TSI Alnor EBT720, EBT721 Operating Manual

OWNER’S MANUAL

Alnor® Electronic Balancing Tool

Models EBT720/EBT721

and

IRFLOW™ Instruments ProHood™

A

Capture Hood Models PH720/PH721

EBT720/PH720 Shown with all
accessory options

EBT721/PH721 Shown with
all accessory options

LIMITATION OF WARRANTY AND LIABILITY

Copyright©

TSI Incorporated / 2005–2009 / All rights reserved.

LIMITATION OF WARRANTY AND LIABILITY (effective July 2000)
Seller warrants the goods sold hereunder, under normal use and service as described in the operator's

manual, shall be free from defects in workmanship and material for twenty-four (24) months, or the length
of time specified in the operator's manual, from the date of shipment to the customer. This warranty
period is inclusive of any statutory warranty. This limited warranty is subject to the following exclusions:

a. Hot-wire or hot-film sensors used with research anemometers, and certain other components when

indicated in specifications, are warranted for 90 days from the date of shipment.

b. Parts repaired or replaced as a result of repair services are warranted to be free from defects in

workmanship and material, under normal use, for 90 days from the date of shipment.

c. Seller does not provide any warranty on finished goods manufactured by others or on any fuses,

batteries or other consumable materials. Only the original manufacturer's warranty applies.

d. Unless specifically authorized in a separate writing by Seller, Seller makes no warranty with respect

to, and shall have no liability in connection with, goods which are incorporated into other products or
equipment, or which are modified by any person other than Seller.

The foregoing is IN LIEU OF all other warranties and is subject to the LIMITATIONS stated herein. NO

OTHER EXPRESS OR IMPLIED WARRANTY OF FITNESS FOR PARTICULAR PURPOSE OR
MERCHANTABILITY IS MADE.

TO THE EXTENT PERMITTED BY LAW, THE EXCLUSIVE REMEDY OF THE USER OR BUYER, AND
THE LIMIT OF SELLER'S LIABILITY FOR ANY AND ALL LOSSES, INJURIES, OR DAMAGES
CONCERNING THE GOODS (INCLUDING CLAIMS BASED ON CONTRACT, NEGLIGENCE, TORT,
STRICT LIABILITY OR OTHERWISE) SHALL BE THE RETURN OF GOODS TO SELLER AND THE
REFUND OF THE PURCHASE PRICE, OR, AT THE OPTION OF SELLER, THE REPAIR OR
REPLACEMENT OF THE GOODS. IN NO EVENT SHALL SELLER BE LIABLE FOR ANY SPECIAL,
CONSEQUENTIAL OR INCIDENTAL DAMAGES. SELLER SHALL NOT BE RESPONSIBLE FOR
INSTALLATION, DISMANTLING OR REINSTALLATION COSTS OR CHARGES. No Action, regardless
of form, may be brought against Seller more than 12 months after a cause of action has accrued. The
goods returned under warranty to Seller's factory shall be at Buyer's risk of loss, and will be returned, if at
all, at Seller's risk of loss.

Buyer and all users are deemed to have accepted this LIMITATION OF WARRANTY AND LIABILITY,
which contains the complete and exclusive limited warranty of Seller. This LIMITATION OF WARRANTY
AND LIABILITY may not be amended, modified or its terms waived, except by writing signed by an Officer
of Seller.

Service Policy

Knowing that inoperative or defective instruments are as detrimental to TSI as they are to our customers,
our service policy is designed to give prompt attention to any problems. If any malfunction is discovered,
please contact your nearest sales office or representative, or call Customer Service department at
[phone] (UK), [phone] (USA), or (1) 651-490-2811 (International).

Trademarks

®

, TSI logo, Alnor®, AIRFLOW™ Instruments, and ProHood™ are trademarks of TSI Incorporated.

TSI

.

CONTENTS

About This Manual.....................................................................................................................iii

Formatting and Typography ....................................................................................................iii

Technical Assistance—Help! ..................................................................................................iii

Chapter 1. Introduction ..............................................................................................................1

Instrument Description ............................................................................................................ 1

Micromanometer ............................................................................................................... 2

Micromanometer ..................................................................................................................... 3

Standard Tools........................................................................................................................ 3

Pitot Tube..........................................................................................................................3

Static Pressure Probe .......................................................................................................3

Optional Tools......................................................................................................................... 3

Capture Hoods .................................................................................................................. 3

Velocity Matrix...................................................................................................................3

Air Flow Probe................................................................................................................... 3

Temperature Probe ........................................................................................................... 3

Temperature/Humidity Probe ............................................................................................3

Chapter 2. Unpacking and Setting Up....................................................................................... 5

Unpacking ............................................................................................................................... 5

Preparing the Instrument for Use ............................................................................................ 6

Power the Micromanometer with the AC Adapter .............................................................6

Power the Micromanometer with Batteries........................................................................ 6

Connecting the Pitot Tube to the Micromanometer................................................................. 8

Connecting the Static Pressure Port to the Micromanometer ................................................. 8

Attaching the Micromanometer to the Capture Hood Base..................................................... 9

Connecting the Velocity Matrix to the Micromanometer.................................................... 9

Connecting the Air Flow Probe to the Micromanometer .......................................................10

Connecting the Temperature Probe or Temperature and Humidity Probe to the

Micromanometer ............................................................................................................. 10

Chapter 3. Getting Started .......................................................................................................13

Keypad Operation ................................................................................................................. 13

Common Terms ....................................................................................................................14

Sample ............................................................................................................................ 14

Logging Interval............................................................................................................... 14

Test ID............................................................................................................................. 14

Step-By-Step Example Operation ......................................................................................... 15

Chapter 4. How To ....................................................................................................................17

Select a Tool ......................................................................................................................... 17

Set the Time and Date ..........................................................................................................19

Change the Currently Selected Test ID ................................................................................19

Recall Sample Data ..............................................................................................................19

Delete Sample Data ..............................................................................................................20

Delete all Sample Data ...................................................................................................20

Delete the Samples Stored in a Single Test ID............................................................... 20

Delete a Single Sample................................................................................................... 20

Select/Set a K-factor for a Tool............................................................................................. 21

i

View/Set Standard Pressure and Temperature ....................................................................21

Set Units of Measure for Temperature, Pressure, Velocity/Flow and Humidity .................... 23

Select the RS232 Output Device (Computer or Printer) .......................................................23

Set the Baud Rate................................................................................................................. 24

Set the Format for Date and Decimal.................................................................................... 24

Set Display Mode for Running Average or Single.................................................................25

Select Discrete or Continuous Logging................................................................................. 25

Turn Back Pressure Compensation On and Off.................................................................... 26

Take Back Pressure Compensated Hood Readings............................................................. 26

Set Deadband On and Off..................................................................................................... 27

Calibrate the Micromanometer (User Calibration)................................................................. 27

Select User Calibration or Factory Calibration ...................................................................... 28

Connect and Download Data to an Optional Printer ............................................................. 28

Connect and Download Data to a Computer .................................................................. 29

Data Acquisition (Polling)......................................................................................................30

Chapter 5. Changing Flow Hoods ........................................................................................... 31

Flow Hood Parts Identification ..............................................................................................31

Hood Assembly..................................................................................................................... 31

Alternate Hood Installation .............................................................................................. 32

Direct Inflow Measurement Hood for Biological Safety Cabinets.................................... 37

Chapter 6. Flow Measurements Using the Capture Hood ..................................................... 43

Non-Backpressure Compensated Measurements ................................................................ 43

Single Measurements ...........................................................................................................43

Running Average Measurements.......................................................................................... 44

Backpressure Compensated Measurements ........................................................................ 44

Error Display ......................................................................................................................... 45

Chapter 7. Maintenance and Troubleshooting....................................................................... 47

Fabric Hood...........................................................................................................................47

Micromanometer ................................................................................................................... 47

Manifold.................................................................................................................................47

Cases .............................................................................................................................. 47

Calibration............................................................................................................................. 48

Error Code....................................................................................................................... 48

Appendix A. Back Pressure ..................................................................................................... 53

Verifying Flow Measurements...............................................................................................53

Appendix B. Actual vs. Standard Air Velocity and Flow Measurements ............................. 55

ii

About This Manual

This manual explains how to set up, operate and maintain the Alnor EBT720/EBT721 and AIRFLOW™
Instruments PH720/PH721. Read it thoroughly before using the instrument.

Caution

CAUTION

W

HILE USING THE BALOMETER® AIR BALANCING INSTRUMENT TO TEST AIR

FLOW IN DUCTS

, POLLEN, MOLD, FUNGUS, OR OTHER AIRBORNE CONTAMINANTS. IF YOU

DUST
ARE OR MAY BE SENSITIVE TO DUST
AIRBORNE CONTAMINANTS
RESPIRATOR WHILE EMPLOYING THE
INSTRUMENT

Formatting and Typography

 Step-by-step instructions are numbered in boldface type: 1, 2, 3, etc., set flush-left against the

margin.

 References to keys on the micromanometer and the instrument's displayed readout are represented by

a typeface called Arial. In addition to the different typeface, displayed messages appear in quotes.

 When reference is made to other sections of the manual, the section title is italicized.

, YOU MAY COME INTO CONTACT WITH OR BE EXPOSED TO

, POLLEN, MOLD, FUNGUS, OR OTHER

, ALWAYS USE AN APPROPRIATE MASK OR

BALOMETER

®

AIR BALANCING

.

Technical Assistance—Help!

For technical assistance or questions about the instrument, or if the instrument needs repair or
recalibration, call Customer Service at [phone] (UK), [phone] (USA), or (1) 651­490-2811 (International). Product application notes are available to provide more information on the
product. These application notes, as well as other related material, can be obtained by calling Customer
Service or by visiting the web site at

www.alnor.com or www.airflowinstruments.co.uk.

iii

Chapter 1. Introduction

The Electronic Balancing Tools EBT720/EBT721 and ProHood™ PH720/PH721 capture hoods are
lightweight and easy-to-use instruments packaged with a variety of accessories for measuring pressure,
temperature, humidity, air velocity, and air volume. Features of the micromanometer include:

 Single-function keys for ease of use

 Auto-zero for pressure measurements, auto-density correction, and back-pressure compensation when

used with a capture hood

 User-selectable English and metric units

 Conversions between actual and standard flow

 Discrete or continuous display and data logging capabilities

 Output port for downloading to a printer or a PC

 Powered by AC adapter or batteries (rechargeable NiMH or alkaline)

 Full field calibration

Designed for:

 Test and balance professionals

 Mechanical contractors

 Industrial hygienists

 Plant engineers and facilities maintenance personnel

Applications include:

 Test, balance, or commission HVAC systems

 Test clean rooms and biological safety cabinets

 Measure fume hood or filter face velocity

 Measure pressure, temperature, relative humidity, air velocity, or air flow

CAUTION

W

HILE USING THE BALOMETER® AIR BALANCING INSTRUMENT TO TEST AIR

FLOW IN DUCTS

, POLLEN, MOLD, FUNGUS, OR OTHER AIRBORNE CONTAMINANTS. IF YOU

DUST
ARE OR MAY BE SENSITIVE TO DUST
AIRBORNE CONTAMINANTS
RESPIRATOR WHILE EMPLOYING THE
INSTRUMENT

, YOU MAY COME INTO CONTACT WITH OR BE EXPOSED TO

, POLLEN, MOLD, FUNGUS, OR OTHER

, ALWAYS USE AN APPROPRIATE MASK OR

BALOMETER

®

AIR BALANCING

.

Instrument Description

The basic EBT720/PH720 includes a micromanometer, carrying case, 18 in. (46 cm) pitot tube, (2) static

®

pressure probes, (2) 8 ft (2.4 m) Norprene
downloading software and RS232 interface cable, neck strap, internal NiMH battery charger, (4) AA
NiMH batteries, AC adapter, and NIST traceable certificate.

®

Norprene is a registered trademark of Norton Performance Plastics, Akron, Ohio, USA.

tubing, user manual, CompuDat™ for Windows® data

1

The basic EBT721/PH721 contains all of the EBT720/PH720 components plus 2 ft × 2 ft (610 mm × 610

A

A

mm) air capture hood, frame, and base. A variety of optional tools (see below) are also available to meet
your measurement needs.

The following paragraphs provide brief descriptions of the micromanometer and the various standard and
optional tools for use with the EBT/PH. Refer to Chapters

3 and 4 for more detailed information on using

the micromanometer and taking measurements with various sensors and probes.

Micromanometer

Figures 1 and 2 show the features of the micromanometer used in the EBT720/EBT721 and
PH720/PH721.

Keypad

C Adapter

Connection

RS232 Port

For Future Use

Figure 1: Features of the EBT720/EBT721 and PH720/PH721 Micromanometer, Front View

irflow

Inlet/Outlet

Display

Headphone
Connection

Probe Connector

Battery
Compartment

Figure 2: Features of the EBT720/EBT721 and PH720/PH721 Micromanometer, Back View

2 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

Micromanometer

The micromanometer is a multifunction instrument useful in obtaining air velocity, air flow, absolute and
differential pressure, temperature, and humidity measurements when used with the tools listed below. The
lightweight micromanometer incorporates auto-zeroing for high-accuracy, low-end pressure
measurements.

Standard Tools

This section gives a brief description of standard tools for the micromanometer.

Pitot Tube

The pitot tube is primarily used to obtain air velocity, air volume, and velocity pressure measurements
within ductwork.

Static Pressure Probe

The static pressure probe is primarily used to obtain static pressure measurements within ductwork.

Optional Tools

This section gives a brief description of optional tools for the micromanometer.

Capture Hoods

Capture hoods are primarily used to obtain volumetric air flow measurements through diffusers, registers
and grilles. Capture hoods are available in a kit with one 2 ft × 2 ft (610 mm × 610 mm) fabric hood,
frame, and base assembly. Alternate hood sizes are available and descriptions and part numbers can be
found in

Table 2 of Chapter 2 in this manual.

Velocity Matrix

The velocity matrix is primarily used to obtain area-averaged multi-point air velocity measurements
useful in laboratory hood face velocity testing, filter face velocity testing, and other applications.

Air Flow Probe

The air flow probe is primarily used to obtain single point air velocity or air volume measurements in
ductwork.

Temperature Probe

The temperature probe is used to obtain temperature measurements over the range of -40 to 250°F (-40 to
121°C).

Temperature/Humidity Probe

The temperature/humidity probe is used to obtain temperature measurements over the range of 14 to
140°F (-10 to 60°C), humidity measurements over the range of 0 to 95% RH, along with calculated wet
bulb temperature of 40 to 140°F (4 to 60°C) and dewpoint temperature of 5 to 120°F (-15 to 49°C).

Chapter 1: Introduction 3

Chapter 2. Unpacking and Setting Up

This chapter describes unpacking and setting up (preparing) the Electronic Balancing Tool (EBT) or
ProHood
matrix measuring the face velocity on a laboratory hood.

Unpacking

™ capture hood for use. Figure 3 shows a picture of the Model EBT720/PH720 with a velocity

Figure 3: Model EBT720/PH720 with Velocity Matrix

As you unpack the instrument and accessories, check the components against your packing list. If any
parts are missing or damaged, notify us immediately. Tables 1 and 2 list available standard and optional
components.

Table 1: List of Standard and Optional Components

Item Part No.

Models EBT720 and EBT721 Electronic Balancing Tools (Alnor)

Models PH720 and PH721 ProHood™ capture hood (AIRFLOW™ Instruments) PH720

Carrying case, EBT720/PH720 1319378
Carrying case, wheeled hood kit, EBT721 1319379
AA-size NiMH battery, four required 1208048
Operation and Service Manual 1980497
Velocity Matrix Add On Kit 801090
Air Flow Probe 800187
Temperature Probe (AIRFLOW™ Instruments) 800208
Temperature and Humidity Probe (AIRFLOW™ Instruments) 800209
Temperature Probe (Alnor) 800188
Temperature and Humidity Probe (Alnor) 800189

EBT720-XXX
EBT721-XXX

PH721

5

Table 2: List of Optional Hood Components

Item Part No.

1 ft × 4 ft (305 mm × 1220 mm) and 2 ft × 4 ft (610 mm × 1220 mm) fabric hood
and frame kit

1 ft × 5 ft (305 mm × 1525 mm) and 3 ft × 3 ft (915 mm × 915 mm) fabric hood
and frame kit

1 ft × 4 ft (305 mm × 1220 mm) fabric hood and frame kit
2 ft × 4 ft (610 mm × 1220 mm) fabric hood and frame kit
1 ft × 5 ft (305 mm × 1525 mm) fabric hood and frame kit
3 ft × 3 ft (915 mm × 915 mm) fabric hood and frame kit
8 in. × 21 in. (203 mm × 533 mm) BSC fabric hood, frame, poles, and stand kit
10 in. × 21 in. (254 mm × 533 mm) BSC fabric hood, frame, poles, and stand kit

Please complete the registration card included with this product and mail it promptly. The card allows us
to inform you of product updates. If you prefer, register through the

Alnor web site or AIRFLOW web site.

801206

801207

801200
801201
801202
801203
801204
801205

Preparing the Instrument for Use

Before you can use the Electronic Balancing Tool, you must decide on a power source.

Power the Micromanometer with the AC Adapter

When the AC adapter is plugged into the micromanometer, the unit automatically turns on, runs a brief
diagnostic check, and briefly lights all segments of the display. It then displays the type of batteries the
unit is set to use (alkaline or rechargeable NiMH) and turns itself OFF.

Whenever the AC adapter is plugged into the micromanometer, the rechargeable batteries are recharged.
(Assuming you are using rechargeable batteries and the switch inside the battery compartment is set to
NiMH. See below.)

Power the Micromanometer with Batteries

When not using the AC adapter, the Electronic Balancing Tool or ProHood™ capture hood requires four
AA-size batteries to operate. These can be either alkaline batteries or rechargeable NiMH batteries. For
your convenience, four NiMH batteries are included with the EBT/PH.

To select the type of batteries you are using:

1. Turn the unit off and locate the battery cover on the back of the micromanometer (see Figure 4).

6 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

Figure 4: Battery Cover Removal

Press down on the compartment cover and slide it down. (The cover slides off.)

2.

3. Remove the battery holder by pulling up on the bottom (to loosen it) and then pulling the battery

holder free.

4. Refer to Figure 5 and set the battery selection switch to indicate the type of batteries you are using.

Battery Selection Switch

Figure 5: Location of Battery Type Selector Switch

5. Reinstall the battery holder and replace the battery compartment cover.

To install replacement batteries:

1. Turn the unit off and locate the battery cover on the back of the micromanometer (see Figure 4).

2. Press down on the compartment cover and slide it down. (The cover slides off.)

3. Remove the battery holder by pulling up on the bottom (to loosen it) and then remove the battery

holder.

Chapter 2: Unpacking and Setting Up 7

4. Remove the old batteries and replace with fresh batteries (alkaline or rechargeable NiMH). Make

certain batteries are correctly oriented.

5. Verify the battery selection switch is correctly set (see Figure 5).

6. Reinstall the battery holder and replace the compartment cover.

Note: Make sure the battery holder is oriented so that its terminals make contact with the spring

contacts in the battery compartment.

If fresh, new alkaline batteries are used, the battery indicator will show 4 bars when first turned on.
With NiMH batteries, the indicator may show a lower value even when they are fully charged.

Notes: The percent power remaining will not be accurate for NiMH batteries because their voltage

does not decrease linearly with power use.

Due to the danger of battery leakage, remove batteries from the battery compartment before
storage. Never mix battery types.

The NiMH batteries should only be charged at room temperature. Starting with batteries that
are too cold or too warm can cause the charge cycle to stop early.

Connecting the Pitot Tube to the Micromanometer

The static pressure port (-) on the pitot tube will be connected to the negative pressure (-) port on the
micromanometer, and the total pressure port (+) on the pitot tube will be connected to the positive (+) port
on the micromanometer (see

Figure 6).

Total Pressure Port (+)

Static Pressure Port (–)

Figure 6: Pitot Tube

Connecting the Static Pressure Port to the Micromanometer

The static pressure port on the static pressure probe will be connected to the (+) port on the
micromanometer. The (-) port on the micromanometer will be open to atmosphere (see

Figure 7).

8 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

Magnet

Static Pressure Port

Figure 7: Static Pressure Probe

Attaching the Micromanometer to the Capture Hood Base

1. Tilt the meter forward and align the tabs in the base of the meter with the two matching slots in the

bottom of the recessed area at the front of the base (see

2. When the tabs are engaged in the slots, press firmly on the face of the meter above the display until

the tab in the top center of the meter “clicks” into the bent metal retaining clip in the base.

Figure 8).

3. Attach the temperature cable and the back pressure flap switch cable to the right side of the meter.

4. To remove the meter from the base, first disconnect the temperature cable and the back pressure flap

switch cable, then press upward on the metal retaining clip to release the meter from the base.

Figure 8: Attaching the Meter to the Capture Hood Base

Connecting the Velocity Matrix to the Micromanometer

The positive port (+) is located on the side of the Velocity Matrix that is opposite the handle assembly.
The positive port (+) on the Velocity Matrix will be connected to the (+) port on the micromanometer,
and the negative port (-) on the Velocity Matrix is connected to the (-) port on the micromanometer.

Standoffs can be screwed together to make different lengths and are used to maintain a fixed and level
orientation away from a filter. The standoffs are attached to the positive (+) side of the velocity matrix.

Chapter 2: Unpacking and Setting Up 9

The handle assembly is attached to the downstream or negative (-) side in the center of the velocity matrix

Figure 9).

(see

Standoffs
Positive
Port (+)

Negative
Port (–)

Handle

Figure 9: Velocity Matrix

Connecting the Air Flow Probe to the Micromanometer

The static pressure port (-) on the Air Flow Probe will be connected to the negative pressure (-) port on
the micromanometer, and the total pressure port (+) on the Air Flow Probe will be connected to the
positive (+) port on the micromanometer (see

Figure 10).

Note: Observe the arrow indicator on the Air Flow Probe when taking air velocity or air volume

measurements.

Total Pressure Port (+)

Static Pressure Port (–)

Figure 10: Air Flow Probe

Connecting the Temperature Probe or Temperature and Humidity Probe to the Micromanometer

The Temperature probe and Temperature/Humidity probe attach to the 8-pin connector located on the
right hand side of the micromanometer. When connecting the probe to the meter, the dimple on the
connector must be aligned to fit the receptacle indentation on the meter (see

Figure 11).

10 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

Match key on plug to
detent on receptacle

Figure 11: Connector for the Temperature Probe or Temperature/Humidity Probe

Chapter 2: Unpacking and Setting Up 11

Chapter 3. Getting Started

This section provides information to help you quickly become familiar with the Models EBT720/EBT721
and PH720/PH721
Sample readings.

Keypad Operation

The keypad lets you enter information, initiate functions, and change values stored in the
micromanometer. It will be helpful before operating the micromanometer to understand more fully what
each of the keys do.

W X T andS

The arrow keys let you navigate through menus or select options. Generally only one set of arrow keys
(S,T or W,X are operational for any given operation. Use W and X to move through menus; use S and
T to increase or decrease a value.

ESC

The ESCAPE key is used to cancel or end an operation or back up to the last screen of displayed
information. The ESC key is useful if you press

The ENTER key is used to accept the present value or move to the next level of a menu.

READ

If the display mode is set to SINGLE, pressing the READ key begins a reading, which stops
automatically when the reading is done.

Micromanometer functions. It also includes step-by-step instructions for taking

and realize you meant to use one of the other keys.

If the display mode is set to RUNAVG, the micromanometer will measure continuously, and pressing
READ will alternately pause or resume the measurement. (See
to SINGLE or RUNAVG.)

There is a red button on the capture hood base that has the same function as the READ key.

Note: Pressing the READ key will not store any measurement to memory.

SAVE

The SAVE key is used to save the currently displayed measurement to the data logging memory.

NEXT TEST

The NEXT TEST key is used to select a new unused Test Id for saving Samples when logging data.

The PRINT key downloads data to an optional printer or to a computer. Refer to information on downloading data.

STATS

The STATISTICS key lets you display COUNT, MINimum, MAXimum and AVeraGe for the Test ID
currently selected for logging data.

Chapter 4 on how to set the display mode

Chapter 4 for

13

I/O

The ON/OFF key is used to turn the micromanometer on or off.

The BACKLIGHT key turns the display’s backlighting on and off. Use backlighting only when working
in areas where you cannot read the display with existing light. Backlighting has a significant impact on
battery life.

Common Terms

In this manual there are several terms that are used in different places. The following is a brief
explanation of the meanings of terms.

Sample

A Sample consists of all of the measurement parameters stored each time the SAVE key is pressed, or
after each logging interval has passed. The maximum number of Samples is 1000.

Logging Interval

The Logging Interval is the frequency period that the micromanometer will log readings, when logging is
set to CONTIN (continuous). For example, if logging is set to CONTIN and the logging interval is set to
60 seconds, a Sample can be taken and saved automatically every 60 seconds. Refer to chapter 4 for more
information on continuous data logging.

Test ID

A Test ID consists of a group of Samples. A Test ID can contain up to 1000 Samples. The maximum
number of Test IDs is 255.

Any new Sample will be saved to the current Test ID. You can change the current Test ID at any time to
keep your data organized, refer to instructions in

The unit does not allow you to store Samples of different character in the same Test ID. If the READ key
is pressed after changes have been made to the Tool or display units or some other parameter, TEST ID
flashes on the display and a new unused TEST ID is selected.

In addition to the data for each Sample, the statistics that are available to view by TEST ID are:

SUM - The sum of all stored values in that TEST ID. (SUM is only available for hood flow or Diffuser
Flow [flow from pressure and K-Factor])

MINIMUM - The lowest value stored in that TEST ID

MAXIMUM - The highest value stored in that TEST ID

AVERAGE - The SUM divided by the number of Samples

COUNT - The number of Samples in that TEST ID

Once you have collected data in a Test ID, you can send it to a printer or a computer. See instructions for
downloading data in

Chapter 4.

Chapter 4.

14 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

Step-By-Step Example Operation

The quickest way to become acquainted with the operation of the Electronic Balancing Tool or
ProHood

To take Samples proceed as follows:

1. Connect the AC adapter to the micromanometer or install batteries in the micromanometer (see

2. Turn on the micromanometer by pressing the I/O key. The unit displays INIT (initializing) and runs a

™ capture hood is to take a few Samples while in the pressure mode.

CAUTION

W

HILE USING THE BALOMETER® AIR BALANCING INSTRUMENT TO TEST AIR

FLOW IN DUCTS

, POLLEN, MOLD, FUNGUS, OR OTHER AIRBORNE CONTAMINANTS. IF YOU

DUST
ARE OR MAY BE SENSITIVE TO DUST
AIRBORNE CONTAMINANTS
RESPIRATOR WHILE EMPLOYING THE
INSTRUMENT

, YOU MAY COME INTO CONTACT WITH OR BE EXPOSED TO

, POLLEN, MOLD, FUNGUS, OR OTHER

, ALWAYS USE AN APPROPRIATE MASK OR

BALOMETER

.

Chapter 2).

brief diagnostic test.

®

AIR BALANCING

3. If the display mode is set to SINGLE, the unit will stop and show READY on the display. Pressing

READ will begin a reading, which stops automatically when the reading is done. If the display mode

is set to RUNAVG, the micromanometer will start measuring continuously, and pressing READ will
pause and resume the measurement. (See

Chapter 4 on how to set the display mode to SINGLE or

RUNAVG.)

4. While the unit reads the measurements, it makes a “clicking” sound.

5. When data collection is finished, the display shows the pressure reading. Press the SAVE key to save

the displayed reading to the currently selected Test ID. (If the SAVE key is pressed before the
micromanometer has collected enough data to save, NO.DATA is displayed.)

6. Repeat steps 4-5 to save additional Samples.

Refer to Chapter 4 for detailed “

How To” information on recalling the saved Samples and many other

specific operations.

Chapter 3: Getting Started 15

Chapter 4. How To

This chapter explains how to perform a variety of operations:

 Select a Tool/Probe

 Set the Time and Date

 Change the Currently Selected Test ID

 Recall Sample Data

 Delete Sample Data

 Delete All Sample Data

 Select/Set a K-factor

 View/Set Standard Pressure and Temperature

 Set Units of Measure for Temperature, Pressure, Flow and Humidity

 Select the RS232C Output Device (Computer or Printer)

 Set the Baud Rate

 Set the Date and Decimal Format

 Set Display Mode for Running Average or Single

 Select Discrete or Continuous Logging

 Turn Back Pressure Compensation On and Off

 Take Back Pressure Compensated Hood Readings

 Set Deadband On and Off

 Calibrate the Micromanometer

 Select User Calibration or Factory Calibration

 Connect and Download to a Printer

 Connect and Download to a Computer

 Data Acquisition (Polling)

Note: The operations described below assume you are starting from the READY display. As you use the

instrument, you will find it unnecessary to return to the READY display each time. Press the ESC
key (one or more times) to return to the READY display.

Select a Tool

The instrument accepts a number of different measurement devices, referred to as Tools. The Tools are:

 Capture hoods for measuring flow from grilles and diffusers.

 A velocity matrix for area-averaged multi-point velocity measurements.

 Pitot tubes for flow and velocity measurements.

 Air Flow probes for flow and velocity measurements.

 A Diffuser Flow tool which can calculate flow for diffusers equipped with differential pressure taps.

(The Diffuser Flow tool is a flow calculation method, not a physical device.) For the Diffuser Flow
tool, flow is calculated from the square root of pressure times a user entered K-factor.

Table 3 identifies each Tool and the units of measure available for that tool.

17

Table 3: Tool Selection Display

Display Shows Tool Units Available

Pressure units only Pressure in H2O, mm H2O, cm H2O, Pa, hPa, kPa,

mm Hg, cm Hg, in Hg,

3

Capture Hood l/s, m

/hr, m3/min, CFM

with flow units

Pressure units with K-

Diffuser Flow l/s, m3/hr, m3/min, CFM

factor and flow units

Air Flow Probe Flow l/s, m

3

/hr, m3/min, CFM

with flow units

Air Flow Probe Velocity ft/min, m/s

with velocity units

3

Pitot Tube Flow l/s, m

/hr, m3/min, CFM

with flow units

Pitot Tube Velocity ft/min, m/s

with velocity units

Velocity Matrix ft/min, m/s

To select a Tool, proceed as follows:

1. Press

to display CHANGE Test ID.

2. Press X until TOOL appears.

3. Press

. The display shows an icon and units (see Table 3 above) to indicate the currently selected

TOOL and the units selected for it.

4. Press S or T to scroll through the available TOOLs. See

5. When the TOOL you want to use is displayed, press

6. If you select “flow” using either a pitot tube or an Air Flow probe, the display will flash a

Table 3 above.

.

and

. This indicates that you need to enter the duct shape and duct size. Proceed with steps 7-10. If

you selected another TOOL, you will return to the TOOL menu.

Note: The only way to change the duct shape or size later is to re-enter the Tool select menu and

re-select the Tool.

7. Use S or T to select the duct shape and stop the flashing.

8. Press

. The display shows the currently selected duct size (flashing).

9. Use S or T to change the size. (If you selected a rectangular size, you need to enter/change the size

for both height and width, even if the duct is square. Change the x dimension first, then press

and

change the y dimension).

10. Press

to exit to the TOOL menu.

18 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

Set the Time and Date

1. Press to display CHANGE Test ID.

2. Press X until SETUP appears.

3. Press

4. Press X until TIME is displayed.

5. Press

6. Use W and X to move between values and S and T to adjust values.

7. Press

Note: You can change the date format (see “Set Format” below). Allowable formats are mm.dd and

.

. The display shows the current time and date. The hours value is flashing.

when you have set the time and date as desired.

dd.mm.

Change the Currently Selected Test ID

To change the Test ID in which Samples will be stored, proceed as follows:

1. Press

2. Press

3. Use S and T to select the Test ID you want to use.

Note: If you press S again after the highest numbered Test ID is displayed, you will add a new Test

to display CHANGE Test ID.

to display the current Test ID.

ID. (The Test ID is empty until you send Samples to it.) Also, if you press SAVE (or try to
automatically log data to a Test ID) and the Tool or display units or measurement
parameters are different from the information already stored in the currently selected Test
ID, the instrument will automatically change the currently selected Test ID to a new unused
Test ID. See the description of “

TEST IDs” in Chapter 3.

Recall Sample Data

To recall Sample data so that you can review it or send it to a printer or computer, proceed as follows:

1. Press

2. Press X until RECALL appears.

3. Press

4. Use S and T to select the Test ID you want to recall a Sample from.

5. Press

Test ID.)
Press S or T to display an entry in the selected Test ID. In addition to displaying individual Sample

values, you can also view the MAX, MIN, AVG, and SUM of the data in the Test ID. (SUM is only
available for hood flow or Diffuser Flow [flow from pressure and K-Factor].) Hold down S or T to
scroll quickly through the data.

Chapter 4: How To 19

to display CHANGE Test ID.

to display the current Test ID.

. The COUNT for the selected Test ID is displayed. (Count is the number of Samples in the

Delete Sample Data

You can delete data in three ways: 1) delete all Sample data in all Test IDs, 2) delete all Sample data for a
single Test ID, and 3) delete only the last Sample currently stored in a Test ID.

Delete all Sample Data

1. Press to display CHANGE Test ID.

2. Press X until DELETE appears.

3. Press

4. Press

Note: This countdown gives you time to change your mind. If you decide not to delete all samples

. The display shows DELETE ALL.

. The instrument counts down from 3 to 0 and then deletes all Sample data.

after pressing

, press ESC before the count reaches 0. Samples will not be deleted.

Delete the Samples Stored in a Single Test ID

1. Press to display CHANGE Test ID.

2. Press X until DELETE appears.

3. Press

4. Press X. The display shows DELETE Test ID.

5. Press

6. Use S and T to display the Test ID whose Samples you want to delete.

7. Press

8. Repeat steps 6 and 7 to delete other Test IDs.

. The display shows DELETE ALL.

. The display shows the currently selected Test ID.

. “DELETE” flashes while all Samples for the selected Test ID are deleted.

Delete a Single Sample

1. Press to display CHANGE Test ID.

2. Press X until DELETE appears.

3. Press

4. Press X. The display shows DELETE Test ID.

5. Press X. The display shows DELETE #.

6. Press

7. Use S and T to display the Test ID containing the Sample you want to delete.

8. Press

9. Press

10. Repeat step 9 to delete other Samples in the selected Test ID.

20 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

. The display shows DELETE ALL.

. The display shows the currently selected Test ID.

. The display shows the last Sample in the Test ID.

. “DELETE” flashes while the last Sample of the selected Test ID is deleted.

Select/Set a K-factor for a Tool

It is possible to enter K-Factors to adjust the calculations of the velocity and flow measurements.

For Hood Flow, Pitot Velocity, Pitot Flow, Air Flow Probe Flow, Air Flow Probe Velocity and Velocity
Matrix, the K-Factor is simply multiplied by the calculated velocity or flow in order to get the displayed
value. For these Tools, use of a K-Factor is optional and setting the K-Factor to 1.0 will turn it off. The
K-factor range for these Tools is 0.500 to 1.500.

For the Diffuser Flow Tool (Flow from Pressure and K-factor), the use of a K-Factor is mandatory. The
displayed flow for this tool is the square root of pressure times the entered K-Factor. The K-factor range
for this Tool is 0.001 to 9.999.

You can only enter a K-factor if you have selected a Tool that can use a K-factor. The Pressure Tool does
not use K-factors.

To select or set a K-factor, proceed as follows:

1. Press

2. Press X until K-FACT appears.

3. Press

4. Press X to scroll through the available K-factors or turn the K-factor Off. The instrument lets you set

four K-factors for each tool that uses a K-factor.

5. If you want to change the value of a K-factor, use S and T to change the K-factor to the value

desired.

6. Press

7. You can repeat steps 3–6 to select and/or adjust other K-factors for the Tool. Once you set a K-factor

it remains set until you change it.

to display CHANGE Test ID.

. The K-factor currently being used flashes on the display.

to accept the desired K-factor. K-FACT is displayed.

View/Set Standard Pressure and Temperature

Temperature and barometric pressure are used for calculating some of the flow and velocity
measurements shown by this instrument, as follows:

For the Pitot Flow, Pitot Velocity, Air Flow "Flow", Air Flow Velocity, Velocity Matrix, and Hood tools,
the instrument uses barometric pressure measured by an internal barometric pressure sensor.

For these tools, the instrument will also use temperature measured by a temperature sensor plugged into
the side of the meter.

The hood base temperature sensor, the accessory temperature sensor, or the accessory
temperature/humidity probe can be used for supplying this temperature measurement. If none of these
temperature sensors are plugged in, you will need to enter the flow temperature using the STP.SET
menu.

For the Diffuser Flow tool (Flow from Pressure and K-factor), temperature and barometric pressure are
not used for calculating flow. Therefore the user is not required to enter a temperature for this tool.

Chapter 4: How To 21

To display the Barometric Pressure:

1. Press

to display CHANGE Test ID.

2. Press X until STP.SET appears.

3. Press

. ACT.STD is displayed.

4. Press X until B.PRESS appears. The measured barometric pressure is displayed. Barometric

pressure is not changeable by the user.

5. Press ESC to return to the STP.SET menu.

To view the Measured Temperature and set the Entered Temperature:

Note: Since the entered temperature is not used for the Diffuser Flow tool (Flow from Pressure and K-

factor), this ENT.MES menu screen is not available if that tool is selected.

1. Press

to display CHANGE Test ID.

2. Press X until STP.SET appears.

3. Press

. ACT.STD is displayed.

4. Press X until ENT.MES appears.

5. Press

. The display shows the user ENTered temperature on the left and the currently MEaSured

temperature on the right (If a temperature sensor is plugged in).

6. Adjust the user entered temperature using S and T, then press

to save it and return to the

STP.SET menu.

Note: To save time, if a temperature probe is installed, you can copy the measured temperature to the

entered temperature, by pressing READ.

ENTered temperature is used for density correction of velocity or flow values only if no
temperature probe is connected. If a temperature probe is connected during velocity or flow
measurement, MEaSured temperature will be used for density correction. For most accurate
density correction, be sure the connected temperature probe is exposed to the temperature of
the flow or velocity being measured.

To Select Actual Flow/Velocity or Standard Flow/Velocity:
(The Actual/Standard selection is used for all tools displaying flow and velocity except the Diffuser Flow
[Flow from Pressure and K-factor] tool.)

1. Press

to display CHANGE Test ID.

2. Press X until STP.SET appears.

3. Press

4. Press

. ACT.STD is displayed.

. The display shows the currently selected option (flashing). Options are ACTUAL and STD.

5. Use S or T to select the option you want to use.

6. Press

. ENT.MES is displayed.

7. Press ESC to return to the STP.SET menu.

22 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

Set Units of Measure for Temperature, Pressure, Velocity/Flow and Humidity

1. Press to display CHANGE Test ID.

2. Press X until SETUP appears.

3. Press

.

4. Press X until UNITS appears.

5. Press

6. Press

. The display shows TEMP.

. The display shows the current temperature units. Options are °F or °C.

7. Use S and T to select between options.

8. Press

when you have selected the desired units.

9. Press X until PRESS is displayed.

10. Press

. The display shows the current pressure units. Options are: in. H2O, cm. H2O, mm H2O, in.

Hg, cm. Hg, mm Hg, kPa, hPa, and Pa.

11. Use S and T to select between options.

12. Press

when you have selected the desired units.

13. Press X until VELFLO is displayed.

14. Press

. The display shows the current velocity/flow units. Options are ft/min for velocity with

CFM for flow, and m/s for velocity with either l/s, m

15. Use S and T to select between options. (If m

3

/h, or m3/min is selected for flow, m/s will be used for

velocity even though “m/s” is not shown on the display.)

16. Press

when you have selected the desired units.

3

/h, or m3/min for flow.

17. Press X until HUMID is displayed.

18. Press

. The display shows the current humidity units. Options are DEWPT, WETBULB, and

%RH.

19. Use S and T to select between options.

20. Press

when you have selected the desired units.

21. Press ESC twice to return to SETUP.

Select the RS232 Output Device (Computer or Printer)

1. Press to display CHANGE Test ID.

2. Press X until SETUP appears.

3. Press

4. Press X until COM.DEV appears.

5. Press

Chapter 4: How To 23

.

. The display shows the current selection: PRINTR or COMPU.

6. Press S or T to change device.

7. Press

. COM.DEV is displayed.

8. Press ESC to return to SETUP.

Set the Baud Rate

Before transferring data to a computer or printer, you must set the baud rate to the speed at which your
printer or computer will accept information.

1. Press

to display CHANGE Test ID.

2. Press X until SETUP appears.

3. Press

.

4. Press X until BAUD appears.

5. Press

. The display shows the currently selected baud rate.

6. Press S or T to change the baud rate. Options are: 19200, 9600, 4800, 2400, and 1200.

7. Press

. BAUD is displayed.

8. Press ESC to return to SETUP.

Set the Format for Date and Decimal

The Format option lets you set the format for the date (mm/dd or dd/mm) and also for the delimiter (. or ,)
the instrument uses.

1. Press

to display CHANGE.

2. Press X until SETUP appears.

3. Press

.

4. Press X until FORMAT appears.

5. Press

. The currently selected format appears.

6. Press S or T to change the format. Options are:

 Peri nndd (use a period for the delimiter and show date as month/day)

 Peri ddnn (use a period for the delimiter and show date as day/month)

 Conn nndd (use a comma for the delimiter and show date as month/day)

 Conn ddnn. (use a comma for the delimiter and show date as day/month)

7. Press

to select the new format. FORMAT is displayed.

8. Press ESC to return to SETUP.

24 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

Set Display Mode for Running Average or Single

If Single is selected, the instrument will show READY on its display, and will not start taking readings
until READ is pressed.

If Running Average is selected, the instrument will constantly measure and display a running average.
The READ button can then be used to stop and start the running average.

1. Press

2. Press X until SETUP appears.

3. Press

4. Press X until DS.MODE appears.

5. Press

SINGLE.

6. Press S or T to change the display mode.

7. Press

8. Press ESC to return to SETUP.

to display CHANGE Test Id.

.

. The display shows the currently selected display mode. Options are: RUNAVG and

. DS.MODE is displayed.

Select Discrete or Continuous Logging

Discrete logging means you have to press SAVE each time you want to save a displayed reading.
Continuous logging means reading and saving is done automatically at the user-selectable Sample
Logging Interval. Then the continuous logging is started and stopped by pressing SAVE.

1. Press

2. Press X until SETUP appears.

3. Press

to display CHANGE.

.

4. Press X until LOG appears.

5. Press

6. Press S or T to change the logging option.

7. Press

CONTIN, the display shows LOG.INT to indicate you must enter a logging interval.

Note: Continuous logging is not available if backpressure compensation is turned on. In this case

8. Press S and T to select the logging interval. Options are (in sec.): 10, 15, 20, 30, 60, 120, 180, 240,

300, 360, 420, 480, 540, and 600.

9. Press

10. Press ESC to return to SETUP.

Chapter 4: How To 25

. The display shows the currently selected option. Options are: DISCRT and CONTIN.

. If you selected DISCRT, LOG is displayed. Continue with step 9. If you selected

the message TURN BP OFF is displayed and the change to continuous logging is not allowed.
Refer to the following section for instructions on how to turn backpressure compensation off.

. LOG is displayed.

Turn Back Pressure Compensation On and Off

Back pressure caused by flow through the capture hood can lower the flow being measured, causing
measurement error. If it is desired to minimize this error, turn the back pressure compensation on.

1. Press

2. Press X until SETUP appears.

3. Press

4. Press X until BP.COMP appears.

5. Press

6. Press S or T to change the option. Options are: ON and OFF.

7. Press

8. Press ESC to return to the main display.

to display CHANGE Test ID.

.

. The display shows whether back pressure compensation is on or off.

. BP.COMP is displayed.

Take Back Pressure Compensated Hood Readings

When back pressure compensation is turned on, the sequence of taking flow readings with the capture
hood is somewhat different.

1. Open the flap in the capture hood base.

2. Hold the capture hood to the diffuser being measured to capture its air flow.

3. Press READ on the meter face or the red “Read Switch” on the left side of the hood base. READ

OPEn flashes on the display.

4. When the open-flap reading is done, CLOSE tHE FLAP is displayed.

5. Close the flap and press READ (or the Read Switch). READ CLOSEd flashes on the display.

6. When the closed-flap reading is done, the backpressure compensated flow is displayed.

7. If you want to save the flow reading to log memory, press SAVE now. STORE is shown on the

display, then the saved reading is shown.

8. Before pressing any more buttons, open the flap.

9. If the display mode is set to SINGLE, pressing READ now will start a new backpressure

compensated reading.

If the display mode is set to RUNAVG, pressing READ now will measure and display a running
average of non-backpressure-compensated readings. Press READ once more to start a new
backpressure compensated reading.

26 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

Set Deadband On and Off

The deadband determines the velocity or volume measurement threshold for displaying 0. If the deadband
is ON, readings below 18 fpm (0.0914 m/s) or 18 cfm (30.58 m
deadband is OFF, readings down to 0 will be displayed. The default is set to ON.

1. Press

2. Press X until SETUP appears.

3. Press

4. Press X until DEADbAnd appears.

5. Press

6. Press S or T to change the option. Options are: ON and OFF.

7. Press

8. Press ESC to return to the main display.

to display CHANGE Test ID.

.

. The display shows whether DEADbAnd is on or off.

. DEADbAnd is displayed.

3

/h, 8.49 l/s) will be displayed as 0. If the

Calibrate the Micromanometer (User Calibration)

A full instrument checkout and calibration with a calibration certificate is available from the factory.
However, some users prefer to calibrate their own instruments. Pressure, temperature and humidity can be
calibrated in the field.

1. Press

to display CHANGE Test ID.

2. Press X until CALIB appears.

3. Press

4. Press X until the desired measurement to calibrate is shown.

5. Press

left. If the current measurement is available for display, it will be shown on the bottom right.

6. Try to expose the sensor being calibrated to a condition close to the requested calibration condition

on the lower left. Press S or T to change the value shown on the lower left to the actual value you
want the display to read under that condition.

7. Press

shows DONE. If any errors are shown on the display it is because the user calibration data taken is
too much different from the factory calibration data. Error codes are explained at the end of

Chapter 7.

Note: The calibration for the accessory temperature/humidity probe is saved on an EEPROM in the

. The display shows CALIB plus which measurement is selected for calibration.

. The display shows SPAN and the requested calibration condition is shown on the bottom

. The display will show the next desired span condition. Repeat steps 6–7 until the display

probe. If that probe is unplugged and used in a different micromanometer, the calibration
will follow the probe. The calibration for the temperature probe and the hood base
temperature sensor is saved in the micromanometer. If those probes are unplugged and used
in a different manometer, the calibration will not follow the probe.

The hood flow calibration is an offset from the factory calibration. An offset of ±12% can be
applied to the hood flow measurement. With the hood icon on the display illuminated and the
display showing FACTOR, use the UP or DOWN key to adjust the offset facto, and press

Chapter 4: How To 27

ENTER to accept. To return to the factory calibration, adjust the factor to 1.000 and press
ENTER to accept.

Select User Calibration or Factory Calibration

Performing a user calibration does not erase the factory calibration because the user calibration is saved in
a different place than the factory calibration. It is possible to re-select whether the micromanometer uses
the user or factory calibration at any time.

1. Press

2. Press X until CALIB appears.

3. Press

4. Press X until the display shows SOURCE U-F for the desired measurement.

5. Press

6. Press S or T to select USEr or FACt.

7. Press

Note: For the accessory temperature/humidity probe it is not possible to mix user and factory

to display CHANGE Test ID.

. The display shows CALIB plus which measurement is selected for calibration.

. The display shows SOURCE and whether USEr or FACt is selected for that measurement.

to save the selection.

calibrations for the different measurements. For example, USEr cannot be selected for
temperature with FACt selected for humidity.

The hood flow calibration factor is applied when the offset factor is changed. There is no
option to select USEr or FACt calibration for hood flow measurement. Set value to 1.000 to
restore factory calibration.

Connect and Download Data to an Optional Printer

To connect a printer, use the RS232 printer cable supplied with the optional printer. Note that the printer
interface cable is different from the computer interface cable.

The printer must be set to the same baud rate as the instrument. To change the baud rate of the printer,
refer to the printer’s operations manual. Always turn the instrument on before the printer. If the printer
prints question marks (??????), asterisks (******), or random characters, reset it by turning it off and then
on again.

Figure 12 illustrates the printout information for a single sample.

28 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

--------------------------­MODEL: EBT721

SERIAL: 0404004

--------------------------­TEST ID: 2
Sample: 1
02/16/04
15:14:31 1.00 CFM
Shape=Round
Dia = 4.0 in. ø
Entered Temp= 74.4 °F
Baro. Press= 29.16 in.Hg
15:14:31 28.5 %rh

Figure 12: Sample Print Out

The Models EBT720/EBT721 and Models PH720/PH721

allow printing of the entire memory, all

Samples stored within a particular Test ID, or an individual Sample.

To print the entire memory, press and hold the

key. This starts a countdown from 3 to 0 on the
display. When the display shows “0”, release the button. If you release the key at any time other than 0
during the countdown, nothing will print. The display will flash “Send dAtA” while printing.

To print all samples stored within a particular Test ID, first enter the RECALL menu. Select the desired
Test ID to print using the up/down arrow keys. Then press and release the

key. The display will

flash “Send dAtA” while sending.

To print an individual sample, first enter the RECALL menu. Select the Test ID containing the desired
sample using the up/down arrow keys and press

. Use the up/down arrow keys to scroll thru MIN,
MAX, etc until the desired Sample is displayed. Then press and release the (print icon) key. The display
will flash “Send dAtA” while sending.

Connect and Download Data to a Computer

Use the RS232 computer interface cable (provided) to connect the instrument to a COM port on the
computer. A 9-pin to 25-pin adapter will be required if your computer has a 25-pin serial port connector.

®

The program “HyperTerminal
sent by the micromanometer. To send data from the micromanometer, use the printing function of the
micromanometer, as shown above.

The program “CompuDat™” which comes with your micromanometer can be used to assist in
downloading data to a Windows
software, run the SETUP.EXE file on the CompuDat distribution disc. Once you open the program, it is
self-directing and provides all the necessary instructions for downloading data.

” which comes with Microsoft Windows® can be used for capturing data

®

-based computer and formatting that data. To install CompuDat

®

HyperTerminal is a registered trademark of Hilgraeve, Inc.

®

Windows is a registered trademark of Microsoft Corporation.

Chapter 4: How To 29

Data Acquisition (Polling)

The micromanometer is designed to allow the user to perform polling through the use of a computer. The
computer must send an upper case ‘V’ to the micromanometer while the micromanometer is taking
measurements. The ‘V’ must be sent alone, without a carriage return or linefeed. The micromanometer
will then output the values of the last measurements read. Note that the ‘V’ polling command will not
start the micromanometer taking new measurements, therefore, it works much better if the
micromanometer display mode is set to RUNAVG.

You must write your own program to use the ‘V’ polling command. Therefore this command is only
designed for medium-to-advanced programmers who need real-time data acquisition. The ‘V’ polling
command cannot be used to request logged data.

30 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

Chapter 5. Changing Flow Hoods

This chapter identifies the flow hood parts and gives instructions for assembling the flow hood.

Flow Hood Parts Identification

Figure 13 identifies the major parts of the capture hood, which are described in the following paragraphs.
Before using the hood, please familiarize yourself with the various parts. You may also refer to
through

3.

1 Fabric hood - Basic hood assembly

2 Base allows micromanometer to be attached

3 Micromanometer with display

4 Flap Actuator

5 Read Switch

1

Tables 1

2

4

5

3

Figure 13: Flow Hood Components

Hood Assembly

The Flow Hood is shipped from the factory partially assembled with the 2 ft × 2 ft (610 mm × 610 mm)
nylon hood attached to the base. If you wish to use another hood size, see “Changing Hoods,” below.

To complete the assembly of the 2 ft × 2 ft (610 mm × 610 mm) hood, follow these six steps:

1. Place the base of the capture hood

2. Lift the top of the fabric. Insert one end of a support pole into its pole mount in the base. There is a

cup in each corner of the frame to accept the other end of each support pole.

3. Grasp the support pole. Bend the pole slightly to insert the top end of the pole into the support pole

cup located in the opposite corner of the fabric frame. The poles are connected to the frame corners in
a crisscross fashion as shown in

on the floor.

Figure 14.

31

Figure 14: Installing a Support Pole

4. Insert the second support pole into the pole mount on the opposite side of the base.

5. Repeat step 3 for the second support pole.

6. Repeat steps 4 and 5 for the remaining two support poles.

Four other hood sizes are available from TSI and can be purchased separately. Available hood sizes are
identified by the dimensions of the frame structure at the top of the hood and include 2 ft × 4 ft (610 mm
× 1220 mm), 1 ft × 4 ft (305 mm × 1220 mm), 1 ft × 5 ft (305 mm × 1525 mm) and 3 ft × 3 ft (915 mm ×
915 mm).

To change hood sizes, first remove the hood currently attached to the base. To remove the attached hood,
first unlatch the cinch belt where the fabric is attached to the base. Then remove the fabric from its frame
structure by pulling the shock cord out of the aluminum frame. Finally, fold up the fabric you just
removed so that it can fit into one of the accessory pockets inside the carrying case. It is a good idea to
fold the fabric so that the tag identifying its size remains visible for future reference.

Alternate Hood Installation

Refer to Figures 15 through 18 to determine the frame channels needed to assemble any of the standard
sized frames. Select the pieces required for the frame size desired and assemble with the aid of the
appropriate figure. Each channel is labeled with its number for easy identification. Several sections
(numbers 1, 3, and 4) consist of a straight channel portion (each a different length) and a corner piece.
This corner piece has an eyelet and slot arrangement which mates with a similar eyelet and slot at the end
of the straight portion of the channel pieces (see
locking by means of a retention spring. The arrangement forms a rugged frame which is additionally
strengthened when the hood is attached.

Figure 19). These pieces can be slid together and are self

32 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

2

1

3

2

3

1

Figure 15: 1 ft × 4 ft (305 mm × 1220 mm) hood and frame. The support poles always cross as
pairs at the front and back of the fabric hood. For the 1 ft × 4 ft (305 mm × 1220 mm), the support
poles are inserted into the outside ferrule locations.

Chapter 5: Changing Flow Hoods 33

2

4

1

1

4

2

Figure 16: 2 ft × 4 ft (610 mm × 1220 mm) hood and frame. The support poles always cross as
pairs at the front and back of the fabric hood. For the 2 ft × 4 ft (610 mm × 1220 mm), the support
poles are inserted into the inside ferrule locations.

The number 1 and 5 channels also have a wing nut at the straight end which will mate with an angle and
studs on the ends of numbers 2, 5 and 6 to form the longer frame sides (see

Figure 20).

34 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

2

5

1

1

5

3

2

3

Figure 17: 1 ft × 5 ft (305 mm × 1525 mm) hood and frame. The support poles always cross as
pairs at the front and back of the fabric hood. For the 1 ft × 5 ft (305 mm × 1525 mm), the support
poles are inserted into the inside ferrule locations.

Chapter 5: Changing Flow Hoods 35

6

1

1

6

6

1

1

6

Figure 18: 3 ft × 3 ft (915 mm × 915 mm) hood and frame. The support poles always cross as pairs
at the front and back of the fabric hood. For the 3 ft × 3 ft (915 mm × 915 mm), the support poles
are inserted into the outside ferrule locations.

Figure 19: Frame Corner Assembly

36 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

Figure 20: Frame Side Coupler Assembly

Each hood is constructed in a trapezoidal shape, sewn together so that one open end forms a round
attachment to the base, and the other forms a square or rectangle large enough to fit its matching frame
assembly. Around the frame end of the hood, an elastic shock cord has been sewn into the hood. This
cord is of a size such that it can be pushed into the open side of the U-shaped channels of the frame.

In general, attach a hood to the frame first, and then to the base unit. By stretching around the frame
corners the cord is slightly reduced in diameter and is easier to press into the frame channel.

Note: The hood corners should always be aligned with the corners of the base, near the hood support

brackets. The base has rivets located in the corners which can be used as a guide for aligning the
hood corners.

Direct Inflow Measurement Hood for Biological Safety Cabinets

The BSC hood kits for the models EBT721/PH721 are designed to measure the inflow or exhaust flow
through a biological safety cabinet (see

Table 2 of this manual.

in

Figure 21: Direct Inflow Measurement Hood

Figure 21). Part numbers and description of each kit can be found

Chapter 5: Changing Flow Hoods 37

The direct inflow BSC hood includes (see

Figure 22):

❑ Fixed frame assembly with four removable flaps

❑ Fabric hood

❑ Hood support poles

❑ Base mounting hardware (threaded insert, washer, and screw)

❑ Telescopic pole stand with case to freely hold the capture hood in a vertical position when mounted to

a biological safety cabinet or lab hood

Figure 22: Direct Inflow Measurement Hood Components

To complete the assembly of the BSC hood, follow these seven steps:

1. Remove the plug located at the back of the base assembly and insert the Philips screw with washer

into the hole from the inside of the base (see

Figure 23). Place the threaded insert on the outside of

the base opposite the screw and tighten with a Philips screwdriver.

Figure 23: Remove Plug Located at Back of Base Assembly

38 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

2. Attach the fabric hood and hood support poles to the frame and base assembly in the same manner as

previously described for the other hood sizes.

3. Insert the flaps into the slots from the side of the frame where the fabric hood is attached to the

U-channel of the frame (see

Figure 24). Use the different flap lengths to fit various cabinet widths.

Figure 24: Attach Fabric Hood and Hood Support Poles to Frame and Base Assembly

4. Mount the capture hood base to the telescopic stand by fastening the screw on the telescopic stand to

the threaded insert mounted on the base opposite the display/manometer (see

Figure 25).

Figure 25: Mount Hood Base to Telescopic Stand

5. Adjust the height and position of the telescopic stand so that the bottom part of the hood frame rests

against the cabinet opening, and the capture hood is horizontal to the cabinet (see

Figure 26).

Chapter 5: Changing Flow Hoods 39

Figure 26: Adjust Height and Position of Telescopic Stand

6. Lower the sash of the cabinet until it rests on the foam lip of the hood frame (see

Figure 27).

Figure 27: Lower Sash of Cabinet Until it Rests on Foam Lip of Hood Frame

7. Adjust the flaps to cover the opening of the cabinet. Tape the edges of the flaps to the sash and frame

of the cabinet to create a tight fit. The unit is now ready to make measurements (see

Figure 28).

40 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

Figure 28: Unit Ready to Make Measurements

Chapter 5: Changing Flow Hoods 41

Chapter 6. Flow Measurements Using the Capture Hood

There are two methods of making flow measurements using the capture hood: Non-Backpressure
Compensated and Backpressure Compensated methods (see “
explanation of the implications of capture hood-induced back pressure on the measured flow). Flows in
both “Supply” and “Return” flow direction can be taken with either non-backpressure compensated or
backpressure compensated mode.

Note: “Return” flows will be indicated by a negative flow number, as long as the tubes leading to the

Matrix manifold in the base are connected properly. The proper tube orientation is from the
upper portion of the Matrix manifold leading to the positive “+” port on the back of the meter.

CAUTION

W

HILE USING THE BALOMETER® AIR BALANCING INSTRUMENT TO TEST AIR

FLOW IN DUCTS

, POLLEN, MOLD, FUNGUS, OR OTHER AIRBORNE CONTAMINANTS. IF YOU

DUST
ARE OR MAY BE SENSITIVE TO DUST
AIRBORNE CONTAMINANTS
RESPIRATOR WHILE EMPLOYING THE
INSTRUMENT

, YOU MAY COME INTO CONTACT WITH OR BE EXPOSED TO

, ALWAYS USE AN APPROPRIATE MASK OR

.

Appendix A. Back Pressure,” for an

, POLLEN, MOLD, FUNGUS, OR OTHER

BALOMETER

®

AIR BALANCING

Non-Backpressure Compensated Measurements

To take non-backpressure compensated measurements, be sure the Back Pressure Compensation function
is turned “OFF” (see “

Turn Back Pressure Compensation On and Off” in Chapter 4).

Non-backpressure compensated measurements can only be made with the back pressure flap in the
“OPEN” position. If you attempt to make a non-backpressure compensated measurement with the flap
closed or partially closed, the meter will display the message “OPEN the FLAP”.

In the non-backpressure compensated mode, it is possible to take either single measurements or running
average measurements (see “

Set Display Mode for Running Average or Single” in Chapter 4).

Single Measurements

“Single” measurements are individual flow measurements initiated by pressing either the “READ” button
on the meter, or the red trigger button on the left side of the base. Depending on the flow being measured,
a single reading will take from one to eight seconds to complete (lower flows take longer).

Note: Keep the hood in place during the entire measurement, otherwise the reading will be in error.

43

Running Average Measurements

In the “Running Average” measurement mode, the meter will constantly measure and display a running
average of flow. This mode is useful when making adjustments to the flow.

If you wish to “hold” a particular value on the display, momentarily press either the “READ” key on the
meter or the red trigger button on the base. To restart the running average measurements from a “held”
value, simply press the “READ” key or the red trigger button again.

Note: The running average utilizes a variable time constant determined by the meter (not user

selectable) depending on the flow. At very low flows, under 100 ft
constant is approximately 8 seconds. When using the “Running Average” mode for adjusting
flows (setting or changing duct damper positions, for instance), keep in mind that there will be a
lag time after flow adjustments are made for the meter to settle at any new flow reading.

3

/min, for example, the time

Backpressure Compensated Measurements

In most cases, backpressure compensated measurements will provide the most satisfactory flow
measurement results.

In order to prepare for backpressure compensated measurements, be sure the Back Pressure
Compensation function is turned “ON” (see “
Chapter 4).

Backpressure compensated measurements require two sequential measurements: first with the back
pressure flap “OPEN” and then with the flap “CLOSED”.

Here is the sequence of operation:

Turn Back Pressure Compensation On and Off” in

1. Place the capture hood over the diffuser, grille or other opening through which you wish to make a

measurement.

2. Open the back pressure flap. This can easily be accomplished by pressing up on the flap handle with

your left hand as you hold the hood in place. Press until the flap clicks into full open position.

3. Press the red trigger button. Again, this is easily accomplished with your left hand as you hold the

hood in place. The message “READ OPEN” will flash as the meter takes its reading. (In very low
flows, this step and step 5 may take as many as 8 seconds each. Higher flows will require less time.)

4. Wait for the message “CLOSE the FLAP”, and then close the flap by pulling down on the flap handle

until it clicks into the fully closed position.

5. Press the red trigger button. The message “READ Closed” will flash as the meter takes its reading.

6. The backpressure compensated measurement value will appear and remain on the display until

another reading is initiated, or some other meter function is initiated.

Note: It is important that the capture hood see the same flow for both parts of the backpressure

compensated flow measurement. It is best to keep the hood in place for both measurements, but it
is alright to remove and replace the hood between the two readings. However, if the flow is
changed or changing during or between the two measurements, the measurement results will be
inaccurate.

44 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

Error Display

If the limits of allowed flow parameters are exceeded during a backpressure compensated measurement,
an error message will be displayed. This can happen if there are flow reversals during the measurement or
other changes in the flow during the measurement (such as changing a damper position), or as a result of
other operator errors.

Chapter 6: Flow Measurements Using the Capture Hood 45

Chapter 7. Maintenance and Troubleshooting

The Electronic Balancing Tool (EBT) EBT720/EBT721 and ProHood™ PH720/PH721 capture hoods are
designed for long-term field use. If used with reasonable care, it should be able to make precise
measurements over a long time period. Some of the components can be cleaned periodically. When
cleaning the components, please follow the instructions given below.

Fabric Hood

The hoods can be washed with mild detergent and cold water. When washing the hood, keep the hood
away from objects with sharp corners or sharp edges. Careless cleaning may cause damage.

If the fabric gets ripped it should be replaced or repaired. Duct tape can be placed over the rip on both
sides of the fabric for temporary repair.

To replace a damaged fabric or to order a different fabric size, contact your local TSI/Alnor

IRFLOW™ Instruments products distributor. To determine who your local TSI/Alnor

A
Instruments products distributor is, you may call toll-free at [phone] (UK), [phone]
(USA), or (1) 651-490-2811 (International).

Micromanometer

®

®

or

or AIRFLOW™

The micromanometer case, display screen and keys can be cleaned using a damp cloth with mild
detergent solution. Do not immerse it in water. Wipe the unit dry before use.

Manifold

If you observe the flow sensing taps of the manifold becoming clogged with dust or other material, clean
them with a damp cloth. The manifold should be kept in place during cleaning. Do not apply excessive
forces on the grid of the manifold. If any part of the grid is damaged, please contact Customer Service for
repair information.

Cases

If the instrument case or storage case needs cleaning, wipe it off with a soft cloth and isopropyl alcohol or
a mild detergent.

47

Calibration

TSI recommends an annual calibration for the instrument. For a nominal fee, we will calibrate the unit
and return it to you with a certificate of calibration and NIST traceability. This “annual checkup” assures
you of consistently accurate readings. To calibrate the instrument, please ship the complete package that
includes the meter, the base, the manifold and any fabrics used. Everything should be packed carefully
within the carrying case and then inside a shipping box. The original shipping box is preferred. Before
sending your instrument for calibration or repair, obtain a Return Material Authorization (RMA) number
by visiting our website at
number, you will also learn the cost of service or calibration and receive shipping instructions.

Tables 5 and 6 list the symptoms, possible causes, and recommended solutions for common problems
encountered with the instrument. If your symptom is not listed, or if none of the solutions solves your
problem, please contact the factory.

Table 4: Troubleshooting the Instrument

Symptom Possible Causes Corrective Action

No display Unit not turned on.

“ ”
flashing on display

“888888”
flashing on display

“8888”
flashing on display

Table 5 lists the possible error codes and their meanings. All error codes are preceded by ‘ERR.’

http://rma.tsi.com or contacting customer service. When obtaining an RMA

Press I/O key.

Low or dead batteries.

Dirty battery contacts.

AC adapter not connected.
Low battery charge.

Replace the batteries.

Clean the battery contacts.

Plug in AC adapter.
Replace or recharge the batteries.

Clean the battery contacts.
Dirty battery contacts.
The pressure is too high to measure.
This same display is shown if

The maximum pressure is shown

on the specifications page.
measuring velocity or flow and the
pressure at that velocity is too high.
The temperature is too high to
measure.

The maximum temperature is

shown on the specifications page.

Table 5: Error Codes

Error Code Possible Causes Corrective Action

10 The AC adapter voltage is too low.

Use correct AC adapter.

The NiMH batteries will not recharge fully
with low AC adapter voltage.

11 The AC adapter voltage is too high.

Use correct AC adapter.

The NiMH batteries will not fast-charge
with high AC adapter voltage.

12 Model number checksum error. Return to factory.

13 Serial number checksum error. Return to factory.

48 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

Error Code Possible Causes Corrective Action

14 Accessory temperature/humidity probe

checksum error for humidity.

15 Accessory temperature/humidity probe

checksum error for temperature.

16 Accessory temperature probe calibration

checksum error.

17 Hood temperature probe calibration

checksum error.

Perform user calibration or return to
factory.

Perform user calibration or return to
factory.

Perform user calibration or return to
factory.

Perform user calibration or return to
factory.

18 Pressure sensor calibration checksum error. Perform user calibration or return to

factory.

19 A to D converter calibration checksum

Return to factory.

error.

20 Barometric pressure sensor calibration

Return to factory.

checksum error.

30 Pressure calibration voltage at 1 in. H2O

must be less than pressure calibration
voltage at 5 in. H

2

O.

31 Pressure calibration voltage at 5 in. H2O

must be less than pressure calibration
voltage at 15 in. H

2

O.

32 While performing user calibration of

accessory temperature/humidity probe, the
correct probe was not found.

33 While performing user calibration of hood

Make sure calibration pressures are
correct.

Make sure calibration pressures are
correct.

The accessory temperature/humidity
probe was either not plugged in or is
faulty.

Plug in the selected probe.
temperature sensor or accessory
temperature sensor, the accessory
temperature/humidity probe was found
instead.

34 Barometric pressure measured was <15.00

in. Hg.

35 Barometric pressure measured was >40.00

in. Hg.

36 Flap closed pressure was < flap open

The barometric pressure is too low to

take a reading.

The barometric pressure is too high to

take a reading.

Take data again.
pressure, or flap open versus flap closed
pressure ratio exceeds allowed limits.

37 There was an error reading the AD7708 A

Return to factory if error re-occurs.
to D converter.

38 There was an error reading the AD7718 A

Return to factory if error re-occurs.
to D converter.

39,40, 41,42 Error in logged data. If using accessory temp/humidity probe,

make sure probe securely connected.

Erase logged data.

Chapter 7: Maintenance and Troubleshooting 49

Error Code Possible Causes Corrective Action

43 Could not send RS232 data because the

receiving device was busy >10 seconds.

Make sure printer or computer is ready

to receive. Check RS232 interface

cable.

50 Pressure sensor zero voltage is too high. Return to factory if error re-occurs.

51 Pressure sensor gain out of range. Perform user calibration or return to

factory.

52 Lithium battery voltage is too low. Replace lithium battery or return to

factory.

53 AD7708 A to D converter calibration

Return to factory.
factor out of range.

54 AD7718 A to D converter calibration

Return to factory.
factor out of range.

55 User entered flow temperature out of

range.

The micromanometer has reset the

temperature to 70.0°F (21.1°C) to

correct it.

56 Barometric pressure zero factor out of

Return to factory.
range.

57 Barometric pressure span factor out of

Return to factory.
range.

58 Offset factor for user temperature sensor

calibration out of range.

Re-do user calibration, set temperature

sensor calibration to FACT, or return to

factory.

59 Slope factor for user temperature sensor

calibration out of range.

Re-do user calibration, set temperature

sensor calibration to FACT, or return to

factory.

60 Humidity sensor voltage at 20% RH out of

range.

61 Humidity sensor voltage at 80% RH out of

range.

Perform user calibration or return to

factory.

Perform user calibration or return to

factory.

62 Pressure sensor gain factor A out of range. Perform user calibration or return to

factory.

63 Pressure sensor gain factor B out of range. Perform user calibration or return to

factory.

64 Pressure sensor gain factor C out of range. Perform user calibration or return to

factory.

68 Pressure sensor divider calibration out of

Return to factory.
range.

69 A to D reference voltage out of range. Return to factory.

70 5V reference voltage out of range. Return to factory.

71, 72 An invalid K-Factor was corrected. The micromanometer has set the K-

factor to 1.0 to correct it.

74 Pressure voltage for user pressure

Re-do user calibration.
calibration out of range.

50 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

Error Code Possible Causes Corrective Action

75 User temperature calibration >5°F (3°C)

different from factory calibration.

Re-do user calibration.

Replace temperature probe.

>100 Internal program error. Please contact the factory.

Chapter 7: Maintenance and Troubleshooting 51

Appendix A. Back Pressure

The quantity of air flowing through a supply diffuser or a return grille is reduced to some extent whenever
a capture hood is placed over the flow opening. The amount of flow reduction will vary depending on the
combined effects of the diffuser/grille resistance, the capture hood resistance, and the flow rate.

The Electronic Balancing Tool and ProHood
measurements which are compensated for the effects of the capture hood-induced back pressure. This is
accomplished by taking two sequential flow measurements at a diffuser or grille, the first with the back
pressure flap “OPEN” and the second with the flap “CLOSED”. The resulting Backpressure Compensated
Flow displayed by the meter represents the air flow through the diffuser/grille in its original state, that is,
without the presence of the capture hood.

Verifying Flow Measurements

It is always the recommended practice to verify the flow measurements obtained with a capture hood by

*

performing appropriate
anemometer.

We recommend the use of the Log-linear method when traversing a round duct, and the Log-Tchebycheff
method when traversing a rectangular duct.

multi-point, in-duct velocity traverses using a Pitot-static tube or a thermal

™ capture hood features a built-in capability to make flow

*

We recommend that you refer to the most up-to-date copy of the duct traverse specification you require from an approved
regulatory or professional organization.

53

Appendix B. Actual vs. Standard Air Velocity and Flow

t

ρ=×ρ

Measurements

Actual Air Velocity is also known as the “local” air velocity. It can be thought of as the speed of a
microscopic dust particle being carried along in the air stream.

Actual Air Velocity is measured with a Pitot tube using the basic formula:

VP

7.1096V

ACT

×=

where: V

is Actual Air Velocity, in units of (Actual Feet per Minute)

ACT

VP is Velocity Pressure, measured in units of (in. H
ρ

is the air density, in units of (lbm/ft3)

air

Air density, ρ

, can be calculated from the equation:

air

air

325.1

×=ρ

ACT

where: P
T

is the atmospheric pressure, in units of (in. Hg)

ACT

is the local air temperature, in units of (°F)

ACT

Standard Air Velocity

is also known as the mass velocity of air. It can be thought of as the local air

velocity corrected to standard conditions of air. Standard Conditions are defined as air at 70°F and P

29.92 in. Hg.

Substituting Standard Conditions into Eq. (2) above we can see that:

air

STD

×=ρ Eq. (3)

325.1

Standard Air Velocity and Standard Air Flow are often the preferred units of measure when evaluating
Heating, Ventilating and Air-Conditioning (HVAC) system performance because the heat-carrying
capacity (and cooling capacity) of air is directly related to Standard, not Actual, units of measure.

Converting between Standard and Actual units of measure simply involves an inverse air density ratio, as
follows.

From the continuity of mass equation, we can state the following:

Eq. (1)

ρ

air

O)

2

P

ACT

Eq. (2)

460T

+

=

STD

92.29

=

+

46070

VV

×

STDACT

STDairACTair

lb

m

0748.0

3

f

Eq. (4)

55

Thus, to convert from Actual Velocity to Standard Velocity, use the following equation:

ρ

air

ACT

ρ

air

STD

VV

=×

Eq. (5)

STDACT

Substituting known values into Eq. (5), we get:

P

ACT

ACT

+

460T

46070

+

×

92.29

VV

=×

STDACT

or,

P

V =×

ACT

ACT

×

ACT

460T

+

Eq (6)

V714.17

STD

where: P

is the local atmospheric pressure, as measured by the EBT/PH, for example, in units

ACT

of (in. Hg)
T
V
V

is the local temperature of the air flow being measured, in units of (°F)

ACT

is Actual Air Velocity, in units of (AFPM)

ACT

is Standard Air Velocity, in units of (SFPM)

STD

Similarly, to convert from Standard to Actual Air Velocity, use the following equation:

460T

+

V =×

STD

ACT

×

P

ACT

Eq (7)

V05645.0

ACT

For Volumetric Flow measurements, the analysis is exactly the same.

Thus:

P

Flow =×

ACT

Flow =×

STD

×

ACT

×

ACT

ACT

P

+

+

ACT

460T

460T

Flow714.17

Flow05645.0

Eq (8)

STD

Eq (9)

ACT

where: Flow
Flow

is Actual Air Flow, in units of (ACFM)

ACT

is Standard Air Flow, in units of (SCFM)

STD

Note: The Models EBT720/EBT721 and Models PH720/PH721 perform these calculations

automatically. You can choose to view velocity or flow measurements in either “Actual” or
“Standard” units of measure.

56 Electronic Balancing Tool EBT720/EBT721 and ProHood PH720/PH721

Alnor® Models EBT720/EBT721 and AIRFLOW™ Instruments

Models PH720/PH721

Specifications

Range

Differential pressure... ±15 in. H

H
pressure

Absolute pressure...... 15 to 40 in. Hg (356 to

1016 mm

Velocity ...................... 25 to 8,000 ft/min (0.125 to

40 m/s) pitot probes;

25 to 5,000 ft/min (0.125 to

25 m/s) air flow probe;

25 to 2,500 ft/min (0.125 to

12.5 m/s) velocity matrix

Volume ...................... 25 to 2,500 ft

4250 m

Temperature .............. -40 to 250°F (-40 to 121°C)

temperature probe

14 to 140°F (-10 to 60°C)

temperature/RH probe

40 to 140°F (4.4 to 60°C)

operating (electronics)

Storage temperature... -4 to 160°F (-20 to 71°C)

Rh .............................. 0 to 95% RH temperature/RH

probe

Resolution

Pressure .................... 0.00001 in. H

and differential;

0.01 in. Hg (1 mm Hg) absolute

Velocity ...................... 1 ft/min (.01 m/s)

Volume ...................... 1 ft

Rh .............................. 0.1% RH

Temperature .............. 0.1°F (0.1°C)

Accuracy

Pressure .................... ±2% of reading ±0.001 in. H

(0.25 pa) static and differential;

±2% of reading absolute

Velocity ...................... ±3% of reading ±7 ft/min

(0.04 m/s) >50 ft/min (>0.25 m/s)

Volume ...................... ±3% of reading ±7 ft

(12 m

Rh .............................. ±3% RH

Temperature .............. ±0.5 °F (0.3°C) from 32 to 160°F

(0 to 71°C);

max ±2.0 °F (1.2°C) from -40 to

32°F (-40 to 0°C) and from 160 to

250°F (71 to 121°C)

*

Specifications are subject to change without notice.

O (3735 pa); 150 in.

2

O maximum safe operating

2

Hg)

3

/min (42 to

3

/h) capture hood

O (0.001 pa) static

2

3

/min (1 m3/h)

3

3

/h) >50 ft3/min (>85 m3/h)

/min

*

Units

Pressure .................... in. H

O, pa, hPa, kPa, mm Hg,

2

in. Hg, cm Hg, mm H

O, cm H2O

2

Velocity ...................... ft/min, m/s

3

Volume ...................... ft

/min, m3/h, m3/min, l/s

Temperature .............. degrees F, degrees C

Statistics ...................... min, max, average up to 1000

readings

Data Storage ................ 1000 readings, time and date

stamped

Logging Interval .......... user selectable (10 to 600

seconds)

Response Time............ 2 to 8 seconds

Display ......................... 6 digit, 0.75 in. character height,

multi-line, sectored, multiple

symbolic icons, high-contrast

backlit LCD

Dimensions

(manometer only) ............. 7.4 in. × 4.5 in. × 2.3 in.

(18.8 cm × 11.4 cm × 5.8 cm)

Pressure connection... ¼ in. OD straight ports for use

with 3/16 in. ID flexible tubing

Weight with batteries .. EBT720/PH720 17 oz (0.5 kg);

EBT721/PH721 7.4 lb (3.4 kg)

Power requirements.... four AA-size cells, rechargeable

NiMH (included) or alkaline, or

AC adapter (included), 7.5 VDC,

1.6 A, regulated

Battery life.................... minimum of 12 hours typical

Recharge time.............. 1 hour (external charger); 4 hours

(internal charger)

Hood sizes available

O

2

Standard .................... 2 ft × 2 ft (610 mm × 610 mm)

Optional........................ 2 ft × 4 ft (610 mm × 1220 mm);

1 ft × 4 ft (305 mm × 1220 mm);

1 ft × 5 ft (305 mm × 1525 mm);

3 ft × 3 ft (915 mm × 915 mm)

RS232C output .............. ASCII character codes;

1200, 2400, 4800, 9600, 19200

baud rate (selectable)

no parity

8 data bits

1 stop bit

no handshaking

Warranty....................... 2 year factory warranty

TSI Incorporated
500 Cardigan Road
Shoreview, MN 55126 USA
Toll Free [phone]
Telephone [phone]
Fax [phone]

E-mail:
Web: www.alnor.com

Part No. 1980497 Rev. G
Copyright © 2008-2009 by TSI Incorporated

[e-mail]

TSI Instruments Ltd.
Stirling Road
Cressex Business Park
High Wycombe
Bucks
HP12 3RT United Kingdom
Tel: [phone]
Fax: [phone]

E-mail:
Web: www.airflowinstruments.co.uk

[e-mail]

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