NuAire LabGard NU-560-400, Operation & Maintenance Manual

Page: 50 / 103

OM0295
Rev 2 September 2020 Page 50 of 103
7.5.3 Airflow Calibration
The NU-560 Airflow Calibration consists of adjustments to balance the airflow within the cabinet and the
calibration of the airflow monitor sensors.
THIS WORK SHOULD BE DONE ONLY BY A QUALIFIED TECHNICIAN
WHO CAN MEASURE THE AIRFLOW FROM THE FILTERS WITH A SUITABLE VELOMETER. NuAire provides one
adjustment to balance the airflow within the cabinet. This is: PWM signal adjust via DC ECM motor control system
The blower speed control system adjusts the cabinet's supply volume of airflow while customer supplied exhaust
system controls the exhaust volume of airflow. Since it has been NuAire's experience that the filters may not
"load" evenly, both adjustments are necessary for proper cabinet performance.
The cabinet is considered to be certifiable if the following airflow measurements are present:
a. Downflow average: 60 LFPM ± 5 LFPM (.30 m/s ± .025 m/s).
b. Inflow average: 105 LFPM ± 5 LFPM (.53 m/s ± .025 m/s) using the Direct Inflow Measurement
(DIM) method or alternate 3” constricted inflow velocity measurement method.
The calibration of the airflow monitor sensors occurs during the cabinet airflow balancing procedure.
The calibration procedure consists using the downflow and inflow averages achieved and entry of those values into
the control system.
7.5.3.1 Exhaust Volume Calibration without the NU-951-012 Motorized Butterfly Valve
Step 1: Activate power to the cabinet
Turn on exhaust system
Access sensor setup menu
Step 2: Access calibrate downflow sensor menu and spot check a few downflow points to verify
downflow is close to the desired setpoint of 60 fpm + 5 fpm. Adjust if necessary.