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POSITIONING — Maintain clearance around and above unit
to provide minimum distance from combustible materials,
proper airflow, and service access. See Fig. 6. A properly
positioned unit will have the following clearances between
unit and roof curb:
1
⁄
4
-in. clearance between roof curb and
base rails on each side and front of unit; 1
5
⁄
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.
Flue vent discharge must have a minimum horizontal clear-
ance of 4 ft from electric and gas meters, gas regulators, and
gas relief equipment.
Minimum distance between unit and other electrically live
parts is 48 inches.
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
Combustion and Ventilation, NFGC (National Fuel Gas
Code), and ANSI (American National Standards Institute)
Z223.1, and NFPA (National Fire Protection Association)
54 TIA-54-84-1. In Canada, installation must be in accor-
dance with the CAN1-B149 installation codes for gas burn-
ing appliances.
After unit is in position, remove rigging skids and ship-
ping materials.
Step 5 — Install Flue Hood —
Flue hood is shipped
screwed to the burner compartment access panel. Remove
from shipping location and using screws provided, install flue
hood and screen in location shown in Fig. 7.
Step 6 — Install Gas Piping —
Unit is equipped for
use with type of gas shown on nameplate. Refer to local build-
ing codes, or in the absence of local codes, to ANSI Z223.1
entitled National Fuel Gas Code. In Canada, installation must
be in accordance with the CAN1.B149.1 and CAN1.B149.2
installation codes for gas burning appliances.
For natural gas applications, gas pressure at unit gas con-
nection must not be less than 4 in. wg or greater than
13.0 in. wg while unit is operating. On 48TJ005,006,007 high
heat units, the gas pressure at unit gas connection must not
be less than 5 in. wg or greater than 13 in. wg while the unit
is operating. For propane applications, the gas pressure must
not be less than 5 in. wg or greater than 13 in. wg at the unit
connection.
Size gas supply piping for 0.5 in. wg maximum pressure
drop. Do not use supply pipe smaller than unit gas connec-
tion. Support gas piping as shown in the table in Fig. 8. For
example, a
3
⁄
4
-in. gas pipe must have one field-fabricated
support beam every 8 ft. Therefore, an 18-ft long gas pipe
would have a minimum of 2 support beams, a 48-ft long
pipe would have a minimum of 6 support beams.
See Fig. 8 for typical pipe guide and locations of external
manual main shutoff valve.
Step 7 — Make Electrical Connections
Unit cabinet must have an uninterrupted, unbroken elec-
trical ground to minimize the possibility of personal
injury if an electrical fault should occur. This ground
may consist of electrical wire connected to unit ground
lug in control compartment, or conduit approved for elec-
trical ground when installed in accordance with NEC
(National Electrical Code), ANSI/NFPA (National Fire
Protection Association), latest edition, and local elec-
trical codes. Do not use gas piping as an electrical ground.
Failure to follow this warning could result in the in-
staller being liable for personal injury of others.
DISCONNECT BOX LOCATION — The field-supplied dis-
connect box may be mounted on the unit’s end panel or on
the corner post. Mount disconnect box on the left side of the
rating plate when mounting on the unit’s end panel. Do not
mount the disconnect box over the unit rating plate. When
mounting disconnect box on corner post, secure disconnect
box to corner post and condenser coil top cover. See Fig. 7.
A disconnect box mounting space is available when an
optional or accessory condenser coil grille is used. Mount
the disconnect on the sheet metal provided with the con-
denser coil grille. The sheet metal is located adjacent to the
corner post on the left side of the power wiring access panel.
4
Summary of Contents for 48TJD Series
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