Engineering guide
Eaton Power Xpert 9395 alarm indicators and events
On an Eaton Power Xpert 9395, a red alarm lamp means an active alarm needing immediate attention, and a flashing one means a new alarm not yet acknowledged. The top line of the display blinks when the system needs attention. Press any pushbutton to silence the horn, open EVENTS to read the active alarms, and call a technician if the Online lamp is out.
Key facts
- Red lamp on: Active alarm, immediate attention
- Red lamp flashing: New alarm, not yet acknowledged
- Event screen: EVENTS: active alarms, notices, commands
- Attention signal: Top display line blinks while scrolling
- Yellow bypass lamp: Load on bypass; Online lamp off
Online, battery, bypass and alarm lamps
- Green on: Online mode, the power module supplies the critical load.
- Yellow (battery) on: Battery mode; Online stays lit because battery mode is normal.
- Yellow (bypass) on: the load is on the bypass source and the Online lamp goes out.
- Red on: an active alarm requiring immediate attention.
- Red flashing: a new alarm, flashing until acknowledged.
Large Power Xpert 9395 installations often sit behind a maintenance bypass; a yellow bypass lamp with nobody on site doing work deserves a call.
Messages on the display
The status area scrolls through the model, date and time, active alarms, active notices, load and battery runtime. When the system needs attention the top line blinks. The manual's own example of a typical message is ALARM: INPUT AC UNDER VOLTAGE: the input supply is below its window, and the UPS will carry the load from battery if it persists.
The EVENTS screen
EVENTS on the main menu opens the active events screen, with current alarms, notices and commands, and a historical log. Photograph both before any reset: a technician reading the order of events (input alarm, transfer to battery, transfer to bypass) can often tell a utility problem from an internal fault without opening the cabinet.
Operator checks and battery planning
Daily, the manual asks the operator to keep the area clear, keep the front intakes and top exhaust free, keep the room within the specified environment, and confirm the Online lamp. If an alarm lamp is lit or Online is out, contact a service representative. The monthly filter check on a 9395 involves removing front panels, so leave it to the visit.
9395 battery plants are large and replaced in planned outages; Eaton battery replacements matched to the existing cabinet configuration keep the runtime you designed for.
When to call for service
- Red lamp lit, or flashing again after acknowledgement.
- Online lamp out with utility present.
- Unplanned bypass operation.
- Input alarms that repeat with a stable utility.
For a 9395 fleet, scheduled maintenance on large Eaton UPS covers modules, fans, filters and batteries; static bypass and generator compatibility explain the two most common causes of transfers.
Related pages
Common questions
What does ALARM: INPUT AC UNDER VOLTAGE mean on a 9395?
It is the manual's example of a typical alarm message: the input voltage is below the acceptable range. The UPS supports the load from battery while it lasts.
How do I silence the 9395 horn?
Press any control panel pushbutton once. The horn stops; the alarm remains until its cause is resolved.
What does a flashing red lamp mean?
A new alarm condition that has not been acknowledged yet. Pressing any pushbutton once acknowledges it.
Where is the 9395 event history?
Select EVENTS on the main menu for active events and the historical log of system events.
Can I change the 9395 air filters?
The manual lists a monthly filter check, but on the 9395 it means removing front panels, so leave it to a service visit.
Sources, checked October 4, 2026:
- Eaton Power Xpert 9395 UPS Installation and Operation Manual, 164201764 Rev 18, pp. 131 (PDF 151), 132 (PDF 152), 229 (PDF 249)
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