30
RT-SVX070B-EN
Roof Curb
Downflow
The roof curbs for these units consists of a “full perimeter”
enclosure to support the unit just inside of the unit base rail.
The 12.5 ton standard efficiency units contain a support
base alignment rail and will extend past the end of the roof
curb as shown in figures below
Before installing any roof curb, verify:
•
It is the correct curb for the unit.
•
The includes the necessary gaskets and hardware.
•
The purposed installation location provides the required
clearance for proper operation.
•
Insure that 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!
Failure to maintain proper clearance between the unit
and combustible materials could cause a fire which
could result in death, serious injury, or property
damage.
Refer to unit nameplate and installation instructions
for proper clearances.
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 joining the roof curb are included in the curb
instruction booklet. Curb ductwork must be fabricated and
installed by the installing contractor before the unit is set
into place.
Note:
For sound consideration, cut only the holes in the
roof deck for the ductwork penetrations. Do not cut
out the entire roof deck within the curb perimeter.
Figure 34.
View for base to roof curb alignment on
C.0 cabinet on a 50" x 84" roof curb
Base Alignment Bracket
Figure 35.
View for base to roof curb alignment on
C.0 cabinet on a 60" x 84" roof curb
If a Curb Accessory Kit is not used:
•
The ductwork can be attached directly to the factory-
provided flanges around the unit’s supply and return air
openings. Be sure to use flexible duct connections at
the unit.
•
For “built-up” curbs supplied by others, gaskets must
be installed around the curb perimeter flange and the
supply and return air opening flanges.
Rigging
WARNING
Heavy Object!
Failure to follow instructions below could result in
unit dropping which could result in death or serious
injury, and equipment or property-only damage.
Ensure that all the lifting equipment used is properly
rated for the weight of the unit being lifted. Each of the
cables (chains or slings), hooks, and shackles used to
lift the unit must be capable of supporting the entire
weight of the unit. Lifting cables (chains or slings)
may not be of the same length. Adjust as necessary
for even unit lift.
See Dimensions and Weights section for rigging
illustration, and center-of-gravity dimensional data. Refer to
the typical unit operating weights table before proceeding.
