Specifications

Typical closet installation with louver door return & with ducted return
Duct and attenuation
Discharge ductwork is normally used with these conditioners. Return air ductwork may also be required, but
will require field installation of a 1" or 2" (21 or 51mm) return air duct collar/ filter rack kit.
The discharge duct system will normally consist of a flexible connector at the unit, a non-insulation piece of
the full duct size, a short run of duct, an elbow without vanes, and a trunk duct teeing into a branch circuit
with discharge diffusers as shown in FIGURE C.
The transition piece must not have an angle greater than 30 ° or severer loss of air performance can result.
Do not connect the full duct size to the unit without using a transition down to the size of the discharge collar
on the unit. With metal duct material, the sides only of the elbow and entirebranch duct should be internally
lined with acoustic insulation for sound attenuation. Glass fiber duct board material is more absorbing and
may permit omission of the flexible connector.
The ductwork should be laid out so that there is no line of sight between the conditioner discharge and the
distribution diffusers.
Return air ducts can be brought in through a wall grille and then to the unit. The return duct system will
normally consist of a flexible connector at the unit and a trunk duct to the return air grille. With metal duct
material, the return air duct should be internally lined with acoustic insulation for sound attenuation. Glass
fiber duct board material is more absorbing and may permit omission of the fiexible connector.
Return air ductwork to the unit requires the optional 2" (51mm) return air duct collar/filter rack kit. The kit can
be installed for face side or bottom filter removal. The flexible connector can then be attached to the 1"
(25mm) duct collar.
Don't use sheet metal screws directly into the unit cabinet for connection of supply or return air ductwork,
especially return air ductwork which can puncture the drain pan or the air coil.
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