010-200002-000
Page 8
HB IOM 1.1 2-13-2014
INSTALLATION—DUCTWORK (CONT’D)
Fig. 6 — HB size 60 and 80 Duct
Connections
DUCTWORK CONNECTIONS
Install supply and return ductwork to the
unit as required for the application. Note
that free discharge or free return is ac-
ceptable.
Return Ductwork:
Install return ductwork
by attaching one side of a field-provided
flexible duct connector to the duct flange
on the return side of the unit (filter side).
Attach the other side of the flexible duct
connector to the return ductwork. Seal the
connections using duct mastic or HVAC
tape.
Supply Ductwork—Unit Sizes 04-40:
Install
supply ductwork by attaching one side of a field-
provided flexible duct to the fan discharge duct
collar on the front of the unit. Attach the other
side to the supply ductwork. Seal the connec-
tions using duct mastic or HVAC tape. Refer to
Figure 5.
Supply Ductwork—Unit Sizes 60-80:
Install
supply ductwork by attaching a field-provided
supply duct plenum over the fan discharges.
Supply duct plenum size is critical to fan perfor-
mance—size as indicated in Figure 6.
CAUTION
: DO NOT USE PANTS-LEG TYPE
DISCHARGE DUCT AT THE FAN DISCHARG-
ES. The fans achieve rated performance ONLY
when installed with the supply duct plenum.
Fig. 5 — HB size 04 to 40
Duct Connections
Attach the supply duct plenum to the supply duct
using a flexible connector. Seal the connections
using duct mastic or HVAC tape.
Refer to Fig-
ure 6.
NOTE:
It is acceptable to omit the flexible duct
connectors, but this may allow normal operating
vibration or noise to transfer through the duct sys-
tem
leading to customer complaints.
Size all ductwork according to SMACNA and
ASHRAE duct design standards.
