Installation manual

Page 36 IM-487
Intake Hood Damper
(0 to 100% Outside Air, RAH 47-77 Only)
Units requiring 100% outside air are provided with a rain hood
and dampers which may be controlled by a single actuator. The
actuator, which may be ordered with factory controls, 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.
Figure 38. Intake Hood Damper - 0-100% Outside Air
Intake Hood Damper
(0 to 30% Outside Air)
These dampers are intended to remain at a fixed position dur-
ing 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™ 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 39. Intake Hood Damper - 0-30% Outside Air
Note: 1. Figure 39 shows the RAH 47-77 (The linkage is
on the RH side).
2. The RDS 800-802 are the same except the link-
age is on the LH side.
OA
Closed
OA
Open
90∞
Stroke
.25" (6mm)
AIRFLOW
Airflow
3.15" (80 mm)
Max. Stroke of
Damper Linkage Bar