Carrier 48LJD - Manual (Page 2)

Ducts passing through an unconditioned space 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 ap­
plicable fire codes.
A minimum clearance is not required around ductwork.
Cabinet return air static shall not exceed —.35 in. wg with
economizer or — .45 in. wg without economizer.
Step 3 — Install External Trap for Condensate
Drain
— All units must have an external trap added for
condensate drainage. A y4-in. NPT connection is located
on the side of the unit. Use a trap at least 4-in. deep and
protect against freeze-up.
If drain line is run to a drain, pitch line away from unit at
1 in. per 10 ft of run. Do not use a pipe size smaller than
the unit connection. See Fig. 4 for more details.
Step 4 — Rig and Place Unit — Inspect unit for
transportation damage. File any claim with transportation
agency. 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 infor­
mation. Operating weight is shown in Table 1 and Fig. 5.
Lifting holes are provided in base rails as shown in
Fig. 6. Refer to rigging instructions on unit.
A CAUTION
I______ All panels must be in place when rigging._________ |
POSITIONING — Maintain clearance around and above
unit to provide minimum distance from combustible mate­
rials, proper airflow, and service access. See Fig. 6. A prop­
erly positioned unit will have the following clearances
between unit and roof curb: 'A-in. clearance between roof
curb and base rails on each side and front of unit; U/32-in.
clearance between roof curb and rear of unit. (See Fig. 2,
section C-C.)
Do not install unit in an indoor location. Do not locate
unit air inlets near exhaust vents or other sources of con­
taminated air.
Be sure that unit is installed such that snow will not block
the combustion intake or flue outlet.
Unit may be installed directly on wood flooring or on
Class A, B, or C roof-covering material when roof curb is
used.
Although unit is weatherproof, guard against water from
higher level runoff and overhangs.
Locate mechanical draft system flue assembly at least
48 in. from any opening through which combustion prod­
ucts could enter the building, and at least 48 in. from an
adjacent building. When unit is located adjacent to public
walkways, flue assembly must be at least 7 ft above grade.
Flue vent discharge must have a minimum horizontal clear­
ance of 4 ft from electric and gas meters, gas regulators,
and gas relief equipment.
Flue gas can deteriorate building materials. Orient unit
such that flue gas will not affect building materials.
Adequate combustion-air space must be provided for proper
operation of this equipment. Be sure that installation
complies with all local codes and Section 5.3, Air for Com­
bustion and Ventilation, NFGC (National Fuel Gas Code),
ANSI (American National Standards Institute) Z223.1-
1984 and addendum Z223.la-1987. In Canada, instal­
lation must be in accordance with the CAN LB 149.1 and
CAN1.B149.2
installation codes for gas burning
appliances.