AAON VCCX-IP User Manual

47VCCX-IP Controller Technical Guide
Alarm Detection and Reporting
The VCCX-IP Controller continuously performs self diagnostics
during normal operation to determine if any operating failures
have occurred. These failures (alarms) can be reported to a Touch
Screen System Manager, a Hand Held Modular Service Tool, or to
a computer running Prism 2 software.
To view an alarm in Prism 2, click the Alarm icon and the ALARM
screen will display all systems and active alarms.
Figure 14: Prism 2 ALARM Button
Figure 15: Prism 2 ALARM Menu
Sensor Failure
Supply Air Sensor
The Supply Air Temperature Sensor failure alarm is generated
when the controller detects an open or short circuit on the Supply
Air Temperature Sensor input. Once the alarm is generated, the
unit will be completely shut down. If a sensor is properly detected
after the unit has alarmed, the alarm will be cleared and the unit
will restart operations.
Return Air Sensor
This alarm is generated if the controller is congured to have a
Return Air sensor, but does not detect it.
Outdoor Air Sensor
The Outdoor Air Temperature Sensor failure alarm is generated
when the controller detects an open or short circuit on the Outdoor
Air Temperature Sensor input. When this occurs, the outdoor air
reading will be articially set to the half point between the Cooling
and Heating Lockout Setpoints. This will allow cooling and
heating to continue operating. For MUA systems, the Outdoor Air
Temperature Sensor is the controlling sensor (Mode Enable Sensor).
This alarm forces the MUA into Heating Mode.
Space Sensor
If the Space Sensor is congured as the controlling sensor (Mode
Enable Sensor) or as the reset sensor, and if the controller detects
an open or short circuit on the space sensor input, or if the
controller detects a missing E-BUS Digital Space Sensor, then a
Space Temperature Sensor failure alarm is generated. If the Space
Sensor is congured as the controlling sensor and the failure alarm
is generated, the unit will shut down. If the Space Sensor is only
congured as a reset sensor and the failure alarm is generated, the
space temperature will default to a value half way between the
Heating and Cooling Mode Enable Setpoints, and the unit will
continue to run.
Carbon Dioxide Sensor
This alarm is generated if the controller is congured to have a CO
2
Sensor, but does not detect it. Indoor Air Quality Mode is disabled
when this occurs. If a sensor is properly detected after the unit has
alarmed, the alarm will be cleared and the unit will return to CO
2
control.
Relief Pressure Sensor
This alarm occurs if the VCCX-IP is receiving the value from a
Broadcast or BACnet and the value is out of an acceptable range.
Airow Alarms
• Outdoor Airow Sensor Alarm
• Exhaust Airow Sensor Alarm
• Supply Airow Sensor Alarm
• Return Airow Sensor Alarm
If the controller is congured to have any of the above airow sensors,
but the controller does not detect that the sensor is connected, then
the applicable alarm will occur. If the sensor is properly detected
after the unit has alarmed, the alarm will be cleared.
Space Humidity Reading
Alarm will be active if controller is congured to detect Space
Humidity but does not read it.
Mixed Air Temp
Alarm will be active if controller is congured to detect Mixed Air
Temperature but does not read it.
SEQUENCE OF OPERATIONS
Alarms

AAON VCCX-IP Specifications

General

Brand	AAON
Model	VCCX-IP
Category	Controller
Language	English