Labconco 3970202 User Manual - With The Speed Control
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Chapter 6: Maintaining Your Filtered PCR Enclosure
Setting the Downflow Velocity
with the Speed Control
Adjustment
1. Remove the front panel by loosening the (2) Phillips screws
on top that secure the front panel.
2. The speed control is located on the electrical subassembly
located behind the switched control panel and below the
front panel. See Figure 6-1.
3. Adjust the speed control with a small Phillips screwdriver
by turning the screw counterclockwise to increase blower
speed or clockwise to decrease the blower speed. The
speed control is very sensitive, so proceed with caution.
4. Measure the downflow velocity per the averaging
technique outlined in Chapter 3 and adjust the speed
control slowly for the desired speed. Allow the speed to
stabilize and re-measure the downflow velocity to confirm.
5. Replace the front panel and tighten the screws.
Calibrate and Operate the Airflow
Monitor
Optional Guardian Airflow Monitor
Refer to Figure 6-2 for operation and calibration.
Labconco Airflow Monitor / Airflow Switch Operation
The Guardian Airflow Monitor consists of a circuit board and an
airflow switch. This switch indicates airflow as safe or low. It
does not provide an actual velocity, but a small setscrew in the
back of the sensor can adjust the airflow level that it classifies as
“good/safe” or “low/alert.”
The circuit board provides power to the sensor and also contains a
“safe (green)” and “alert (red)” airflow LED indicators, as well as
a “SILENCE ALARM” button to quiet the audio alarm. When
first powered up, the Printed Circuit Board (PCB) will light both
red and green LED indicators and sound the alarm to indicate it is
working. After 5 seconds, the air monitor will indicate either good
or bad airflow based on what the connected airflow switch detects.
For low airflow, the unit will wait for 10 seconds after low
indications before it sounds both the audio alarm and the red
“alert” LED indicator. If
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