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Table 4. Troubleshooting
PROBLEM
UV light is dim or flickering
Airflow Alert goes off and/or
there is a slight decrease in
filter life remaining gauge
Exhaust Airflow Check goes
off and alarm sounds
30 seconds after the blower
is started
Contamination of work in
the cabinet
1500 Series Class II, Type B2 Biological Safety Cabinet
CAUSE
Lamp is defective or is at end of
operating lifetime
Lamp wiring is disconnected
Defective lamp ballast
HEPA filter loading
Blockage of the supply air intake
Blockage of the exhaust outlet
Blockage or restriction under the work
surface
Roof blower is off
Exhaust damper is improperly set
Remote blower is improperly sized
Mechanical failure of the exhaust
system
Obstruction in the exhaust system
Leak or additional 'load' on the
exhaust system
Loading of the exhaust HEPA filter
Airflow Sensor out of calibration
Improper technique or procedure for
the Biosafety Cabinet
Restriction of the return air slots or
grille – blockage of the exhaust outlet
External factors are disrupting the
cabinet airflow patterns or acting as a
source of contamination
Cabinet is out of adjustment / HEPA
filter(s) are defective
CORRECTIVE ACTION
Replace defective or worn out lamp
Inspect lamp wiring
Replace lamp ballast
The gauge reading steadily decreases as the
cabinet is used. A very slow decrease (over
months) is normal
Check supply air intake and supply prefilter to
ensure that they are not blocked or restricted
Ensure that the exhaust outlet is not blocked
or restricted
Ensure that the towel catch and plenum
beneath the work surface are unobstructed
Ensure that roof blower is working
Ensure that the exhaust damper is properly set
by a qualified certifier
Confirm that the roof mounted blower meets
the volume and pressure requirements of the
cabinet
Inspect the exhaust system
Inspect the exhaust system
Inspect the exhaust system
Replace the Exhaust HEPA filter
Have qualified certifier recertify airflows and
recalibrate the sensor
Refer to Working In the Biosafety Cabinet
section at the end of Chapter 5 in this manual
Ensure that all return air slots, grilles and the
exhaust outlet are unobstructed
Refer to Working In the Biosafety Cabinet
section of this manual
Have cabinet recertified. If HEPA filters are
defective or damaged, replace them
Troubleshooting |
31
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