Roof Curb - American Standard YSC036A Installation, Operation And Maintenance Manual

Installation
Figure 10. 4-5 ton High Efficiency R410a, 6-10 ton R22 and R410a
Horizontal Unit Supply & Return Air Opening
Figure 11. 4-5 ton High Efficiency R410a, 6-10 ton R22 and R410a
Downflow Unit Supply & Return Air Openings
Ductwork
Figure 8, p. 18 illustrates the supply
and return air openings as viewed
from the rear of the unit.
Elbows with turning vanes or
splitters are recommended to
minimize air noise due to turbulence
and to reduce static pressure.
RT-SVX21F-EN
When attaching the ductwork to the
unit, provide a water tight flexible
connector at the unit to prevent
operating sounds from transmitting
through the ductwork.
All outdoor ductwork between the
unit and the structure should be
weather proofed after installation is
completed.

Roof Curb

Downflow
The roof curbs for these units
consists of a "full perimeter"
enclosure to support the unit.
Before installing any roof curb,
verify;
• it is the correct curb for the unit,
• it includes the necessary gaskets
and hardware,
• the purposed installation
location provides the required
clearance for proper operation,
• the curb is level and square. The
top surface of the curb must be
true to assure an adequate curb-
to-unit seal.
WARNING
Combustible Materials!
Maintain proper clearance between
the unit heat exchanger, vent
surfaces and combustible materials.
Refer to unit nameplate and
installation instructions for proper
clearances. Improper clearances
could result in a fire hazard. Failure to
maintain proper clearances could
result in death or serious injury or
property damage.
Verify that appropriate materials
were used in the construction of roof
and ductwork. Combustible materials
should not be used in the
construction of ductwork or roof curb
that is in close proximity to heater
elements or any hot surface. Any
combustible material on the inside of
the unit base should be removed and
replaced with appropriate material.
Step-by-step curb assembly and
installation instructions ship with
each accessory roof curb kit. Follow
the instructions carefully to assure
proper fit-up when the unit is set into
place.
Note: To assure proper condensate
flow during operation, the
unit (and curb) must be level.
If the unit is elevated, a field
constructed catwalk around the unit
is strongly recommended to provide
easy access for unit maintenance and
service.
Recommendations for installing the
Supply Air and Return Air ductwork
19