Greenheck DGX Installation, Operation And Maintenance Manual page 5

Installation - Roof Mounted Unit Arrangement DBC
Step 1 Install Curb/Equipment
Support(s)
Position curb/equipment support(s) on the roof
(reference the CAPS submittal for placement of
curb/equipment support(s) in relation to the unit).
Verify that all unit supports are level, shim if
necessary. Attach curb to roof and flash into place.
Attach the equipment support(s) to the roof, remove
metal cover, flash to wooden nailer and reinstall
cover. See figure #7.
Step 2 Install Combination Extension
Install combination extension over curb. Lag into
place using wood screws. Locate the extension so
the tall vented side is over the exhaust opening. See
figure #8.
Step 3 Install Ductwork
Good duct practices should be followed for all
ductwork. All ductwork should be installed in
accordance with SMACNA and AMCA guidelines,
NFPA 96 and any local codes. Reference the CAPS
submittal for ductwork size and location. Refer to
figure #9.
NOTE!
The use of a duct adapter is recommended on a
downblast (DBC) arrangement to align the
ductwork with the supply unit and is only a guide
and is not to be used as support for the
ductwork.
Step 4 Apply Sealant
Apply an appropriate sealant around the perimeter of
the curb and duct adapter(s) to isolate fan vibration
and prevent water penetration. See figure #10.
Metal Cover
Equipment
Support
Figure 7. Curb and Unit Support
Figure 8. Combination Extension
Figure 9. Ductwork
Supply Duct with Duct
Adapter Installed
Figure 10. Sealing Ductwork
5
Roof Curb
Exhaust
Supply
Exhaust
Ductwork
by Others
Supply
Ductwork
by Others
Exhaust Duct Installed
Sealant
1 inch Inside
Flange