NuAire LabGard D NU-543-400, Manual

Page: 44 / 70

OM0283 Page 44 of 70
Rev 2 July/2021
7.5.4.1 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 blower speed parameter.
Step 3: Adjust blower speed with ↑ (increase) and ↓ (decrease) as needed.
Note: As the blower speed is adjusted, a settling countdown timer will appear.
After blower speed adjustment is made, the settling timer is used to allow enough time for the controller to
receive the proper amount of rpm feedback to establish a valid base line point.
There are no limits on the number of adjustments that can be made.
Step 4: Proceed to inflow calibration with blower speed menu on display.
7.5.4.2 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 ENT key to accept and enter the blower speed calibration point
(If the blower speed calibration point was not successfully entered; a half second
audible alarm will occur. The calibration process must then be repeated for successful
entry of 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.
Calibration Parameters
Blower Speed
Sensor value adjust
Alarm validation Sec
30
Alarm verification
Normal Blower Calibration
105
1020rpm, 50.1%
fpm, 26.0⁰
Settling time

