12
PositioningonCurb—
Position the unit on the roof curb so that the following
clearances are maintained:
S 1/4 inch (6.4 mm) clearance between the roof curb and
the base rail inside the front and rear
S 0.0 inch clearance between the roof curb and the base
rail inside on the duct end of the unit
This will result in the distance between the roof curb and
the base rail inside on the control box end of the unit
being approximately 1/4 inch.
Although the unit is weatherproof, guard against water
from higher level runoff and overhangs.
After the unit is in position, remove the rigging skids and
shipping materials.
Step 7 — Convert to Horizontal and Connect
Ductwork (when required)
The unit is shipped in the vertical duct configuration. Units
without the factory- ins talled economizer may be
field- converted to horizontal ducted configuration. To
convert to horizontal configuration, remove screws from the
side duct opening covers and remove the covers . Using the
same screws, install the covers on vertical duct openings
with the insulation- side down. Seals around duct openings
must be tight (See Fig. 9).
Fig. 9 - Horizontal Conversion Panels
Field- supplied flanges should be attached to horizontal
duct openings, and all ductwork should be secured to the
flanges. Insulate and weatherproof all external ductwork,
joints, and roof or building openings with counter flashing
and mastic in accordance with applicable codes.
Do not cover or obscure visibility to the unit’s informative
data plate when insulat ing horizontal ductwork.
Ste p 8 — Insta ll Exte r nal Conde ns at e Tra p and
Line
Unit has one 3/4 inch condensate drain connection on the
end of the condensate pan and an alternate connection on
the bottom (See Fig. 10). Unit airflow configuration does
not determine which drain connection to use. Either drain
connec tion can be used with vertical or horizontal
applications.
DRAIN
(FACTORY-INSTALLED)
PLUG
CONDENSATE PAN (SIDE VIEW)
STANDARD
SIDE DRAIN
ALTERNATE
BOTTOM DRAIN
Fig. 10 - Condensate Drain Pan (Side V iew)
To use the alternate bottom drain connection, remove the
red drain plug from the bottom connection (use a 1/2 in.
square socket drive extension), and install it in the side
drain connection.
The piping for the conde nsate drain and external trap can
be completed after the unit is in place (See Fig. 11).
NOTE: Trap should be deep enough to offset maximum unit static
difference. A 4” (102) trap is recommended.
MINIMUM PITCH
1” (25mm) PER
10’ (3m) OF LINE
BASE RAIL
OPEN
VENT
TO ROOF
DRAIN
DRAIN PLUG
ROOF
CURB
SEE NOTE
2˝ (51) MIN
Fig. 11 - Condensate Drain Piping Details
All units must have an external trap for condensate
drainage. Install a trap at least 4 inches (102 mm) deep
and protect against freeze-up. If drain line is installed
downstream from external trap, pi tch line away from the
unit at 1 inch per 10 feet (25 mm per 3 m) of run. Do not
use a pipe size gsmaller than the unit connection (3/4
inch).
40QQ
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