35
Ductless
Fume
Hoods
Motor
failure
•
Check
the
motor.
If
motor
is
not
running,
refer
to
‘Blower
doesn’t
function’
problem.
•
If
motor
is
working
properly,
proceed
to
next
step.
Problem
4:
Contaminated
Lab
Cause
Corrective
Action
Low
airflow
•
Adjust
the
motor
speed
controller
to
get
the
optimum
airflow.
Leaking
filters
•
Change
the
filters.
•
Re
‐
certify
the
cabinet
after
the
new
filter
has
been
installed.
Problem
5:
Excessive
Fan
Noise
Cause
Corrective
Action
Resonance
•
See
Component
Layout
A
or
B
to
locate
the
motor
speed
controller.
•
Increase
the
motor
speed
by
5
–
10
VAC.
Check
whether
the
noise
disappears.
If
the
noise
is
already
gone,
measure
the
actual
airflow
velocity.
o
If
the
velocity
is
still
in
the
acceptable
range,
maintain
it.
o
If
velocity
is
out
of
acceptable
range,
or
if
noise
persists,
go
to
next
step.
Loosed
motor
or
impeller
wheel
mounting
•
Refer
to
Problem
2
‐
Faulty
Capacitor
section,
to
check
the
capacitor,
and
replace
if
necessary.
•
Open
the
blower
access
panel
(see
figure
5
‐
1)
and
check
if
the
blower
mounting
bolts
have
been
fully
tightened.
•
Also
check
whether
the
motor
can
rotate
properly
and
not
loosed
(see
figure
5
‐
2).
•
If
motor
is
physically
damaged,
replace
it.
Figure
3
‐
2
Sensor
Back
Panel
Access
Figure
3
‐
3
Figure
5
‐
1
Figure
5
‐
2
Summary of Contents for Ascent max
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