Chapter 5 UPS Operation Instructions 41
Liebert
®
ITA 5kVA And 6kVA UPS User Manual
obstacle at the airduct or increase the clearance between the UPS and the wall. After the UPS is cooled, connect it to
the mains and restart it.
5.7.6 Transferring UPS To Fault State From Output Short Protection
If the UPS load is short connected, the UPS will terminate output, the FAULT indicator will turn on, the yellow indicator
of the load indicator will blink and the UPS will beep for a long time. At this moment, you should disconnect the short
connected load from the UPS, cut off the input power supply and wait for ten minutes until the UPS turns off
automatically (or turn off the UPS by pressing the OFF key manually after 10 seconds). After removing the short
connecting fault, connect the UPS to the mains and restart it.
5.7.7 Transferring UPS To Maintenance Bypass Mode From Inverter Output
When the UPS is operating in inverter output mode, follow the procedures below to transfer load to Maintenance
Bypass mode from Inverter Output.
Note
1. Before transferring the UPS, ensure that the bypass is normal and synchronizes with the inverter. Failure to meet these
requirements may cause power supply interrupt of the load in short time.
2. To realize this function, you need to select a POD or configure a maintenance bypass MCB.
1. Press and hold the OFF key for one second. The INVERTER indicator turns off and the buzzer beeps. The load
transfers to static bypass, and the inverter turns off.
2. Close the maintenance bypass MCB on the front panel of the POD, the load power is supplied by the maintenance
bypass.
Warning
If you need to maintain the UPS, wait for 10 minutes approximately until the capacitance and voltage of the internal DC bus finish
discharging.
3. Open the UPS input MCB and output MCB.
5.7.8 Transferring UPS To Inverter Mode From Maintenance Bypass
After maintaining the UPS, follow the procedures below to transfer the load to inverter output from maintenance
bypass.
Warning
Because no auxiliary contact information of the maintenance bypass MCB is introduced in the UPS, UPS operation restoration after
maintenance must be carried out strictly following the procedures below. Failure to observe these procedures may cause damage
to the equipment.
1. Close the output MCB on the front panel of the POD.
2. Close the main input MCB and bypass input MCB on the front panel of the POD.
3. Wait until the UPS starts to operate in Bypass mode, and open the maintenance bypass MCB on the front panel of
the POD.
4. Press and hold the ON/SILENCE key for more than one second, the UPS will transfer to the Inverter mode.
5.8 UPS Complete Turn-off
For the UPS system with POD, if you need to turn off the UPS completely, transfer the UPS from Inverter mode to
Maintenance Bypass mode according to the procedures in
5.7.7 Transferring UPS To Maintenance Bypass
Mode
From Inverter Output
, to ensure that the use of the load during UPS power-off will not be affected. If the load needs no
power supply, open the maintenance bypass MCB directly, as shown in Figure 5-8.
