Eaton UPS alarm and error codes: complete troubleshooting guide

1. How Eaton reports problems: events, notices, alarms and faults

An Eaton UPS sorts what it detects by severity, and the sound and light tell you the tier before you read a word. The wording changes between families, so the first job is to know which vocabulary your unit uses.

• 9PX, 9SX and 5PX: Eaton’s manuals for all three use the same three tiers [1][13][14]. Events are silent entries in the Event log, such as “AC freq in range”. Alarms are logged and shown on the screen with the logo blinking; some beep every 3 seconds, such as “Battery low”. Faults sound a continuous beep, light the red LED, go to a separate Fault log and open a message box, such as an output short circuit [1].
• 9130: events are silent, notices beep every 5 seconds (“UPS on Battery”, “UPS on Bypass”), and alarms beep every second and light the alarm indicator (“Output Overload”, “Heatsink Overtemperature”) [2].
• 9E: the only family in this guide that prints letter-and-number codes. Codes starting with A are alarms, “minor” problems that reduce performance; codes starting with F are faults, which are “normally preceded by an alarm” and switch the load to the bypass line [3].
• Three-phase 93PM and 93E: a red alarm symbol, a horn and a text message in the status area, written to an events log. The 93E groups messages into alarms, notices, status and commands [4][5].

The practical consequence: if you are searching for a code number that your screen does not show, you are probably on a model that reports in words. Search for the words instead, and use the tables below.

Scope, terms and assumptions

This guide covers the Eaton and Powerware-heritage UPS families GDF Technologies services in Canada, using only what Eaton publishes in user manuals and public guides. Where codes are not in the public user manuals we reviewed (numbered alarms on the 9130, the 9395 and older Powerware frames), we say so rather than guess. “Bypass” means the load is fed from the utility through the UPS without battery protection. “Load” means the equipment plugged into or wired to the UPS output. Thresholds quoted are the published values for the named model; other models in the same family can differ, so the manual for your exact model number wins.

2. Identify your Eaton family first

The model designation is on the front label or the rear nameplate, and on most screens under an identification menu. Eaton’s 9355 guide, for example, lists UPS type, part number and serial number under IDENTIFICATION [6]. Once you know the family, Table 1 tells you how it reports problems and where the authoritative list sits.

If your unit says Powerware, Best Power or Exide rather than Eaton, it is a heritage product. Eaton’s end-of-service-life master table maps those names to current equivalents, for example the Powerware PW9125 range to 9PX models [8]. That matters for parts, as section 10 explains.

3. Beep and light decoder

When you cannot see the screen, or the unit has none, the beep rate is the fastest clue. Eaton does not use one cadence across all models, which is why a generic “beep chart” can mislead you. Table 2 lists the published patterns by model; Figure 1 shows them on one time scale.

Silencing is not clearing. On the 9PX the ESC button stops the beep, and the alarm sounds again if the condition changes [1]; on the 9130 any button silences it [2]. The cause is still there until the message goes away. If you need the same decoding for APC hardware, our guide to APC UPS beeping and alarm patterns covers it, since APC uses different cadences.

4. 9PX, 9SX, 5PX and desktop units: the plain-language messages

The 9PX is the most common Eaton rack UPS we see in Canadian server rooms. Its manual describes the messages in Table 3. Eaton’s 9SX 700 to 3000 VA manual and the 5PX G2 guide use the same messages, beeps and log menus [13][14], so Table 3 applies to them too, with the differences noted after it. Thresholds still vary by model, so check the manual for your exact part number.

Causes are Eaton’s wording; the first actions follow the manual’s “Action” column, with short GDF additions such as “do not wait for the timer”. ABM is Eaton’s charging method that alternates charging and resting the battery.

Where the 9SX and 5PX differ: on the line-interactive 5PX G2, an overtemperature that climbs another 10 °C shuts the UPS down, and an overload can shut it down, because it has no bypass to fall back on [14]. The 9SX gives a battery replacement notification after 4 years of operation, and its site wiring fault (no ground, or line and neutral reversed) beeps once per second [13].

Two details in the 9PX manual explain many “random” transfers to bypass. First, overtemperature is staged: at the warning level the UPS only alarms, but if the temperature rises another 10 °C it transfers to bypass, or shuts down if bypass is unusable, and it returns only when the temperature falls 5 °C below the warning level [1]. Second, overload is timed. Table 4 shows how long the 9PX and the 9E tolerate each overload band before they act.

Worked example: a 9PX6K carrying a rack at 115 % will transfer to bypass after about a minute. The rack keeps running on utility power, so nobody notices, and the next outage drops it. Once it is on bypass, if the overload continues, the 9PX shuts down after 1 minute between 125 and 150 % and after 1 second above 150 %, and the load drops [1]. That is why an overload alarm deserves the same urgency as a battery alarm.

Eaton 3S and other desktop units

Desktop models have no screen. On the 3S 550/700 (other 3S sizes have their own manual), a red LED with a beep every 30 seconds means an internal fault and the battery outlets are no longer supplied; a flashing red LED means the battery has reached the end of its service life [7]. If the UPS runs on battery while the wall outlet is live, Eaton points to the output circuit breaker under the unit, tripped by an overload [7]. A desktop unit with an internal fault is normally replaced rather than repaired; a worn battery is not a reason to discard it.

5. Eaton 9130 messages, and why “alarm 191” is not in the manual

The 9130 is retired, but thousands still run in Canadian offices. Its user’s guide lists the conditions in Table 5 [2].

Signals and causes are Eaton’s wording from table 31; the short actions are condensed from the same table.

People also search for numbered 9130 alarms such as “alarm 191” or “alarm 34”. Those numbers do not appear in the 9130 user’s guide we checked. They come from service-level documentation, and we have no Eaton source we can cite for their meaning, so we do not publish one. What you can do safely: read the active alarm text as in the box above, export the Event Log (the guide explains how to retrieve it in ASCII), and send that file with the model and serial number to whoever services the unit [2]. Eaton’s own list of what to have ready is model number, serial number, date and symptoms [2].

Eaton’s end-of-service-life table lists the 9130 rack and tower models as Retired and End of Service Life from 2025, with the 9PX as the equivalent replacement [8]. A 9130 battery alarm is still worth fixing with a new battery set; an electronics fault is the point to plan the replacement.

6. Eaton 9E: the A and F codes

The A-and-F code list that circulates online, often presented as “Eaton UPS codes”, comes from the Eaton 9E 6 to 20 kVA manual. It is accurate for that family. It is not the code system of the 93PM, the 9PX or the 9130. Table 6 gives the codes listed in Eaton’s 9E manual, with the source of each action marked [3].

“Eaton:” marks actions from the manual’s troubleshooting table (section 4.4); “GDF:” marks our guidance where the manual lists a code without an action. A004 and A900 appear in that troubleshooting table rather than in the section 4.5 code list.

Two points matter more than the individual codes. First, Eaton notes that faults are normally preceded by an alarm [3], so the event history before an F code often tells the real story; read it before anyone clears it. Second, the capacitor-bank and inverter faults (F300 to F305, F704, F70C, F70D) are internal. Eaton’s own instruction is one off-on attempt, then support [3]. Repeated restarts on a capacitor fault can turn a board repair into a larger one.

7. Three-phase frames: 93PM, 93E, 9355 and 9395

On three-phase Eaton UPS the screen shows named alarms, not short codes, and the logs are the real diagnostic tool.

• 93PM: four status symbols sit under the display. Green means normal; yellow battery means battery mode (green stays lit, because battery mode is a normal state); yellow bypass means the load is on the bypass source (green goes off); red means an active alarm that “requires immediate attention”, with a horn that one button press silences [4]. Messages appear in the status bar and in the Active Events log [4].
• 93E: a flashing red symbol means a new alarm not yet acknowledged; the horn cycles at a half-second rate; the history log holds 512 events and overwrites the oldest [5].
• 9355: the UPS STATUS screen lists active alarms and notices and the battery state (resting, charging, floating, not connected, discharging); the event log separates notices from alarms; the control menu includes “Reset error state” [6].

The 93PM user’s guide publishes one numbered list: Appendix A, the alarms that can be assigned to relay outputs, each with an ID. These IDs are useful when a monitoring card or a building management system mapping refers to an alarm by number. Table 7 lists the ones we meet most in the field.

The “What it points to” column is our plain-language reading of Eaton’s alarm names, not Eaton text; Appendix A of the manual has the full list. For the 9395, 9390, 9315 and older Powerware frames we did not find a public user manual with a code list we could verify, and we will not reproduce lists of unknown origin. On those units, export the event history, photograph the screen, and hand both to a qualified technician. Our article on 9395 battery and capacitor alarms covers what those alarms usually lead to.

8. A safe first-response method

Every Eaton troubleshooting table answers the same few questions in the same order. Figure 2 puts them in one flow you can follow from the front panel, without tools.

1. Is the load still powered? If not, check whether the UPS is simply in standby. The 9E and 9130 manuals both describe a lit display with no output, solved by the ON button [2][3]. If a fault dropped the load, do not cycle it repeatedly.
2. Read and record the message exactly as shown, with the time, before you press anything that clears it.
3. Act by category: battery mode means check the utility and plan shutdown; battery low means shut down now; bypass means the load is unprotected; overload means shed load; batteries disconnected or a failed battery test means note the message and call for service; a short backup time means charge for 48 hours and retest [1][2].
4. Stop at the boundary: any internal fault, any three-phase alarm you cannot explain, and any repeat after one restart goes to a qualified technician (section 11).

When an alarm has put the unit in bypass, our guide to UPS bypass mode: when it is normal and when it is critical goes through the checks in more depth.

9. Battery alarms and what they predict

Most Eaton alarms we are called for are battery alarms, and most of them are honest: the battery is worn. The published numbers explain why.

• The 9PX battery is sealed lead-acid with a minimum 3-year float service life (its life when kept on continuous charge) at 25 °C, and Eaton states its lifetime is reduced above 30 °C [1]. The 9SX reminds you to replace its batteries after 4 years of operation [13].
• Eaton’s lifecycle checklist recommends full replacement of sealed batteries between 3 and 5 years of age [9].
• IEEE 1188, the standard for valve-regulated lead-acid batteries in stationary service, sets replacement when capacity falls below 80 % of rating [11].

Read the alarms in that light. “Battery low” arriving early means remaining runtime is shorter than the display suggested; the 9PX can warn before 20 % capacity and the 9130 before 25 % [1][2]. “Battery fault” after a self-test means the string failed the test; Eaton’s procedure starts with a connection check and a new test, which is a job for a qualified technician [1]. “Expected backup time not provided” usually means the battery is simply not charged yet: 48 hours on utility power first, then retest [1]. If the second test fails, plan the replacement.

On a 9PX or 9130 the battery is a replaceable pack, so a battery alarm on a unit with healthy electronics is a battery job, not a UPS replacement. GDF does that work on site through our UPS battery replacement service. If you replace it yourself, the range of replacement batteries for Eaton UPS at UPS Plus Battery lists packs by model; match the part number on your existing pack, check the warranty terms on your unit, and follow the manual’s battery replacement procedure, since packs are heavy and the DC string is hazardous. External battery strings and three-phase batteries are technician work. For the wider picture of battery ageing, see our guide to the UPS battery as the critical component, and for the 9155 specifically, signs of weak 9155 batteries and the tests to demand.

10. Canadian conditions and heritage Powerware fleets

Three local realities change how an Eaton alarm should be read in Canada.

Eaton defines four lifecycle phases: Active with full support; Mature on a best-efforts basis; Retired, with no contract coverage, where time-and-material, preventive and battery services may be available; and End of Service Life, obsolete [8]. When a unit in the last two phases shows an inverter or rectifier fault, the honest answer is usually replacement, and the alarm is the moment to plan it rather than the moment to discover it. The 9355 firmware also offers French as a display language [6], which helps when operators on Quebec sites read alarms on the front panel.

For a full overview of the families and what each costs to maintain, see our Eaton UPS service guide by model.

11. Safety boundaries: when to stop and call

Work by non-Eaton personnel may affect Eaton warranty or service-contract coverage; check your terms before choosing who services the unit.

In Quebec, the CNESST requires work on electrical installations to be done de-energized with lockout, unless that is not possible and an equivalent method is justified by a risk analysis (RSST sections 195 to 207) [12]. Practically, that means the front panel is the limit for staff, and anything behind a cover is technician work with lockout.

Call a qualified technician, without further restarts, when:

• any 9E F code that returns after Eaton’s single off-on attempt, and F811 or any other F code you still cannot explain after that attempt [3];
• any inverter, rectifier, DC link, fuse or capacitor alarm on any model;
• a fault returns after one off-on attempt;
• a three-phase unit is on bypass and you do not know why, or “Bypass Not Available” is active;
• EPO was triggered and nobody knows why;
• the unit protects a hospital, data centre or other critical load, whatever the alarm.

GDF Technologies services Eaton and Powerware units across Canada as an alternative to manufacturer support; our Eaton and Powerware UPS maintenance service describes what a visit covers.

12. What to record before anyone resets an alarm

A reset erases the evidence a technician needs. Eaton’s 9PX and 9130 manuals ask for the same basic facts when you call for service [1][2]; Table 9 adds what makes a diagnosis fast on site.

If you are writing these requirements into a service contract, our UPS preventive maintenance checklist turns them into report items. The same discipline applies to APC units, covered in our APC UPS fault codes guide.

13. Quick answers

What does a continuous beep on an Eaton UPS mean?

On the 9PX, 9SX and 5PX, a continuous beep is a fault, such as no battery, battery fault, power overload or wiring error; the screen shows a message box with the name [1][13][14]. On the 9E, a continuous buzzer comes with a code on the display [3].

Why is my Eaton UPS beeping every few seconds?

On a 9PX, 9SX or 5PX, one beep every 10 seconds is battery mode and one every 3 seconds is battery low or overtemperature [1][13][14]. On a 9130, one every 5 seconds is a notice (on battery or bypass) and one per second is an alarm [2].

What does the red light mean on an Eaton 3S?

Red LED flashing: the battery has reached the end of its service life. Red LED on with a beep every 30 seconds: the UPS has a fault and the battery outlets are no longer supplied [7].

Where is the list of Eaton UPS fault codes?

There is no single list. The A and F codes belong to the 9E manual [3]; the 9PX and 9130 use named messages [1][2]; the 93PM publishes relay alarm IDs in Appendix A of its user’s guide [4].

What does A806 mean?

On the Eaton 9E, A806 is “E.P.O. control active”: the emergency power off input has been triggered [3]. Find out why before restoring power.

The display is on but my equipment has no power. Why?

The UPS is probably in standby; the 9E and 9130 manuals say to press the ON button [2][3]. If a fault message is showing instead, record it before restarting.

14. Sources

1. Eaton, 9PX 5/6 kVA installation and user manual, 614-09274-02, sections 5.7, 5.8, 8 and tables 6 and 9.
2. Eaton, 9130 UPS 700/3000 VA user’s guide, 164201718 rev 7, chapter 8 and table 31.
3. Eaton, 9E 6 to 20 kVA user’s manual, 614-06847-05, sections 4.4, 4.5 and technical data.
4. Eaton, 93PM UPS 30 to 250 kVA user’s and installation guide, P-164000249 rev 006, chapter 2, section 7.1 and Appendix A.
5. Eaton, 93E UPS 15 to 80 kVA installation and operation manual, 614-01975-00, sections 7.2.1 to 7.2.6.
6. Eaton, 9355 UPS 20 to 40 kVA user’s guide, 1025358 rev D, chapter 8.
7. Eaton, 3S 550/700 installation and user manual, troubleshooting table.
8. Eaton, UPS End of Service Life master table, PL161010EN, revision 05/29/2026.
9. Eaton, UPS life cycle checklist, SER110FXA (August 2026).
10. NFPA 70B-2023, Standard for Electrical Equipment Maintenance, Table 9.2.2, as summarized in the HVM NFPA 70B maintenance chart.
11. IEEE 1188, Recommended Practice for Maintenance, Testing and Replacement of VRLA Batteries for Stationary Applications, section 8 replacement criterion as quoted in the Battcon 2008 paper Report on the long-term results of battery capacity recovery processes for VRLA cells; current edition on the IEEE SA record.
12. CNESST, Électricité : danger d’électrisation (in French), citing RSST sections 195 to 207.
13. Eaton, 9SX 700 to 3000 VA installation and user manual, section 7.
14. Eaton, 5PX G2 advanced user guide, 614-40095-00, section 7.

Revision note, 2 October 2026: rebuilt from Eaton’s manuals. Earlier versions listed codes such as A502, A604 and A612 as Eaton codes; they are not in the 9E manual and were removed.

Eaton, Powerware and the model names above are trademarks of Eaton. GDF Technologies is a third-party UPS service company and is not affiliated with, authorized by or endorsed by Eaton. Descriptions of alarms follow Eaton’s published manuals; the plain-language readings and the first-response method are GDF’s own and are labelled as such.

Authored by Christian Barkley
Director, GDF Technologies
LinkedIn: https://www.linkedin.com/in/christian-b-a22619a1/