Step 5 - Field Fabricate Ductwork; Step 6 - Rig And Place Unit - Carrier WeatherMaster 48HC14 Installation Instructions Manual

A
B
MAXIMUM ALLOWABLE DIFFERENCE IN. (MM)
A-B
0.5" (13) 1.0" (25)
Fig. 5 — Unit Leveling Tolerances
Install insulation, cant strips, roofing felt, and counter flash-
ing as shown. Ductwork must be attached to curb and not to the
unit.
IMPORTANT: If the unit's gas connection and/or electric
and control wiring is to be routed through the basepan and
the unit is equipped with the factory-installed Thru-the-
Base service option see the following sections:
• Factory-Option Thru-Base Connections (Gas Con-
nection) on page 14
• Factory-Option Thru-Base Connections (Electrical
Connections) on page 22
If using the field--installed Thru-the-Base accessory follow
the instructions provided with the accessory kit.
NOTE: If gas and/or electrical connections are not going to
occur at this time, tape or otherwise cover the fittings so that
moisture does not get into the building or conduit in the
interim.
SLAB MOUNT (HORIZONTAL UNITS ONLY) — Pro-
vide a level concrete slab that extends a minimum of 6 in. (150
mm) beyond unit cabinet. Install a gravel apron in front of con-
denser coil air inlet to prevent grass and foliage from obstruct-
ing 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.
B-C A-C
1.0" (25)
Step 5 — Field Fabricate Ductwork
NOTE: 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 open-
C
ing 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 insu-
lated 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 applica-
ble fire codes.
PROPERTY DAMAGE HAZARD
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.
Step 6 — Rig and Place Unit —
ready to be rigged and no longer will be lifted by a fork truck,
the wood protector under the basepan must be removed. Re-
move 4 screws from each base rail. Wood protector will drop to
the ground. See instructions on the unit base rails.
Keep unit upright and do not drop. Spreader bars are not re-
quired. 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.
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment dam-
age.
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.
Before setting the unit onto the curb, recheck gasketing on
curb.
9
CAUTION
When the unit is
CAUTION