•
Two 1/4 in. x 1/4 in. (6.35 mm x 6.35 mm) brass
fittings
•
One self-drilling No. 10 x 25 mm (1 in.) screw
•
Two 12-in. (30.48 cm.) pieces of flexible tubing
•
One controller/sensor Y cable adapter
•
One 8-pin to 6-pin single-socket cable adapter
Note:
Remove the cap plug from the TSTAT port of the
controller and save for future use. The cap plug
is used on existing sensor ports that are no longer
used.
Materials and Special Tools Needed
Note:
You may not require all the materials listed for
your controller installation.
•
Several 6 mm (1/4 in.) female spade terminals for
input and output wiring and crimping tool or spade
mounted terminal blocks
•
Small straight-blade screwdriver for securing wires in
the terminal blocks
•
8 mm (5/16 in.) wrench or 10 mm (3/8 in.) 12-point
socket to tighten the square coupler bolt
•
Several shims or washers to mount the VMA
•
Power screwdriver, 100 mm (4 in.) extension socket,
punch, drill, and 3.5 mm (9/64 in.) drill bits to mount
the VMA
•
Pliers to open and close the damper
•
Required length of 3.97 mm (5/32 in.) ID pneumatic
tubing and barbed fittings
Mounting
Observe these guidelines when mounting a VMA:
Important:
When the air supply to the VAV box is below
10°C (50°F), make sure that any
condensation on the VAV box, particularly
on the damper shaft, does not enter the
VMA electronics. Mount the VMA vertically
above the damper shaft to allow any shaft
condensation to fall away from the VMA.
Additional measures may be required in
some installations.
•
Ensure the mounting surface can support the VMA
and any user-supplied enclosure.
•
Mount the VMA on a hard, even surface whenever
possible.
•
Use shims or washers to mount the VMA securely
and evenly on the mounting surface.
•
Mount the VMA in an area free of corrosive vapors
that matches the ambient conditions specified in the
Technical Specifications
section.
•
Provide sufficient space around the VMA for cable
and wire connections and adequate ventilation
through the controller (50 mm [2 in.] minimum on the
top, bottom, sides, and front of the controllers).
•
Do not mount the VMA in areas where
electromagnetic emissions from other devices or
wiring can interfere with controller communication.
•
Avoid mounting the VMA on surfaces with excessive
vibration.
•
Because the VMA controller is smaller than the
VMA1410, VMA1415, VMA1420, and the VMA1440
controllers, 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.
On panel or enclosure mount applications, observe these
additional guidelines:
•
Do not install the VMA in an airtight enclosure.
•
Mount the VMA so that the enclosure walls do not
obstruct cover removal or ventilation through the
controller.
•
Mount the VMA so that the power transformer and
other devices do not radiate excessive heat to the
controller.
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
requirements (
Figure 1
).
Figure 1: Possible VMA18 Series Controller
Mounting Positions
Make sure the VMA controller base is parallel to the
VAV box (perpendicular to the damper shaft). If
2
VMA1826/1832 VAV Controller Installation Instructions
