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

Page: 90 / 103

OM0295
Rev 2 September 2020 Page 90 of 103
8.3 Airflow Sensor Performance Verification
The individual airflow sensors can be routinely checked during calibration or in diagnostics to assure they are reading and
active within the range of use (0 to 200 fpm) (0 to 1.02 mps). The airflow sensors can also be checked in the run mode
through performance verification, for responsiveness to changing airflow conditions.
8.3.1 Run Mode
To check the airflow sensor in run mode, first allow the cabinet to operate normally for a minimum of 5 minutes.
Then, place a rolled piece of paper over the downflow sensor in the workzone and leave the paper on the sensor
for at least 2 minutes and then remove. This action will cause the cabinet to go into a downflow alarm condition.
The exhaust airflow reading should increase during this test. However, the downflow reading should go down
below 25 fpm (.13 m/s). There should also be a noticeable increase in motor/blower noise. It would also be
recommended to monitor motor/blower voltage during the test. The motor/blower voltage should be monitored
from when the cabinet is running normally. During the test, when the downflow sensor is covered, the
motor/blower voltage should be steadily increasing to slightly under line voltage. When the downflow sensor is
uncovered, the motor/blower voltage should decrease and airflow readings should be within the calibration range.
If the motor/blower voltage does not change, an airflow sensor problem could exist.
Please consult with NuAire Technical Service.