Labconco Logic+ A2 Technical Manual page 49

3. The nominal set point for Inflow has been set in the previous step. Now the
alarm set point must be established. The screen below is displayed. While on
this screen, reduce the remote or building exhaust system until the TOTAL
volume of air drawn by the remote exhaust system is reduced to 90% of nominal.
For a B2 biosafety cabinet, the remote exhaust system pulls both the downflow
air volume AND inflow air volume from the cabinet and exhausts it.
REDUCE EXHAUST FLOW
TO 90%, PRESS OK
AIR SENSOR:
ZERO / NOMINAL:
4. Once the total exhaust airflow has been reduced to 90% of nominal, look at the
Current Sensor
Sensor Value. These values are not velocity or flow values, they are the raw
digital output values from the airflow sensor. To avoid nuisance alarms in
operation, these two values should be at least 4 or 5 points apart. Press
[OK/MUTE].
5. Restore the remote exhaust system to nominal airflow. Press [OK/MUTE].
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Nominal Current
Sensor Sensor
Value Value
Value. It should be at least 4 or 5 points less than the
RESTORE EXHAUST FLOW
TO 100%, PRESS OK
AIR SENSOR:
ZERO / NOMINAL:
Note: To set alarm point airflow, if unable to
measure airflow in the exhaust duct above the
biosafety cabinet, slowly close the Air-Tight
Damper until the Inflow into the cabinet equals
the values in Table 9-1.
Logic+ Type B2 Model
4-foot, 8" Sash
6-foot, 8" Sash
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49
Table 9-1
Inflow @ 90%
Alarm Set Point
3
ft /min m 3 /hr
216 367
322 547
Nominal