Liebert 8 Tons Evaporator Air Distribution Filter Box, Connections for Ducted Systems, Static

Site Preparation and Installation

2.4.2Evaporator Air Distribution Filter Box

The optional filter box mounts directly to the return air opening of the evaporator. The filter box is supplied with two (2) 20% (Liebert part no. A-0320) or 30% (Liebert part no. A-0400) 25" x 20" x 4" fil- ters.

NOTE

Do not operate the unit without filters installed in return air system.

Connections for Ducted Systems

Use flexible duct work or non-flammable cloth collars to attach duct work to the unit and to help con- trol the transmission of vibrations to building structures. Insulation of duct work is vital to prevent condensation during the cooling cycle. The use of a vapor barrier is required to prevent absorption of moisture from the surrounding air into the insulation.

If the return air duct is short, or if noise is likely to be a problem, sound-absorbing insulation should be used on the duct. Duct work should be fabricated and installed in accordance with local and national codes.

Table 5 Evaporator external static pressure (60) at 3750 CFM (6371 CMH)

	2 hp Motor (std)		3 hp Motor (opt)
Turns
		External		External
Open	RPM	Static, in.	RPM	Static, in.
0	n/a	n/a	1146	1.9
0.5	n/a	n/a	1125	1.8
1	n/a	n/a	1104	1.7
1.5	946	0.9	1083	1.6
2	922	0.8	1063	1.5
2.5	972	0.7	1042	1.4
3	899	0.6	1021	1.3
3.5	851	0.5	1000	1.2
4	828	0.4	979	1.1
4.5	804	0.3	958	1.0
5	780	0.2	938	0.9
5.5	757	0.1	917	0.8
6	733	0	896	0.7

If free-cooling or hot water coil is ordered, reduce available external static pressure by 0.3" (8 mm). Contact Liebert Representative for other Air Volumes.

Factory setting is 0.5" (13 mm) with 2 hp motor. Field adjust to suit application.

NOTE

Maximum return air static pressure should not exceed 0.3" (8 mm) to provide proper drainage of the unit.

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