Vertiv | Liebert PEX4 | User Manual
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Troubleshooting
Chapter 5: Troubleshooting
Troubleshooting is to be performed by the trained and qualified service personnel. However, the checklists have
been provided just for reference purpose.
• Certain circuits carry lethal voltages. Only professional technicians are allowed to maintain the unit.
Extreme care and caution is required while troubleshooting online.
• If jumpers are used for troubleshooting, remember to remove the jumpers after the troubleshooting, if
not removed the connected jumpers may bypass certain control functions and increase the risk to the
equipment.
5.1. Componentwise Alarm and Solutions
5.1.1. Fan Troubleshooting
Refer
for fan fault diagnosis and treatment.
Table 5-1 Fault Diagnosis and Treatment of Fans
Symptom
Potential Causes
Items to be Examined or Handled Process
EC fan cannot
be started
Fan power supply
failure
Check if the fan MCB is closed.
When the MCB is closed, check if the phase voltage is normal.
Control board failure
•
Check if the output percentage of fans are 0.
•
If not, check terminal J64 (1-Bay unit) or terminal J64 & J86
(2-Bay unit) is/ are analog output of 0 Vdc to 10 Vdc. If so, the
control board probably fails and needs to be changed.
Fan power module
failure
Check the alarm indicator of the fan power module to judge if the
control board fails.
Loss of airflow alarm
Check whether there is Loss of Airflow Alarm. If the alarm default
temperature difference value is too low (10
°C
plus is suggested)
EC fan fault
•
Check if the fans L1, L2 and L3 are power-off, or have phase failure
or under voltage.
•
Check if the analog output of J64 or J86 is in the range of 0 Vdc to
10 Vdc.
•
Check if the motor is blocked (over current).
•
Check if the motor is over heated.
•
If the issue is #1, #2 or #3, the motor can recover its operation after
clearing the fault.
•
If the motor is over heated, power-off the fan, and power-on after
the motor cools down.
•
If there is other failure mode, then it should be sent to manufacture
for maintenance.