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OM0228
Page
46
of
99
February/2014
7.5.3
Airflow
Calibration
The
NU
‐
430
Airflow
Calibration
consists
of
adjustments
to
balance
the
airflow
within
the
cabinet
and
the
calibration
of
the
airflow
monitor
sensors.
THIS
WORK
SHOULD
BE
DONE
ONLY
BY
A
QUALIFIED
TECHNICIAN
WHO
CAN
MEASURE
THE
AIRFLOW
FROM
THE
FILTERS
WITH
A
SUITABLE
VELOMETER.
NuAire
provides
one
adjustment
to
balance
the
airflow
within
the
cabinet.
This
is:
PWM
signal
adjust
via
DC
ECM
motor
control
system
The
blower
speed
control
system
adjusts
the
cabinet's
supply
volume
of
airflow
while
customer
supplied
exhaust
system
controls
the
exhaust
volume
of
airflow.
Since
it
has
been
NuAire's
experience
that
the
filters
may
not
"load"
evenly,
both
adjustments
are
necessary
for
proper
cabinet
performance.
The
cabinet
is
considered
to
be
certifiable
if
the
following
airflow
measurements
are
present:
a.
Downflow
average:
60
LFPM
5
LFPM
(.30
m/s
.025
m/s).
b.
Inflow
average:
105
LFPM
5
LFPM
(.53
m/s
.025
m/s)
using
the
Direct
Inflow
Measurement
(DIM)
method
or
alternate
3”
constricted
inflow
velocity
measurement
method.
The
calibration
of
the
airflow
monitor
sensors
occurs
during
the
cabinet
airflow
balancing
procedure.
The
calibration
procedure
consists
using
the
downflow
and
inflow
averages
achieved
and
entry
of
those
values
into
the
control
system.
DC
ECM
motor
PWM
signal
DC
voltage
should
also
be
monitored
and
recorded
upon
final
calibration.
The
DC
voltage
may
be
monitored
using
an
independent
digital
voltmeter
in
the
Vdc
mode.
The
two
test
points
to
measure
DC
ECM
motor
voltage
are
located
on
the
DC
motor
signal
connector
on
the
main
control
board.
MOTOR
VOLTAGE
TEST
POINTS
BEFORE
STARTING
AIRFLOW
CALIBRATION
PROCEDURE
LET
THE
CABINET
RUN
FOR
AT
LEAST
10
MINUTES.
Summary of Contents for Labgard NU-430-400
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