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A
MAXIMUM ALLOWABLE DIFFERENCE IN. (MM)
A-B
0.5 (13)
Fig. 5 — Unit Leveling Tolerances
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 (IN LIEU OF CURB OR
SLAB MOUNT)
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.
Step 5 — Field Fabricate Ductwork
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 di-
mensions 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 all external ductwork, joints, and
roof openings with counter flashing and mastic in accor-
dance 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 such
roof.
12
B
B-C
A-C
1.0 (25)
1.0 (25)
Specifications subject to change without notice.
FOR UNITS WITH ACCESSORY ELECTRIC HEATERS
All installations require a minimum clearance to combustible
surfaces 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.
C
PERSONAL INJURY HAZARD
Failure
to
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.
Step 6 — Rig and Place Unit
Keep unit upright and do not drop. Spreader bars are re-
quired. Rollers may be used to move unit across a roof.
Level by using unit frame as a reference. See Table 2 on
page 10 and Fig. 6 on page 13 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 or wood to 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 alternate bottom connection is tight. Do this
before setting the unit in place. The red drain pan can be
tightened with a 1/2 in. square socket drive extension. For
further details see Install External Condensate Trap and
Line on page 15.
Before setting the unit onto the curb, recheck gasketing on
curb.
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 when packaging
is removed.
If using top crate as spreader bar, once unit is set,
carefully lower wooden crate off building roof top to
ground. Ensure that no people or obstructions are below
prior to lowering the crate.
POSITIONING ON CURB
Position unit on roof curb so that the following clearances
are maintained: 1/4 in. (6.4 mm) clearance between the roof
curb and the base rail inside the front and back, 0.0 in.
clearance between the roof curb and the base rail inside on
the duct end of the unit. This will result in the distance be-
tween the roof curb and the base rail inside on the
condenser end of the unit being approximately 1/4 in.
(6.4 mm).
Although unit is weatherproof, guard against water from
higher level runoff and overhangs.
After unit is in position, remove rigging skids and shipping
materials.
WARNING
follow
this
warning
CAUTION
RHV-090-120-01SI
could
cause
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