Unit Installation; Ductwork And Attenuation; Discharge Ducting; Return Air Ducting - Daikin Enfinity VFC Installation And Maintenance Manual

Ductwork and Attenuation

Discharge ductwork is normally used with these units.
Where return air ductwork is required, the unit is
supplied with a 1" filter rack/duct collar for connection of
return air ductwork. An optional 2" return air duct collar
filter rack is available as a field-installed accessory or
a factory-installed, selectable option. The 2" filter rack
allows tool less entry for easy filter replacement.
Figure 4: Sizes 007 thru 070 Optional 2" Return Air Duct
Collar Filter Rack

Discharge Ducting

All ductwork should conform to industry standards of
good practice as described in ASHRAE Systems Guide.
A field supplied discharge duct system will normally
consist of a flexible connector at the unit, a non-insulated
transition piece to 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 5.
Figure 5: Suggested Unit Ducting
Square Elbow
(Both Sides
Internally Lined
With Acoustic
Insulation)
Branch Duct
(Internally Lined)
Flexible
Duct Collar
Duct
Transition
www.DaikinApplied.com
Trunk Duct
2 ft. x 2 ft. Diffuser
Discharge Collar
Heat Pump
The transition piece must not have an angle greater than
30° or severe loss of air performance can result. Do
not connect the full duct size to the unit without using a
transition piece down to the size of the discharge collar
on the unit. With metal duct material, the sides of the
elbow and entire branch 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 unit discharge and the distribution
diffusers.

Return Air Ducting

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 flexible connector.
Return air ductwork to the unit requires the 1" (25mm)
standard return air duct collar or the optional 2" (51mm)
filter rack kit (see Figure 4). The 2" filter rack kit allows
for side filter removal. A flexible duct collar can then
be attached between a duct transition and the return
air ductwork. The return air duct transition must be the
same size as the return air coil face area.
Connections of supply and return air ductwork should be
made at the duct collar of the unit. Do not puncture the
unit cabinet with sheet metal screws as this can damage
the drain pan or the coil.
Figure 6: Suggested Return Air Unit Ducting
Transition Duct
Flexible Duct Collar
Full Vibration Isolation Pad
7 Enfinity Vertical Water Source Heat Pumps • IM 930-6
u i
nit nstallation
Discharge Duct
Flexible
Duct Collar