Manual 2100-651D
Page
5 of 32
DUCT WORK
All duct work, supply and return, must be properly
sized for the design airflow requirement of the
equipment. Air Conditioning Contractors of America
(ACCA) is an excellent guide to proper sizing. All duct
work or portions thereof not in the conditioned space
should be properly insulated in order to both conserve
energy and prevent condensation or moisture damage.
Refer to Maximum ESP of operation Electric Heat Table
9 on page 28.
Design the duct work according to methods given by
the Air Conditioning Contractors of America (ACCA).
When duct runs through unheated spaces, it should
be insulated with a minimum of 1" of insulation. Use
insulation with a vapor barrier on the outside of the
insulation. Flexible joints should be used to connect the
duct work to the equipment in order to keep the noise
transmission to a minimum.
Models J18 and J24 are approved for 0" clearance to
the supply duct. For model series J30, J36, J42, J48,
J60 and J72, a 1/4" clearance to combustible material
for the first 3' of duct attached to the outlet air frame
is required. See wall mounting instructions on page 6
and Figures 3A – 3D (pages 8 – 11) for further details.
Ducts through the walls must be insulated and all joints
taped or sealed to prevent air or moisture entering the
wall cavity.
Some installations may not require any return air duct.
A metallic return air grille is required with installations
not requiring a return air duct. The spacing between
louvers on the grille shall not be larger than 5/8".
Any grille that meets with 5/8" louver criteria may
be used. It is recommended that Bard Return Air
Grille Kit RG2 through RG5 or RFG2 through RFG5
be installed when no return duct is used. Contact
distributor or factory for ordering information. If using
a return air filter grille, filters must be of sufficient size
to allow a maximum velocity of 400 fpm.
NOTE:
If no return air duct is used, applicable
installation codes may limit this cabinet to
installation only in a single story structure.
FILTERS
A 2" pleated filter is standard with each unit. The
internal filter brackets are adjustable to accommodate
a 1" filter by bending two tabs up on each side of the
filter support bracket.
FRESH AIR INTAKE
All units are built with fresh air inlet slots punched in
the service door.
If the unit is equipped with a fresh air damper
assembly, the assembly is shipped already attached
to the unit. The damper blade is locked in the
closed position. To allow the damper to operate, the
maximum and minimum blade position stops must be
installed (see Figure 1).
All capacity, efficiency and cost of operation
information is based upon the fresh air blank-off plate
in place and is recommended for maximum energy
efficiency.
The blank-off plate is available upon request from the
factory and is installed in place of the fresh air damper
shipped with each unit.
CONDENSATE DRAIN
A plastic drain hose extends from the drain pan at
the top of the unit down to the unit base. There are
openings in the unit base for the drain hose to pass
through. In the event the drain hose is connected to
a drain system of some type, it must be an open or
vented type system to assure proper drainage.
FIGURE 1
Fresh Air Damper Assembly
