UPS Fault Logs - Backfeed Relay Hardware Fault

[IT-UPS]

After a small power cut, I came back to the office to find our Smart-UPS X 3000 beeping away and not providing any power to our rack. After a reboot, the UPS has continued to work as normal but the UPS Fault Logs shows an Event Code of 135 and Event description stating: Backfeed Relay Hardware Fault. I've read up on the fault and understand the feature, but would this be an actual physical fault that needs a part replacing? How would I tell if so? Or will this just have been an unclean power input so the UPS decided to not power up any further? In the past, the UPS has stayed on battery until it sees a clean power input, then flips back to mains. 

[Teken]

What is the serial number and years of service on the unit?!?! Provide the following logs in their entirety minus any PI data for review: Event, Data, UPS, Diagnostics.

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[IT-UPS]

Hi!

The logs only go back to the morning after the power cut unfortunately.

The Events logs around the time are full of records that alert emails could not be sent out (because our firewall went down, so it couldnt talk out to the internet).

The Data logs are all consistent and nothing abnormal or different to its normal operation.

The UPS logs are the only place it states the Backfeed Relay Hardware fault (below):

Number Time (ms) Event Code EventNumber Time (ms) Event Code Event

UPS Transfer Logs
1	821085121940	8	Acceptable Input
2	821085120675	4	rapid change of input
3	821085097079	8	Acceptable Input
4	821085095571	4	rapid change of input
5	821084852138	8	Acceptable Input
6	821084850663	4	rapid change of input
7	817763203297	8	Acceptable Input
8	817755171307	3	distorted input
9	817414785604	8	Acceptable Input
10	817414778677	3	distorted input
UPS Fault Logs
1	821085121940	135	Backfeed Relay Hardware Fault
2	0	0	None
3	0	0	None
4	0	0	None
5	0	0	None
6	0	0	None
7	0	0	None
8	0	0	None
9	0	0	None
10	0	0	None

The model details are below:

Model:	Smart-UPS X 3000
SKU:	SMX3000RMHV2UNC
Serial Number:	AS1608155561
Firmware Revision:	UPS 07.4 (ID1003)
Manufacture Date:	27.02.2016
Apparent Power Rating:	3000 VA
Real Power Rating:	2700 W
Internal Battery SKU:	APCRBC117
External Battery SKU:	APCRBC118

I also changed the battery over in 2020 and it states its recommended to be replaced Aug 2024. Appreciate it may need a new one (under the recommendations) but I don't know enough to say if its related to this particular fault. Its back on mains power as normal and the front panel on the unit states its as full battery capacity and has the same amount of time left as its always shown, if it failed over to battery (about 2.5 hours on current load). 

Thanks for replying and any help you can give!

[Teken]

Based on the information you have provided here I would probably say the RBC needs to be replaced.

The average service life is 2-5 years based on usage, temperature, and environmental conditions.

The following action item(s) will need to be scheduled during the next maintenance window to help identify root cause and narrow down the problem.

There are two basic tests that should be completed so report the outcome and results here:

Static Test: Disconnect the Anderson connector from all of the RBC if there are external packs installed.

The only thing that should happen is the system will declare a RBC disconnected fault but will continue to run.

Should the unit drop the load and turn off you have an internal hardware fault.

Dynamic Test: The following test simply requires you to remove AC Mains from the unit while the RBC is in place.

The expected outcome is the unit will continue to operate on battery only power.

Should the system turn off immediately or within a few seconds / minutes which is outside the expected operational runtime than the RBC is EOL and expired and needs to be replaced / rebuilt.

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