Table 1: VMA18 Series Controller feature callout numbers and descriptions
Physical features: description and references
3
Binary Outputs, 24 VAC Triacs (see Table 4)
4
Configurable Outputs: Voltage Analog Output (0–10 VDC) and Binary Output (24 VAC Triac) (see Table 4)
5
Dual Port Fitting (see Figure 1)
Not included in the VMA1826 model.
6
)
7
Controller Coupler (see
8
Coupler Bolt (see
9
Universal Input: Voltage Analog Input (0–10 VDC)
Resistive Analog Inputs (0–600k ohm) (see Table 4):
0–2k Potentiometer
RTD: 1k Nickel, 1k Platinum, or A99B SI
NTC: 10K Type L (10K JCI Type II is equivalent to Type L) or 2.252K Type II
Dry Contact Binary Input
10
N2/FC Bus Pluggable Screw Terminal Block (see
)
11
EOL (End-of-Line) Switch (see
)
12
)
13
TSTAT Modular Port: RJ-45 8-Pin Modular Jack (see
14
Captive Spacer and Screw (see Figure 1)
15
LED Status Indicators (see Table 8)
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
VMA1832 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.
VMA1826/1832 VAV Controller Installation Guide
3
