Labconco XPert Nano Enclosures 38876 Series - Manual (Page 38)

Chapter 6: Maintaining the Nano Enclosure
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unless an airflow change is detected. If safe airflow is later detected for 10 seconds,
the green “safe” LED will be lit and the “alert” (red) LED will be shut off. At any
time the airflow is safe/good, one can press the SILENCE ALARM test button and
the audio alarm and the red LED will turn on as long as this button is held down.
The circuit board has also a two-pin connector for use as an external output with
isolated relay contacts that close when the red/alert LED is lit (low airflow). These
relay contacts are not affected by the “SILENCE ALARM” button.
The circuit board is mounted behind the front panel using standoffs and an
appropriate label is used to highlight the “SILENCE ALARM” button with clear
areas for the red and green LED’s. No holes to allow sound to be broadcast louder
are necessary.
The circuit board can be prepared as a factory special with an additional connector
for the following external inputs, and having the following possible functions:

External Alarm allows an external signal to sound the alarm, such as a sash
open switch, or a “fail” signal from the building airflow system.
 Alarm Disable allows an external signal to prevent a “low” airflow alarm from
occurring.
Contact Labconco for ordering information on this special circuit board.
Calibration
1. Ensure the flow switch and alarm circuit board are installed and
operational.
2. Allow the enclosure to operate for at least two minutes.
3. If factory installed, the monitor will alarm at 60±10 fpm with the inflow
velocity set at 90±10 fpm.
4. To change the factory setting, set the inflow velocity required by your
Safety Officer to the desired alarm condition using the speed control
adjustment procedure outlined in Chapter 6.
5. Once the alarm condition is set, use a small screwdriver to turn the
adjustment screw on the airflow switch counterclockwise (facing the
screw) until the “low” airflow red LED lights and the audible flow alarm
sounds.
6. Adjust the inflow velocity to the nominal operating point required by your
Safety Officer.
7. Over time the ULPA filter will load and eventually slow the inflow
velocity. Once the alarm condition is met, simply increase the speed
control outlined in Chapter 6 or replace the ULPA filter if the speed control
is maximized.