Sealant
Ductwork
Duct Adaptor
Supply
Ductwork
by Others
Installation with Down Discharge
Step 1 Roof Opening
Determine the location of the supply duct
roof opening. See pgs 19-21 for the
recommended roof opening dimensions.
These sizes can be smaller based on codes
and ductwork sizes.
Step 2 Install Roof Curb and
Optional Equipment Support
Center curb on 3 sides of roof opening, as shown in
installation diagram. Level the curb and shim if
necessary. Attach curb to roof and flash in place.
NOTE: An equipment support is required under the
cooling/filter section if the unit has cooling. See
submittals or consult factory for placement of
support.
Step 3 Install Ductwork
The chart above shows shows the duct sizes
recommended. Good duct practices should be
followed for the remaining ductwork. The use of a
duct adapter with the supply duct is strongly
recommended to properly align the ductwork with
the supply fan discharge. The duct adapter is only
a guide and is not intended to be used as support
for the ductwork.
3
Before beginning this installation:
Make sure that there is room to access the unit from all sides.
The inlet must be located at least 10 feet away from any
exhaust vents.
This unit has a 6" clearance tolerance from the rear and a 24”
clearance tolerance from the sides to any combustibles.
A 48” clearance on the burner control side is recommended for
service and removal of the burner.
Units are for outdoor installation only!
Lifting Lugs
(4 places)
Step 5 Install Unit
Use a crane and a spreader bar
hooked to the factory lifting lugs
(as shown in the diagram) to lift
and center the unit on the curb and
equipment support.
NOTE: Use ALL lifting lugs on unit.
Use self-tapping sheet metal
screws to fasten unit to the curb
and equipment support through
holes provided.
Electrical and gas lines can be
connected at this time.
Recommended Supply
Ductwork Sizes
IG
Duct
Size
Size
100 to 300
18x30
400 to 1200
24x40
Step 4 Apply Sealant
Before installing fan, apply a
sealant around the perimeter of the
supply duct adapter to isolate
the fan and minimize vibration.
