| Input Power Supply fault | Fault generated by the MVVSD drive after 10 seconds of input power loss. During the first 10 seconds the drive deactivates the output to the compressor motor while maintaining adequate bus voltage charge level, and the OptiView control panel holds the condenser level control, PRV, VGD, and Hot Gas at the current commanded positions. | Input power supply drops below 85% of nominal voltage overall and is not restored within 10 seconds. | If the input power is restored within 10 seconds, the condenser level control, PRV, VGD, and Hot Gas are returned to automatic control and the VSD speed command is set to the same or slightly less than the VSD speed command prior to the input power loss. If the input power is restored within 30 seconds, an enhanced quick start is initiated: the condenser level control, PRV, VGD, and Hot Gas are returned to automatic control, coastdown is shortened and the chiller is transitioned to run while the compressor is potentially rotating. | 2 |
| Low Frequency Fault | Fault occurring when the VSD speed remains below the minimum speed longer than the allowed VSD Low Frequency Fault Time. | VSD speed below the minimum speed for longer than the VSD Low Frequency Fault Time. The VSD Low Frequency Fault Time (Power Fault Recovery screen, Button 8) is adjustable from 60 sec to 120 sec with a default of 60 sec, visible in view mode but only editable in Admin access level and above. When Power Fault Recovery Control is not enabled, this setting has no affect and the Low Frequency Fault will be the standard time of 25 seconds. | | 3 |
