8
Ducting
Installing Duct
The Comfort-D is equipped with either an 8" (D75) or 10” (D95) round duct collar
inlet, and an 8" (D75) or 10” (D95) round exhaust/supply collar that provides for
connecting to the supply distribution system� In all cases sound duct design prac-
tices must be followed such as those provided in ACCA manual “D”, or ASHRAE’s
“Fundamentals of Air System design”.
Ducting for Dehumidification
For the ideal installation, draw air from the central part of the home and return it to
the isolated areas of the home like the bedrooms, den, utility room, or family room�
The ductwork of the existing HVAC system can be used to supply air to the home.
If the existing supply duct adequately serves all areas of the home, discharge the
supply air of the Comfort-D into the return of the existing HVAC system where it
can distributed throughout the space. The existing return duct, if adequate, may
be used as return for the Comfort-D� DO NOT draw air directly from the kitchen,
laundry, or isolated basement� You may draw air from a basement that is open to
the home. All flexible ducting connected to the Comfort-D should be approved by
local codes and in most cases insulated�
Return air ducts should be designed to allow unimpeded air flow to the return side
of the system. For returns less than 10 feet in length, an 8" (D75) or 10” (D95)
round or equal may be utilized� Multiple returns are acceptable�
The supply air outlet and the return air inlet are located on each end of the Com-
fort-D. A length of acoustical flex ducting on the outlet of the Comfort-D will reduce
air noise from the fan. A length of flexible ducting on all Comfort-D duct connec
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tions is recommended to reduce noise and vibration transmitted to rigid ductwork
in the structure�
Ducting the Comfort-D as mentioned in the “Ducting” sections requires consider
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ation of the following points:
Duct Sizing
: For total duct lengths up to 10', use a minimum 8" (D75) or 10” (D95)
diameter round or equivalent rectangular� For longer lengths, up to 25’, use a mini-
mum 10" (D75) or 12" (D95) diameter or equivalent duct size. Grills or diffusers
utilized must not excessively restrict airflow.
Isolated Areas
: Effective dehumidification may require that ducting be branched
to isolated, stagnant areas. Use 8" (D75) or 10” (D95) or larger diameter branch
ducting to each of two or three areas, use 6" or larger to each of four or more areas�
Connecting to Existing HVAC Systems
: For proper operation, connecting to
existing air handler and duct systems requires the fans of each system to be in
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terlocked utilizing the low voltage interlock method provided in the Comfort-D low
voltage connection diagram� Refer to low voltage connection diagram in this docu-
ment and on the unit�
