PMGB0406B rev.1
13
4. Duct Work and Connections
For air supply and return, use up
À
ow, horizontal, or down
À
ow, as applicable to the installation.
The vast majority of problems encountered with heating and cooling systems are linked to improperly
designed or installed duct systems. The success of an installation highly depends upon the proper design and
installation of the duct system.
When installing a central air or return grill in or near the living space, design the duct work so the grille is not
in direct line with the opening in the unit. Ensure a quieter system by using one or two elbows and acoustical
duct liner. Where the return air duct is short or where sound may be a problem, use acoustical duct liner inside
the duct. Use
À
exible duct connectors to minimize the transmission of vibration/noise into the conditioned
space.
Do not bring in return air from a location which could introduce hazardous substances into the air
À
ow. Use 1/2”
screws to connect duct work to cabinet. If pilot holes are drilled, drill only through
¿
eld duct and unit
À
ange.
Insulation of duct work is a must where it runs through an unheated space during the heating season or
through an uncooled space during the cooling season. The use of a vapor barrier is recommended to prevent
absorption of moisture from the surrounding air into the insulation.
Properly size the supply air duct by use of a transition to match unit opening. Suspend all ducts using
À
exible
hangers and never fastened directly to the structure.
Fabricate and install duct work in accordance with local and/or national codes. This includes the standards of
the National Fire Protection Association for Installation of Air-Conditioning and Ventilating Systems, NFPA No.
90B. Design duct systems in accordance with the Air Conditioning Contractors of America (ACCA) – Manual D.
This unit is not designed for non-ducted (freeblow) applications. Do not operate without duct work attached to
unit. Never operate equipment without
¿
lters.
Horizontal Suspension
These air handlers may be suspended in horizontal applications. Use angle steel support brackets with
minimum 3/8” threaded rods, supporting the unit from the bottom. Attach the threaded rods at the locations
shown in the Figure 6, leaving enough clearance between door and rod so that doors easily remove for
service.
DO NOT lift air handler by the cabinet brace. The cabinet brace is held in place by the coil channel. The cabinet
brace could become disengaged from the cabinet causing the air handler to fall, potentially causing injury or
damaging property. See Figure 1 for location of cabinet braces.
NOTICE
When assembling the support structure, be sure to size and provide clearance for removal of the access door.
(Ins)DX-Kit̲4e-rev1.indd C-13
(Ins)DX-Kit̲4e-rev1.indd C-13
2016/11/25 15:32:21
2016/11/25 15:32:21