Dedicated Outdoor Air Unit8
Additional Clearances for
Packaged DX Units
Packaged DX units require additional clearance
because they must have unrestricted air movement
around the condenser coil and condenser fans. Hot air
is being discharged from the condenser fans during
operation. Enough clearance must be provided to
avoid recirculation or coil starvation. When equipped
with condenser coils, the unit should never be placed
under an overhang or inside a building. A minimum of
48inches above the condenser fans is acceptable, but
unobstructed is strongly recommended.
END VIEW OF MAKE-UP AIR UNIT
WITH PACKAGED DX
Minimum 48 inches clearance
Minimum 18 inches
clearance
Condenser Coil
Condenser Fans
End view of rooftop unit with Packaged DX
Installation
Additional Clearances for
Air Source Heat Pump
Air-source heat pump units require additional clearance
because they must have unrestricted air movement
around the outdoor coil and outdoor fans. Enough
clearance must be provided to avoid recirculation or
coil starvation. Air-source heat pump units should
never be placed under an overhang or inside a building.
A minimum of 48-inches above the outdoor fans is
acceptable, but unobstructed is strongly recommended.
IMPORTANT
Air-source heat pumps are equipped with a defrost
cycle to remove ice from the outdoor coil. During
defrost cycles, melted water may drip from the bottom
of the refrigeration section under the outdoor coil.
In cold climates, proper drainage/heat tape must be
installed under the outdoor coil to prevent the buildup
of ice on the roof.
Handling Concerns for
Packaged DX or Air-Source Heat Pump
Units with PDX or ASHP have a system that is
pressurized with refrigerant. If damage occurs, the
refrigerant could leak into the atmosphere or cause
bodily harm due to the extreme cold nature of
expanding refrigerant. Use protective equipment such
as gloves and safety glasses to minimize or prevent
injury in case of a system leak during installation.
Before Lifting
Before lifting, be sure that all shipping materials have
been removed from the unit.
Vestibule
Determine whether or not the unit has a vestibule that
must be field-attached to the side of the unit. Vestibules
are shipped assembled but detached from the unit.
They have lifting lugs on them so they can also be lifted
by crane, but the installed location of the unit may make
it preferable to install the vestibule on the unit prior to
lifting.
Field Power Access
Determine where high voltage and low voltage wiring is
to be brought into the cabinet. If wiring is to be brought
into the cabinet through the floor, see Alternate Supply
Entry Locations in this manual. If unit is to be installed
on a roof, cut access openings in the roof deck as
needed.
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