Installation manual

IM-487 Page 35
Damper Assemblies
The optional damper assemblies described in this section are
provided with manually adjustable linkages, or may be
shipped with factory installed actuators and linkages in units
that include factory controls.
Economizer Dampers
Outside air intake is provided on both sides of the unit, and
the return air path is at the center of the damper set. As the
single actuator modulates the outside air dampers open, the
return air dampers close. Exhaust air exits the unit through
the gravity relief dampers provided at the end of the econo-
mizer section.
The outside air return air damper assembly (economizer)
comes with manually adjustable linkage. This adjustable
linkage can also be used for connection of a damper operator.
The damper is set so that the crankarm moves through a 90-
degree angle to bring the economizer dampers from full open
to full close. Mechanical stops have been placed in the cran-
karm mounting bracket. Do not remove stops. If crankarm is
driven past stops, damage to linkage or damper will result.
The unit will ship with a shipping bolt securing the linkage
crankarm. Remove shipping bolt before use.
Figure 37. Economizer Dampers
Note: For good airflow control, adjust linkages so damper blades do not open beyond 70 degrees. Opening a damper blade
beyond 70 degrees has little effect on its airflow. Do not "overclose " low leak damper blades. The edge seal should just
lightly contact the adjoining blade. The blades will lock-up if they are closed so far that the seal goes over center.
OA
Closed
OA
Open
90∞
Stroke
.25" (6mm)
Outside
Air
Outside
Air
Optional Return Air Fan
Economizer
.500 (13mm) Dia. Shaft
x 1.30" (33mm) Long
OA
Closed
OA
Open
3.00
.25
.75
90∞
Stroke
Shaft .500 Dia.
x 1.50 Long
RAH 047C - 077C
RDS 800C & 802C