Manual 2100-585B
Page
5 of 19
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 Table 5 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.
For model series H42, H48 and H60 a 1/4 inch
clearance to combustible material for the first three feet
of duct attached to the outlet air frame is required. See
Wall Mounting Instructions and Figures 2 and 3 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 inch.
Any grille that meets with 5/8 inch louver criteria may
be used. It is recommended that Bard Return Air Grille
Kit RG5 or 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-inch pleated MERV 8 is standard with each
unit. The filter slides into position making it easy to
service. This filter can be serviced from the outside by
removing the filter access panel.
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.
