To mount the VMA18 Series controller, complete the
following steps:
1. Place the VMA18 Series controller in the proper
mounting position on the damper shaft so that
the wiring connections are easily accessible.
Note:
The line from the captive spacer and
screw through the center of the damper
shaft must be either horizontal or vertical,
and the wall plate must be wall-mounted
to comply with UL requirements. See the
following figure for possible mounting
positions.
Figure 2: Possible VMA18 Series Controller
Mounting Positions
Make sure the VMA controller base is parallel
to the VAV box (perpendicular to the damper
shaft). If needed, use a spacer to offset tipping
of the VMA controller caused by the shaft
bushings.
Note:
Using the alignment marks to center
the captive spacer ensures sufficient
VMA18 controller movement in either
direction.
2. Secure the self-drilling No. 10 screw through
the shoulder washer (Figure 1) with a power
screwdriver and 100 mm (4 in.) extension
socket. Otherwise, use a punch to mark the
position of the shoulder washer, and then drill a
hole into the VAV box using a 3.5 mm (9/64 in.)
drill bit. Insert the mounting screw and tighten
against the washer.
Note:
The mounting screw for the VMA
controller does not use the same hole
as the screw for the VMA1410, VMA1415,
VMA1420, and the VMA1440 controller.
We recommend plugging the unused
open hole with the screw from the original
VMA14 mounting when using the VMA18
to replace a VMA14 Series controller.
Important:
Do not overtighten the screws,
or the threads may strip. If mounting to
the VAV box, make sure the screws do not
interfere with damper blade movement.
3. Locate the damper position using the typical
marking on the end of the damper shaft. See
the following figure.
Figure 3: Typical damper end shaft icons
4. Note the direction, clockwise (CW) or
counterclockwise (CCW), required to close the
damper. Grasp the damper shaft firmly with
pliers, and either manually close the damper
(for 90° boxes) or manually open the damper
(for 45° or 60° boxes).
5. Push down and hold the Manual Override
button (Figure 1) and turn the VMA controller
coupler until it contacts the mechanical end-
stop at either the fully closed (90° boxes) or
fully open (45° and 60° boxes) position.
6. If the damper for a 90° box closes CCW, rotate
the coupler to the CCW mechanical limit. If the
damper for a 90° box closes CW, rotate the
coupler to the CW mechanical limit. The open
end-stop is automatically set for 90° boxes. For
45° and 60° boxes, hard stops must be provided
at both fully closed and fully open damper
positions. By installing the VMA controller at the
fully open position, the VMA controller provides
the open stop for 45° and 60° boxes. The closed
damper seal provides the fully closed stop.
Important:
The integrated actuator has
a stroke time of 60 seconds for 90° of
travel. The stroke time is the amount of
time (in seconds) that it takes the actuator
to move from the fully closed to fully
opened position or from fully open to fully
closed position. For proper operation, the
actuator stroke time must be configured
in the CCT application based on the actual
time it takes the actuator to drive the
damper. The default setting is 60 seconds
VMA1826/1832 VAV Controller Installation Guide
4
