11
Step 5 — Field Fabricate Ductwork
Cabinet ret urn-air static pressure (a negati ve 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 structur e. Do not connect ductwork to unit.
Fabrica te supply ductwork so that the cross sectional
dimensions are equal to or greater than the unit supply
duct opening dimensions for the first 18 in. (458 mm) of
duct length from the unit basepan.
Insulate and weatherproof a ll externa l 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 i s not required around duct work.
PROPER TY 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.
CAUTION
!
Step 6 — Rig and Place Unit
Keep unit upright and do not drop. Spreader bars are
required. Rollers may be used to move unit across a roof.
Level by using unit frame as a reference. See Table 1 and
Fig. 6 for additional information.
Lifting holes are provided in base rails as shown in Fig. 6.
Refer to rigging instructions on unit.
Rigging materials under unit (cardboard t o prevent base
pan damage) must be removed PRIOR to placing the unit
on the roof curb.
When using the standard side drain connection, ensure the
red plug in the altern ate bottom connection is tight. Do this
befor e s ettin g th e unit in place. The red drain pan p lug can
be tightened with a
1
/
2
--in. square socket drive extension. For
further details see “Step 12 -- Install External Condensate
Trap and Line” on page 18.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in
equipment damage.
All panels must be in place when rigging. Unit is not
designed for handling by fork truck.
CAUTION
!
Before setting the unit onto the curb, recheck gasketing on
curb.
582J
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