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IM 738-2
49
Mechanical Installation:
Cabinet Weather Protection
Cabinet Weather Protection
This unit ships from the factory with fully gasketed access
doors and cabinet caulking to provide weather resistant
operation. After the unit is set in place, inspect all door gaskets
for shipping damage and replace if necessary.
Protect the unit from overhead runoff from overhangs or other
such structures.
Recaulk field-assembled options such as external piping or
vestibules per the installation instructions provided with the
option.
expose the discharge duct collars on a side discharge unit,
remove the plenum section access door and the door gasketing.
Use flexible connections between the unit and ductwork to
avoid transmission of vibration from the unit to the structure.
To minimize losses and sound transmission, design duct work
per ASHRAE and SMACNA recommendations.
Where return air ducts are not required, connect a sound
absorbing T or L section to the unit return to reduce noise
transmission to the occupied space.
Ductwork exposed to outdoor conditions must be built in
accordance with ASHRAE and SMACNA recommendations
and local building codes
.
Installing Ductwork
On bottom-supply/bottom-return units, if a
Daikin
roof curb is
not used, installing contractor should make an airtight
connection by attaching field fabricated duct collars to the
bottom surface of either the roof curb’s duct flange or the
unit’s duct opening. Do not support the total weight of the
duct work from the unit or these duct flanges. See Figure 60.
Units with optional back return, side discharge, or end
discharge (on RFS units) all have duct collars provided. To
Figure 60. Installing duct work
CAUTION
Transportation, rigging, or maintenance can damage the unit’s
weather seal. Periodically inspect the unit for leakage. Standing
moisture can promote microbial growth, disease, or damage to
the equipment and building.
WARNING
Mold can cause personal injury. Materials such as gypsum wall
board can promote mold growth when damp. Such materials
must be protected from moisture that can enter units during
maintenance or normal operation.
NOTICE
Installer must provide access in the ductwork for
plenum-mounted controls.
Once duct work is installed in units with side discharge, access
to plenum-mounted components is difficult.
Unit duct opening
Unit base
9.76"
4.58"
Roof curb
Duct flanger
in roof curb
Flexible
connector
Ductwork