Vertiv
™
| Liebert® XDC | User Manual
54
7 Troubleshooting
This chapter introduces troubleshooting and fault handling of Vertiv
™
Liebert® XDC unit.
Certain circuits have lethal high voltages, and only professional technicians are allowed to operate the
unit. You must be especially careful when troubleshooting with power on.
Note: When using jumpers for troubleshooting, always remember to remove the jumpers after the repair work is
completed. The remaining connected jumpers may overrun the control function and cause equipment damage.
provides the troubleshooting and treatment of each component of Liebert XDC unit.
Table 7-1 Troubleshooting Compressor and Cooling System
Symptom
Possible Cause
Items to be Checked or Handling Method
Compressor
cannot start
No power (shutdown)
Check the main power switch, fuse or circuit breaker
and connecting wires
MCB tripped due to overload
Manual reset, check the average current
Loose circuit connection
Fasten the circuit connector
Compressor coil is short-circuited and
burned out
Check the motor windings, if any defect is found,
replace them immediately
The contactor is
not closed and
the compressor
is not running
No cooling demand output
Check the PACC controller status
High voltage switch action
Check the high voltage switch, whether there is a high
voltage alarm
Contactor failure
Check the contactor, check whether there is 24Vac
between the terminals of J18-3 (compressor 1) and
J20-1 (compressor 2) and G
Low pressure sensor failure (11 minutes
after shutdown)
Check whether the low-pressure sensor wiring of the
system is intact and the reading is normal
Motor drive failure (11 minutes after
shutdown)
Check whether the wiring is normal, whether the
current is too large, check whether the ventilation of
the motor drive is normal
Motor drive communication failure (11
minutes after shutdown)
Check whether the wiring of the RS458
communication line of the motor drive is intact, then
re-power on and reset or the panel will eliminate this
fault alarm
