Step 5 - Field Fabricate Ductwork; Units With Accessory Electric Heaters; Step 6 - Rig And Place Unit - Carrier 50HCQA07 Installation Instructions Manual

A
Fig. 6 — Unit Leveling Tolerances
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 dimen-
sions 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 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
Failure to follow this caution may result in damage to roof-
ing materials.
Membrane roofs can be cut by sharp sheet metal edges. Be
careful when placing any sheet metal parts on such roof.

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.
NOTE: A 90-degree elbow must be provided in the ductwork to
comply with UL (Underwriters Laboratories) code for use with
electric heat.
C
MAXIMUM ALLOWABLE
DIFFERENCE IN. (MM)
B
A-B B-C
0.5 (13) 1.0 (25) 1.0 (25)
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 condi-
tioned 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 required.
Rollers may be used to move unit across a roof. Rigging mate-
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rials under unit (cardboard or wood) must be removed PRIOR
to placing the unit on the roof curb. Level by using unit frame
as a reference. See Table 2 on page 9 and Fig. 7 for additional
information.
Lifting holes are provided in base rails as shown in Fig. 7. Re-
fer to rigging instructions on unit.
Before setting the unit onto the curb, recheck gasketing on
curb.
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 panels or pack-
aging are 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.
Position unit on roof curb so that the following clearances are
maintained: 1
and the base rail inside the front and rear, 0.0 in. clearance be-
tween the roof curb and the base rail inside on the duct end of
the unit. This will result in the distance between the roof curb
and the base rail inside on the condenser end of the unit being
approximately
Although unit is weatherproof, guard against water from higher
level runoff and overhangs.
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 panels or pack-
aging are removed.
After unit is in position, remove the compressor access panel.
Holding the blocking between compressors with one hand, cut
the strapping. Carefully remove the blocking without damag-
ing tubing, wiring, or controls. Remove the strapping and re-
place the access panel.
After unit is in position, remove rigging skids and shipping
materials.
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WARNING
CAUTION
/ in. (6.4 mm) clearance between the roof curb
4
1 / in. (6.4 mm).
4
CAUTION