McQuay RAH 047C Installation And Maintenance Manual page 41

Intake Hood Damper (0% to 100% outside air, RAH
047C–077C only)
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 III 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 46: Intake Hood Damper, 0% To 30% Outside Air
Note: Figure 46 shows the RAH 47–77 (The linkage is on the
RH side). The RDS 800–802 are the same except the
linkage is on the LH side.
McQuay IM 987
3 . 1 5 " ( 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
Mechanical Installation
Figure 47: Intake Hood Damper Adj., 0% to 100% Outside
Air
OA
closed
Airflow
90
stroke
OA
open
.25" (6mm)
41