Manual 2100-594
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 Maximum ESP of operation Electric Heat
Table.
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 W48 and W60, 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 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
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.
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.
FILTERS
NOTE: W48A23, W48L23, W60A23 and W60L23 models
require the use of a return air filter grille.
