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Downflow Velocities
All Logic+ models, EXCEPT 30248xx80) are classified as having uniform downflow, and
the average downflow velocity for all models is 55+/-5 FPM, tested as per ANSI/NSF
Standard 49:2012.
All readings should be in a plane 4 inches above the bottom edge of the sash, and the
UV Lamp, IV bar and all other accessories must be removed before performing
downflow test. The test grid dimensions are outlined in Table 5-4. When taking readings
in the back two rows, the anemometer probe should be pointing toward the nearest side
wall, as shown in figure 5-16. When reading the front row, the probe should point
outward, toward the front of the cabinet, as shown in Figure 5-17. The thermal
anemometer’s time constant should be set at 10-15 seconds for greater data stability.
Table 5-4
Downflow Test Specifications
Cabinet Width (Feet)
3
3
4
4*
4
5
5
6
6
Sash Height (inches)
8, 9
10, 12
8, 9
8
10, 12
8, 9
10, 12
8, 9
10, 12
Nominal Avg. Downflow
(FPM)
55+/-5
55+/-5
55+/-5
75+/-5
55+/-5
55+/-5
55+/-5
55+/-5
55+/-5
Downflow test grid # of
points
21
21
24
24
24
30
30
36
36
Test Grid (# rows x #
columns)
3 x 7
3 x 7
3 x 8
3 x 8
3 x 8
3 x 10
3 x 10
3 x 12
3 x 12
Test Grid Data (in
inches)
Grid distance from back & sides
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
6.0
Distance between rows
5.75
5.55
5.75
5.75
5.55
5.75
5.55
5.75
5.55
Distance between columns
4.08
4.08
5.21
5.21
5.21
5.39
5.39
5.50
5.50
- Model #s 30248xx8x Only
Figure 5-16
