NuAire LabGard NU-540-300E, Operation And Maintenance Manual

Page: 38 / 63

OM0280 Page 38 of 63
Rev 3 July/2021
7.5.3.1 Downflow Calibration
Step 1: Place a velometer in the cabinet workzone on the horizontal plane 4 inches (102mm) above the
bottom edge of the viewing window. Spot check several points on the recommended downflow
velocity test grid in table 7.0
Step 2: If necessary, enter active blower speed adjustment.
•
Press and hold key, then press hidden – blower - ↑ keys sequentially.
LED indicator above blower (green) key will blink fast.
Step 3: Press ↑ or ↓ keys to adjust blower speed.
•
LED segments will indicate blower speed percentage and active blower speed adjustment
o
Right end red LED indicates active blower speed adjust
The red LED will blink as soon as any adjustments are made and will continue to blink as the
motor rpm settles. Once the red LED stops blinking, the motor will run steady state at the
new percentage.
Note: The red LED must be non-blinking to save or exit
o
Green LED’s indicate percentage on of scale (0 -100%)
o
Yellow LED’s indicate minimum (left/maximum (right) blower speed has been achieved
Note: At any time during the process
•
Press hidden key to accept and enter the blower speed calibration point (confirmed with 3 audible
beeps).
(If the blower speed calibration point was not successfully entered with the 3 audible beeps. The
calibration process must then be repeated for successful entry of blower speed calibration point.)
•
Press key to abort and exit
Step 4: Proceed to inflow calibration leaving in active blower speed adjustment
7.5.3.2 Inflow Calibration
Step 1: Measure the inflow velocity using the recommended procedure found in Table 7.0. If necessary,
adjust the exhaust filter choke, located under the front decorative panel, to achieve the correct
average inflow velocity within the stated range of 105 ± 5 LFPM (.53 ± .025 m/s).
•
Less than 100 LFPM (.51 m/s);
First open the choke plate or make sure it is open.
If this is insufficient, then increase blower speed.
•
Greater than 110LFPM (.56 m/s)
First decrease blower speed to achieve ½ the exhaust excess, then close the choke plate to
achieve the balance. In this fashion, the downflow should remain nearly constant (i.e. what
the reduced speed took away, the choke plate restores).
Note:
The choke plate adjustment requires a standard blade screwdriver.
To adjust, loosen the liquid-tight fitting around the choke adjustment shaft.
While monitoring the exhaust flow to check position, turning the choke adjustment shaft
clockwise will open the choke while turning counter clockwise closed the choke.
Step 2: Once exhaust adjustment is complete, return to the downflow calibration process and measure
average downflow velocity. If the downflow average remains within the correct range, the
calibration is complete. Press hidden key to accept the blower speed calibration point. If not,
readjust as necessary to obtain the correct calibration range. Once entire cabinet has been
balanced, tighten liquid-tight fastener around choke adjustment shaft.
Note: Upon exit from the active blower speed adjustment, the PresurFlow ™ will be calibrated to the
center green LED indicator. High/low alarm limits will be based on the default values established
from the calibration point.
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