OPERATOR'S MANUAL BIOPROtect II JR Vent to ... - Baker Company

The Airflow Balance
Warning!
This procedure should be performed by qualified technicians only.
The airflow balance which is set at the factory provides your unit with the air volume and velocity control
to minimize leakage or airborne contamination either in or out of the work area.
In order to duplicate as closely as possible the airflow characteristics described in the original factory test
report, please follow these steps:
1. Make certain that the front door and viewscreen are closed and secured so as to make an 8” x 42”
horizontal access opening.
2. Using a DIM (Direct Intake Measurement) measure the flow rate into the front access opening. Take at
least five (5) consecutive readings. Average the readings and divide by 2.3 square feet (area of the front
access opening). Acceptable range of the average shall be 100-110 FPM.
3. Using a hot wire anemometer mounted on a ring stand within the work area, take readings with the
anemometer probe set 6” below the diffuser. The location of these readings should be the same as shown in
the factory test report. The average of these velocity readings must be in the range between 50 and 70 FPM.
4. After you have compared your figures with those originally taken at the factory, make whatever
adjustments are necessary. Use the motor speed control and the exhaust damper to bring the intake and
downflow average values within the specifications.
5. As the HEPA filters load up with particulates, airflow will be maintained automatically to some extent.
When the air flow is diminished you will have to increase the motor speed to maintain the specified intake
and downflow velocity averages. This is done via the speed controller located in the light canopy.
Warning!
When the light canopy is lowered, some electrical parts are exposed. Do not perform this work unless
you are a trained electrician or electronic technician.
!!!!Note that terminals M1 & M2 as well as L1 & L2 are high Voltage.!!!!
On the speed controller, turn the potentiometer clockwise until you have the desired airflow. Use a
voltmeter to check the voltage across terminals M1 & M2. This is the voltage out to the motor. If the airflow
cannot be maintained, it will necessary to replace the HEPA filters.
(See “Procedure for HEPA Filter Replacement” later in this section.).
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