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Chapter 6: Maintaining Your Filtered Enclosure
Operation
The Guardian Digital Airflow Monitor consists of the airflow
sensor, the Alarm Unit, and the 15 VDC power supply. For 115V
operation the alarm unit is powered by plugging the power supply
into the factory-prepared digital airflow monitor socket. For
230V operation, the Alarm Unit is powered by plugging the power
supply into a building outlet. The alarm has “Enter,” “+,” and “-”
buttons to program the monitor. There is also a green LED
“SAFE,” yellow LED “CAUTION,” and red LED “LOW” with
audible alarm for airflow conditions. The audible alarm can be
permanently muted if desired. The Guardian Digital 1000 Airflow
Monitor displays a face velocity value, provides an RS232
communications port to a PC or building computer system, can be
configured for external input connections such as night setback or
external alarm and provides up to three output relays that can be
configured. For complete detailed information, please refer to the
separate Labconco 1000 Alarm User’s Manual provided with the
enclosure.
Digital 1000 Calibration
The filtered enclosure comes factory calibrated with the monitor
alarm at 60 ± 10 fpm with the inflow velocity set at 90± 10 fpm.
To change the calibration, review the Labconco 1000 Alarm User’s
Manual that comes with the enclosure. To successfully calibrate, it
will be necessary to change the face velocity by adjusting the
airflow exhaust volume with the speed control. The exhaust
volume can be adjusted with the speed control or by using an
adjustable damper for outside exhaust. NOTE: For accurate
calibration, the front panel needs to be in place for each low
calibration and high calibration set points to simulate real usage.
Typical calibration conditions are set at face velocity air sample
differences of a least 50 feet per minute. However, the airflow
monitor is factory set and calibrated with a difference of at least 20
fpm and can be changed in the CAL CONFIG MENU by changing
the “lower/higher air sample difference.” If changed, then also
change the “sensor difference” in CAL CONFIG MENU from
10% to 3%. To change the red “Low” airflow alarm and yellow
“CAUTION” adjust the values in CAL CONFIG MENU. Set
“WARNING or CAUTION” air reset to 3 fpm. To complete the
CAL CONFIGURATION, be sure to enter “Done.”