Manual 2100-489
Page
8 of 26
Any grille that meets the 5/8 inch louver criteria may be
used. It is recommended that Bard Return Air Grille Kit
RG-2 through RG-5 or RFG-2 through RFG-5 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 1-inch throwaway filter is supplied with each unit.
The filter slides into position making it easy to service.
This filter can be serviced from the outside by removing
the service door. A 1-inch washable filter and a 2-inch
pleated filter are also available as optional accessories.
The internal filter brackets are adjustable to
accommodate the two inch filter by loosening two
screws in each bracket assembly and sliding the brackets
apart to the required width and retightening the four
screws.
Refer to Table 12 for maximum static pressure available
for duct design.
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 one inch 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.
A 1/4 inch clearance to combustible material for the
first three (3) feet of duct attached to the outlet air frame
is required. See Wall Mounting Instructions and
Figures 3, 4, 7 & 8 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.
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.
FRESH AIR INTAKE
All units are built with fresh air inlet slots punched in
the service panel.
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 2.
All capacity, efficiency and cost of operation
information as required for Department of Energy
“Energyguide” Fact Sheets 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.
FIGURE 2
FRESH AIR DAMPER ASSEMBLY
CAUTION
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 inches.