Installation; Step 1 - Provide Unit Support; Roof Curb; Alternate Unit Support - Carrier WeatherMaker 48A020 Installation Instructions Manual

INSTALLATION

CAUTION
Ensure clearances are in accordance with local installation
codes, the requirements of the gas supplier and the
manufacturer's installation instructions.
ATTENTION
Assurez-vous que les dégagements sont conformes aux codes
d'installation locaux, aux exigences du fournisseur de gaz et
aux instructions d'installation du fabricant.
Step 1 — Provide Unit Support
CAUTION
1. All panels must be in place when rigging or damage to
unit may occur.
2. Unit is not designed for handling by fork truck. Damage
to unit may occur.

ROOF CURB

For vertical discharge units, assemble or install accessory roof
curb in accordance with instructions shipped with this accessory.
(See Fig. 2-4.) Install insulation, cant strips, roofing, and counter
flashing as shown. Ductwork can be installed to roof curb before
unit is set in place. Curb should be level. This is necessary to
permit unit drain to function properly. Unit leveling tolerance is
shown in Fig. 2-4. Refer to Accessory Roof Curb Installation
Instructions for additional information as required. When
accessory roof curb is used, unit may be installed on class A, B, or
C roof covering material.
IMPORTANT: The gasketing of the unit to the roof curb is
critical for a watertight seal. Install gasket with the roof curb
as shown in Fig. 2-4. Improperly applied gasket can also result
in air leaks and poor unit performance.

ALTERNATE UNIT SUPPORT

When the preferred curb or slab mount cannot be used, support
unit with sleepers on perimeter, using unit curb support area. If
sleepers cannot be used, support long sides of unit (refer to Fig. 5-
13) with a minimum number of 4-in. x 4-in. pads spaced as
follows: 48A20-035 units require 3 pads on each side; 48A040-
050 units require 4 pads on each side; 48A060 units require 6 pads
on each side. Unit may sag if supported by corners only.
Step 2 — Rig and Place Unit
Inspect unit for transportation damage. See Tables 1-6 for physical
data and specifications. File any claim with transportation agency.
Do not drop unit; keep upright. Use spreader bars over unit to pre-
vent sling or cable damage. This unit must be handled with a crane
and cannot be handled by a fork truck. Level by using unit frame
as a reference; leveling tolerance is shown in Fig. 2-4. See Fig. 14
for additional information. Unit operating weight is shown in
Table 2.
NOTE: On retrofit jobs, ductwork may be attached to the old unit
instead of a roof curb. Be careful not to damage ductwork when
removing old unit. Attach existing ductwork to roof curb instead
of unit.
Four lifting lugs are provided on the unit base rails as shown in
Fig. 5-13. Refer to rigging instructions on unit.

POSITIONING

Maintain clearance, per Fig. 5-13, around and above unit to pro-
vide minimum distance from combustible materials, proper air-
flow, and service access.
Do not install unit in an indoor location. Do not locate unit air
inlets near exhaust vents or other sources of contaminated air.
For proper unit operation, adequate combustion and ventilation
air must be provided in accordance with Section 5.3 (Air for
Combustion and Ventilation) of the National Fuel Gas Code,
ANSI Z223.1 (American National Standards Institute).
Although unit is weatherproof, guard against water from higher
level runoff and overhangs.
Locate mechanical draft system flue assembly at least 4 ft from
any opening through which combustion products could enter the
building, and at least 4 ft from any adjacent building. When unit is
located adjacent to public walkways, flue assembly must be at
least 7 ft above grade.

ROOF MOUNT

Check building codes for weight distribution requirements. See
Fig. 14. Unit operating weight is shown in Table 2.
4
Instructions continued on page 22.