Friedrich 49 Indoor-Air Conditioned Supply Air System, Indoor Fan Performance, Return Air Options

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.

Indoor Fan Performance

Table 2

	Indoor Blower Air Flow, SCFM (ARI RATED as shown)						RA Grille Minimum Net
Model	ESP	0.1	0.2	0.3	0.4	0.5	Free Open Area (Sq. In.)
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.

Figure 10

Return Air Options

Front Free	Front Ducted	Side Ducted
Return	Return	Return

NOTE: Ducted return air configurations require field fabrication of a duct-mounted filter box. Filters are not supplied with units configured for ducted return.

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