Mounting and Wiring VMA1400 Series Controllers Technical Bulletin
20
Gear Release
Lever
Damper shaft in
fully closed position.
Set Screw
SHLD
Collar rotated to its
fully closed position.
(CW to close in this example.)
ENDSTOP2
Figure 9: Positioning the End Stop (VMA1410 or VMA1420)
3. Tighten the set screw to the shaft using a 8 mm (5/16 in.) wrench
or 10 mm (3/8 in.) 12-point socket wrench. Tighten to
17 to 21 N⋅m [150 to 180 lb⋅in (14 lb⋅ft)].
Note: Default configuration for the VMA is 90° rotation in
30 seconds. Autocalibration resets the stroke time, based on
the actual rotation between hard stops. This adjustment
allows for dampers that travel 45° or 60° as well as slight
variations from 90°, provided that hard stops are available.
For example, for 45° rotation, the stroke time attribute
autocalibrates to approximately 15 seconds.
4. Push the gear release lever down, and turn the VMA coupler by
hand to ensure that the damper rotates from full closed to full
open positions without binding.
5. Plug or seal the end of a hollow damper shaft to stop cold duct air
from affecting the circuitry when the VMA is mounted in another
enclosure.
6. Attach the pneumatic tubing to the pressure sensor with the
HI (red) tubing connected to the inlet or high pressure side. The
clear tube connects to the LO inlet of the VAV box.
Note: It is recommended that tubing is routed as shown below, or
that a loop is taped in the tubing. This provides a low spot
for collecting condensation.
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