load Factory Defaults
Press “Edit“ to load factory defaults. Press “Prev“ or
“Next“ to select “Yes“,
then press “Enter“.
• No (default)
• Yes (changes all settings to factory default)
Load Customer Defaults
Press “Edit“ to load customer defaults. Press “Prev“ or
“Next“ to select “Yes“,
then press “Enter“.
• No (default)
• Yes (loads all customer default settings)
Greenheck
Sure-Aire V 2.00
Display Brightness %:
75
Exit Prev Next Edit /
Enter
Greenheck
Sure-Aire V 2.00
Load Factory Defaults:
No
Exit Prev Next Edit /
Enter
Greenheck
Sure-Aire V 2.00
Load Customer Defaults:
No
Exit Prev Next Edit /
Enter
Save Customer Defaults
Press “Edit“ to save current electronics settings as the
customer default.
Press “Prev“ or “Next“ to select “Yes“, then press
“Enter“.
• No (default)
• Yes (saves current settings as the customer
default)
Greenheck
Sure-Aire V 2.00
Save Customer Defaults:
No
Exit Prev Next Edit /
Enter

Sure-Aire™ Flow Monitoring System12
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1. Test Equipment
1.1 Digital multimeter - set multimeter to read mA
DC.
1.2 Load resistor - select a series load resistor
between 200 and 900 ohms.
2. Interconnect wiring
2.1 Validate the electronics is set up for 4-20 mA
output signal.
2.2 Validate the power is OFF on the DC power
supply and the Sure-Aire electronics.
2.3 Validate the multimeter is set to read mA DC.
2.4 Select a series Load Resistor between 200 and
900 ohms and install one end to TB3-6.
2.5 Interconnect the multimeter (+) probe to the
other end of the load resistor.
2.6 Interconnect the multimeter (-) probe to TB3-7
to complete the current loop.
2.7 Apply power to the Sure-Aire electronics.
2.8 Press the “Setup” button on the touch panel
interface.
4-20 mA Transmitter Calibration Procedure
NOTE
Apply a vacuum to the Low Port and the 4-20 mA
transmitter to track the span of the pressure range.
For example, the Sure-Aire electronics with a pressure
sensor of 0 - 41.51 in. wg installed, 4.00 mA = 0 in.
wg, 20.00 mA = 41.52 in. wg.
WARNING
Due to load resistance change from product to
product, it may be necessary to recalibrate the 4-20
mA transmitter.
2.9 Keep pressing the “Next” button until you reach
the Transmitter Min Value parameter screen.
2.10 Press “Edit”, then “Inc” or “Dec” until the digital
multimeter reads exactly 4.00 mA.
2.11 Press “Enter” to store the new value.
2.12 Press “Next”.
2.13 On the Transmitter Max Value screen, press
“Edit”, then “Inc” or “Dec” until the digital
multimeter reads exactly 20.00 mA.
2.14 Press “Enter” to store the new value.
2.15 Press “Exit” to return to the main screen.
The 4-20 mA transmitter calibration is complete.
Greenheck
Sure-Aire V 2.00
Transmitter Min Value:
1827
Exit Prev Next Edit /
Enter
Greenheck
Sure-Aire V 2.00
Transmitter Max Value:
720
Exit Prev Next Edit /
Enter

Sure-Aire™ Flow Monitoring System 13
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2-10 VDC Transmitter Calibration Procedure
1. Test Equipment
1.1 Digital multimeter - set multimeter to read DC
voltage.
1.2 Make sure Output Signal type is set to 2-10
VDC.
2. Interconnect wiring
2.1 Validate the power is OFF on the DC power
supply and the Sure-Aire electronics.
2.2 Validate the multimeter is set to read DC
voltage.
2.3 Interconnect the multimeter (+) probe to TB3-6.
2.4 Interconnect the multimeter (-) probe to TB3-7.
2.5 Apply power to the Sure-Aire electronics.
2.6 Press the “Setup” button on the touch panel
interface.
2.7 Keep pressing the “Next” button until you reach
the Transmitter Min Value screen.
2.8 Press “Edit”, then “Inc” or “Dec” until the digital
multimeter reads exactly 2.00 VDC.
2.9 Press “Enter” to store the new value.
Greenheck
Sure-Aire V 2.00
Transmitter Min Value:
1827
Exit Prev Next Edit /
Enter
2.10 Press “Next”.
2.11 On the Transmitter Max Value screen, press
“Enter”, then “Inc” or “Dec” until the digital
multimeter reads exactly 10.00 mA.
2.12 Press “Enter” to store the new value.
2.13 Press “Exit” to return to the main screen.
The 2-10 VDC transmitter calibration is complete.
Greenheck
Sure-Aire V 2.00
Transmitter Max Value:
720
Exit Prev Next Edit /
Enter
NOTE
Apply a vacuum to the Low Port and the 2-10 VDC
transmitter to track the span of the pressure range.
For example, the Sure-Aire electronics with a pressure
sensor of 0 - 41.51 in. wg installed, 2 VDC = 0 in. wg,
10 VDC = 41.52 in. wg.

Sure-Aire™ Flow Monitoring System14
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Temperature Sensor
Interconnect the remote temperature sensor by connecting the temperature sensor to pins 4 and 5 of TB2. The
Remote Temperature Sensor will adjust the air density value in the differential pressure electronics based on the
sensor measurement when Temperature Compensation is set to “Yes”. This density compensation will affect the flow
rate accordingly. If Temperature Compensation is set to “No”, the air density value will be a function of standard air.
(70°F/21°C).
Network Protocol - Optional
Greenheck’s Sure-Aire™ electronics has the ability to connect to a Building Automation System (BAS) through the
on-board RS-485 port. The electronics can be configured as either BACnet MS/TP or Modbus RTU Slave. When in
the display menu, scroll through the options until the Network Protocol screen. Pressing edit will permit changing the
network protocol type and associated data. This information should be set to match the BAS.
BACnet MS/TP Server
When the electronics is configured for BACnet, it will
expose a total of eight (8) objects on the network.
BACnet MS/TP Server Device Settings
Setting Value
Baud Rate Set to match BMS
Parity No Parity (1 Stop Bit)
APDU Timeout (ms) 1000
Number of APDU Retries 3
Max Master Address 127
Max Info Frames 1
Modbus RTU Slave
When the electronics is configured for Modbus, it will
expose a total of seven (7) registers on the network. The
Modbus RTU Slave settings and list of registers can be
seen below.
Modbus RTU Slave Device Settings
Setting Value
Baud Rate Set to match BMS
Parity No Parity (1 Stop Bit)
Timeout (ms) 0
Response Delay (ms) 0
BACnet MS/TP Server Objects
Object Name Object Type Data Type Units
Sure-Aire™ Device Object N/A N/A
K-Factor Analog Input 16-Bit
Unsigned None
Elevation Analog Input 16-Bit
Unsigned None
Outlet Area Analog Input 32-Bit Floating
Point None
Flow
Temperature Analog Input 16-Bit Signed None
Pressure Analog Input 32-Bit Floating
Point None
Volume Analog Input 32-Bit Floating
Point None
Velocity Analog Input 32-Bit Floating
Point None
Modbus RTU Slave Registers
Register Name Register Type Data Type Units
K-Factor Input Register 16-Bit
Unsigned None
Elevation Input Register 16-Bit
Unsigned None
Outlet Area Input Register 16-Bit
Unsigned None
Flow
Temperature Input Register 16-Bit Unsigned None
Pressure Input Register 16-Bit
Unsigned None
Volume Input Register 16-Bit
Unsigned None
Velocity Input Register 16-Bit
Unsigned None
NOTE
All of the objects / registers that are exposed on the network do not have a unit associated with them. The units of
the values exposed on the network will be based on the units that are selected on the Sure-Aire™ electronics.

Sure-Aire™ Flow Monitoring System 15
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Greenheck’s Sure-Aire™ differential pressure electronics provides either a 2-10 VDC or 4-20 mA analog output
signal. The output signal can be configured linearly proportional to either the pressure range or the flow within the
setup. The ranges for Greenheck’s Sure-Aire™ electronics are listed by model on cover.
Calculation Using Manual Pressure Gauge or Third Party Transducer
Calculating Flow from Differential Pressure
The volumetric flow through the fan (cfm) can be calculated from the equation:
where K is the K-Factor for the specific fan model and size, ΔP is the measured differential pressure across the inlet
cone (in. wg), and ρis the density of air (lb/ft³ °F). K-Factors for Greenheck models are found on the back cover.
CFM = K
ΔP
ρ
Calculating Flow from Voltage Signal
If using the analog signal linear to flow, the max flow is automatically calculated based on the pressure range and
K-factor input into the electronics. The max value is displayed in the setup menu.
If output signal is linear to pressure, the corresponding equations are used to calculate the flow.
Calculating flow for 2-10 VDC output signal:
Calculating flow for 4-20 mA output signal:
CFM = K
(V - 2) Pmax
8ρ
CFM = K
(mA - 4) Pmax
16ρ
Analog Output Signal - Optional
K Constant dependent on fan model and size (see page 9)
Pmax Maximum pressure of electronics (in. wg)
ρAir density (lb/ft³ °F) [0.075 at 70°F and 0 ft elevation]
V Output voltage of 2-10 VDC signal
mA Output current of 4-20 mA signal
Density Corrections
Air density, ρ, is affected by elevation and temperature. The Sure-Aire differential pressure electronics allows the user
to input the elevation for the application. This elevation input automatically updates the density used for the flow
calculation.
The Remote Temperature sensor will adjust the air density value in the electronics based on the sensor measurement
when Temperature Compensation is set to “Yes”. This density compensation will affect the flow rate displayed on
the transmitter. If Temperature Compensation is set to “No”, the air density value will be a function of standard air
(70°F/21°C).
The density being used by the Sure-Aire differential pressure measurement can be viewed on the main menu by
scrolling up or down through the settings.

1021624 • Sure-Aire™ User and Service Manual, Rev. 4, January 2022 Copyright 2022 © Greenheck Fan Corporation16
As a result of our commitment to continuous improvement, Greenheck reserves the right to change specifications
without notice.
Product warranties can be found online at Greenheck.com, either on the specific product page or in the literature
section of the website at Greenheck.com/Resources/Library/Literature.
®
Phone: [phone] • Fax: [phone] • Parts: 800.355.5354 • E-mail: [email protected] • Website: www.greenheck.com
Our Commitment
AMCA Publication 410-96, Safety Practices for Users and
Installers of Industrial and Commercial Fans, provides
additional safety information. This publication can be obtained
from AMCA International, Inc. at www.amca.org.
Greenheck’s Sure-Aire™ Flow Monitoring System catalog
provides additional information describing the equipment, fan
performance, available accessories, and specification data.
K-Factors
Size APD Size APH / APM
HPA AFDW / BIDW FJI QEI / QEID
USF-500
& Vektor-C
series
Vektor-H
Belt Drive Vektor-M series
315 257 7 not applicable not applicable 179 not applicable 179 not applicable not applicable
355 329 8 not applicable not applicable 179 not applicable 179 not applicable not applicable
400 406 9 not applicable not applicable 179 408 179 248 not applicable
450 536 10 not applicable not applicable 179 not applicable 179 202 not applicable
500 652 12 355 592 244 408 244 296 not applicable
560 847 13 not applicable 701 not applicable not applicable 296 351 not applicable
630 1053 15 355 861 366 603 366 not applicable 526
16 421 1062 not applicable 724 443 531 634
18 517 1083 542 897 542 787
20 617 1301 651 1088 651 not applicable 955
22 759 1610 805 1321 805 1161
24 913 1964 976 1631 976 1436
27 1105 2369 not applicable 1962 1186 not applicable 1729
30 1355 2928 not applicable 2400 1464 2116
33 1625 3540 not applicable 2923 1771 not applicable 2581
36 1967 4336 not applicable 3576 2167 3154
40 2361 5259 not applicable 4331 2635 not applicable 3825
44 2854 6440 not applicable 5318 3220 not applicable 4698
49 3411 7808 not applicable 6525 3905 not applicable 5766
54 4121 9571 not applicable 7891 4786 not applicable 6975
60 4972 11707 not applicable 9648 5855 not applicable not applicable
66 5960 14166 not applicable not applicable 7084 not applicable not applicable
73 7276 17330 not applicable not applicable 8667 not applicable not applicable
Vektor-H Direct Drive
Fan
Size
Nozzle Size
4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
10 487 511 540 547 554 563 573 – – – – – – – – –
12 577 616 664 674 685 697 700 704 708 – – – – – – –
13 – – – 839 851 861 868 872 876 880 – – – – – –
14 – – – – 1223 1239 1257 1260 1263 1267 1272 – – – – –
16 – – – – 1290 1409 1542 1563 1586 1587 1588 1597 1607 – – –
18 – – – – – 1923 1937 1952 1965 1979 1990 2003 1994 1983 1995 2007
20 – – – – – 2248 2296 2348 2367 2387 2408 2431 2432 2432 2429 2426