SLAB MOUNT (Horizontal Units Only) — Provide a level
concrete slab that extends a minimum of 6 in. beyond unit
cabinet. Install a gravel apron in front of condenser coil air
inlet to prevent grass and foliage from obstructing airflow.
NOTE: Horizontal units may be installed on a roof curb if
required.
Step 2 — Field Fabricate Ductwork —
Secure all
ducts to roof curb and building structure on vertical units.
Do not connect ductwork to unit. For horizontal applica-
tions, field-supplied flanges should be attached to horizontal
discharge openings and all ductwork secured to the flanges.
Insulate and weatherproof all external ductwork, joints, and
roof openings with counter flashing and mastic in accor-
dance with applicable codes.
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
Durablade or PARABLADE economizer or .45 in. wg with-
out economizer.
These units are designed for a minimum continuous return-
air temperature of 50 F (dry bulb), or an intermittent opera-
tion down to 45 F (dry bulb), such as when used with a night
set-back thermostat.
Step 3 — Install External Trap for Condensate
Drain —
The unit’s
3
⁄
4
-in. condensate drain connections
are located at the bottom and side of the unit. Unit discharge
connections do not determine the use of drain connections;
either drain connection can be used with vertical or hori-
zontal applications.
When using the standard side drain connection, make sure
the plug in the alternate bottom connection is tight before
installing the unit.
To use the bottom drain connection for a roof curb in-
stallation, relocate the factory-installed plug from the
bottom connection to the side connection. See Fig. 4. The
piping for the condensate drain and external trap can be com-
pleted after the unit is in place.
All units must have an external trap for condensate drain-
age. Install a trap at least 4-in. deep and protect against freeze-
up. See Fig. 5. If drain line is installed downstream from the
external trap, pitch the line away from the unit at 1 in. per
10 ft of run. Do not use a pipe size smaller than the unit
connection.
Step 4 — Rig and Place Unit —
Inspect unit for trans-
portation 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 ref-
erence. See Table 1 and Fig. 6 for additional information.
Operating weight is shown in Table 1 and Fig. 6.
Lifting holes are provided in base rails as shown in
Fig. 6 and 7. Refer to rigging instructions on unit.
All panels must be in place when rigging.
POSITIONING — Maintain clearance around and above unit
to provide minimum distance from combustible materials,
proper airflow, and service access. See Fig. 7.
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 so 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.
Position unit on roof curb so that the following clearances
are maintained:
1
⁄
4
-in. clearance between roof curb and base
rails on each side and front of unit; 1
5
⁄
32
-in. clearance be-
tween roof curb and rear of unit. (See Fig. 2, section C-C.)
Fig. 1 — Horizontal Conversion Panels
2
