JOHNSON CONTROLS
38
FORM 100.50-NOM12
ISSUE DATE: 04/02/2019
SECTION 2 – INSTALLATION
DUCT SYSTEM
Duct Connection Guidelines
All intake and discharge air duct connection to the
unit may be made directly to the unit. These air duct
connections should be on flexible material and should
be installed so they are sufficiently loose. Duct runs
and transitions must be made carefully to hold friction
loss to a minimum. Avoid short turns, and duct elbows
should contain splitters or turning vanes.
Duct work connected to the fan discharge should run in
a straight line for at least
two
equivalent outlet diame-
ters. Never deadhead the discharge into the flat surface
of a plenum.
Installation of elbows, discharge damper
and other abrupt flow area changes in
-
stalled directly at the fan outlet will cause
system losses. These losses must be taken
into account during the design phase and
must be added to any field measurements.
SOUND AND VIBRATION TRANSMISSION
All roof mounted air handling units generate some
sound and vibration, which may or may not require
some special treatment of the air conditioned space.
The noise generated by the air handling unit is depen-
dent on the speed of the fan, the amount of air the fan
is moving, the fan type and the static efficiency of the
fan. In applications where sound and vibration trans-
missions may be objectionable, good acoustical engi-
neering practices must be incorporated in the system
design.
Static Pressure Probe
A
A
VIEW A-A
LD06758A
FIGURE 12 -
STATIC PRESSURE PROBE LOCATION