Pace PAI - Preparing the Site; Clearance for Outdoor AHUs

Form PA102.20-N1
23
Installation & Assembly Manual │ PACESECTION 3 - HANDLING, STORAGE, AND INSTALLATION
Issue Date: 07/03/2018
3
AL13768
Figure 10 - Proper Lifting with Shackle at Lifting Lug
LD13766
Figure 11 - Proper Lifting with Base Rail
PREPARING THE SITE
Do not weld or use torches on the ex-
terior or interior of the AHU housing.
The housing contains polyurethane in-
sulation, which, under combustion, will
produce harmful, toxic gases resulting
in personal injury or death.
Never use silicone caulk/sealant in or
on any AHU.
If the AHU has HEPA lters, the lter
frames, bulkheads, and segment panels
are factory sealed, and must remain
sealed to prevent air bypass.
Clearance for Outdoor AHUs
Locate the AHU away from building flue stacks or ex-
haust ventilators to prevent possible introduction of
contaminated air through the outside air intakes as
shown in Figure 12 on page 24.
To make sure that the AHU fits properly into the se-
lected location, use the following instructions.
• Allow sufcient space around the AHU to remove
the access panels and various parts.
• Provide a minimum clearance equal to the width
of the AHU plus 6 in. on one side to remove the
coil or fan assembly. Consider the coil access
panel for coil removal.
• Add the dimensions of the pipe chase, air hoods,
ducts, control/electrical panels, etc. to meet mini-
mum clearances.
• Allow any additional clearances as required by lo-
cal and National Electrical Codes (NEC).
Mounting the Outdoor AHU
Install AHUs to provide enough elevation for proper-
ly designed condensation traps as discussed under
Drains and Traps on page 93 in this section.
The area of the roof on which the curb is to be installed
must be structurally adequate to support the combined
weight of curb, AHU, and system fluids. With these
combined weights in place, the resting surface for the
AHU MUST be flat and level.
Concrete pads may not be as flat as they should be.
Shimming and/or grouting may be necessary. Whether
under the AHU base or curb, the AHU base needs to
be on a flat plane.