Labconco Protector Demonstration Hoods 3945021 - Manual (Page 31)

Chapter 6: Maintaining Your Protector Demonstration Hood
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Guardian 500 Calibration Procedure
Each alarm module and enclosure/fume hood is unique and needs to be individually
calibrated in the field. The procedure for the adjustment is as follows:
1. Double check the installation to make sure that monitor and power supply are
properly installed.
2. Allow 10 minutes for the monitor to warm up once power has been connected.
3. Determine the low flow set point for your monitor. This is the value where
the monitor will first indicate a low flow condition. The red light will be on
for this value. Refer to your industrial hygiene officer for the proper low flow
set point or consult the table below.
4. Adjust your enclosure/fume hood airflow to the low flow set point as
previously determined. The exhaust flow can be lowered by adjusting the
speed control on the FilterMate or by using an adjustable damper on the
exhaust blower. Typical alarm conditions are set at face velocities of 10 to 20
feet per minute below the normal operating conditions due to supply air and
exhaust air fluctuations, as well as room air cross drafts. See note 8 if the low
airflow volume or sash opening cannot be adjusted.
5. Using a properly calibrated thermoanemometer, determine the velocity
through the face of the enclosure by taking a detailed velocity traverse.
Divide the face area into equal increments. One reading per square foot of
face area is normally recommended for an accurate traverse. Compute the
average velocity for this area.
6. If the red light alarm is on, slowly turn the adjustment screw counterclockwise
until the green light is activated. If the green light is on, slowly turn the
adjustment screw clockwise until the red light comes on. Slowly turn the
adjustment screw back until the red light is activated. It is important that
these adjustments be done in small increments, at intervals about 30 seconds
apart to allow for delayed reaction of the alarm itself. The alarm low flow set
point should now be set and the red light activated.
7. Readjust the enclosure airflow to its normal operating levels. The green light
should now be activated. Calibration is now complete.
Enclosure Operating In Flow Speed Alarm Condition Set Point Speed
100 fpm 80 - 90 fpm
80 fpm 60 - 70 fpm
60 fpm 40 - 50 fpm
8. Note: If the low airflow volume or sash opening cannot be adjusted, then a 1/4 to
1/3 of a turn counterclockwise can be adjusted to set the airflow alarm condition
at 10-25% below normal operating levels.
Guardian 500 Alarm Activation
The audio and visual alarm will activate approximately 10-30 seconds after an alarm condition
is detected. To temporarily mute the audible alarm, press and release the test/reset button.
NOTE: After an alarm condition has been detected, the red light will stay on. The
audible alarm will remain muted until airflow returns to normal levels.