7
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage.
Do not slide unit to position when it is sitting on the curb.
Curb gasketing material may be damaged and leaks may
result.
CAUTION
!
Step 3 — Field Fabricate Ductwork
On vertical units, secure all ducts to roof curb and building
structure.
Do not connect ductwork to unit.
Insulate and
weatherproof all external ductwork, joints, and roof openings with
counter flashing and mastic in accordance with applicable codes.
Ducts passing through an unconditioned space must be insulated
and covered with a vapor barrier.
If a plenum return is used on a vertical unit, the return should be
ducted through the roof deck to comply with applicable fire codes.
A minimum clearance is not required around ductwork if electric
heat is not used. Cabinet return-air static pressure (a negative
condition) shall not exceed 0.35--in. wg with economizer or
0.45--in. wg without economizer.
Step 4 — Make Unit Duct Connections
Vertical Supply/Return Configuration
Unit is shipped in vertical supply/return configuration. Ductwork
openings are shown in Fig. 1 and 3. Attach the ductwork to the
roof curb. Do not attach duct directly to the unit.
Duct connections are shown in Fig. 4. Field-fabricated concentric
ductwork may be connected as shown in Fig. 5.
PERSONAL INJURY HAZARD
Failure to follow this caution may result in personal injury.
For vertical supply and return units, tools or parts could
drop into ductwork and cause an injury. Install a 90
_
turn
in the return ductwork between the unit and the conditioned
space. If a 90
_
elbow cannot be installed, then a grille of
sufficient strength and density should be installed to prevent
objects from falling into the conditioned space.
CAUTION
!
AIR
OUT
AIR
IN
ECONOMIZER
C06307
Fig. 4 -- Air Distribution -- Vertical Supply and Return
AIR OUT
AIR IN
AIR OUT
ECONOMIZER
C06308
Fig. 5 -- Air Distribution -- Concentric Duct
Horizontal Applications
Horizontal units are shipped with an outer panel that allows for
side by side horizontal duct connections. If specified during
ordering, the unit will be shipped with the vertical duct openings
blocked off from the factory, ready for side supply installation. If
the horizontal supply/return option was not specified at time of
ordering the unit, a field--installed accessory kit is required to
convert the vertical unit into a horizontal supply configuration.
Installation of the duct block--off covers should be completed prior
to placing the unit unless sufficient side clearance is available. A
minimum of 66 in. is required between the unit and any
obstruction to install the duct block--off covers. Slide supply duct
dimensions and locations are shown on Fig. 3. Install ductwork to
horizontal duct flange connections on side of unit.
Units with electric heat require a 1-in. clearance for the first 24 in.
of ductwork. Outlet grilles must not lie directly below unit
discharge.
NOTE
: A 90
_
elbow must be provided in the supply ductwork to
comply with UL (Underwriters Laboratories) codes for use with
electric heat.
Step 5 — Install External Trap for Condensate
Drain
The unit’s
3
/
4
-in. condensate drain connections are located on the
bottom and side of the unit. Unit discharge connections do not
determine the use of drain connections; either drain connection can
be used with vertical or horizontal applications. See Fig. 3 for
locations.
When using the standard side drain connection, make sure the plug
(red) in the alternate bottom connection is tight before installing the
unit. (See Fig. 7.)
To use the bottom drain connection for a roof curb installation,
relocate the factory-installed plug (red) from the bottom connection
to the side connection. A
1
/
2
-in. socket extension can be used to
remove the plug. (See Fig. 7.) The piping for the condensate drain
and external trap can be completed after the unit is in place.
50PG16
