www.DaikinApplied.com 67
IM 817-7
Draftstop™ System/Window Down-
draft Installation
Figure 125: DraftStop System Concept
Falling Cold Air
from Window
Table 44: DraftStop Grille Length
Unit
Nominal
CFM
20
"
High DraftStop
Wall Enclosure
24
"
High DraftStop
Wall Enclosure or
Storage Cabinets
Minimum
Length (Ft .)
Each Side
Maximum
Length (Ft .)
Each Side
Minimum
Length (Ft .)
Each Side
Maximum
Length (Ft .)
Each Side
750
3
13
3
22
1000
4
18
4
30
1250
5
22
5
36
1500
6
25
6
42
Figure 126: Unit Back Showing knockouts for DraftStop
Applications
14"
(356mm)
5"
(127 mm)
5" (127 mm)
Outdoor Air Intake Opening
End compartment Draftstop
knockouts must be removed
for proper Draftstop operation.
(21-7/8" units only)
Window down-draft protection is recommended for
classrooms where the following conditions exist:
1 .
Window area exceeds 40% of the total outside wall
area.
2 .
Single-pane glass is used.
3 .
Outside temperatures are below 35°F for a significant
portion of the occupied period.
The need for window down-draft protection will not
always be so clear cut. Where uncertainty exists, a
further check can be made by calculating the window
heat loss at an outdoor temperature of 35°F. If estimated
window heat loss exceeds 250 Btuh/Ft, window down-
draft protection is recommended. If estimated window
heat loss is less than 250 Btuh/Ft., the need for down-
draft protection is marginal but should not be arbitrarily
dismissed.
Figure 124:
Cabinet(s) Meeting Unit Ventilator (refer to the instructions specific to the installation, included with the cabinets)
Remove debris, dust, dirt, and
any obstruction from the area
in front of the return air intake
grille at the floor (approximately
3' - see shaded area) as this
will affect unit performance. If
a draftstop system has been
installed be sure that all draftstop
intake grilles are unobstructed.
NOTICE