11
C. Indoor-Air (Conditioned Supply Air) System
The VEB/VHB series unit may be applied in either a free return air configuration or a ducted return air configuration. The supply
air path is intended to be ducted. The design and construction of the indoor-air system must provide adequate air distribution
to ensure comfort levels throughout the structure.
The combined pressure losses of the return and supply air paths must not exceed the external static capabilities of the system
at the design airflow (See Table 2).
If the unit is installed in a closet behind a door and the return air louver or grille is directly opposite the unit RA opening, 2-
in. clearance is required between the front of the unit and the back side of the louver or grille. If the louver or grille is located
elsewhere on the door so it is not directly in front of the RA opening, a minimum of 7-in. clearance is required between the
front of the unit and the back side of the door. The minimum "net free open area" required for the RA louver or grille is listed
in Table 2.
Return Air Options
Front Free
Front Free
Front Free
Front Free
Front Free
Return
Return
Return
Return
Return
Side Ducted
Return
Front Ducted
Return
Figure 10
NOTE: Ducted return air configurations require field fabrication of a duct-mounted filter box. Filters are not
supplied with units configured for ducted return.
Indoor Fan Performance
Table 2
Indoor Blower Air Flow, SCFM (ARI RATED as shown)
Model
ESP
0.1
0.2
0.3
0.4
0.5
VE/HB18
Indoor
850
750
640
550
450
250
VE/HB24
Indoor
980
890
800
720
650
300
VE/HB30
Indoor
1120
1070
1000
940
830
375
VE/HB36
Indoor
1220
1120
1050
990
860
400
VE/HB42
Indoor
1570
1510
1470
1400
1350
525
VE/HB49
Indoor
1670
1610
1570
1500
1450
525
VE/HB60
Indoor
1980
1920
1860
1800
1700
675
Note:
Italic
indicates performance outside the required operating window of +/- 10% of rated SCFM. All values are wet
coil with filter installed.
RA Grille Minimum Net
Free Open Area (Sq. In.)
