
48
IM 738-2
Mechanical Installation:
Damper Assemblies
Intake Hood Damper (0% to 100% outside air)
Units requiring 100% outside air are provided with a rain hood
and dampers that can be controlled by a single actuator. The
actuator provides two-position control for opening the
dampers fully during unit operation and closing the dampers
during the off cycle. No unit mounted exhaust dampers are
provided.
Intake Hood Damper (0% to 30% outside air)
These dampers are intended to remain at a fixed position
during unit operation, providing fresh air quantities from 0 to
30% of the total system airflow, depending on the damper
setting. This setting is made at the linkage rod on units with
manually adjustable linkages.
On units provided with MicroTech II controls, the damper
position may be set at the controller keypad. During unit
operation, the two-position actuator drives the damper to the
position set on the keypad. During the off cycle, the damper is
automatically closed.
No unit-mounted exhaust dampers are provided with this
option.
Figure 58. Damper linkage bar typical for all sizes, sizes
15C to 40C shown
Figure 59. Intake hood damper adjustment
A i r
f l o
w
.
" ( 8 0 m m )
M a x . S t r o k e o f
D a m p e r L i n k a g e B a r