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UPS Alarm and Status Messages
55
Inv Overload Ph B
An overload condition is active on B phase.
B phase load condition exceeds 105%.
A countdown timer is displayed on the One-Line
Display in response to this alarm, and indicates
the time remaining until a transfer to bypass
occurs. The length of time remaining until transfer
is directly proportional to the severity of the
overload.
This alarm is self-clearing. When the condition is
no longer present, the alarm and any control
activity tied to the alarm reverts to normal.
Press “SILENCE” to silence the audible alarm.
Check the Module Output Meter and note the B
phase load percentage.
If possible, reduce B phase loading.
If the steady state load remains above 105%, allow
the UPS to transfer to bypass and contact your
factory-authorized service provider.
If the displayed load percentage is less than 100%
and the alarm is still active, contact your factory-
authorized service provider.
Inv Overload Ph C
An overload condition is active on C phase.
C phase load condition exceeds 105%.
A countdown timer is displayed on the One-Line
Display in response to this alarm, and indicates
the time remaining until a transfer to bypass
occurs. The length of time remaining until transfer
is inversely proportional to the severity of the
overload.
This alarm is self-clearing. When the condition is
no longer present, the alarm and any control
activity tied to the alarm reverts to normal.
Press “SILENCE” to silence the audible alarm.
Check the Module Output Meter and note the C
phase load percentage.
If possible, reduce C phase loading.
If the steady state load remains above 105%, allow
the UPS to transfer to bypass and contact your
factory-authorized service provider.
If the displayed load percentage is less than 100%
and the alarm is still active, contact your factory-
authorized service provider.
Inv Ovld Exceeded
This message is displayed in response to an
overload on one or more output phases.
When an overload occurs, the controls display a
countdown timer that displays the time remaining
until a transfer to bypass occurs. The length of the
timer is inversely proportional to the amplitude of
the overload. When the timer reaches zero, the
UPS transfers to bypass and populates the Active
Event Window with this alarm.
This fault is non-latching. When the underlying
condition is no longer present, this fault and any
control activity tied directly to this fault reverts to
normal.
Press “SILENCE” to silence the audible alarm.
Observe the load percentages for each phase on
the Module Output Meter. If the load is less than
100%, attempt to transfer back to Inverter by
pressing “Transfer,” “UPS.”
If the transfer is successful, investigate the reason
for the overload and take appropriate action.
If the transfer is unsuccessful, contact your factory-
authorized service provider.
Inverter Fault
This summary event indicates a potentially
serious problem in the Inverter.
The controls react to an Inverter fault in different
ways depending on the root event that caused the
fault. If bypass is available, the controls transfer to
static bypass.
A restart may or may not be possible
Press “SILENCE” to silence the audible alarm.
Check the One-Line Display to determine the state
of the UPS. If both the Rectifier and Inverter are
shut off, press “RESET” to attempt to clear any
latched alarms or faults.
Attempt a restart by pressing “Startup,” “Manual
Start,” and follow the prompts to place the UPS
back in service.
If the startup fails, contact your factory-authorized
service provider.
If the Rectifier and Inverter appear to be running,
press “RESET” to attempt to clear any latched
alarms or faults, then attempt a transfer by pressing
“Transfer,” “UPS.” If the transfer is successful,
contact your factory-authorized service provider.
If the transfer is unsuccessful, contact your factory-
authorized service provider.
ISS SCR Shorted
The controls have detected voltage on the
Inverter (Line side) side of the Inverter Static
Switch.
This indicates that an SCR is shorted.
With the Output SCRs turned off, there should be
no voltage present inside the UPS.
This is a non-recoverable fault, and inhibits
normal start up of the UPS.
Press “SILENCE” to silence the audible alarm.
Turn off Control Power to clear the event. Wait 5
minutes before re-applying Control Power.
If the fault fails to clear, contact your factory-
authorized service representative.
Table 7 Liebert NXL alarm and status messages (continued)
Event Message Event Definition Recommended Action