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CURB-MOUNTED INSTALLATION
1.
Install curb
2.
Install field-fabricated ductwork inside curb
3.
Install accessory thru-base service connection package
(affects curb and unit) (refer to accessory installation
instructions for details)
4.
Prepare bottom condensate drain connection to suit planned
condensate line routing (see Install External Condensate
Trap and Line on page 11 for details)
5.
Rig and place unit
6.
Install outdoor air hood
7.
Install condensate line trap and piping
8.
Make electrical connections
9.
Install other accessories
PAD-MOUNTED INSTALLATION
1.
Prepare pad and unit supports
2.
Check and tighten the bottom condensate drain connection
plug
3.
Rig and place unit
4.
Convert unit to side duct connection arrangement
5.
Install field-fabricated ductwork at unit duct openings
6.
Install outdoor air hood
7.
Install condensate line trap and piping
8.
Make electrical connections
9.
Install other accessories
FRAME-MOUNTED INSTALLATION
Frame-mounted applications generally follow the sequence for a
curb installation. Adapt as required to suit specific installation
plan.
Step 3 — Inspect Unit
Inspect unit for transportation damage. File any claim with trans-
portation agency. Confirm before installation of unit that voltage,
amperage and circuit protection requirements listed on unit data
plate agree with power supply provided.
Step 4 — Provide Unit Support
ROOF CURB MOUNT
Accessory roof curb details and dimensions are shown in Fig. 5.
Assemble and install accessory roof curb in accordance with in-
structions shipped with the curb. Curb should be level. This is nec-
essary for unit drain to function properly. Unit leveling tolerances
are shown in Fig. 4. Refer to Accessory Roof Curb Installation In-
structions for additional information as required.
A
MAXIMUM ALLOWABLE DIFFERENCE in. (mm)
A-B
0.5 (13)
Fig. 4 — Unit Leveling Tolerances
NOTE: The gasketing of the unit to the roof curb is critical for a
watertight seal. Install gasket supplied with the roof curb as shown
in Fig. 5. Improperly applied gasket can also result in air leaks and
poor unit performance.
C
B
B-C
A-C
1.0 (25)
1.0 (25)
Install insulation, cant strips, roofing felt, and counter flashing as
shown. Ductwork must be attached to curb and not to the unit.
SLAB MOUNT (HORIZONTAL UNITS ONLY)
Provide a level concrete slab that extends a minimum of 6 in.
(150 mm) beyond unit cabinet. Install a gravel apron in front of
condenser coil air inlet to prevent grass and foliage from obstruct-
ing airflow.
NOTE: Horizontal units may be installed on a roof curb if
required.
ALTERNATE UNIT SUPPORT (IN LIEU OF CURB OR
SLAB MOUNT)
A non-combustible sleeper rail can be used in the unit curb sup-
port area. If sleeper rails cannot be used, support the long sides of
the unit with a minimum of 3 equally spaced 4 in. x 4 in. (102 mm
x 102 mm) pads on each side.
Step 5 — Field Fabricate Ductwork
NOTE: Cabinet return-air static pressure (a negative condition)
shall not exceed 0.35 in. wg (87 Pa) with economizer or
0.45 in. wg (112 Pa) without economizer.
For vertical ducted applications, secure all ducts to roof curb and
building structure. Do not connect ductwork to unit.
Fabricate supply ductwork so that the cross sectional dimensions
are equal to or greater than the unit supply duct opening dimen-
sions for the first 18 in. (458 mm) of duct length from the unit
basepan.
Insulate and weatherproof all external ductwork, joints, and roof
openings with counter flashing and mastic in accordance with
applicable codes.
Ducts passing through unconditioned spaces 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.
PROPERTY DAMAGE HAZARD
Failure to follow this caution may result in damage to roofing
materials.
Membrane roofs can be cut by sharp sheet metal edges. Be
careful when placing any sheet metal parts on such roof.
FOR UNITS WITH ACCESSORY ELECTRIC HEATERS
All installations require a minimum clearance to combustible sur-
faces of 1 in. (25 mm) from duct for first 12 in. (305 mm) away
from unit.
Outlet grilles must not lie directly below unit discharge.
PERSONAL INJURY HAZARD
Failure to follow this warning could cause personal injury.
For vertical supply and return units, tools or parts could drop
into ductwork and cause an injury. Install a 90 degree turn in
the return ductwork between the unit and the conditioned
space. If a 90 degree elbow cannot be installed, then a grille of
sufficient strength and density should be installed to prevent
objects from falling into the conditioned space. Due to electric
heater, supply duct will require 90 degree elbow.
7
CAUTION
WARNING
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