B. 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.
C. Alternate Unit Support
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. pads on each side.
II. STEP 2 — FIELD FABRICATE DUCTWORK
Secure all ducts to roof curb and building structure on verti-
cal ducted units. Do not connect ductwork to unit. For hori-
zontal applications, field-supplied flanges should be attached
to horizontal duct openings and all ductwork should be
secured to the flanges. Insulate and weatherproof all exter-
nal ductwork, joints, and roof openings with counter flashing
and mastic in accordance with applicable codes.
Ducts passing through an unconditioned space 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 appli-
cable fire codes.
A minimum clearance is not required around ductwork. Cab-
inet return air static shall not exceed –.20 in. wg with
economizer or –.45 in. wg without economizer.
These units are designed for a minimum continuous heating
return-air temperature of 50 F (dry bulb), or an intermittent
operation down to 45 F (dry bulb), such as when used with a
night set-back thermostat.
To operate at lower return-air temperatures, a field-supplied
outdoor air temperature control must be used to initiate both
stages of heat when the temperature is below 45 F. Indoor
comfort may be compromised when these lower air tempera-
tures are used with insufficient heating temperature rise.
Fig. 2 — Horizontal Conversion Panels
III. STEP 3 — INSTALL EXTERNAL TRAP FOR CONDEN-
SATE DRAIN
The unit's
the bottom and side of the unit. Unit discharge connections do
not determine the use of drain connections; either drain con-
nection can be used with vertical or horizontal applications.
When using the standard side drain connection, make sure
the plug (Red) in the alternate bottom connection is tight
before installing the unit.
To use the bottom drain connection for a roof curb installation,
relocate the factory-installed plug (Red) from the bottom con-
nection to the side connection. The center drain plug looks like
a star connection, however it can be removed with a
socket drive. See Fig. 5A. The piping for the condensate drain
and external trap can be completed after the unit is in place.
All units must have an external trap for condensate drainage.
Install a trap at least 4-in. deep and protect against freeze-up.
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 (
See Fig. 5B.
IV. 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. 6 for
additional information.
Lifting holes are provided in base rails as shown in Fig. 1A
and 1B. Refer to rigging instructions on unit.
A. Positioning
Maintain clearance around and above unit to provide mini-
mum distance from combustible materials, proper airflow,
and service access. See Fig. 1A and 1B. A properly positioned
unit will have the following clearances between unit and roof
curb:
each side and duct end of unit;
curb and condenser coil end of unit. (See Fig. 3, section C-C.)
—
—
4
3
/
-in. condensate drain connections are located on
4
CAUTION: All panels must be in place when rigging.
1
/
-in. clearance between roof curb and base rails on
4
1
1
/
-in.
2
3
/
in.).
4
/
-in. clearance between roof
4