Trane VUV Installation, Operation And Maintenance Manual page 37

Power Supply
Please read all of the warnings, cautions, and notices below
before proceeding with this section.
WARNING
Hazardous Voltage!
Failure to disconnect power before servicing could
result in death or serious injury. Disconnect all electric
power, including remote disconnects before servicing.
Follow proper lockout/tagout procedures to ensure the
power can not be inadvertently energized. Verify that
no power is present with a voltmeter.
CAUTION
Proper Ground Connection Required!
Failure to follow instructions below could result in
death or serious injury. After installation, ensure that
the 24 Vac transformer is grounded through the
controller. Measure the voltage between chassis
ground and any ground terminal on the controller.
Expected result: Vac <4.0 volt.
NOTICE
Equipment Damage!
Sharing 24 Vac power between controllers could result
in equipment damage.
A separate transformer is recommended for each UC400-B/
Symbio™ 400-B controller. The line input to the transformer
must be equipped with a circuit breaker sized to handle the
maximum transformer line current.
If a single transformer is shared by multiple UC400-B/
Symbio™ 400-B controllers:
• The transformer must have sufficient capacity.
• Polarity must be maintained for every UC400-B/
Symbio™ 400-B controller powered by the transformer.
Important: If the polarity is inadvertently reversed between
two controllers powered by the same
transformer, a difference of 24Vac will occur
between the grounds of each controller, which
can result in:
• Partial or full loss of communication on the
entire BACnet® MS/TP link
• Improper function of the UC400-B/
Symbio™ 400-B controller outputs
• Damage to the transformer or a blown
transformer fuse
Transformer Recommendations
A 24Vac power supply must be used for proper operation of the
binary inputs, which requires 24Vac detection. In addition, the
spare 24Vac outputs may be used to power relays and
TRIACS.
UV-SVX005G-EN
• AC transformer requirements: UL listed, Class 2 power
transformer, 24Vac ±15%, device max load 24VA. The
transformer must be sized to provide adequate power to
the controller (12VA) and outputs (maximum 12VA per
binary output).
• CE-compliant installations: The transformer must be CE
marked and SELV compliant per IEC standards.
Wiring Requirements
To ensure proper operation of the UC400-B/Symbio™ 400-B
controller, install the power supply circuit in accordance with
the following guidelines:
• A dedicated power circuit disconnect switch must be near
the controller, easily accessible by the operator, and
marked as the disconnecting device for the controller.
2
• 18 AWG (0.823 mm ) copper wire is recommended for the
circuit between the transformer and the controller.
Important: The controller must receive AC power from a
dedicated power circuit; failure to comply may
cause the controller to malfunction. DO NOT run
AC power wires in the same wire bundle with
input/output wires; failure to comply may cause
the controller to malfunction due to electrical
noise.
Connecting Wires
Figure 35. Grounding the controller
1 2 3 4 5
J15
Alternate
Phoenix
Ground
Method
24 Vac
Transformer
To connect the wires:
1. Disconnect power to the transformer.
2. Connect the 24Vac secondary wires from the transformer
to the 24Vac and terminals on the UC400-B/
Symbio™ 400-B controller (refer to the illustration below).
3. Do one of the following to ensure the controller is
adequately grounded:
• Connect a grounding pigtail at some point along the
secondary wire that runs between the controller
terminal and the transformer.
• Ground one of the
enclosure (if the enclosure is adequately grounded) or
to an alternate earth ground.
Installation - Controls
6 1 2 3 4 5 6
J16
Phoenix
terminals on the controller to the
37