18-BB42D1-1A-EN
15
Ductwork Installation
Attaching Downflow Ductwork to Roof
Curb
Supply and return air flanges are provided on the roof
curb for easy duct installation. All ductwork must be
run and attached to the curb before the unit is set into
place. Refer to the Roof Mounting Curb Installer's
Guide for details.
Attaching Downflow Ductwork to Roof
Frame
Follow these guidelines for ductwork construction:
Connections to the unit should be made with three (3)
inch canvas connectors to minimize noise and vibration
transmission.
Elbows with turning vanes or splitters are
recommended to minimize air noise and resistance.
The first elbow in the ductwork leaving the unit should
be no closer than two (2) feet from the unit, to minimize
noise and resistance.
To prevent leaking, do not attach the ductwork to the
bottom of the unit base. Refer to the bottom example in
the figure below.
Figure 5. Attaching Down Airflow Ductwork
FIELD DUCT
UNIT DUCT
FLANGE
UNIT BASE
AIR PROOF
THIS SEAM
FIELD DUCT
UNIT DUCT
FLANGE
UNIT BASE
AIR PROOF
THIS SEAM
FIELD
DUCT
UNIT DUCT FLANGE
UNIT BASE
AIR PROOF
THIS SEAM
FIELD DUCT
UNIT DUCT
FLANGE
UNIT BASE
NOT RECOMMENDED
WATERPROOF SEAM
WITH BUTYL OR
SILICONE
Attaching Horizontal Ductwork to Unit
All conditioned air ductwork should be insulated to
minimize heating and cooling duct losses. Use a
minimum of two (2) inches of insulation with a vapor
barrier. The outside ductwork must be weatherproofed
between the unit and the building.
When attaching ductwork to a horizontal unit, provide a
flexible watertight connection to prevent noise
transmission from the unit to the ducts. The flexible
connection m
muusstt be indoors and made out of heavy
canvas.
N
No
otte
e:: Do not draw the canvas taut between the solid
ducts.
Figure 6. Attaching Horizontal Airflow Ductwork
FIELD DUCT
UNIT EXTERIOR
WEATHERPROOF
THIS SEAM
FIELD DUCT
UNIT EXTERIOR
WEATHERPROOF
THIS SEAM
Condensate Drain Piping
A 3/4-inch female NPT condensate drain connection is
provided on the evaporator access panel end of the
unit. Provide a trap and fill it with water before starting
the unit to avoid air from being drawn through. Follow
local codes and standard piping practices when
running the drain line. Pitch the line downward away
from the unit. Avoid long horizontal runs. See
N
No
otte
e:: Do not use reducing fittings in the drain lines.
The condensate drain must be:
•
Made of 3/4” pipe size
•
Pitched 1/4” per foot to provide free drainage to
convenient drain system
•
Trapped
•
Must be connected to a closed drain system unless
the trap is properly vented
Figure 7. Typical Condensate Drain Piping
3
/
4
" PVC OR COPPER
TUBING AND FITTINGS
1-1/2" MIN.
1-1/2" MIN.
Air Filter Installation
The packaged unit requires an air filter. The unit does
not come with a factory installed filter rack in it,
however, two filter frame accessories are offered that
will allow the installation of a filter within the unit,
BAYFLTR101 & BAYFLTR201. Otherwise a field
