PKGP-SVX011A-EN
21
Table 3.
Clearance required from duct to combustible
surfaces
Model Number
Clearance required from duct to
combustible surfaces (inches)
WHJ150
0
WHJ180
0
WHJ240
0
WHJ300
0
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.
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.
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.
1. Confirm unit does not need additional moves by fork lift.
2. For 12.5 to 25 ton units, prepare unit for rigging by
removing the front and end base rail bumper protection.
Note:
For unit protection, the top crate should remain in
place during lifting. If it must be removed prior to
lifting, protect unit from damage. Top crate must
be removed prior to operation.
WARNING
Improper Unit Lift!
Failure to properly lift unit in a LEVEL position could
result in unit dropping and possibly crushing
operator/technician which could result in death or
serious injury, and equipment or property-only
damage.
Test lift unit approximately 24 inches (61 cm) to verify
proper center of gravity lift point. To avoid dropping of
unit, reposition lifting point if unit is not level.
3. Rig the unit as shown in the weights section. Attach
adequate strength lifting slings to all four lifting brackets
in the unit base rail. Do not use cables, chains, or slings
except as shown.
4. Install a lifting bar, as shown in the Dimensions and
Weights chapter, to protect the unit and to facilitate a
