Orion System VCC-X Controller - Manual (Page 68)

Zone
Zone
SEQUENCE OF OPERATIONS
VCC-X Controller Technical Guide 68
Failure Mode Alarms
High and Low Supply Temp Alarm
These alarms are activated when the Supply Air Temperature (SAT)
rises above the High Cutoff Temperature Setpoint (immediate) or
drops below the Low Cutoff Temperature Setpoint (for 10 minutes).
Both cutoff setpoints are user-adjustable. This mode shuts off the unit
(with a 3 minute fan off delay) until the mode is cancelled.
This mode is cancelled when the SAT drops 5 degrees below the
High Cutoff Temperature Setpoint or rises 5 degrees above the Low
Temp Cutoff Temperature Setpoint, or when the unit changes back
into Occupied Operation.
High and Low Control Temp Failure
When the Controlling Sensor Temperature rises above the Cooling
Mode Enable Setpoint plus the Control Mode High Alarm Offset
setpoint, the controller will generate a High Control Temp Failure
Alarm. When the Controlling Sensor Temperature drops below the
Heating Mode Enable Setpoint minus the Control Mode Low Alarm
Offset setpoint, the controller will generate a Low Control Temp
Failure Alarm. Both offset setpoints are user-adjustable.
High Head Pressure Alarm
If the Head Pressure exceeds an acceptable limit, this alarm will be
generated. The alarm will be cleared if the Head Pressure falls back
within acceptable limits.
Title 24 Economizer Alarms
Economizer Temperature Sensor Failure
Outside Air or Supply Air Temperature Sensor is shorted or missing.
Economizer Not Economizing When it Should
Economizer is enabled but not following the desired Economizer
position commanded.
Economizer Is Economizing When It Should Not
Economizer is not enabled but the feedback signal indicates a position
more open than the minimum.
Economizer Damper Not Modulating
Economizer is enabled but not within 10% of desired position within
150 seconds.
Economizer Excess Outdoor Air Filter
Economizer feedback is lost or Economizer is not following
commanded position.
Alarms
RSMV Alarms
No Suction Pressure Sensor Detected
This alarm indicates the Suction Pressure Sensor is not detected by the
system. This alarm will cause the system to shut down. The system
will shut down due to Unsafe Suction safety. The system will reset
at the next system startup.
High Head Pressure Detected
This indicates a High Head Pressure Alarm condition which is
activated when the Head Pressure rises above 550 PSIG. This will
cause the condenser to go to 100%.
No Head Pressure Sensor Detected
This alarm indicates the Head Pressure Sensor is not detected by the
system. This alarm will cause the system to shut down. The system
will reset at the next system startup.
Coil Temp A1 Failure
This alarm will occur if the coil temperature is not within operable
range (below -32F or above 310F). This could be the result of a bad
sensor or faulty wiring. This alarm will shut down the system. The
system will reset at the next system startup.
Coil Temp A2 Failure
This alarm will occur if the coil temperature is not within operable
range (below -32F or above 310F). This could be the result of a bad
sensor or faulty wiring. This alarm will shut down the system. The
system will reset at the next system startup.
Compressor A1 Failure
This alarm will occur if the compressor fails to run 45 seconds after
the relay is activated. This alarm will send notifi cation to the Main
Controller for staging and an alarm and will shut down the compressor
(relay) until the unit goes to off/vent mode.
Compressor A2 Failure
This alarm will occur if the compressor fails to run 45 seconds after
the relay is activated. This alarm will send notifi cation to the Main
Controller for staging and an alarm and will shut down the compressor
(relay) until the unit goes to off/vent mode.