12
Air Handling Unit
Installation, Operation, and Maintenance Manual
April 2021
Figure 6-13.
6.4 Stacked Unit Assembly
When a ClimateCraft air handling unit contains a
“stacked” configuration where one unit section sits
atop a lower section, it is essential to seal any air
openings between the sections. Gasket is provided by
ClimateCraft for this purpose and must be installed per
the instructions below.
Figure 6-14.
LOWER SECTION
UPPER SECTION
GASKET PERIMETER
OF OPENING WITH
DOUBLE WIDTH OF
PGSK-001-001
PANEL JOINT GASKET
BEFORE SETTING
UPPER SECTION
LOWER SECTION
PERIMETER OPENING
UPPER SECTION
PERIMETER OPENING
PTAP-001-002
DOUBLE-SIDED ADHESIVE
TRANSFER TAPE
PRIOR TO INSTALLING UPPER SECTION,
INSTALL PGSK-001-001 COMPLETELY
AROUND THE TOP PERIMETER OF THE
LOWER SECTION OPENING.
7.0 Condensate Drain
Static pressure in the drain pan section will be negative
if the cooling coil is in a draw through application.
Static pressure will not allow the drain pan to empty if
a properly plumbed trap is not used. Cooling coils and
drain pans in a blow through or positive pressure section
also need to be properly trapped to prevent air from
blowing through the drain.
The following trap sizes are required as a minimum for
proper operation of the air handling unit. On startup,
it may be necessary to fill the trap manually. If the air
handling unit is exposed to freezing conditions during
winter months, an antifreeze solution should be placed
in the trap or the trap should be drained and plugged.
Figure 7-1. Negative Internal Static Pressure in Coil Section-
Fan Off (Draw-Through Application)
Condensate drain pan
H/2
minimum
H = Fan inlet pressure
(in. W.C.) + 1 in.
H
Sea level
with fan off
Trap for draw-thru unit, fan off.
H = Negative Internal Static Pressure in Drain Pan
Section (in w.g.)+1”
H/2 = Negative Internal Static Pressure in Drain Pan
Section (in. wg) divided by 2.
Example:
Neg SP in Drain Pan Section=3.6 in/w.g.
H = 3.6+1 = 4.6”
H/2 = (3.6 / 2) = 1.8”
