TSI Incorporated Alnor LoFlo Balometer Mode D'emploi page 9

Supply/Return Button
The LoFlo Balometer 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
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 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 is the 1-point
measurement mode. If you are in 2-point 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:
. Open the vents by loosening
7
10–150 cfm (17–255 m
! NOTE: In Vent Closed Mode, volume rates below
3
8 cfm (13 m /h, 3.6 l/s) are displayed as 0; volume
rates above 517 cfm (879 m
displayed as Or.
Use Vent Open Mode for measurements between:
150–500 cfm (255–850 m
! NOTE: In Vent Open Mode, volume rates below
3
150 cfm (255 m
volume rates above 517 cfm (879 m
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 resistance-
compensated volume flow rate.
The process starts with the vents closed and the display
showing the vent closed indicator.
1. Place the LoFlo Balometer over the 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.
3
/h, 4.7–71 l/s).
3
/hr, 244 l/s) are
3
/h, 71–236 l/s)
/h, 71 l/s) are displayed as Ur;
3
/h, 244 l/s) are
7