Section 1 General Description; Section 2 Theory Of Operation - TSI ALNOR LOFLO BALOMETER Manuel Du Propriétaire

®
The Alnor LoFlo Balometer
compact instrument that measures very low air
flow rates in HVAC systems. It measures from 10
to 500 cfm (17 to 850 m
®
LoFlo Balometer 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
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
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 using a large hood on a small diffuser. For
General Description
®
Capture Hood is a
3
/h, 4.7 to 236 l/s). The
Capture Hood has a vent
Theory of Operation: Capture Hoods
and Thermo-anemometry Sensing
®
Capture Hood.
SECTION 1
of volume rates. The LoFlo Balometer
Hood 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
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.
SECTION 2
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,
3
m /h and l/s are used for simplicity. Note,
however, that the LoFlo Balometer
Hood actually reads in standard cubic feet per
minute (scfm), standard cubic meters per hour
3
(std. m
(std. l/s).
®
Capture Hood is battery
/h), or standard liters per second
®
Capture
®
Capture
1