General Description - TSI Incorporated Alnor LoFlo Balometer Mode D'emploi

The Alnor LoFlo Balometer is a compact instrument
that measures very low air flow rates in HVAC
systems. It measures from 10–500 cfm (17–850 m
4.7–236 l/s). The LoFlo Balometer 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 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
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
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SECTION 1

General Description

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/h,
SECTION 2
Theory of Operation: Capture Hoods
and Thermo-anemometry Sensing
LoFlo Balometer should be 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 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.
! NOTE: Throughout this manual, the units cfm, m
and l/s are used for simplicity. Note, however, that
the LoFlo Balometer actually reads in standard
cubic feet per minute (scfm), standard cubic meters
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per hour (std. m /h), or standard liters per second
(std. l/s).
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/h