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7
A-B
0.5” (13)
B-C
1.0” (25)
A-C
1.0” (25)
MAXIMUM ALLOWABLE
DIFFERENCE IN. (MM)
C06110
Fig. 4 -- 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.
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.
For Units with Accessory Electric Heaters —
Horizontal applications require a minimum clearance to
combustible surfaces of 1--in (25 mm) from duct for first
12--in (305 mm) away from unit. Vertical applications do not
require a minimum clearance.
Minimum clearance is not required around ductwork.
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.
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, 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.
!
WARNING
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 unit frame as a
reference. See Table 1 and Fig. 5 for additional information.
Lifting holes are provided in base rails as shown in Fig. 5.
Refer to rigging instructions on unit.
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.
50HCQA