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Fig. 7 - Unit Leveling Tolerances
Step 5 — Field Fabricate Ductwork
Cabinet return-air static pressure (a negative condition)
shall not exceed 0.35 inch wg (87 Pa) with economizer or
0.45 inch 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 dimensions for the first 18 inches (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.
CAUTION
!
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 this type of roof.
For Optional Electric Heaters —
All installations require a minimum clearance to
combustible surfaces of 1 inch (25 mm) from the duct for
the first 12 inch (305 mm) away from unit.
NOTE: A 90 degree elbow must be provided in the
ductwork to comply with UL (Underwriters Laboratories)
code for use with electric heat.
MAXIMUM ALLOWABLE
DIFFERENCE IN. (MM)
A-B
B-C
A-C
0.5" (13)
1.0" (25)
1.0" (25)
WARNING
!
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, a grille of sufficient strength and
density should be installed to prevent objects from
falling into the conditioned space. Due to electric
heater, the supply duct will require a 90
elbow.
Step 6 — Rig and Place Unit
Keep unit upright and do not drop. Spreader bars are not
required if top crating is left on unit. Rollers may be used
to move unit across a roof. Level by using the unit frame
as a reference. See Table 3 and Fig. 8 for additional
information.
Lifting holes are provided in base rails as shown in Fig. 8.
Refer to rigging instructions on unit.
Before setting unit onto curb, recheck gasketing on curb.
Rigging materials under unit (cardboard or wood) 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 alternate bottom connection is tight. Do this
before setting the unit in place. The red drain pan plug can
be tightened with a 1/2 inch square socket drive extension.
For further details see "Step 8 - Install External Condensate
Trap and Line."
CAUTION
!
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 forklift when packaging is
removed.
If using the top crate as spreader bar once unit is set,
carefully lower wooden crate off of the building roof
top to the ground. Ensure that no people or
obstructions are in the way before lowering the crate.
10
degree
°
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