APC PDUM160H-B User Manual

External DC Disconnect Switch 
Open

The external

 DC 

DISCONNECT

 switch 

tripped. Battery power is not 
available or the runtime is lower than 
expected.

Close the external 

DC D

ISCONNECT

 switch. 

Check the fuse on the XR battery 
enclosure. If the fuse has blown, contact 
APC Customer Support.

External Switch Gear 
Communication Card Fault

The external switch gear 
communication card has failed.

External Switch Gear 
Communication Card Removed

The system no longer detects an 
external switch gear communication 
card.

Option 1: Ensure the external switch gear 
communication card is installed properly.
Option 2: Replace the external switch gear 
communication card.

Graceful Shutdown Initiated

A graceful shutdown or reboot has 
been initiated from the display 
interface or other accessory.

No corrective action necessary.

High Isolation Transformer 
Temperature

The isolation transformer 
temperature is too high.

Contact APC Customer Support.

Internal Communications Failed One of the buses used for the 

communication between the UPS 
modules has failed.

Contact APC Customer Support.

In Bypass: Hardware Fault

The system has transferred into 
bypass because a fault has occurred.

Contact APC Customer Support.

In Bypass: Overload

The system has transferred into 
bypass because the load has 
exceeded the power capacity of the 
system.

Option 1: Decrease the load.
Option 2: Add a power module to the 
system.

In Bypass: User-Initiated

The system has been transferred into 
bypass due to user action.

Check for any problems with the system. 
Transfer the system to normal operation.

Input Voltage or Frequency 
Cannot Support Bypass

The frequency or voltage is out of 
acceptable range for bypass. This 
message occurs when the UPS is 
online, and indicates that the bypass 
mode may not be available if 
required.

Correct the input voltage to provide 
acceptable voltage or frequency.

Intelligence Module Fault

The main intelligence module has 
failed and requires replacement.

Replace the main intelligence module. See 
“How to replace an intelligence module 
(MIM/RIM)” on page 18.

Load (kVA) Alarm Violation

The load has exceeded the user-
specified load alarm threshold.

Option 1: Use the display interface to raise 
the alarm threshold.
Option 2: Reduce the load.

Local Management-To-UPS 
Communication Lost

Internal communications in the 
system have failed.

Contact APC Customer Support.