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Step 2 — Plan for Sequence of Unit Installation
The support method used for this unit will dictate different
sequences for the steps of unit installation. For example,
on curb--mounted units, some accessories must be
installed on the unit before the unit is placed on the curb.
Review the following for recommended sequences for
installation steps.
Curb--Mounted Installation —
Install curb
Install field--fabricated ductwork inside curb
Install accessory thru--base service connection package
(affects curb and unit) (refer to accessory installation
instructions for details)
Prepare bottom condensate drain connection to suit
planned condensate line routing (refer to Step 11 for
details)
Rig and place unit
Install outdoor air hood
Install flue hood
Install gas piping
Install condensate line trap and piping
Make electrical connections
Install other accessories
Pad--Mounted Installation —
Prepare pad and unit supports
Check and tighten the bottom condensate drain
connection plug
Rig and place unit
Convert unit to side duct connection arrangement
Install field--fabricated ductwork at unit duct openings
Install outdoor air hood
Install flue hood
Install gas piping
Install condensate line trap and piping
Make electrical connections
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 transportation 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. 4 and Fig. 5. Assemble and install accessory roof curb
in accordance with instructions shipped with the curb.
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. 4 and Fig. 5. Improperly
applied gasket can also result in air leaks and poor unit
performance.
Curb should be level. This is necessary for unit drain to
function properly. Unit leveling tolerances are show in
Fig. 6. Refer to Accessory Roof Curb Installation
Instructions for additional information as required.
Install insulation, cant strips, roofing felt, and counter
flashing as shown. Ductwork must be attached to curb and
not to the unit. The accessory thru--the--base power and
gas connection package must be installed before the unit
is set on the roof curb. If field--installed thru--the--roof
curb gas connections are desired, use factory--supplied
pipe coupling and gas plate assembly to mount the
thru--the--roof curb connection to the roof curb. Gas
connections and power connections to the unit must be
field installed after the unit is installed on the roof curb.
If electric and control wiring is to be routed through the
basepan, attach the accessory thru--the--base service
connections to the basepan in accordance with the
accessory installation instructions.
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 obstructing airflow.
NOTE: Horizontal units may be installed on a roof curb
if required.
Alternate Unit Support
(InLieuofCurborSlabMount)—
A non--combustible sleeper rail can be used in the unit
curb support 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.
581J