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 LIMITATIO N S 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 W A RRA NTY AND
LIABILITY may not be amended, modified or its term s
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 at
(800) 874-2811 (USA) and (1) 651-490-2811
(International).
Trademarks
®
TSI
, TSI logo, Alnor®, and Balometer® are
trademarks of TSI Incorporated.
.
iii
iii v
TABLE OF CONTENTS
Section 1 General Description ......................................................... 1
Section 2 Theory of Operation ........................................................ 1
The Alnor® LoFlo Balometer® Capture Hood is a
compact instrument that measures very low air flow
rates in HVAC systems. It measures from 10 to 500
cfm (17 to 850 m
Balometer
3
®
/h, 4.7 to 236 l/s). The LoFlo
Capture Hood displays standard air volume
rate when placed at supply or return diffusers, registers,
or grilles located on the ceiling, wall, or floor.
®
The LoFlo Balometer
Capture Hood has a vent
mechanism which reduces the restriction of air flow
caused by the instrument. This unique venting system
(patent pending) allows the instrument to remain
compact while still measuring a wide range of volume
rates. The LoFlo Balometer
®
Capture Hood should be
SECTION 2
Theory of Operation: Capture Hoods
and Thermo-anemometry Sensing
As air exits a diffuser, it is captured in the hood or base
and directed over a manifold. The manifold averages
the velocity pressure and directs air over the sensors.
The velocity and temperature of the air passing through
the manifold are sensed, using a constant temperature
thermo-anemometer principle. The voltage output from
the sensor is then calibrated for the entire volume rate
passing through the LoFlo Balometer
All capture hoods are susceptible to “odd” air flow
patterns. “Odd” could refer to any air flow pattern
different from the pattern where it was calibrated.
Substantial negative effects can be observed when
®
Capture Hood.
used with the vents closed at lower volume rates, but
higher volume rates should be measured with the vents
open to minimize any resistance effects. A 2-point
measurement may be taken to compensate for the
resistance effect of the instrument at higher volume
rates.
®
The LoFlo Balometer
Capture Hood is battery
powered and may be used with or without optional
hoods. It weighs just over 6 pounds with the 2' x 2'
hood, helping to reduce worker fatigue.
using a large hood on a small diffuser. For example,
using a 2' x 2' hood on a 10" x 10" diffuser. This creates
large recirculation regions on the sides of the fabric
hood and causes an “odd” air flow pattern as it passes
over the manifold. It is recommended to match the
hood closely to the size of the diffuser.
3
NOTE: Throughout this manual, the units cfm, m
and l/s are used for simplicity. Note, howeve r , that
the LoFlo Balometer
in standard cubic feet per minute (scfm), standard
cubic meters per hour (std. m
®
Capture Hood actually reads
3
/h), or standard liters
/h
per second (std. l/s).
1
SECTION 3
Safety
When using the LoFlo Balometer® Capture Hood to
check air flow at ceiling diffusers, make certain that
you can safely raise and hold the unit while making
measurements. Be especially careful when working on
a ladder.
WHILE USING THE LOFLO BALOMETER
MAY COME INTO CONTACT WITH OR BE EXPOSED TO DUST
OTHER AIRBORNE CONTAMINANTS
, FUNGUS, OR OTHER AIRBORNE CONTAMINANTS,ALWAYS USE AN APPROPRIATE
MOLD
MASK OR RESPIRATOR WHILE EMPLOYING THE
SECTION 4
Instrument Setup and Storage
Hood Setup
1. Locate the four (4) aluminum channels for the
hood and position them into a square with the foam
facing up. Slide the “U” opening on the channel
end (Fig. 1) and corner bracket toward the brass
eyelets until you feel it latch.
2. Continue with the other two channels until you
have a square frame that is locked tightly in all
four corners.
3. Locate the hood for the frame size you have
assembled.
4. Position a corner seam of the hood onto the corner
of the frame. Stretch the nylon hood to an adjacent
corner until the hood corner meets the frame
corner.
Observe all necessary precautions so that the unit does
not become caught in moving machinery or touch any
exposed electrical wiring.
®
The LoFlo Balometer
Capture Hood is not designed
for gas mixtures other than air. Use with corrosive or
other dangerous or explosive gas mixtures is not
recommended and is at the user’s risk.
CAUTION
®
INSTRUMENT TO TEST AIR FLOW IN DUCTS, YOU
, POLLEN, MOLD, FUNGUS, OR
.IF YOU ARE OR MAY BE SENSITIVE TO DUST, POLLEN,
LOFLO BALOMETER
®
INSTRUMENT.
Rotate the hood assembly until the metal cups are
above the spring-loaded pins.
8. Locate the hood support rods. Extend the hood so
it is taut and insert one support rod onto the springloaded pin closest to you.
9. Push the support rod down and insert the top end
of the rod into the metal cup on the hood frame.
Fig 1.
10. Install the rod on the opposite side, then install the
last two rods.
Foam
5. Push the elastic cord into the channel along the
“U” Opening
side of the frame.
6. Repeat steps 4 and 5 until the hood assembly is
complete and ready to mount onto the base.
7. Place hood on a table or clean floor with the base
inside the opening. Pull the hood over the base.
2
Metal Cup
Figure 1
Hood Frame Channel
Instrument Storage
The hood and frame assemblies can be detached from
the instrument base and placed inside their own
carrying case without disassembly.
®
The LoFlo Balometer
turned off before re-packing the instrument. If storing
the LoFlo Balometer
Capture Hood should always be
®
Capture Hood for an extended
period of time, remove the batteries to prevent damage
due to leakage.
Battery Installation
3
®
2. Turn the LoFlo Balometer
3. Reconnect the fully charged battery holder to the
LoFlo Balometer
®
Capture Hood and slide battery
Capture Hood off.
holder into the battery compartment.
4. Replace battery cover.
Do not try to charge
alkaline batteries.
To install the 4 C-size batteries that ship with the LoF lo
Balometer
1. Make sure the LoFlo Balometer
®
Capture Hood:
®
Capture Hood
switch is off.
2. Remove the battery cover located on top of the
meter.
3. Slide the battery holder up until the snap connector
is exposed.
4. Disconnect the battery holder from the LoFlo
Balometer
®
Capture Hood.
5. Install the 4 C size batteries in the holder.
6. Reconnect the snap connector and slide the battery
holder into the battery compartment.
7. Replace battery cover.
To use and install rechargeable batteries:
NOTE: As an alternative to alkaline batteries, four
Nickel Cadmium (NiCd) rechargeable batteries are
available from TSI for use in the LoFlo Balometer
®
Capture Hood.
1. Connect the battery holder loaded with
rechargeable NiCd batteries to the charger and
charge for 12–14 hours.
Figure 2
Battery Holder
Do not use the
charger as a battery
substitute. Damage
to the instrument
will result.
3
About the Instrument Display
This display is an analog display, simulated with 26
LCD segments to give the user the response of a
mechanical Balometer
an exact digital number, using 3½ digit numeric
section. The LCD has indicators for supply, return,
manual range, vent modes, and low battery.
Figure 3 shows the front of the LoFlo Balometer
Capture Hood.
1 Digital Readout
2 Simulated Analog Display
3 Manual Range Indicator
4 Supply/Return Indicator
5 2-Point Mode Indicator
6 Vent Indicator
7 Units Indicator
8 Low Battery Indicator
4
LoFlo Balometer
Figure 4
®
Capture Hood LCD
SECTION 6
Getting Started
NOTE: The instrument should be allowed to
stabilize to room conditions in order to achieve
specified accuracy.
1. If you are using a hood with the unit, assemble
the LoFlo Balometer
in Section 4, “Instrument Setup and Storage.”
2. Turn on the unit using the slide switch located on
the right side of the meter.
3. When turned on, the LoFlo Balometer
Hood displays the vent closed indicator. Close the
vent on the base by turning the top baffle counter
clockwise.
4. Select the proper mode for air flow direction,
supply or return.
5. Place the LoFlo Balometer
the diffuser or grille to be measured.
®
Capture Hood as described
®
Capture
®
Capture Hood over
5
6. The auto range feature of the LoFlo Balometer
Capture Hood will choose the correct scale and
display the volume rate in the digital readout
section. A quick press on the handle switch will
freeze the display.
7. Another quick press will unfreeze the display.
8. For volume rates above 150 cfm (255 m
71 l/s), it is recommended to use the vent open
mode to minimize air flow resistance effects. See
Section 7, “Detailed Operation.”
NOTE: Make sure that there are no gaps between
the LoFlo Balometer
®
Capture Hood and the
surface around the diffuser or grille. Also, make
sure that your body or other objects are not
blocking or diverting the air flow where the a ir is
exiting (supply) or entering (return). This will affect
the reading.
3
/h,
®
SECTION 7
Detailed Operation
HandleButton
In 1-point mode, the handle button will freeze the
digital reading and flash the value when it is pressed for
less than three seconds. When the handle button is
pressed for more than three seconds, it switches the
LoFlo Balometer
mode and vent open mode.
In 2-point mode, the handle button cycles the
instrument through the 2-point measurement process.
See 2-point mode section for detail.
Auto/Manual Ranging Button
When turned on, the instrument is in auto-range mode.
The user can switch to manual range mode by pressing
the range button. The manual range indicator will
show. By pressing the range button, the meter display
switches to the next volume range. To return to autorange mode, press and hold the range switch until the
manual range indicator disappears.
®
Capture Hood between vent closed
Changing Measurement Units
To change measurement units:
1. Turn the instrument off.
2. Press and hold the supply/return button and switch
the instrument on at the same time.
3. The display will flash one of the three available
measurement units: cfm, m
4. Press and hold the supply/return button or the
range button to scroll through the measurement
units.
5. When the units you desire are displayed, switch the
instrument off.
6. When you turn the instrument on again, your
chosen units will be displayed.
3
/h, l/s.
5
Supply/Return Button
The LoFlo Balometer® Capture Hood is in supply mode
when turned on. This is indicated on the display with
the supply indicator
. To take return air
measurements, press the supply/return button on the
front of the meter. Return air mode will be indicated on
the display with the return indicator
.
Significant errors may result if:
• Instrument is not in proper mode.
• Fabric hood is not used with vent open
mode.
Vent Closed/Vent Open Modes
When the instrument is turned on, it is in the vent
closed mode
. When the vent closed indicator is on,
the vents must be closed to take the measurement.
Close the vents by loosening the thumbscrew and
sliding the vent baffle to the fully closed position and
locking the vent in place again.
The vent open mode is indicated with the vent open
indicator on the LCD
. Open the vents by loosening
the thumb screw and sliding the vent baffle to the fully
open position and locking it into place again. Then
press and hold the handle switch for more than 3
seconds to switch the LoFlo Balometer
®
Capture Hood
to the open vent mode.
The vent open mode was developed for higher volume
rates on larger diffusers; the 2' x 2' or 650 mm x
650 mm hood should always be used with vent open
mode.
1-Point Measurement Mode
The default mode of the LoFlo Balometer® Capture
Hood is the 1-point measurement mode. If you are in 2point measurement mode, simply turn the instrument
off and turn back on.
The 1-point measurement mode is described in the
Getting Started section earlier in this manual. This is
the faster, simpler way to take measurements.
Use Vent Closed Mode for measurements between:
3
10–150 cfm (17–255 m
/h, 4.7–71 l/s).
NOTE: In Vent Closed Mode, volume rates below
8 cfm (13 m
rates above 517 cfm (879 m
3
/h, 3.6 l/s) are displayed as 0; volume
3
/hr, 244 l/s) are
displayed as Or.
Use Vent Open Mode for measurements between:
150–500 cfm (255–850 m
NOTE: In Vent Open Mode, volume rates below
150 cfm (255 m
volume rates above 517 cfm (879 m
3
/h, 71–236 l/s)
3
/h, 71 l/s) are displayed as Ur;
3
/h, 244 l/s) are
displayed as Or.
2-Point Measurement Mode—Supply
Only
To activate the 2-point measurement mode, turn the
instrument off. While pressing the handle button, turn
the instrument back on. The 2-point mode indicator will
show.
The 2-point measurement mode takes both vent open
and vent closed measurements to calculate a resistancecompensated volume flow rate.
The process starts with the vents closed and the display
showing the vent closed indicator.
®
1. Place the LoFlo Balometer
diffuser to be measured and press the handle
switch once to take the vent closed measurement.
2. The instrument stores that reading.
3. The display will now show the open vent indicator
and you should open the vents.
NOTE: Make certain you are using a fabric hood
when in 2-point mode.
4. Again place the LoFlo Balometer
over the diffuser to be measured and press the
handle switch to take the vent open measurement.
5. The instrument calculates and displays the
compensated reading.
6. The numeric display will flash; press the handle
switch again and the instrument will display the
vent closed indicator. Close the vents.
7. Return to Step 1 to take another resistance
compensated reading.
NOTE: Return to 1- point measurement mode at
any time by turning the power off and on.
Capture Hood over the
®
Capture Hood
6
7
When “–––” is displayed at the last step of the 2-point mode, the calculation fo r th e r esistan ce ef f ect can not be made. It
can be caused by any of the conditions listed here.
Condition Reason
The vent closed or vent open measurement is less than 150
3
cfm (70 l/s, 255 m
/h).
• Calculations are not made at the low end since the
effect is small and can generally be neglected. Use 1point mode.
The vent closed or vent open measurement is greater than
3
500 cfm (235 l/s, 850 m
/h).
The vent open measurement minus the vent closed
measurement is too small (< 0).
• Calculations are not made beyond the calibrated range.
• A mistake has occurred in the process. Repeat the
two-point measurement.
• The resistance effect is small and was overwhelmed
by natural fluctuations. Use single-point mode.
The vent open measurement minus the vent closed
measurement is too large.
• A mistake has occurred in the process. The vent may
not have been open for the open vent measurement.
Repeat the two-point measurement.
• The effect is beyond the range of the compensation
equation. Perform a traverse of the system instead.
NOTE: The display will also show “–––” when th e retu rn mode is selected. The 2-point measurement mode is for
supply only.
7
SECTION 8
Troubleshooting
Symptom Possible Cause and Corrective Action
Meter does not turn on.
Meter reading lower than expected.
• Battery holder snap connector not connected. Connect
battery holder to instrument.
• Batteries may be discharged. Charge or replace them.
• Switch failure, wiring failure, or cir c uit failure. Call
• Odd air flow pattern present. Perform traverse and use
proportional balancing.
• Meter out of calibration. Call TSI.
• Instrument not at room temperature. Allow instrument
to acclimate before turning on the power.
• The LoFlo Balometer
room air currents. Place on floor with a piece of
cardboard over the top to determine if it is measuring
real air currents.
®
Capture Hood is reading real
• Meter out of calibration. Call TSI.
• Self test failed. Call TSI.
• Call TSI.
8
9
SECTION 9
Maintenance
Hoods
Hoods may be cleaned in cool water with a mild
detergent.
Sensing Manifold
The manifold should be checked visually before using
to be certain that the sensing holes have not become
clogged with dirt or dust particles. Do not immerse the
manifold in water. It is recommended that cleaning be
done with extreme care with the manifold in place. Do
not use highly compressed air to clean the manifold
tubes.
Calibration
It is recommended that your LoFlo Balometer® Capture
Hood be returned to the factory once a year for a
calibration check. When shipping the LoFlo
Balometer
®
Capture Hood for factory calibration, pack
it carefully, and follow the Instructions for Return in
this manual.
Vent Operation
If the vent becomes difficult to operate, remove both
thumbscrews from the vent mechanism and spray the
contacting surfaces with silicone spray lubricant. Wipe
off excess and reassemble vent mechanism.
Performance Check
If the calibration is to be checked, the best way is to use
a reference flow standard more accurate than the LoFlo
Balometer
used for this purpose include orifice plates, venturis,
nozzles, and laminar flow elements. These devices
require accurate differential pressure, barometric
pressure, and temperature reading instruments to
measure either actual or standard volume rate.
If the LoFlo Balometer
against a velocity instrument such as a pitot
probe/manometer or thermo-anemometer, there may be
errors. If a velocity standard is used, the average
velocity must be obtained by taking a traverse.* The
accuracy of the traverse is dependent on the flow
uniformity, the number of readings taken, the accuracy
of the velocity instrument, and operator expertise. This
average velocity reading must then be multiplied by the
area over which the traverse was taken.
Finally, air flow instrumentation is dependent on
environmental conditions such as temperature,
atmospheric pressure, humidity, and even turbulence.
These conditions can have very different effects on
various instrument types. Caution must be exercised
when making comparisons.
*A traverse is a set of velocity readings taken in a prescribed
pattern which will provide an overall velocity value when
averaged together. Any of the Alnor velocity measuring
instruments can be used for this purpose.
®
Capture Hood. Flow standards that may be
®
Capture Hood is checked
9
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