101
Mixing Box/Filter Mixing Box Damper Linkage
Refer to Fig. 47 for typical damper arrangement and connecting
rod position.
CONTROL DAMPERS
Control dampers may be operated with pneumatic or electric actu
-
ators. These items should be set up in accordance with the control
manufacturer’s installation instructions.
DAMPER LINKAGE ADJUSTMENT
After the air-handling unit has been powered, the dampers should
be checked to ensure they move freely and close tightly. Adjust
-
ment of the linkage may be required.
LINKAGE ADJUSTMENT
1. With the damper actuator unpowered and the damper linkage
disconnected, rotate the outdoor-air damper so that it is fully
closed. Make sure the spring return actuator has completed its
stroke (with power disconnected this will be achieved). The
return-air damper should be fully open at this point.
2. Tighten the actuator on the damper jackshaft, ensure all link
-
age is connected, secure and moves freely.
3. With power applied to the actuator, check for a complete
stroke and free movement in dampers and damper linkage.
.
CAUTION
It is important to properly link the outdoor-air and return-air
dampers. Failure to do so may cause mixing problems,
stratification, or coil freezing under some conditions,
especially in combination type filter mixing boxes.
CAUTION
Dampers and linkage must be checked prior to applying
power. Make certain that there are no obstructions that could
interfere with the operation of the dampers, or equipment
damage could result.
Fig. 45 —
Zone Damper Assembly Details (Horizontal Discharge Shown)
a39-2970
